AIM: To investigate the viral and host causes of fatty liver in chronic hepatitis B patients and the role of fat deposits in liver damage.METHODS: A total of 164 patients (113 males and 51 females, average age 35±...AIM: To investigate the viral and host causes of fatty liver in chronic hepatitis B patients and the role of fat deposits in liver damage.METHODS: A total of 164 patients (113 males and 51 females, average age 35±11.3 years, and range 10-62 years) with previously untreated chronic hepatitis B were included in the study. The patients were divided into two groups depending on the result of liver biopsy: group without steatosis (100 patients with ＜5% hepatosteatosis) and group with steatosis (64 patients with ＞5% hepatosteatosis). The groups were compared in terms of gender, body mass index (BMI), liver enzymes (ALT, AST, ALP, GGT), cholesterol, triglyceride, HBeAg, viral load, and histological findings. In the group with steatosis, the patients were subdivided depending on the degree of steatosis into mild group (45 patients with 5-24% steatosis), and severe group (19 patients with ＞25% steatosis). RESULTS: In the group of chronic hepatitis B with steatosis, the mean age, BMI, cholesterol, and triglyceride levels were significantly higher than those in the group without steatosis (P＜0.05). Steatosis was found in 53 (46.9%) of male patients and 11 (22%) of female patients (P＜0.05). No significant difference was found in the positivity of ALT, AST, ALP, GGT, HBeAg, viral load, histological activity index (HAI) and stage between the two groups (P＞0.05). In the group with severe steatosis, the BMI was significantly higher than that in the group with mild steatosis (P＜0.05). No significant difference was found in the other parameters between the groups (P＞0.05). CONCLUSION: Steatosis in chronic hepatitis B appears to be a result of metabolic factors of the host rather than the effect of viruses. Steatosis is unrelated to the HAI and degree of fibrosis, which are considered as the histological indicators of liver damage.展开更多
The chemical composition, mineral profile and in vitro fermentation characteristics of maize （MZ）, high sugar forage sorghum （HS） and forage sorghum （FS）, and silages made from each forage type were measured. Th...The chemical composition, mineral profile and in vitro fermentation characteristics of maize （MZ）, high sugar forage sorghum （HS） and forage sorghum （FS）, and silages made from each forage type were measured. The MZ and MZ silage （MZS） had higher crude protein, starch and ether extract contents than both sorghum forages and sorghum silages. HS had higher ash and water-soluble carbohydrate concentrations than FS and MZ. MZ, MZS, HS and HS silage （HSS） had lower neutral detergent fibre, acid detergent fibre and acid detergent lignin than FS and FS silage （FSS）. FSS had higher dry matter （DM） and pH than MZS and HSS. HSS contained higher concentrations of P and K than FSS and MZS. MZS and HSS had higher in vitro dry matter and organic matter digestibility, CH4 production, total volatile fatty acids, acetate and propionate than FSS. pH was higher for FSS than for HSS, and ammonia was lower for HSS than for MZS and FSS. HSS had higher gas production than MZS and FSS after 2, 4, 6 and 8 h incubation. MZS had higher gas production than HSS and FSS after 26 and 28 h of incubation. The results indicate that HS may substitute for MZ to make good quality silage. However, animal studies are needed to assess the acceptability and feeding values of HSS vs. MZS for ruminant production.展开更多
Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called ＂cultured＂ or ＂synthetic＂ or ＂in vitro＂ meat could in theory be construct...Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called ＂cultured＂ or ＂synthetic＂ or ＂in vitro＂ meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.展开更多
Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribo...Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribological situation for many moving mechanical systems mainly because friction consumes large amounts of energy and causes greenhouse gas emissions[2].Superlubric sliding can also improve performance and durability of these systems.In this paper,we attempt to provide an overview of how controlled or targeted bulk,surface,or tribochemistry can lead to superlubricity in diamond-like carbon(DLC)films.Specifically,we show that how providing hydrogen into bulk and near surface regions as well as to sliding contact interfaces of DLC films can lead to super-low friction and wear.Incorporation of hydrogen into bulk DLC or near surface regions can be done during deposition or through hydrogen plasma treatment after the deposition.Hydrogen can also be fed into the sliding contact interfaces of DLCs during tribological testing to reduce friction.Due to favorable tribochemical interactions,these interfaces become very rich in hydrogen and thus provide super-low friction after a brief run-in period.Regardless of the method used,when sliding surfaces of DLC films are enriched in hydrogen,they then provide some of the lowest friction coefficients(i.e.,down to 0.001).Time-of-flight secondary ion mass spectrometer(TOF-SIMS)is used to gather evidence on the extent and nature of tribochemical interactions with hydrogen.Based on the tribological and surface analytical findings,we provide a mechanistic model for the critical role of hydrogen on superlubricity of DLC films.展开更多
