AIM： To evaluate contrast-enhanced ultrasonography （CEUS） using SonoVue in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI a...AIM： To evaluate contrast-enhanced ultrasonography （CEUS） using SonoVue in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI and clinical/histological data. METHODS： It is an international multicenter study, and there were 12 centres and 125 patients （64 males, 61 females, aged 59 ± 11 years） involved, with 102 patients per protocol. Primary tumors were colorectal in 35%, breast in 27%, pancreatic in 17% and others in 21%. CEUS using SonoVue was employed with a Iow-mechanical-index technique and contrast-specific software using Siemens Elegra, Philips HDI 5000 and Acuson Sequoia; continuous scanning for at least five minutes. RESULTS： CEUS with SonoVue increased significantly the number of focal liver lesions detected versus unenhanced sonography. In 31.4% of the patients, more lesions were found after contrast enhancement. The total numbers of lesions detected were comparable with CEUS （55）, triple-phase spiral CT （61） and HRI with a liverspecific contrast agent （53）. Accuracy of detection of metastatic disease （i.e. at least one metastatic lesion） was significantly higher for CEUS （91.2%） than for unenhanced sonography （81.4%） and was similar to that of triple-phase spiral CT （89.2 %）. In 53 patients whose CEUS examination was negative, a follow-up examination 3-6 months later confirmed the absence of metastatic lesions in 50 patients （94.4%）. CONCLUSION： CEUS is proved to be reliable in the detection of liver metastases in patients with known extrahepatic primary tumors and suspected liver lesions.展开更多
Stress-related mucosal disease is a typical complication of critically ill patients in the intensive care unit(ICU). It poses a risk of clinically relevant upper gastrointestinal(GI) bleeding. Therefore, stress ulcer ...Stress-related mucosal disease is a typical complication of critically ill patients in the intensive care unit(ICU). It poses a risk of clinically relevant upper gastrointestinal(GI) bleeding. Therefore, stress ulcer prophylaxis(SUP)is recommended in high-risk patients, especially those mechanically ventilated > 48 h and those with a manifest coagulopathy. Proton pump inhibitors(PPI) and, less effectively, histamine 2 receptor antagonists(H2RA) prevent GI bleeding in critically ill patients in the ICU. However, the routine use of pharmacological SUP does not reduce overall mortality in ICU patients. Moreover, recent studies revealed that SUP in the ICU might be associated with potential harm such as an increased risk of infectious complications, especially nosocomial pneumonia and Clostridium difficile-associated diarrhea. Additionally, special populations such as patients with liver cirrhosis may even have an increased mortality rate if treated with PPI. Likewise, PPI can be toxic for both the liver and the bone marrow, and some PPI show clinically relevant interactions with important other drugs like clopidogrel. Therefore, the agent of choice, the specific balance of risks and benefits for individual patients as well as the possible dose of PPI has to be chosen carefully. Alternatives to PPI prophylaxis include H2 RA and/or sucralfate. Instead of routine SUP, further trials should investigate risk-adjusted algorithms, balancing benefits and threats of SUP medication in the ICU.展开更多
This paper presents an extensive survey of the most commonly used tools for diagnosing unbalanced flow in the atmosphere, namely the Lagrangian Rossby number, Psi vector, divergence equation, nonlinear balance equatio...This paper presents an extensive survey of the most commonly used tools for diagnosing unbalanced flow in the atmosphere, namely the Lagrangian Rossby number, Psi vector, divergence equation, nonlinear balance equation, generalized omega-equation, and departure from fields obtained by potential vorticity (PV) inversion. The basic thoery, assumptions as well as implementation and limitations for each of the tools are all discussed. These tools are applied to high—resolution mesoscale model data to assess the role of unbalanced dynamics in the generation of a mesoscale gravity wave event over the East Coast of the United States. Comparison of these tools in this case study shows that these various methods agree to a large extent with each other though they differ in details. Key words Unbalanced flow - Geostrophic adjustment - Gravity waves - Nonlinear balance equation - Potential vorticity inversion - Omega equations - Rossby number This research was conducted under support from NSF grant ATM-9700626 of the United States. The numerical computations described herein were performed on the Cray T90 at the North Carolina Supercomputing Center and the Cray supercomputer at the NCAR Scientific Computing Division, which also provided the initialization fields for the MM5. Thanks are extended to Mark Stoelinga at University of Washington for the RIP post-processing package.展开更多
An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion yea...An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes(i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350–450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models. Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing features.Superhydrophilicity and superhydrophobicity are focal points in this work. We estimate that superhydrophobic plant leaves(e.g., grasses) comprise in total an area of around 250 million km^2, which is about 50% of the total surface of our planet. A survey of structures and functions based on own examinations of almost 20,000 species is provided, for further references we refer to Barthlott et al.(Philos. Trans. R. Soc. A 374: 20160191, 1). A basic difference exists between aquatic nonvascular and land-living vascular plants; the latter exhibit a particular intriguing surface chemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular wax and the curvature of single cells up to complex multicellular structures. A descriptive terminology for this diversity is provided. Simplified, the fun展开更多
