A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require on...A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require only three (new) function evaluation per iteration and per step integration. These methods have minimal local truncation error (LTE) and smaller phase-lag of sixth order than some sixth orders P-stable methods in [1-3,10-11]. The theoretical and numerical results show that these methods in this paper are more accurate and efficient than some methods proposed in [1-3,10].展开更多
The excitation function of the 58Ni(n,p)58Co reaction was measured using the well-established neutron activation technique andγ-ray spectroscopy.Neutrons in the energy range of 1.7 to 2.7 MeV were generated using the...The excitation function of the 58Ni(n,p)58Co reaction was measured using the well-established neutron activation technique andγ-ray spectroscopy.Neutrons in the energy range of 1.7 to 2.7 MeV were generated using the 7Li(p,n)reaction.The neutron flux was measured using the standard 115In(n,n’)115mIn monitor reaction.The results of the neutron spectrum averaged cross-section of 58Ni(n,p)58Co reactions were compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries such as ENDF/B-VIII.0,JEFF-3.3,JENDL-4.0,and CENDL-3.2.Theoretical calculations were performed using the nuclear reaction code TALYS.Various nuclear level density(NLD)models were tested,and their results were compared with the present findings.Realistic NLDs were also obtained through the spectral distribution method(SDM).The cross-section results,along with the absolute errors,were obtained by investigating the uncertainty propagation and using the covariance technique.Corrections forγ-ray true coincidence summing,low-energy background neutrons,andγ-ray self attenuation were performed.The experimental cross-section obtained in the present study is consistent with previously published experimental data,evaluated libraries,and theoretical calculations carried out using the TALYS code.展开更多
In this study,we measured the^(58)Ni(n,p)^(58)Co reaction cross section with neutron energies of 1.06,1.86,and 2.85 MeV.The cross section was measured using neutron activation techniques andγ-ray spectroscopy,and it ...In this study,we measured the^(58)Ni(n,p)^(58)Co reaction cross section with neutron energies of 1.06,1.86,and 2.85 MeV.The cross section was measured using neutron activation techniques andγ-ray spectroscopy,and it was compared with cross section data available in the EXFOR.Furthermore,we calculated the covariance matrix of the measured cross section for the aforementioned nuclear reaction.The uncertainties of the theoretical calculation for^(58)Ni(n,p)^(58)Co reaction cross section were calculated via Monte Carlo method.In this study,we used uncertainties in the optical model and level density parameters to calculate uncertainties in the theoretical cross sections.The theoretical calculations were performed by using TALYS-1.96.In this study,we aim to analyze the effect of uncertainties of the nuclear model input as well as different experimental variables used to obtain the values of reaction cross section.展开更多
Four different varieties of charnockitic rocks, with different modes of formation, from the Mesoproterozoic Natal belt are described and new C isotope data presented. Excellent coastal exposures in a number of quarrie...Four different varieties of charnockitic rocks, with different modes of formation, from the Mesoproterozoic Natal belt are described and new C isotope data presented. Excellent coastal exposures in a number of quarries and river sections make this part of the Natal belt a good location for observing charnockitic field relationships. Whereas there has been much debate on genesis of charnockites and the use of the term charnockite, it is generally recognized that the stabilization of orthopyroxene relative to biotite in granitoid rocks is a function of low aH2O （-- high CO2）, high temperature, and composition （especially Fe/（Fe ＋Mg））. From the Natal belt exposures, it is evident that syn-emplacement, magmatic crystallization of charnockite can arise from mantle-derived differentiated melts that are inherently hot and dry （as in the Oribi Gorge granites and Munster enderbite）, as well as from wet granitic melts that have been affected through interaction with dry country rock to produce localized charnockitic marginal facies in plutons （as in the Portobello Granite）. Two varieties of post-emplacement sub-solidus charnock- ites are also evident. These include charnockitic aureoles developed in leucocratic, biotite, garnet granite adjacent to cross-cutting enderbitic veins that are attributed to metamorphic-metasomatic processes （as in the Nicholson＇s Point granite, a part of the Margate Granite Suite）, as well as nebulous, patchy charnocki- tic veins in the Margate Granite that are attributed to anatectic metamorphic processes under low-aH2O fluid conditions during a metamorphic event. These varieties of charnockite show that the required physical conditions of their genesis can be achieved through a number of geological processes, providing some important implications for the classification of charnockites, and for the interpretation of charnock- ite genesis in areas where poor exposure obscures field relationships.展开更多