AIM: Oxygen free radical mediated tissue damage is well established in pathogenesis of acute pancreatitis (AP).Whether nitric oxide (NO) plays a deleterious or a protective role is unknown. In alcohol-induced AP, we s...AIM: Oxygen free radical mediated tissue damage is well established in pathogenesis of acute pancreatitis (AP).Whether nitric oxide (NO) plays a deleterious or a protective role is unknown. In alcohol-induced AP, we studied NO, lipooxidative damage and glutathione in pancreas, lung and circulation.METHODS: AP was induced in rats (n = 25) by injection of ethyl alcohol into the common biliary duct. A sham laparatomy was performed in controls (n = 15). After 24 h the animals were killed, blood and tissue sampling were done.RESULTS: Histopathologic evidence confirmed the development of AP. Marked changes were observed in the pulmonary tissue. Compared with controls, the AP group displayed higher values for NO metabolites in pancreas and lungs, and thiobarbituric acid reactive substances in circulation. Glutathione was lower in pancreas and in circulation. Glutathione and NO were positively correlated in pancreas and lungs of controls but negatively correlated in circulation of experimental group. In the experimental group, plasma thiobarbituric acid reactive substances were negatively correlated with pancreas thiobarbituric acid reactive substances but positively correlated with pancreas NO.CONCLUSION: NO increases in both pancreas and lungs in AP and NO contributes to the pathogenesis of AP under oxidative stress.展开更多
Optical wireless communication(OWC)using the ultra-broad spectrum of the visible-to-ultraviolet(UV)wavelength region remains a vital field of research for mitigating the saturated bandwidth of radio-frequency(RF)commu...Optical wireless communication(OWC)using the ultra-broad spectrum of the visible-to-ultraviolet(UV)wavelength region remains a vital field of research for mitigating the saturated bandwidth of radio-frequency(RF)communication.However,the lack of an efficient UV photodetection methodology hinders the development of UV-based communication.The key technological impediment is related to the low UV-photon absorption in existing silicon photodetectors,which offer low-cost and mature platforms.To address this technology gap,we report a hybrid Sibased photodetection scheme by incorporating CsPbBr_(3) perovskite nanocrystals(NCs)with a high photoluminescence quantum yield(PLQY)and a fast photoluminescence(PL)decay time as a UV-to-visible colourconverting layer for high-speed solar-blind UV communication.The facile formation of drop-cast CsPbBr_(3) perovskite NCs leads to a high PLQY of up to ~73% and strong absorption in the UV region.With the addition of the NC layer,a nearly threefold improvement in the responsivity and an increase of ~25% in the external quantum efficiency(EQE)of the solar-blind region compared to a commercial silicon-based photodetector were observed.Moreover,timeresolved photoluminescence measurements demonstrated a decay time of 4.5 ns under a 372-nm UV excitation source,thus elucidating the potential of this layer as a fast colour-converting layer.A high data rate of up to 34 Mbps in solar-blind communication was achieved using the hybrid CsPbBr_(3)-silicon photodetection scheme in conjunction with a 278-nm UVC light-emitting diode(LED).These findings demonstrate the feasibility of an integrated high-speed photoreceiver design of a composition-tuneable perovskite-based phosphor and a low-cost silicon-based photodetector for UV communication.展开更多
Air pollution has environmental issue owing become a serious to its diverse harmful effects on the physical and biological environment. According to the Environmental Protection Agency （EPA） and the World Health Org...Air pollution has environmental issue owing become a serious to its diverse harmful effects on the physical and biological environment. According to the Environmental Protection Agency （EPA） and the World Health Organization （WHO）, air pollution affects millions of people worldwide. Hundreds of thousands of deaths each year and a range of diseases, particularly among vulnerable groups （i.e., children, the elderly, and people with special medical conditions）, are attributed to air pollution. These effects are not always caused by single pollutant in the air; rather, they are considered consequences of the multi-pollutants to which people are simultaneously exposed.展开更多
Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, he...Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial workup of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions.展开更多