AIM:To investigate the comparative effect of laparoscopic and open cholecystectomy in elderly patients.METHODS:Laparoscopic cholecystectomy has induced a revolution in the treatment of gallbladder disease.Nevertheless...AIM:To investigate the comparative effect of laparoscopic and open cholecystectomy in elderly patients.METHODS:Laparoscopic cholecystectomy has induced a revolution in the treatment of gallbladder disease.Nevertheless,surgeons have been reluctant to implement the concepts of minimally invasive surgery in older patients.A systematic review of Medline was embarked on,up to June 2013.Studies which provided outcome data on patients aged 65 years or older,subjected to laparoscopic or open cholecystectomy were considered.Mortality,morbidity,cardiac and pulmonary complications were the outcome measures of treatment effect.The methodological quality of selected studies was appraised using valid assessment tools.Τhe random-effects model was applied to synthesize outcome data.RESULTS:Out of a total of 337 records,thirteen articles(2 randomized and 11 observational studies)reporting on the outcome of 101559 patients(48195in the laparoscopic and 53364 in the open treatment group,respectively)were identified.Odds ratios(OR)were constantly in favor of laparoscopic surgery,in terms of mortality(1.0%vs 4.4%,OR=0.24,95%CI:0.17-0.35,P<0.00001),morbidity(11.5%vs 21.3%,OR=0.44,95%CI:0.33-0.59,P<0.00001),cardiac(0.6%vs 1.2%,OR=0.55,95%CI:0.38-0.80,P=0.002)and respiratory complications(2.8%vs 5.0%,OR=0.55,95%CI:0.51-0.60,P<0.00001).Critical analysis of solid study data,demonstrated a trend towards improved outcomes for the laparoscopic concept,when adjusted for age and co-morbid diseases.CONCLUSION:Further high-quality evidence is necessary to draw definite conclusions,although bestavailable evidence supports the selective use of laparoscopy in this patient population.展开更多
AIM To investigate whether immune mediated diseases(IMD) are more frequent in patients with inflammatory bowel disease(IBD).METHODS In this population based registry study,a total of 47325 patients with IBD were alive...AIM To investigate whether immune mediated diseases(IMD) are more frequent in patients with inflammatory bowel disease(IBD).METHODS In this population based registry study,a total of 47325 patients with IBD were alive and registered in the Danish National Patient Registry on December 16,2013. Controls were randomly selected from the Danish Civil Registration System(CRS) and matched for sex,age,and municipality. We used ICD 10 codes to identify the diagnoses of the included patients. The IBD population was divided into three subgroups: Ulcerative colitis(UC),Crohn's disease(CD) and Both the latter referring to those registered with both diagnoses. Subsequently,odds-ratios(OR) and 95%CI were obtained separately for each group and their respective controls. The use of Bonferoni post-test correction adjusted the significance level to P < 0.00125. P-values were estimated using Fisher's exact test.RESULTS There were significantly more women than men in the registry,and a greater percentage of comorbidity in the IBD groups(P < 0.05). Twenty different IMDs were all significantly more frequent in the IBD group. Sixteen were associated with UC versus twelve with CD. In both UC and CD ORs were significantly increased(P < 0.00125) for primary sclerosing cholangitis(PSC),celiac disease,type 1 diabetes(T1D),sarcoidosis,asthma,iridocyclitis,psoriasis,pyoderma gangrenosum,rheumatoid arthritis,and ankylosing spondylitis. Restricted to UC(P < 0.00125) were autoimmune hepatitis,primary biliary cholangitis,Grave's disease,polymyalgia rheumatica,temporal arteritis,and atrophic gastritis. Restricted to CD(P < 0.00125) were psoriatic arthritis and episcleritis. Restricted to women with UC(P < 0.00125) were atrophic gastritis,rheumatoid arthritis,temporal arteritis,and polymyalgia rheumatica. Restricted to women with CD were episcleritis,rheumatoid arthritis,and psoriatic arthritis. The only disease restricted to men(P < 0.00125) was sarcoidosis. CONCLUSION Immune mediated diseases were significantly more frequent in patients with IBD. 展开更多
This paper discusses approaches to measure moisture in power transformers by analyzing the dielectric response of the main insulation. Dielectric diagnostic methods deduce moisture in the solid insulation from dielect...This paper discusses approaches to measure moisture in power transformers by analyzing the dielectric response of the main insulation. Dielectric diagnostic methods deduce moisture in the solid insulation from dielectric properties like polarisation depolarisation currents and dissipation factor vs. frequency. A new instrument "Dirana" combines time domain (PDC) and frequency domain (FDS) measurements and thus substantially shortens the measurement duration. New software was developed which bases on a new data pool,measured at new and aged pressboard samples with various moisture contents and oil impregnation. Its analysis algorithm compares measurements from a transformer to modelled dielectric responses,obtained from the so-called XY-model. To avoid overestimation of moisture for aged transformers,the analysis algorithm compensates for the influence of conductive aging by-products. Moisture especially increases the losses in the low frequency range of the dielectric response of pressboard. Thus,data on the left-hand side of the area dominated by interfacial polarization (insulation geometry) are required for reliable moisture determination. Case studies illustrate the application of moisture determination by dielectric response methods.展开更多
Besides obvious benefits,the Three Gorges Dam＇s construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir（TGR） ecosystem.In order to record organic contamination,to...Besides obvious benefits,the Three Gorges Dam＇s construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir（TGR） ecosystem.In order to record organic contamination,to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring,several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method.Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels,mutagenic potentials and genotoxic impacts.Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013.Only polycyclic aromatic hydrocarbons（PAHs） could be detected in sediments in 2011（165-1653 ng/g）,emphasizing their roles as key pollutants of the area.Their ubiquity was confirmed at Chongqing（150-433 ng/g） and Kaixian（127-590 ng/g） in2013.Concentrations were comparable to other major Chinese and German rivers.However,the immense sediment influx suggested a deposition of 216-636 kg PAH/day（0.2-0.6 mg PAH/（m2·day））,indicating an ecotoxicological risk.PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section,whereas petrogenic sources dominated the mid-low section.Furthermore,sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay.Additionally,significant genotoxic impairments in erythrocytes of P.vachellii were detected（Chongqing/Kaixian）,demonstrating the relevance of genotoxicity as animportant mode of action in the TGR＇s fish.PAHs,their derivatives and non-target compounds are considered as main causative agents.展开更多