A study of the NW Kakamas Domain in South Africa/Namibia provides a new,unified lithostratigraphy and evolutionary history applicable to the whole Namaqua Sector.The Mesoproterozoic history ranges from~1350 Ma to 960 ...A study of the NW Kakamas Domain in South Africa/Namibia provides a new,unified lithostratigraphy and evolutionary history applicable to the whole Namaqua Sector.The Mesoproterozoic history ranges from~1350 Ma to 960 Ma,but isotopic evidence suggests it was built upon pre-existing Paleoproterozoic continental crust that extended west from the Archaean Craton.In eastern Namaqualand,early rift-related magmatism and sedimentation at~1350 Ma occurred in a confined ocean basin.Subsequent tectonic reversal and subduction at~1290–1240 Ma led to establishment of the Areachap,Konkiep and Kaaien Domains.In the Kakamas Domain,widespread deposition of pelitic sediments occurred at~1220 Ma(Narries Group).These contain detrital zircons derived from proximal crust with ages between~2020 Ma and 1800 Ma(western Palaeoproterozoic domains)and 1350–1240 Ma(eastern early Namaqua domains),suggesting pre-sedimentation juxtaposition.The pelites underwent granulite grade metamorphism at~1210 Ma(peak conditions:4.5–6 kbar and 770–850°C),associated with voluminous,predominantly S-type granitoid orthogneisses between~1210 Ma and 1190 Ma(Eendoorn and Ham River Suites)and low-angle ductile(D_(2))deformation which continued until~1110 Ma,interspersed with periods of sedimentation.This enduring P-T regime is inconsistent with the expected crustal over-thickening associated with the generally-accepted collision-accretion Namaqualand model.Rather,we propose the Namaqua Sector is a‘hot orogen’developed in a wide continental back-arc with subduction west of the present-day outcrop.The observed high geotherm resulted from thinned back-arc lithosphere accompanied by an influx of mantle-derived melts.Ductile D_(2)deformation resulted from"bottom-driven"tectonics and viscous drag within the crust by convective flow in the underlying asthenospheric mantle.This extended tectonothermal regime ceased at~1110 Ma when SW-directed thrusting stacked the Namaqua Domains into their current positions,constrained in the Kakamas Domain by late-to post-展开更多
The rapid development of high-throughput sequencing techniques has led biology into the big-data era.Data analyses using various bioinformatics tools rely on programming and command-line environments,which are challen...The rapid development of high-throughput sequencing techniques has led biology into the big-data era.Data analyses using various bioinformatics tools rely on programming and command-line environments,which are challenging and time-consuming for most wet-lab biologists.Here,we present TBtools(a Toolkit for Biologists integrating various biological data-handling tools),a stand-alone software with a userfriendly interface.The toolkit incorporates over 130 functions,which are designed to meet the increasing demand for big-data analyses,ranging from bulk sequence processing to interactive data visualization.A wide variety of graphs can be prepared in TBtools using a new plotting engine("JIGplot")developed to maximize their interactive ability;this engine allows quick point-and-click modification of almost every graphic feature.TBtools is platform-independent software that can be run under all operating systems with Java Runtime Environment 1.6 or newer.It is freely available to non-commercial users at https://github.com/CJ-Chen/TBtools/releases.展开更多