AIM： To assess the practically usefulness and diagnostic yield of this new method in a group of patients with suspected small bowel lesions. METHODS： Capsule endoscopic （CE） examination by using M2A capsule endosc...AIM： To assess the practically usefulness and diagnostic yield of this new method in a group of patients with suspected small bowel lesions. METHODS： Capsule endoscopic （CE） examination by using M2A capsule endoscope TM （Given Imaging, Yoqneam, Israel） was performed in thirty nine patients （26 males, 13 females） with suspected small intestinal lesions. The composing of the patients was as follows： obscure gastrointestinal bleeding in twenty three patients, known Crohn＇s disease in 6 patients, in whom CE was used to evaluate the severity and extension of the diseases, chronic diarrhea in 8 patients, abdominal pain in one patient and malignancy in one patient with unknown origin. RESULTS： In two patients CE failed. Different abnormalities were revealed in 26 patients overall. Detection rate of abnormalities was highest among patients with obscure gastrointestinal bleeding and the source of bleeding was demonstrated in 17 of 23 patients with obscure bleeding （73.9%）. Entero-Behcet was diagnosed in two patients by CE as a source of obscure gastrointestinal bleeding. In 6 patients with known Crohn＇s disease, CE revealed better evaluation of the disease extension. In 3 of 8 （37.5%） patients with chronic diarrhea; CE revealed some mucosal abnormalities as the cause of chronic diarrhea. In a patient with unexplained abdominal pain and in a cancer patient with unknown origin, CE examination was normal. CONCLUSION： In our relatively small series, we found that capsule endoscopy is a useful diagnostic tool particularly in diagnosis of obscure gastrointestinal bleeding, chronic diarrhea and in estimating the extension of Crohn＇s disease.展开更多
AIM： To share our experience of the management and outcomes of patients with pneumatosis cystoides in- testinalis （PCI）. METHODS： The charts of seven patients who under- went surgery for PCI between 2001 and 2009 ...AIM： To share our experience of the management and outcomes of patients with pneumatosis cystoides in- testinalis （PCI）. METHODS： The charts of seven patients who under- went surgery for PCI between 2001 and 2009 were re- viewed retrospectively. Clinical features, diagnoses and surgical interventions of patients with PCI are discussed. RESULTS： Seven patients with PCI （3 males, 4 fe- males; mean age, 50 ~ 16.1 years; range, 29-74 years） were analyzed. In three of the patients, abdominal pain was the only complaint, whereas additional vomiting and/or constipation occurred in four. Leukocytosis was detected in four patients, whereas it was within normal limits in three. Subdiaphragmatic free air was observed radiologically in four patients but not in three. Six of the patients underwent an applied lapa- rotomy, whereas one underwent an applied explorative laparoscopy. PCI localized to the small intestine only was detected in four patients, whereas it was localized to the small intestine and the colon in three. Three patients underwent a partial small intestine resection and four did not after PCI was diagnosed. Five patients were diagnosed with secondary PCI and two with pri- mary PCI when the surgical findings and medical his- tory were assessed together. Gastric atony developed in one case only, as a complication during a postopera- tive follow-up of 5-14 d. CONCLUSION： Although rare, PCl should be consid- ered in the differential diagnosis of acute abdomen. Diagnostic laparoscopy and preoperative radiological tests, including computed tomography, play an impor- tant role in confirming the diagnosis.展开更多
Coal extraction in Huainan area is basically characterized by one of typical multi-seam mining conditions observed in China, where coal is mined in soft seams characterized by high gas content, high stress, low permea...Coal extraction in Huainan area is basically characterized by one of typical multi-seam mining conditions observed in China, where coal is mined in soft seams characterized by high gas content, high stress, low permeability and difficult geological conditions. The average mining depth in Huainan area is 875 m and continues to increase by 15-25 m annually. The rise in mining depth increases the risk of coal and gas outbursts and makes it more difficult to control outburst risk in Huainan coalmines. This paper reviews the main achievements（e.g. theories, technologies and equipment） in outburst control in Huainan, and tries to analyze some key challenging issues, and to present associated strategies to address these issues.It suggests that the outburst control in Huainan must take a combination approach of both regional and localized control in which the former plays a dominant role. Other outburst prevention principles include（1） non-outburst seams protecting outburst seams,（2） less outburst-prone seams protecting strong outburst-prone seams,（3） stress-releasing mining, and（4） the combination of ground and underground gas drainage（the model is dubbed as ＂walking on two legs＂）. The paper concludes that we should conduct fundamental researches on outburst mechanism, and develop outburst control technologies and equipment to ensure safe and efficient coal mining of deep coal resources in Huainan area.展开更多
Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River N...Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.展开更多
Percutaneous angioplasty and stenting for the treatment of extracranial vertebral artery(VA) stenosis seems a safe,effective and useful technique for resolving symptoms and improving blood flow to the posterior circul...Percutaneous angioplasty and stenting for the treatment of extracranial vertebral artery(VA) stenosis seems a safe,effective and useful technique for resolving symptoms and improving blood flow to the posterior circulation,with a low complication rate and good long-term results.In patients with severe tortuosity of the vessel,stent placement is a real challenge.The new coronary balloon-expandable stents may be preferred.A large variability of restenosis rates has been reported.Drug-eluting stents may be the solution.After a comprehensive review of the literature,it can be concluded that percutaneous angioplasty and stenting of extracranial VA stenosis is technically feasible,but there is insufficient evidence from randomized trials to demonstrate that endovascular management is superior to best medical management.展开更多