AIM：To evaluate whether optical coherence tomography angiography（OCTA） can detect altered vessel density（VD） at the optic nerve head（ONH） in glaucoma patients.Special attention is paid to the accuracy of the OC...AIM：To evaluate whether optical coherence tomography angiography（OCTA） can detect altered vessel density（VD） at the optic nerve head（ONH） in glaucoma patients.Special attention is paid to the accuracy of the OCTA technique for distinguishing healthy from glaucomatous eyes.METHODS：A total of 171 eyes were examined by the OCTA system Angio Vue^TM（Optovue）：97 eyes diagnosed with glaucoma and 74 healthy control eyes.The papillary and peripapillary VD was measured.Furthermore,the VD was correlated with different structural and functional measurements.In order to test the accuracy of differentiation between eyes with and without glaucoma,we calculated the receiver operating characteristic curve（ROC） and the area under the curve（AUC）.RESULTS：The papillary and peripapillary VD in glaucomatous eyes was significantly lower than in healthy eyes（P〈0.05）.The VD of the nasal peripapillary sector was significantly lower than in the other sectors.The further the disease had progressed [measured by determining the thickness of the ganglion cell complex（GCC） and the retinal nerve fiber layer（RNFL）] the greater the VD reduction.The AUC discriminated well between glaucomatous and normal eyes（consensus classifier 94.2%）.CONCLUSION：OCTA allows non-invasive quantification of the peripapillary and papillary VD,which is significantly reduced in glaucomatous eyes and accurately distinguishes between healthy and diseased eyes.OCTA expands the spectrum of procedures for detecting and monitoring glaucoma.展开更多
We developed a novel two-photon polymerization(2PP)configuration for fabrication of high-aspect three-dimensional(3D)structures,with an overall height larger than working distance of the microscope objective used for ...We developed a novel two-photon polymerization(2PP)configuration for fabrication of high-aspect three-dimensional(3D)structures,with an overall height larger than working distance of the microscope objective used for laser beam focusing into a photosensitive material.This method is based on a modified optical 2PP setup,where a microscope objective(1003 high N.A.),immersion oil and cover glass can be moved together into the photosensitive material,resulting in an effective higher and wider objective working range(WOW-2PP).The proposed technique enables the fabrication of high-aspect structures with sub-micrometer process resolution.3D structures with a height of 7 mm are demonstrated,which could hardly be built with the conventional 2PP set-up due to refractive index mismatch and laser beam disturbances.展开更多
The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction,named as gate-controlled supercurrent(GCS),has raised great interest for fundamental an...The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction,named as gate-controlled supercurrent(GCS),has raised great interest for fundamental and technological reasons.To gain a deeper understanding of this effect and develop superconducting technologies based on it,the material and physical parameters crucial for the GCS effect must be identified.Top-down fabrication protocols should also be optimized to increase device scalability,although studies suggest that top-down fabricated devices are more resilient to show a GCS.Here,we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of the noncentrosymmetric superconductor niobium rhenium with varying ratios of the constituents(NbRe).Unlike other devices previously reported and made with a top-down approach,our NbRe devices systematically exhibit a GCS effect when they were fabricated from NbRe thin films with small grain size and etched in specific conditions.These observations pave the way for the realization of top-down-made GCS devices with high scalability.Our results also imply that physical parameters like structural disorder and surface physical properties of the nanobridges,which can be in turn modified by the fabrication process,are crucial for a GCS observation,providing therefore also important insights into the physics underlying the GCS effect.展开更多
In this paper we report a multifunctional nanostructured surface on glass that, for the first time, combines a wide range of optical, wetting and durability properties, including low omnidirectional reflectivity, low ...In this paper we report a multifunctional nanostructured surface on glass that, for the first time, combines a wide range of optical, wetting and durability properties, including low omnidirectional reflectivity, low haze, high transmission, superhydrophobicity, oleophobicity, and high mechanical resistance. Nanostructures have been fabricated on a glass surface by reactive ion etching through a nanomask, which is formed by dewetting ultrathin metal films （〈 10 nm thickness） subjected to rapid thermal annealing （RTA）. The nanostructures strongly reduce the initial surface reflectivity （-4%）, to less than 0.4% in the 390--800 nm wavelength range while keeping the haze at low values （〈 0.9%）. The corresponding water contact angle （0c） is -24.5~, while that on a flat surface is -43.5~. The hydrophilic wetting nanostructure can be changed into a superhydrophobic and oleophobic surface by applying a fluorosilane coating, which achieves contact angles for water and oil of -156.3~ and -116.2~, respectively. The multicomponent composition of the substrate （Coming~ glass） enables ion exchange through the surface, so that the nanopillars＇ mechanical robustness increases, as is demonstrated by the negligible changes in surface morphology and optical performance after 5,000-run wipe test. The geometry of the nanoparticles forming the nanomask depends on the metal material, initial metal thickness and RTA parameters. In particular we show that by simply changing the initial thickness of continuous Cu films we can tailor the metal nanoparticles＇ surface density and size. The developed surface nanostructuring does not require expensive lithography, thus it can be controlled and implemented on an industrial scale, which is crucial for applications.展开更多