Kolbroek pigs have numerous advantages as an indigenous breed including its contributions to food security. However, there are numerous concerns over the current feed regime that compromises its growth performance and...Kolbroek pigs have numerous advantages as an indigenous breed including its contributions to food security. However, there are numerous concerns over the current feed regime that compromises its growth performance and carcass quality. Therefore, this study was conducted to evaluate the growth performance traits, attainment of puberty, backfat thickness (BFT), and carcass traits when boar fed diets supplemented with 10% (standard diet), 13% and 16% crude protein. Fifteen pigs per protein diets were individually housed and fed <em>ad-libitum</em> for eight weeks in a complete randomised design. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were measured on a weekly basis. At the end of the trial, all boars were slaughtered and carcass quality parameters measured. Pearson’s correlation coefficients were calculated between growth performance parameters. Our data revealed that there was an increase in final body weight, ADG, ADFI accompanied by decreases in BFT and the age of attainment of puberty. There was also a positive correlation between ADFI and ADG (r = 0.78) accompanied by a low positive correlation between ADG and BFT (r = 0.12) with a high negative correlation between FCR and ADG (r = -0.94). The water holding capacity (WHC), dressing percentage and marbling mass appeared to decrease while the eye muscle area increased with protein supplementation of the diet. There were also increases in the lungs, liver, small plus large intestines and stomach with no changes in the pancreas and heart tissues. Accompanying these was observations that the meat colour lightness improved accompanied by a decline in meat redness and yellowness. In conclusion, supplementation of boar diet with increasing crude protein improved the carcass quality and growth performance of Kolbroek boars.展开更多
比利时新基尔里斯(Senzeilles)地区是西欧晚泥盆世地层研究的一个经典地区,也是法门期石燕贝类腕足动物的重要比产区。然而针对本区弓石燕类的现代研究却较为匮乏,此外,早期的分类工作已难以满足现代专题性的课题资料要求(即层位清楚、...比利时新基尔里斯(Senzeilles)地区是西欧晚泥盆世地层研究的一个经典地区,也是法门期石燕贝类腕足动物的重要比产区。然而针对本区弓石燕类的现代研究却较为匮乏,此外,早期的分类工作已难以满足现代专题性的课题资料要求(即层位清楚、鉴定准确的系统分类工作),因此对比利时地区法门期的“弓石燕属”足动物进行系统古生物学研究及对比具有重要意义。当前研究在华南现有成果的基础上,通过对壳面特征(贝体大小、基面特征、微细纹饰特征、中槽壳褶发生方式)及内部构造(齿板特征、内窗板特征等)的系统研究及对比,拓展了Plicapustula属的定义,即:褶上和褶间均发育微瘤纹饰。欧洲的Plicapustula属分子褶间均发育放射状细瘤微细纹饰,而华南的该属分子褶间均缺失微瘤纹饰。由于该特征存在明显的地域性,因此当前研究以此为依据建立了Paraplicapustula亚属,并将欧洲的标本归入该亚属。此外,本文还首次识别并描述了欧洲的Sinospirifer属。大部分西欧Sinospirifer属和Plicapustula属与华南地区相比,在种级组成上存在明显的差异,包括标本大小、齿板是否增厚、壳褶数目及分枝情况、微细纹饰类型等。本文共描述了上述2属的5种,包括1新亚属、3新种[Plicapustula(Paraplicapustula) eleganta subgen. et sp. nov. Ma and Wang, Plicapustula(Paraplicapustula) magna subgen. et sp.nov. Ma and Wang, Sinospirifer transversus sp. nov. Ma and Wang, Plicapustula(Paraplicapustula) sp.及Sinospirifer subextensus(Martelli, 1902)]。展开更多
Glioblastoma multiforme is the most common and lethal brain tumour-type.The current standard of care includes Temozolomide(TMZ)chemotherapy.However,inherent and acquired resistance to TMZ thwart successful treatment.T...Glioblastoma multiforme is the most common and lethal brain tumour-type.The current standard of care includes Temozolomide(TMZ)chemotherapy.However,inherent and acquired resistance to TMZ thwart successful treatment.The direct repair protein methylguanine DNA methyltransferase(MGMT)removes the cytotoxic O6-methylguanine(O6-MeG)lesion delivered by TMZ and so its expression by tumours confers TMZ-resistance.DNA mismatch repair(MMR)is essential to process O6-MeG adducts and MMR-deficiency leads to tolerance of lesions,resistance to TMZ and further DNA mutations.In this article,two strategies to overcome TMZ resistance are discussed:(1)synthesis of imidazotetrazine analogues-designed to retain activity in the presence of MGMT or loss of MMR;(2)preparation of imidazotetrazine-nanoparticles to deliver TMZ preferably to the brain and tumour site.Our promising results encourage belief in a future where better prognoses exist for patients diagnosed with this devastating disease.展开更多
The brain is protected from toxins by a tightly regulated network of specialized cells,including endothelial cells,pericytes,astrocyes,and neurons,known collectively as the blood-brain barrier(BBB).This selectively pe...The brain is protected from toxins by a tightly regulated network of specialized cells,including endothelial cells,pericytes,astrocyes,and neurons,known collectively as the blood-brain barrier(BBB).This selectively permeable barrier permits only the most crucial molecules essential for brain function to enter and employs a number of different mechanisms to prevent the entry of potentially harmful toxins and pathogens.In addition to a physical barrier comprised of endothelial cells that form tight junctions to restrict paracellular transport,there is an active protective mechanism made up of energy-dependent transporters that efflux compounds back into the bloodstream.Two of these ATP-binding cassette(ABC)transporters are highly expressed at the BBB:P-glycoprotein(P-gp,encoded by the ABCB1 gene)and ABCG2(encoded by the ABCG2 gene).Although a number of in vitro and in vivo systems have been developed to examine the role that ABC transporters play in keeping compounds out of the brain,all have inherent advantages and disadvantages.Zebrafish(Danio rerio)have become a model of interest for studies of the BBB due to the similarities between the zebrafish and mammalian BBB systems.In this review,we discuss what is known about ABC transporters in zebrafish and what information is still needed before the zebrafish can be recommended as a model to elucidate the role of ABC transporters at the BBB.展开更多