AIMTo evaluate the reversibility of minimal hepatic encephalopathy (MHE) following liver transplantation (LT) in Egyptian cirrhotic patients. METHODSThis prospective study included twenty patients with biopsy-proven l...AIMTo evaluate the reversibility of minimal hepatic encephalopathy (MHE) following liver transplantation (LT) in Egyptian cirrhotic patients. METHODSThis prospective study included twenty patients with biopsy-proven liver cirrhosis listed for LT and twenty age- and sex-matched healthy control subjects. All underwent neuro-psychiatric examination, laboratory investigations, radiological studies and psychometric tests including trail making test A (TMT A), TMT B, digit symbol test and serial dotting test. The psychometric hepatic encephalopathy score (PHES) was calculated for patients to diagnose MHE. Psychometric tests were repeated six months following LT in the cirrhotic patient group. RESULTSBefore LT, psychometric tests showed highly significant deficits in cirrhotic patients in comparison to controls (P P P P = 0.005). More patients in whom reversal of MHE was observed had a pre-transplant MELD score CONCLUSIONReversal of MHE in cirrhotic patients could be achieved by LT, especially in those with a MELD score展开更多
With the advances in technical skills, management of postoperative complications and improvements in immunosuppressive drugs, liver transplantation is the standard treatment for many patients with chronic liver diseas...With the advances in technical skills, management of postoperative complications and improvements in immunosuppressive drugs, liver transplantation is the standard treatment for many patients with chronic liver disease. Today, shortage of donor organs seems to be the major limiting factor for the application of liver transplantation. This review focuses on five issues that are challenging to clinical practice of liver transplantation and relevant to gastroenterologists. These include living donor liver transplantation, recurrent viral hepatitis, non-heart-beating donors, hepatocellular carcinoma, and ABO incompatible liver transplantation. Living donor and non-heart beating donor transplantations were initiated as a solution to increase the donor organ pool and it is expected that there will be an increase in the number of these donors. Recurrent hepatitis C and hepatocellular carcinoma following liver transplantation are among major problems and ongoing research in these diseases may lead to better outcomes in these recipients.展开更多
Dear editor, Following its entrance into the human body through inhalation, carbon monoxide （CO） forms carboxyhemoglobin （COHb） by binding to hemoglobin （Hb） within the blood. Massive ischemic tissue necrosis oc...Dear editor, Following its entrance into the human body through inhalation, carbon monoxide （CO） forms carboxyhemoglobin （COHb） by binding to hemoglobin （Hb） within the blood. Massive ischemic tissue necrosis occurs in 0.5%-1% of cases with CO poisoning. The affinity of CO to Hb is 200-250 times more when compared to the affinity of oxygen. As a result of CO binding to Hb, oxygen delivery to the tissues is reduced, and tissue hypoxia develops. This affects mostly the brain and heart, which are the organs with the highest demand for oxygen.展开更多
文摘AIM: To investigate the viral and host causes of fatty liver in chronic hepatitis B patients and the role of fat deposits in liver damage.METHODS: A total of 164 patients (113 males and 51 females, average age 35±11.3 years, and range 10-62 years) with previously untreated chronic hepatitis B were included in the study. The patients were divided into two groups depending on the result of liver biopsy: group without steatosis (100 patients with ＜5% hepatosteatosis) and group with steatosis (64 patients with ＞5% hepatosteatosis). The groups were compared in terms of gender, body mass index (BMI), liver enzymes (ALT, AST, ALP, GGT), cholesterol, triglyceride, HBeAg, viral load, and histological findings. In the group with steatosis, the patients were subdivided depending on the degree of steatosis into mild group (45 patients with 5-24% steatosis), and severe group (19 patients with ＞25% steatosis). RESULTS: In the group of chronic hepatitis B with steatosis, the mean age, BMI, cholesterol, and triglyceride levels were significantly higher than those in the group without steatosis (P＜0.05). Steatosis was found in 53 (46.9%) of male patients and 11 (22%) of female patients (P＜0.05). No significant difference was found in the positivity of ALT, AST, ALP, GGT, HBeAg, viral load, histological activity index (HAI) and stage between the two groups (P＞0.05). In the group with severe steatosis, the BMI was significantly higher than that in the group with mild steatosis (P＜0.05). No significant difference was found in the other parameters between the groups (P＞0.05). CONCLUSION: Steatosis in chronic hepatitis B appears to be a result of metabolic factors of the host rather than the effect of viruses. Steatosis is unrelated to the HAI and degree of fibrosis, which are considered as the histological indicators of liver damage.