BACKGROUND Endofaster is an innovative technology that can be combined with upper gastrointestinal endoscopy(UGE)to perform gastric juice analysis and real-time detection of Helicobacter pylori(H.pylori).AIM To assess...BACKGROUND Endofaster is an innovative technology that can be combined with upper gastrointestinal endoscopy(UGE)to perform gastric juice analysis and real-time detection of Helicobacter pylori(H.pylori).AIM To assess the diagnostic performance of this technology and its impact on the management of H.pylori in the real-life clinical setting.METHODS Patients undergoing routine UGE were prospectively recruited.Biopsies were taken to assess gastric histology according to the updated Sydney system and for rapid urease test(RUT).Gastric juice sampling and analysis was performed using the Endofaster,and the diagnosis of H.pylori was based on real-time ammonium measurements.Histological detection of H.pylori served as the diagnostic gold standard for comparing Endofaster-based H.pylori diagnosis with RUT-based H.pylori detection.RESULTS A total of 198 patients were prospectively enrolled in an H.pylori diagnostic study by Endofasterbased gastric juice analysis(EGJA)during the UGE.Biopsies for RUT and histological assessment were performed on 161 patients(82 men and 79 women,mean age 54.8±19.2 years).H.pylori infection was detected by histology in 47(29.2%)patients.Overall,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value(NPV)for H.pylori diagnosis by EGJA were 91.5%,93.0%,92.6%,84.3%,and 96.4%,respectively.In patients on treatment with proton pump inhibitors,diagnostic sensitivity was reduced by 27.3%,while specificity and NPV were unaffected.EGJA and RUT were comparable in diagnostic performance and highly concordant in H.pylori detection(κ-value=0.85).CONCLUSION Endofaster allows for rapid and highly accurate detection of H.pylori during gastroscopy.This may guide taking additional biopsies for antibiotic susceptibility testing during the same procedure and then selecting an individually tailored eradication regimen.展开更多
Background: We hypothesised that supplementation of green tea extract(GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum(ER) stress in the liver ...Background: We hypothesised that supplementation of green tea extract(GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum(ER) stress in the liver of these cows. Thirty Holstein cows with an average parity of 3.06(± 1.31, SD) were divided into a control group and a group that received a daily amount of 10 g of GTE from d 7 before the calving day and a daily amount of 20 g of GTE from the day of calving until d 7 of lactation.Results: Cows supplemented with GTE did not show differences in energy intake or milk yield in weeks 2–7 of lactation. However, these cows had a lower milk fat concentration and a lower energy corrected milk yield than the control cows and showed a trend of improved energy balance. The relative m RNA concentrations of proinflammatory genes, genes involved in the acute phase reaction and antioxidant genes in the liver in weeks 1, 4 and 7 of lactation were not different between the two groups of cows. The concentrations of α-tocopherol and the Trolox equivalent antioxidant capacity in plasma were not different between the two groups. However, the group supplemented with GTE showed significant reductions of some genes of the unfolded protein response(UPR) in week 1 and a trend of lower liver triacylglycerol(TAG) concentrations in the liver compared to the control group.Conclusions: This study shows that supplementation of GTE in dairy cows lowers the fat concentration in the milk but overall has no effect on the expression of inflammatory genes and the antioxidative status in dairy cows during early lactation. The finding of reduced m RNA levels of genes involved in the UPR at week 1, however, supports other results showing that supplementation of polyphenols could prevent the development of ER stress in the liver of cows during early lactation. The finding of a tendency towards a reduced TAG concentration in the liver of cows supplemented with GTE might be due to an improved energy balance in these cows.展开更多
文摘AIM： To evaluate contrast-enhanced ultrasonography （CEUS） using SonoVue in the detection of liver metastases in patients with known extrahepatic primary tumors versus the combined gold standard comprising CT, MRI and clinical/histological data. METHODS： It is an international multicenter study, and there were 12 centres and 125 patients （64 males, 61 females, aged 59 ± 11 years） involved, with 102 patients per protocol. Primary tumors were colorectal in 35%, breast in 27%, pancreatic in 17% and others in 21%. CEUS using SonoVue was employed with a Iow-mechanical-index technique and contrast-specific software using Siemens Elegra, Philips HDI 5000 and Acuson Sequoia; continuous scanning for at least five minutes. RESULTS： CEUS with SonoVue increased significantly the number of focal liver lesions detected versus unenhanced sonography. In 31.4% of the patients, more lesions were found after contrast enhancement. The total numbers of lesions detected were comparable with CEUS （55）, triple-phase spiral CT （61） and HRI with a liverspecific contrast agent （53）. Accuracy of detection of metastatic disease （i.e. at least one metastatic lesion） was significantly higher for CEUS （91.2%） than for unenhanced sonography （81.4%） and was similar to that of triple-phase spiral CT （89.2 %）. In 53 patients whose CEUS examination was negative, a follow-up examination 3-6 months later confirmed the absence of metastatic lesions in 50 patients （94.4%）. CONCLUSION： CEUS is proved to be reliable in the detection of liver metastases in patients with known extrahepatic primary tumors and suspected liver lesions.