A machine learning model was created to predict the electron spectrum generated by a GeV-class laser wakefield accelerator.The model was constructed from variational convolutional neural networks,which mapped the resu...A machine learning model was created to predict the electron spectrum generated by a GeV-class laser wakefield accelerator.The model was constructed from variational convolutional neural networks,which mapped the results of secondary laser and plasma diagnostics to the generated electron spectrum.An ensemble of trained networks was used to predict the electron spectrum and to provide an estimation of the uncertainty of that prediction.It is anticipated that this approach will be useful for inferring the electron spectrum prior to undergoing any process that can alter or destroy the beam.In addition,the model provides insight into the scaling of electron beam properties due to stochastic fluctuations in the laser energy and plasma electron density.展开更多
The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter space.This limits the utility of sequential 1D scanning of experimental parameters for ...The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter space.This limits the utility of sequential 1D scanning of experimental parameters for the optimization of secondary radiation,although to-date this has been the accepted methodology due to low data acquisition rates.High repetition-rate(HRR)lasers augmented by machine learning present a valuable opportunity for efficient source optimization.Here,an automated,HRR-compatible system produced high-fidelity parameter scans,revealing the influence of laser intensity on target pre-heating and proton generation.A closed-loop Bayesian optimization of maximum proton energy,through control of the laser wavefront and target position,produced proton beams with equivalent maximum energy to manually optimized laser pulses but using only 60%of the laser energy.This demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.展开更多
基金State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation (PLN0115).
文摘A family of symmetric (hybrid) two step sixth P-stable methods for the accurate numerical integration of second order periodic initial value problems have been considered in this paper. These methods, which require only three (new) function evaluation per iteration and per step integration. These methods have minimal local truncation error (LTE) and smaller phase-lag of sixth order than some sixth orders P-stable methods in [1-3,10-11]. The theoretical and numerical results show that these methods in this paper are more accurate and efficient than some methods proposed in [1-3,10].
基金One of the authors(A.H.)sincerely acknowledges the Department of Science and Technology(DST),Government of Indiafor the INSPIRE Fellowship award(No.DST/INSPIRE Fellowship/2019/IF190924)+1 种基金partial support from the SERBwith grants No.SIR/2022/000566 and CRG/2021/000101,respectively。
文摘The excitation function of the 58Ni(n,p)58Co reaction was measured using the well-established neutron activation technique andγ-ray spectroscopy.Neutrons in the energy range of 1.7 to 2.7 MeV were generated using the 7Li(p,n)reaction.The neutron flux was measured using the standard 115In(n,n’)115mIn monitor reaction.The results of the neutron spectrum averaged cross-section of 58Ni(n,p)58Co reactions were compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries such as ENDF/B-VIII.0,JEFF-3.3,JENDL-4.0,and CENDL-3.2.Theoretical calculations were performed using the nuclear reaction code TALYS.Various nuclear level density(NLD)models were tested,and their results were compared with the present findings.Realistic NLDs were also obtained through the spectral distribution method(SDM).The cross-section results,along with the absolute errors,were obtained by investigating the uncertainty propagation and using the covariance technique.Corrections forγ-ray true coincidence summing,low-energy background neutrons,andγ-ray self attenuation were performed.The experimental cross-section obtained in the present study is consistent with previously published experimental data,evaluated libraries,and theoretical calculations carried out using the TALYS code.