基金jointly supported by the Nati onal Natural Science Foundation of China (31160472)the Chancellor Funds of Tarim University, China (TDZKBS201102)funded by Agmardt Post-Doctoral Fellowship (New Zealand)
文摘The chemical composition, mineral profile and in vitro fermentation characteristics of maize （MZ）, high sugar forage sorghum （HS） and forage sorghum （FS）, and silages made from each forage type were measured. The MZ and MZ silage （MZS） had higher crude protein, starch and ether extract contents than both sorghum forages and sorghum silages. HS had higher ash and water-soluble carbohydrate concentrations than FS and MZ. MZ, MZS, HS and HS silage （HSS） had lower neutral detergent fibre, acid detergent fibre and acid detergent lignin than FS and FS silage （FSS）. FSS had higher dry matter （DM） and pH than MZS and HSS. HSS contained higher concentrations of P and K than FSS and MZS. MZS and HSS had higher in vitro dry matter and organic matter digestibility, CH4 production, total volatile fatty acids, acetate and propionate than FSS. pH was higher for FSS than for HSS, and ammonia was lower for HSS than for MZS and FSS. HSS had higher gas production than MZS and FSS after 2, 4, 6 and 8 h incubation. MZS had higher gas production than HSS and FSS after 26 and 28 h of incubation. The results indicate that HS may substitute for MZ to make good quality silage. However, animal studies are needed to assess the acceptability and feeding values of HSS vs. MZS for ruminant production.
文摘Growing muscle tissue in culture from animal stem cells to produce meat theoretically eliminates the need to sacrifice animals. So-called ＂cultured＂ or ＂synthetic＂ or ＂in vitro＂ meat could in theory be constructed with different characteristics and be produced faster and more efficiently than traditional meat. The technique to generate cultured muscle tissues from stem cells was described long ago, but has not yet been developed for the commercial production of cultured meat products. The technology is at an early stage and prerequisites of implementation include a reasonably high level of consumer acceptance, and the development of commercially-viable means of large scale production. Recent advancements in tissue culture techniques suggest that production may be economically feasible, provided it has physical properties in terms of colour, flavour, aroma, texture and palatability that are comparable to conventional meat. Although considerable progress has been made during recent years, important issues remain to be resolved, including the characterization of social and ethical constraints, the fine-tuning of culture conditions, and the development of culture media that are cost-effective and free of animal products. Consumer acceptance and confidence in in vitro produced cultured meat might be a significant impediment that hinders the marketing process.
基金supported by the U.S.Department of Energy,Office of Energy Efficiency and Renewable Energy,under Contract No.DE-AC02-06CH11357。
文摘Superlubricity refers to a sliding regime in which contacting surfaces move over one another without generating much adhesion or friction[1].From a practical application point of view,this will be the most ideal tribological situation for many moving mechanical systems mainly because friction consumes large amounts of energy and causes greenhouse gas emissions[2].Superlubric sliding can also improve performance and durability of these systems.In this paper,we attempt to provide an overview of how controlled or targeted bulk,surface,or tribochemistry can lead to superlubricity in diamond-like carbon(DLC)films.Specifically,we show that how providing hydrogen into bulk and near surface regions as well as to sliding contact interfaces of DLC films can lead to super-low friction and wear.Incorporation of hydrogen into bulk DLC or near surface regions can be done during deposition or through hydrogen plasma treatment after the deposition.Hydrogen can also be fed into the sliding contact interfaces of DLCs during tribological testing to reduce friction.Due to favorable tribochemical interactions,these interfaces become very rich in hydrogen and thus provide super-low friction after a brief run-in period.Regardless of the method used,when sliding surfaces of DLC films are enriched in hydrogen,they then provide some of the lowest friction coefficients(i.e.,down to 0.001).Time-of-flight secondary ion mass spectrometer(TOF-SIMS)is used to gather evidence on the extent and nature of tribochemical interactions with hydrogen.Based on the tribological and surface analytical findings,we provide a mechanistic model for the critical role of hydrogen on superlubricity of DLC films.