基金The German Research Foundation,No.DFG Ta434/5-1the Interdisciplinary Center for Clinical Research(IZKF)Aachen
文摘Stress-related mucosal disease is a typical complication of critically ill patients in the intensive care unit(ICU). It poses a risk of clinically relevant upper gastrointestinal(GI) bleeding. Therefore, stress ulcer prophylaxis(SUP)is recommended in high-risk patients, especially those mechanically ventilated > 48 h and those with a manifest coagulopathy. Proton pump inhibitors(PPI) and, less effectively, histamine 2 receptor antagonists(H2RA) prevent GI bleeding in critically ill patients in the ICU. However, the routine use of pharmacological SUP does not reduce overall mortality in ICU patients. Moreover, recent studies revealed that SUP in the ICU might be associated with potential harm such as an increased risk of infectious complications, especially nosocomial pneumonia and Clostridium difficile-associated diarrhea. Additionally, special populations such as patients with liver cirrhosis may even have an increased mortality rate if treated with PPI. Likewise, PPI can be toxic for both the liver and the bone marrow, and some PPI show clinically relevant interactions with important other drugs like clopidogrel. Therefore, the agent of choice, the specific balance of risks and benefits for individual patients as well as the possible dose of PPI has to be chosen carefully. Alternatives to PPI prophylaxis include H2 RA and/or sucralfate. Instead of routine SUP, further trials should investigate risk-adjusted algorithms, balancing benefits and threats of SUP medication in the ICU.
文摘This paper presents an extensive survey of the most commonly used tools for diagnosing unbalanced flow in the atmosphere, namely the Lagrangian Rossby number, Psi vector, divergence equation, nonlinear balance equation, generalized omega-equation, and departure from fields obtained by potential vorticity (PV) inversion. The basic thoery, assumptions as well as implementation and limitations for each of the tools are all discussed. These tools are applied to high—resolution mesoscale model data to assess the role of unbalanced dynamics in the generation of a mesoscale gravity wave event over the East Coast of the United States. Comparison of these tools in this case study shows that these various methods agree to a large extent with each other though they differ in details. Key words Unbalanced flow - Geostrophic adjustment - Gravity waves - Nonlinear balance equation - Potential vorticity inversion - Omega equations - Rossby number This research was conducted under support from NSF grant ATM-9700626 of the United States. The numerical computations described herein were performed on the Cray T90 at the North Carolina Supercomputing Center and the Cray supercomputer at the NCAR Scientific Computing Division, which also provided the initialization fields for the MM5. Thanks are extended to Mark Stoelinga at University of Washington for the RIP post-processing package.
基金supported by the Deutsche Bundesstiftung Umwelt DBUthe German Research Council DFG+1 种基金the Federal Ministry for Science and Education BMBFthe Academy of Science and Literature in Mainz
文摘An overview of plant surface structures and their evolution is presented. It combines surface chemistry and architecture with their functions and refers to possible biomimetic applications. Within some 3.5 billion years biological species evolved highly complex multifunctional surfaces for interacting with their environments: some 10 million living prototypes(i.e., estimated number of existing plants and animals) for engineers. The complexity of the hierarchical structures and their functionality in biological organisms surpasses all abiotic natural surfaces: even superhydrophobicity is restricted in nature to living organisms and was probably a key evolutionary step with the invasion of terrestrial habitats some 350–450 million years ago in plants and insects. Special attention should be paid to the fact that global environmental change implies a dramatic loss of species and with it the biological role models. Plants, the dominating group of organisms on our planet, are sessile organisms with large multifunctional surfaces and thus exhibit particular intriguing features.Superhydrophilicity and superhydrophobicity are focal points in this work. We estimate that superhydrophobic plant leaves(e.g., grasses) comprise in total an area of around 250 million km^2, which is about 50% of the total surface of our planet. A survey of structures and functions based on own examinations of almost 20,000 species is provided, for further references we refer to Barthlott et al.(Philos. Trans. R. Soc. A 374: 20160191, 1). A basic difference exists between aquatic nonvascular and land-living vascular plants; the latter exhibit a particular intriguing surface chemistry and architecture. The diversity of features is described in detail according to their hierarchical structural order. The first underlying and essential feature is the polymer cuticle superimposed by epicuticular wax and the curvature of single cells up to complex multicellular structures. A descriptive terminology for this diversity is provided. Simplified, the fun