基金Project supported by the Scientific and Industrial Research(CSIR)Government of India(File No 09/013(882)/2019-EMR-1)for providing senior research fellowships+1 种基金the IUAC-UGC,Government of India(Sanction No.IUAC/XIII.7/UFR-71353)Institutions of Eminence(Io E)BHU(Grant No.6031)。
文摘In this study,we measured the^(58)Ni(n,p)^(58)Co reaction cross section with neutron energies of 1.06,1.86,and 2.85 MeV.The cross section was measured using neutron activation techniques andγ-ray spectroscopy,and it was compared with cross section data available in the EXFOR.Furthermore,we calculated the covariance matrix of the measured cross section for the aforementioned nuclear reaction.The uncertainties of the theoretical calculation for^(58)Ni(n,p)^(58)Co reaction cross section were calculated via Monte Carlo method.In this study,we used uncertainties in the optical model and level density parameters to calculate uncertainties in the theoretical cross sections.The theoretical calculations were performed by using TALYS-1.96.In this study,we aim to analyze the effect of uncertainties of the nuclear model input as well as different experimental variables used to obtain the values of reaction cross section.
文摘Four different varieties of charnockitic rocks, with different modes of formation, from the Mesoproterozoic Natal belt are described and new C isotope data presented. Excellent coastal exposures in a number of quarries and river sections make this part of the Natal belt a good location for observing charnockitic field relationships. Whereas there has been much debate on genesis of charnockites and the use of the term charnockite, it is generally recognized that the stabilization of orthopyroxene relative to biotite in granitoid rocks is a function of low aH2O （-- high CO2）, high temperature, and composition （especially Fe/（Fe ＋Mg））. From the Natal belt exposures, it is evident that syn-emplacement, magmatic crystallization of charnockite can arise from mantle-derived differentiated melts that are inherently hot and dry （as in the Oribi Gorge granites and Munster enderbite）, as well as from wet granitic melts that have been affected through interaction with dry country rock to produce localized charnockitic marginal facies in plutons （as in the Portobello Granite）. Two varieties of post-emplacement sub-solidus charnock- ites are also evident. These include charnockitic aureoles developed in leucocratic, biotite, garnet granite adjacent to cross-cutting enderbitic veins that are attributed to metamorphic-metasomatic processes （as in the Nicholson＇s Point granite, a part of the Margate Granite Suite）, as well as nebulous, patchy charnocki- tic veins in the Margate Granite that are attributed to anatectic metamorphic processes under low-aH2O fluid conditions during a metamorphic event. These varieties of charnockite show that the required physical conditions of their genesis can be achieved through a number of geological processes, providing some important implications for the classification of charnockites, and for the interpretation of charnock- ite genesis in areas where poor exposure obscures field relationships.