文摘AIM: Oxygen free radical mediated tissue damage is well established in pathogenesis of acute pancreatitis (AP).Whether nitric oxide (NO) plays a deleterious or a protective role is unknown. In alcohol-induced AP, we studied NO, lipooxidative damage and glutathione in pancreas, lung and circulation.METHODS: AP was induced in rats (n = 25) by injection of ethyl alcohol into the common biliary duct. A sham laparatomy was performed in controls (n = 15). After 24 h the animals were killed, blood and tissue sampling were done.RESULTS: Histopathologic evidence confirmed the development of AP. Marked changes were observed in the pulmonary tissue. Compared with controls, the AP group displayed higher values for NO metabolites in pancreas and lungs, and thiobarbituric acid reactive substances in circulation. Glutathione was lower in pancreas and in circulation. Glutathione and NO were positively correlated in pancreas and lungs of controls but negatively correlated in circulation of experimental group. In the experimental group, plasma thiobarbituric acid reactive substances were negatively correlated with pancreas thiobarbituric acid reactive substances but positively correlated with pancreas NO.CONCLUSION: NO increases in both pancreas and lungs in AP and NO contributes to the pathogenesis of AP under oxidative stress.
基金supported by funding from King Abdullah University of Science and Technology(KAUST),BAS/1/1614-01-01,KCR/1/2081-01-01 and GEN/1/6607-01-01,and the KAUST-KFUPM Special Initiative,REP/1/2878-01-01the financial support from the King Abdulaziz City for Science and Technology(KACST),Grant no.KACST TIC R2-FP-008.
文摘Optical wireless communication(OWC)using the ultra-broad spectrum of the visible-to-ultraviolet(UV)wavelength region remains a vital field of research for mitigating the saturated bandwidth of radio-frequency(RF)communication.However,the lack of an efficient UV photodetection methodology hinders the development of UV-based communication.The key technological impediment is related to the low UV-photon absorption in existing silicon photodetectors,which offer low-cost and mature platforms.To address this technology gap,we report a hybrid Sibased photodetection scheme by incorporating CsPbBr_(3) perovskite nanocrystals(NCs)with a high photoluminescence quantum yield(PLQY)and a fast photoluminescence(PL)decay time as a UV-to-visible colourconverting layer for high-speed solar-blind UV communication.The facile formation of drop-cast CsPbBr_(3) perovskite NCs leads to a high PLQY of up to ~73% and strong absorption in the UV region.With the addition of the NC layer,a nearly threefold improvement in the responsivity and an increase of ~25% in the external quantum efficiency(EQE)of the solar-blind region compared to a commercial silicon-based photodetector were observed.Moreover,timeresolved photoluminescence measurements demonstrated a decay time of 4.5 ns under a 372-nm UV excitation source,thus elucidating the potential of this layer as a fast colour-converting layer.A high data rate of up to 34 Mbps in solar-blind communication was achieved using the hybrid CsPbBr_(3)-silicon photodetection scheme in conjunction with a 278-nm UVC light-emitting diode(LED).These findings demonstrate the feasibility of an integrated high-speed photoreceiver design of a composition-tuneable perovskite-based phosphor and a low-cost silicon-based photodetector for UV communication.
文摘Air pollution has environmental issue owing become a serious to its diverse harmful effects on the physical and biological environment. According to the Environmental Protection Agency （EPA） and the World Health Organization （WHO）, air pollution affects millions of people worldwide. Hundreds of thousands of deaths each year and a range of diseases, particularly among vulnerable groups （i.e., children, the elderly, and people with special medical conditions）, are attributed to air pollution. These effects are not always caused by single pollutant in the air; rather, they are considered consequences of the multi-pollutants to which people are simultaneously exposed.