文摘AIM:To investigate the comparative effect of laparoscopic and open cholecystectomy in elderly patients.METHODS:Laparoscopic cholecystectomy has induced a revolution in the treatment of gallbladder disease.Nevertheless,surgeons have been reluctant to implement the concepts of minimally invasive surgery in older patients.A systematic review of Medline was embarked on,up to June 2013.Studies which provided outcome data on patients aged 65 years or older,subjected to laparoscopic or open cholecystectomy were considered.Mortality,morbidity,cardiac and pulmonary complications were the outcome measures of treatment effect.The methodological quality of selected studies was appraised using valid assessment tools.Τhe random-effects model was applied to synthesize outcome data.RESULTS:Out of a total of 337 records,thirteen articles(2 randomized and 11 observational studies)reporting on the outcome of 101559 patients(48195in the laparoscopic and 53364 in the open treatment group,respectively)were identified.Odds ratios(OR)were constantly in favor of laparoscopic surgery,in terms of mortality(1.0%vs 4.4%,OR=0.24,95%CI:0.17-0.35,P<0.00001),morbidity(11.5%vs 21.3%,OR=0.44,95%CI:0.33-0.59,P<0.00001),cardiac(0.6%vs 1.2%,OR=0.55,95%CI:0.38-0.80,P=0.002)and respiratory complications(2.8%vs 5.0%,OR=0.55,95%CI:0.51-0.60,P<0.00001).Critical analysis of solid study data,demonstrated a trend towards improved outcomes for the laparoscopic concept,when adjusted for age and co-morbid diseases.CONCLUSION:Further high-quality evidence is necessary to draw definite conclusions,although bestavailable evidence supports the selective use of laparoscopy in this patient population.
文摘AIM To investigate whether immune mediated diseases(IMD) are more frequent in patients with inflammatory bowel disease(IBD).METHODS In this population based registry study,a total of 47325 patients with IBD were alive and registered in the Danish National Patient Registry on December 16,2013. Controls were randomly selected from the Danish Civil Registration System(CRS) and matched for sex,age,and municipality. We used ICD 10 codes to identify the diagnoses of the included patients. The IBD population was divided into three subgroups: Ulcerative colitis(UC),Crohn's disease(CD) and Both the latter referring to those registered with both diagnoses. Subsequently,odds-ratios(OR) and 95%CI were obtained separately for each group and their respective controls. The use of Bonferoni post-test correction adjusted the significance level to P < 0.00125. P-values were estimated using Fisher's exact test.RESULTS There were significantly more women than men in the registry,and a greater percentage of comorbidity in the IBD groups(P < 0.05). Twenty different IMDs were all significantly more frequent in the IBD group. Sixteen were associated with UC versus twelve with CD. In both UC and CD ORs were significantly increased(P < 0.00125) for primary sclerosing cholangitis(PSC),celiac disease,type 1 diabetes(T1D),sarcoidosis,asthma,iridocyclitis,psoriasis,pyoderma gangrenosum,rheumatoid arthritis,and ankylosing spondylitis. Restricted to UC(P < 0.00125) were autoimmune hepatitis,primary biliary cholangitis,Grave's disease,polymyalgia rheumatica,temporal arteritis,and atrophic gastritis. Restricted to CD(P < 0.00125) were psoriatic arthritis and episcleritis. Restricted to women with UC(P < 0.00125) were atrophic gastritis,rheumatoid arthritis,temporal arteritis,and polymyalgia rheumatica. Restricted to women with CD were episcleritis,rheumatoid arthritis,and psoriatic arthritis. The only disease restricted to men(P < 0.00125) was sarcoidosis. CONCLUSION Immune mediated diseases were significantly more frequent in patients with IBD.
文摘This paper discusses approaches to measure moisture in power transformers by analyzing the dielectric response of the main insulation. Dielectric diagnostic methods deduce moisture in the solid insulation from dielectric properties like polarisation depolarisation currents and dissipation factor vs. frequency. A new instrument "Dirana" combines time domain (PDC) and frequency domain (FDS) measurements and thus substantially shortens the measurement duration. New software was developed which bases on a new data pool,measured at new and aged pressboard samples with various moisture contents and oil impregnation. Its analysis algorithm compares measurements from a transformer to modelled dielectric responses,obtained from the so-called XY-model. To avoid overestimation of moisture for aged transformers,the analysis algorithm compensates for the influence of conductive aging by-products. Moisture especially increases the losses in the low frequency range of the dielectric response of pressboard. Thus,data on the left-hand side of the area dominated by interfacial polarization (insulation geometry) are required for reliable moisture determination. Case studies illustrate the application of moisture determination by dielectric response methods.