基金the Ministry of Mines and Energy of Namibia for providing the financial support。
文摘A study of the NW Kakamas Domain in South Africa/Namibia provides a new,unified lithostratigraphy and evolutionary history applicable to the whole Namaqua Sector.The Mesoproterozoic history ranges from~1350 Ma to 960 Ma,but isotopic evidence suggests it was built upon pre-existing Paleoproterozoic continental crust that extended west from the Archaean Craton.In eastern Namaqualand,early rift-related magmatism and sedimentation at~1350 Ma occurred in a confined ocean basin.Subsequent tectonic reversal and subduction at~1290–1240 Ma led to establishment of the Areachap,Konkiep and Kaaien Domains.In the Kakamas Domain,widespread deposition of pelitic sediments occurred at~1220 Ma(Narries Group).These contain detrital zircons derived from proximal crust with ages between~2020 Ma and 1800 Ma(western Palaeoproterozoic domains)and 1350–1240 Ma(eastern early Namaqua domains),suggesting pre-sedimentation juxtaposition.The pelites underwent granulite grade metamorphism at~1210 Ma(peak conditions:4.5–6 kbar and 770–850°C),associated with voluminous,predominantly S-type granitoid orthogneisses between~1210 Ma and 1190 Ma(Eendoorn and Ham River Suites)and low-angle ductile(D_(2))deformation which continued until~1110 Ma,interspersed with periods of sedimentation.This enduring P-T regime is inconsistent with the expected crustal over-thickening associated with the generally-accepted collision-accretion Namaqualand model.Rather,we propose the Namaqua Sector is a‘hot orogen’developed in a wide continental back-arc with subduction west of the present-day outcrop.The observed high geotherm resulted from thinned back-arc lithosphere accompanied by an influx of mantle-derived melts.Ductile D_(2)deformation resulted from"bottom-driven"tectonics and viscous drag within the crust by convective flow in the underlying asthenospheric mantle.This extended tectonothermal regime ceased at~1110 Ma when SW-directed thrusting stacked the Namaqua Domains into their current positions,constrained in the Kakamas Domain by late-to post-
基金This work was funded by the National Key Research and Developmental Program of China(2018YFD1000104)This work is also supported by awards to R.X.,Y.H.,and H.C.from the National Key Research and Developmental Program of China(2017YFD0101702,2018YFD1000500,2019YFD1000500)+4 种基金the National Science Foundation of China(#31872063)the Special Support Program of Guangdong Province(2019TX05N193)the Key-Area Research and Development Program of Guangdong Province(2018B020202011)the Guangzhou Science and Technology Key Project(201804020063)Support to M.H.F.comes from the NSF Faculty Early Career Development Program(IOS-1942437).
文摘The rapid development of high-throughput sequencing techniques has led biology into the big-data era.Data analyses using various bioinformatics tools rely on programming and command-line environments,which are challenging and time-consuming for most wet-lab biologists.Here,we present TBtools(a Toolkit for Biologists integrating various biological data-handling tools),a stand-alone software with a userfriendly interface.The toolkit incorporates over 130 functions,which are designed to meet the increasing demand for big-data analyses,ranging from bulk sequence processing to interactive data visualization.A wide variety of graphs can be prepared in TBtools using a new plotting engine("JIGplot")developed to maximize their interactive ability;this engine allows quick point-and-click modification of almost every graphic feature.TBtools is platform-independent software that can be run under all operating systems with Java Runtime Environment 1.6 or newer.It is freely available to non-commercial users at https://github.com/CJ-Chen/TBtools/releases.
文摘Kolbroek pigs have numerous advantages as an indigenous breed including its contributions to food security. However, there are numerous concerns over the current feed regime that compromises its growth performance and carcass quality. Therefore, this study was conducted to evaluate the growth performance traits, attainment of puberty, backfat thickness (BFT), and carcass traits when boar fed diets supplemented with 10% (standard diet), 13% and 16% crude protein. Fifteen pigs per protein diets were individually housed and fed <em>ad-libitum</em> for eight weeks in a complete randomised design. Average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR) were measured on a weekly basis. At the end of the trial, all boars were slaughtered and carcass quality parameters measured. Pearson’s correlation coefficients were calculated between growth performance parameters. Our data revealed that there was an increase in final body weight, ADG, ADFI accompanied by decreases in BFT and the age of attainment of puberty. There was also a positive correlation between ADFI and ADG (r = 0.78) accompanied by a low positive correlation between ADG and BFT (r = 0.12) with a high negative correlation between FCR and ADG (r = -0.94). The water holding capacity (WHC), dressing percentage and marbling mass appeared to decrease while the eye muscle area increased with protein supplementation of the diet. There were also increases in the lungs, liver, small plus large intestines and stomach with no changes in the pancreas and heart tissues. Accompanying these was observations that the meat colour lightness improved accompanied by a decline in meat redness and yellowness. In conclusion, supplementation of boar diet with increasing crude protein improved the carcass quality and growth performance of Kolbroek boars.