文摘Carotid cavernous sinus fistulas are abnormal communications between the carotid system and the cavernous sinus. Several classification schemes have described carotid cavernous sinus fistulas according to etiology, hemodynamic features, or the angiographic arterial architecture. Increased pressure within the cavernous sinus appears to be the main factor in pathophysiology. The clinical features are related to size, exact location, and duration of the fistula, adequacy and route of venous drainage and the presence of arterial/venous collaterals. Noninvasive imaging (computed tomography, magnetic resonance, computed tomography angiography, magnetic resonance angiography, Doppler) is often used in the initial workup of a possible carotid cavernous sinus fistulas. Cerebral angiography is the gold standard for the definitive diagnosis, classification, and planning of treatment for these lesions. The endovascular approach has evolved as the mainstay therapy for definitive treatment in situations including clinical emergencies. Conservative treatment, surgery and radiosurgery constitute other management options for these lesions.
文摘AIM： To assess the practically usefulness and diagnostic yield of this new method in a group of patients with suspected small bowel lesions. METHODS： Capsule endoscopic （CE） examination by using M2A capsule endoscope TM （Given Imaging, Yoqneam, Israel） was performed in thirty nine patients （26 males, 13 females） with suspected small intestinal lesions. The composing of the patients was as follows： obscure gastrointestinal bleeding in twenty three patients, known Crohn＇s disease in 6 patients, in whom CE was used to evaluate the severity and extension of the diseases, chronic diarrhea in 8 patients, abdominal pain in one patient and malignancy in one patient with unknown origin. RESULTS： In two patients CE failed. Different abnormalities were revealed in 26 patients overall. Detection rate of abnormalities was highest among patients with obscure gastrointestinal bleeding and the source of bleeding was demonstrated in 17 of 23 patients with obscure bleeding （73.9%）. Entero-Behcet was diagnosed in two patients by CE as a source of obscure gastrointestinal bleeding. In 6 patients with known Crohn＇s disease, CE revealed better evaluation of the disease extension. In 3 of 8 （37.5%） patients with chronic diarrhea; CE revealed some mucosal abnormalities as the cause of chronic diarrhea. In a patient with unexplained abdominal pain and in a cancer patient with unknown origin, CE examination was normal. CONCLUSION： In our relatively small series, we found that capsule endoscopy is a useful diagnostic tool particularly in diagnosis of obscure gastrointestinal bleeding, chronic diarrhea and in estimating the extension of Crohn＇s disease.
文摘AIM： To share our experience of the management and outcomes of patients with pneumatosis cystoides in- testinalis （PCI）. METHODS： The charts of seven patients who under- went surgery for PCI between 2001 and 2009 were re- viewed retrospectively. Clinical features, diagnoses and surgical interventions of patients with PCI are discussed. RESULTS： Seven patients with PCI （3 males, 4 fe- males; mean age, 50 ~ 16.1 years; range, 29-74 years） were analyzed. In three of the patients, abdominal pain was the only complaint, whereas additional vomiting and/or constipation occurred in four. Leukocytosis was detected in four patients, whereas it was within normal limits in three. Subdiaphragmatic free air was observed radiologically in four patients but not in three. Six of the patients underwent an applied lapa- rotomy, whereas one underwent an applied explorative laparoscopy. PCI localized to the small intestine only was detected in four patients, whereas it was localized to the small intestine and the colon in three. Three patients underwent a partial small intestine resection and four did not after PCI was diagnosed. Five patients were diagnosed with secondary PCI and two with pri- mary PCI when the surgical findings and medical his- tory were assessed together. Gastric atony developed in one case only, as a complication during a postopera- tive follow-up of 5-14 d. CONCLUSION： Although rare, PCl should be consid- ered in the differential diagnosis of acute abdomen. Diagnostic laparoscopy and preoperative radiological tests, including computed tomography, play an impor- tant role in confirming the diagnosis.
基金the Ministry of Education, Malaysia for the MTCP scholarship awarded to the first author
文摘Coal extraction in Huainan area is basically characterized by one of typical multi-seam mining conditions observed in China, where coal is mined in soft seams characterized by high gas content, high stress, low permeability and difficult geological conditions. The average mining depth in Huainan area is 875 m and continues to increase by 15-25 m annually. The rise in mining depth increases the risk of coal and gas outbursts and makes it more difficult to control outburst risk in Huainan coalmines. This paper reviews the main achievements（e.g. theories, technologies and equipment） in outburst control in Huainan, and tries to analyze some key challenging issues, and to present associated strategies to address these issues.It suggests that the outburst control in Huainan must take a combination approach of both regional and localized control in which the former plays a dominant role. Other outburst prevention principles include（1） non-outburst seams protecting outburst seams,（2） less outburst-prone seams protecting strong outburst-prone seams,（3） stress-releasing mining, and（4） the combination of ground and underground gas drainage（the model is dubbed as ＂walking on two legs＂）. The paper concludes that we should conduct fundamental researches on outburst mechanism, and develop outburst control technologies and equipment to ensure safe and efficient coal mining of deep coal resources in Huainan area.