基金the Tongji University, Shanghai, and the Chongqing University, Chongqing, as part of the MICROTOX project ("Transformation, Bioaccumulation and Toxicity of Organic Micropollutants in the Yangtze Three Gorges Reservoir" No. FKZ 02WT1141)+5 种基金the Sino-German joint environmental research program "Yangtze-Hydro - Sustainable Management of the Newly Created Ecosystem at the Three Gorges Dam" (No. FKZ 02WT Bergmann et al. (2011) www.yangtzeproject.de)part of the research cluster "Pollutants/Water/Sediment-Impacts of Transformation and Transportation Processes on the Yangtze Water Quality"supported by a cooperation project with Chinese colleagues also sponsored by the Federal Ministry of Education and Research, Germany (No. DLR FKZ 01DO12007)the Chinese 111 Program
文摘Besides obvious benefits,the Three Gorges Dam＇s construction resulted in new pollution scenarios with the potentials to threaten the Three Gorges Reservoir（TGR） ecosystem.In order to record organic contamination,to find links to ecotoxicological impacts and to serve as reference for ensuing monitoring,several sites in the TGR area were screened applying the triad approach with additional lines-of-evidence as a holistic assessment method.Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011 and 2012 to determine organic pollution levels,mutagenic potentials and genotoxic impacts.Two regional hot-spots near the cities of Chongqing and Kaixian were identified and further investigated in 2013.Only polycyclic aromatic hydrocarbons（PAHs） could be detected in sediments in 2011（165-1653 ng/g）,emphasizing their roles as key pollutants of the area.Their ubiquity was confirmed at Chongqing（150-433 ng/g） and Kaixian（127-590 ng/g） in2013.Concentrations were comparable to other major Chinese and German rivers.However,the immense sediment influx suggested a deposition of 216-636 kg PAH/day（0.2-0.6 mg PAH/（m2·day））,indicating an ecotoxicological risk.PAH source analysis highlighted primary impacts of combustion sources on the more industrialized upper TGR section,whereas petrogenic sources dominated the mid-low section.Furthermore,sediment extracts from several sites exhibited significant activities of frameshift promutagens in the Ames fluctuation assay.Additionally,significant genotoxic impairments in erythrocytes of P.vachellii were detected（Chongqing/Kaixian）,demonstrating the relevance of genotoxicity as animportant mode of action in the TGR＇s fish.PAHs,their derivatives and non-target compounds are considered as main causative agents.
文摘AIM：To evaluate whether optical coherence tomography angiography（OCTA） can detect altered vessel density（VD） at the optic nerve head（ONH） in glaucoma patients.Special attention is paid to the accuracy of the OCTA technique for distinguishing healthy from glaucomatous eyes.METHODS：A total of 171 eyes were examined by the OCTA system Angio Vue^TM（Optovue）：97 eyes diagnosed with glaucoma and 74 healthy control eyes.The papillary and peripapillary VD was measured.Furthermore,the VD was correlated with different structural and functional measurements.In order to test the accuracy of differentiation between eyes with and without glaucoma,we calculated the receiver operating characteristic curve（ROC） and the area under the curve（AUC）.RESULTS：The papillary and peripapillary VD in glaucomatous eyes was significantly lower than in healthy eyes（P〈0.05）.The VD of the nasal peripapillary sector was significantly lower than in the other sectors.The further the disease had progressed [measured by determining the thickness of the ganglion cell complex（GCC） and the retinal nerve fiber layer（RNFL）] the greater the VD reduction.The AUC discriminated well between glaucomatous and normal eyes（consensus classifier 94.2%）.CONCLUSION：OCTA allows non-invasive quantification of the peripapillary and papillary VD,which is significantly reduced in glaucomatous eyes and accurately distinguishes between healthy and diseased eyes.OCTA expands the spectrum of procedures for detecting and monitoring glaucoma.
基金This work was supported by the Deutsche Forschungsgemeinschaft(German Research Foundation)Cluster of Excellence REBIRTH and EU/FP7 project Phocam.We thank E Fadeeva and J Koch for helpful technical discussions.
文摘We developed a novel two-photon polymerization(2PP)configuration for fabrication of high-aspect three-dimensional(3D)structures,with an overall height larger than working distance of the microscope objective used for laser beam focusing into a photosensitive material.This method is based on a modified optical 2PP setup,where a microscope objective(1003 high N.A.),immersion oil and cover glass can be moved together into the photosensitive material,resulting in an effective higher and wider objective working range(WOW-2PP).The proposed technique enables the fabrication of high-aspect structures with sub-micrometer process resolution.3D structures with a height of 7 mm are demonstrated,which could hardly be built with the conventional 2PP set-up due to refractive index mismatch and laser beam disturbances.
基金the European Union’s Horizon 2020 Research and Innovation Program under Grant Agreement No.964398(SuperGate)the US ONR(Nos.N00014-21-1-2879,N00014-20-1-2442,and N00014-23-1-2866).
文摘The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction,named as gate-controlled supercurrent(GCS),has raised great interest for fundamental and technological reasons.To gain a deeper understanding of this effect and develop superconducting technologies based on it,the material and physical parameters crucial for the GCS effect must be identified.Top-down fabrication protocols should also be optimized to increase device scalability,although studies suggest that top-down fabricated devices are more resilient to show a GCS.Here,we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of the noncentrosymmetric superconductor niobium rhenium with varying ratios of the constituents(NbRe).Unlike other devices previously reported and made with a top-down approach,our NbRe devices systematically exhibit a GCS effect when they were fabricated from NbRe thin films with small grain size and etched in specific conditions.These observations pave the way for the realization of top-down-made GCS devices with high scalability.Our results also imply that physical parameters like structural disorder and surface physical properties of the nanobridges,which can be in turn modified by the fabrication process,are crucial for a GCS observation,providing therefore also important insights into the physics underlying the GCS effect.
文摘In this paper we report a multifunctional nanostructured surface on glass that, for the first time, combines a wide range of optical, wetting and durability properties, including low omnidirectional reflectivity, low haze, high transmission, superhydrophobicity, oleophobicity, and high mechanical resistance. Nanostructures have been fabricated on a glass surface by reactive ion etching through a nanomask, which is formed by dewetting ultrathin metal films （〈 10 nm thickness） subjected to rapid thermal annealing （RTA）. The nanostructures strongly reduce the initial surface reflectivity （-4%）, to less than 0.4% in the 390--800 nm wavelength range while keeping the haze at low values （〈 0.9%）. The corresponding water contact angle （0c） is -24.5~, while that on a flat surface is -43.5~. The hydrophilic wetting nanostructure can be changed into a superhydrophobic and oleophobic surface by applying a fluorosilane coating, which achieves contact angles for water and oil of -156.3~ and -116.2~, respectively. The multicomponent composition of the substrate （Coming~ glass） enables ion exchange through the surface, so that the nanopillars＇ mechanical robustness increases, as is demonstrated by the negligible changes in surface morphology and optical performance after 5,000-run wipe test. The geometry of the nanoparticles forming the nanomask depends on the metal material, initial metal thickness and RTA parameters. In particular we show that by simply changing the initial thickness of continuous Cu films we can tailor the metal nanoparticles＇ surface density and size. The developed surface nanostructuring does not require expensive lithography, thus it can be controlled and implemented on an industrial scale, which is crucial for applications.
基金Supported by the Deutsches Zentrum für Infektionsforschung,Partner Site Munich,Germany,No.TTU 06.715_00the Bavarian Ministry of Science and the Arts within the framework of the Bavarian Research Network“New Strategies Against Multi-Resistant Pathogens by Means of Digital Networking–bayresq.net”.
文摘BACKGROUND Endofaster is an innovative technology that can be combined with upper gastrointestinal endoscopy(UGE)to perform gastric juice analysis and real-time detection of Helicobacter pylori(H.pylori).AIM To assess the diagnostic performance of this technology and its impact on the management of H.pylori in the real-life clinical setting.METHODS Patients undergoing routine UGE were prospectively recruited.Biopsies were taken to assess gastric histology according to the updated Sydney system and for rapid urease test(RUT).Gastric juice sampling and analysis was performed using the Endofaster,and the diagnosis of H.pylori was based on real-time ammonium measurements.Histological detection of H.pylori served as the diagnostic gold standard for comparing Endofaster-based H.pylori diagnosis with RUT-based H.pylori detection.RESULTS A total of 198 patients were prospectively enrolled in an H.pylori diagnostic study by Endofasterbased gastric juice analysis(EGJA)during the UGE.Biopsies for RUT and histological assessment were performed on 161 patients(82 men and 79 women,mean age 54.8±19.2 years).H.pylori infection was detected by histology in 47(29.2%)patients.Overall,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value(NPV)for H.pylori diagnosis by EGJA were 91.5%,93.0%,92.6%,84.3%,and 96.4%,respectively.In patients on treatment with proton pump inhibitors,diagnostic sensitivity was reduced by 27.3%,while specificity and NPV were unaffected.EGJA and RUT were comparable in diagnostic performance and highly concordant in H.pylori detection(κ-value=0.85).CONCLUSION Endofaster allows for rapid and highly accurate detection of H.pylori during gastroscopy.This may guide taking additional biopsies for antibiotic susceptibility testing during the same procedure and then selecting an individually tailored eradication regimen.
文摘Background: We hypothesised that supplementation of green tea extract(GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum(ER) stress in the liver of these cows. Thirty Holstein cows with an average parity of 3.06(± 1.31, SD) were divided into a control group and a group that received a daily amount of 10 g of GTE from d 7 before the calving day and a daily amount of 20 g of GTE from the day of calving until d 7 of lactation.Results: Cows supplemented with GTE did not show differences in energy intake or milk yield in weeks 2–7 of lactation. However, these cows had a lower milk fat concentration and a lower energy corrected milk yield than the control cows and showed a trend of improved energy balance. The relative m RNA concentrations of proinflammatory genes, genes involved in the acute phase reaction and antioxidant genes in the liver in weeks 1, 4 and 7 of lactation were not different between the two groups of cows. The concentrations of α-tocopherol and the Trolox equivalent antioxidant capacity in plasma were not different between the two groups. However, the group supplemented with GTE showed significant reductions of some genes of the unfolded protein response(UPR) in week 1 and a trend of lower liver triacylglycerol(TAG) concentrations in the liver compared to the control group.Conclusions: This study shows that supplementation of GTE in dairy cows lowers the fat concentration in the milk but overall has no effect on the expression of inflammatory genes and the antioxidative status in dairy cows during early lactation. The finding of reduced m RNA levels of genes involved in the UPR at week 1, however, supports other results showing that supplementation of polyphenols could prevent the development of ER stress in the liver of cows during early lactation. The finding of a tendency towards a reduced TAG concentration in the liver of cows supplemented with GTE might be due to an improved energy balance in these cows.