文摘Water quality of the river Nile and trace elements of the water, sediments and fish tissues were investigated in the current work. Eighteen different sampling points were selected along the whole course of the River Nile from its spring at Aswan to its estuaries at Rosetta and Damietta. Higher mean value of conductivity, alkalinity, chemical oxygen demand (COD), total organic carbon (TOC), ammonia (NH3), nitrate (NO3), total solid (TS), sulphate (SO4), chloride (Cl), orthophosphate were recorded in the water of Damietta and Rosetta branches comparing to other sites. Also trace metals in the water, sediments and tissues of Clarias gariepinus increased significantly (P Fe > Cu > Pb > Mn > Cr> Cd > Hg. In the gill tissues theses metals were accumulated in the following order Fe > Zn > Mn > Pb > Cr > Cu > Cd> Hg. The low accumulation of metals in muscle may be due to lack of binding affinity of these metals with the proteins of muscle. This is particularly important because muscles contribute the greatest mass of the flesh that is consumed as food.
文摘Percutaneous angioplasty and stenting for the treatment of extracranial vertebral artery(VA) stenosis seems a safe,effective and useful technique for resolving symptoms and improving blood flow to the posterior circulation,with a low complication rate and good long-term results.In patients with severe tortuosity of the vessel,stent placement is a real challenge.The new coronary balloon-expandable stents may be preferred.A large variability of restenosis rates has been reported.Drug-eluting stents may be the solution.After a comprehensive review of the literature,it can be concluded that percutaneous angioplasty and stenting of extracranial VA stenosis is technically feasible,but there is insufficient evidence from randomized trials to demonstrate that endovascular management is superior to best medical management.
文摘AIMTo evaluate the reversibility of minimal hepatic encephalopathy (MHE) following liver transplantation (LT) in Egyptian cirrhotic patients. METHODSThis prospective study included twenty patients with biopsy-proven liver cirrhosis listed for LT and twenty age- and sex-matched healthy control subjects. All underwent neuro-psychiatric examination, laboratory investigations, radiological studies and psychometric tests including trail making test A (TMT A), TMT B, digit symbol test and serial dotting test. The psychometric hepatic encephalopathy score (PHES) was calculated for patients to diagnose MHE. Psychometric tests were repeated six months following LT in the cirrhotic patient group. RESULTSBefore LT, psychometric tests showed highly significant deficits in cirrhotic patients in comparison to controls (P P P P = 0.005). More patients in whom reversal of MHE was observed had a pre-transplant MELD score CONCLUSIONReversal of MHE in cirrhotic patients could be achieved by LT, especially in those with a MELD score
文摘With the advances in technical skills, management of postoperative complications and improvements in immunosuppressive drugs, liver transplantation is the standard treatment for many patients with chronic liver disease. Today, shortage of donor organs seems to be the major limiting factor for the application of liver transplantation. This review focuses on five issues that are challenging to clinical practice of liver transplantation and relevant to gastroenterologists. These include living donor liver transplantation, recurrent viral hepatitis, non-heart-beating donors, hepatocellular carcinoma, and ABO incompatible liver transplantation. Living donor and non-heart beating donor transplantations were initiated as a solution to increase the donor organ pool and it is expected that there will be an increase in the number of these donors. Recurrent hepatitis C and hepatocellular carcinoma following liver transplantation are among major problems and ongoing research in these diseases may lead to better outcomes in these recipients.
文摘Dear editor, Following its entrance into the human body through inhalation, carbon monoxide （CO） forms carboxyhemoglobin （COHb） by binding to hemoglobin （Hb） within the blood. Massive ischemic tissue necrosis occurs in 0.5%-1% of cases with CO poisoning. The affinity of CO to Hb is 200-250 times more when compared to the affinity of oxygen. As a result of CO binding to Hb, oxygen delivery to the tissues is reduced, and tissue hypoxia develops. This affects mostly the brain and heart, which are the organs with the highest demand for oxygen.