文摘比利时新基尔里斯(Senzeilles)地区是西欧晚泥盆世地层研究的一个经典地区,也是法门期石燕贝类腕足动物的重要比产区。然而针对本区弓石燕类的现代研究却较为匮乏,此外,早期的分类工作已难以满足现代专题性的课题资料要求(即层位清楚、鉴定准确的系统分类工作),因此对比利时地区法门期的“弓石燕属”足动物进行系统古生物学研究及对比具有重要意义。当前研究在华南现有成果的基础上,通过对壳面特征(贝体大小、基面特征、微细纹饰特征、中槽壳褶发生方式)及内部构造(齿板特征、内窗板特征等)的系统研究及对比,拓展了Plicapustula属的定义,即:褶上和褶间均发育微瘤纹饰。欧洲的Plicapustula属分子褶间均发育放射状细瘤微细纹饰,而华南的该属分子褶间均缺失微瘤纹饰。由于该特征存在明显的地域性,因此当前研究以此为依据建立了Paraplicapustula亚属,并将欧洲的标本归入该亚属。此外,本文还首次识别并描述了欧洲的Sinospirifer属。大部分西欧Sinospirifer属和Plicapustula属与华南地区相比,在种级组成上存在明显的差异,包括标本大小、齿板是否增厚、壳褶数目及分枝情况、微细纹饰类型等。本文共描述了上述2属的5种,包括1新亚属、3新种[Plicapustula(Paraplicapustula) eleganta subgen. et sp. nov. Ma and Wang, Plicapustula(Paraplicapustula) magna subgen. et sp.nov. Ma and Wang, Sinospirifer transversus sp. nov. Ma and Wang, Plicapustula(Paraplicapustula) sp.及Sinospirifer subextensus(Martelli, 1902)]。
基金This studentship is supported by the Engineering and Physical Sciences Research Council(EP/L01646X).
文摘Glioblastoma multiforme is the most common and lethal brain tumour-type.The current standard of care includes Temozolomide(TMZ)chemotherapy.However,inherent and acquired resistance to TMZ thwart successful treatment.The direct repair protein methylguanine DNA methyltransferase(MGMT)removes the cytotoxic O6-methylguanine(O6-MeG)lesion delivered by TMZ and so its expression by tumours confers TMZ-resistance.DNA mismatch repair(MMR)is essential to process O6-MeG adducts and MMR-deficiency leads to tolerance of lesions,resistance to TMZ and further DNA mutations.In this article,two strategies to overcome TMZ resistance are discussed:(1)synthesis of imidazotetrazine analogues-designed to retain activity in the presence of MGMT or loss of MMR;(2)preparation of imidazotetrazine-nanoparticles to deliver TMZ preferably to the brain and tumour site.Our promising results encourage belief in a future where better prognoses exist for patients diagnosed with this devastating disease.
文摘The brain is protected from toxins by a tightly regulated network of specialized cells,including endothelial cells,pericytes,astrocyes,and neurons,known collectively as the blood-brain barrier(BBB).This selectively permeable barrier permits only the most crucial molecules essential for brain function to enter and employs a number of different mechanisms to prevent the entry of potentially harmful toxins and pathogens.In addition to a physical barrier comprised of endothelial cells that form tight junctions to restrict paracellular transport,there is an active protective mechanism made up of energy-dependent transporters that efflux compounds back into the bloodstream.Two of these ATP-binding cassette(ABC)transporters are highly expressed at the BBB:P-glycoprotein(P-gp,encoded by the ABCB1 gene)and ABCG2(encoded by the ABCG2 gene).Although a number of in vitro and in vivo systems have been developed to examine the role that ABC transporters play in keeping compounds out of the brain,all have inherent advantages and disadvantages.Zebrafish(Danio rerio)have become a model of interest for studies of the BBB due to the similarities between the zebrafish and mammalian BBB systems.In this review,we discuss what is known about ABC transporters in zebrafish and what information is still needed before the zebrafish can be recommended as a model to elucidate the role of ABC transporters at the BBB.
基金supported by UK STFC ST/V001639/1,UK EPSRC EP/V049577/1 and EP/V044397/1Horizon 2020 funding under European Research Council(ERC)Grant Agreement No.682399+1 种基金support from the Royal Society URF-R1221874support from US DOE grant DESC0016804
文摘A machine learning model was created to predict the electron spectrum generated by a GeV-class laser wakefield accelerator.The model was constructed from variational convolutional neural networks,which mapped the results of secondary laser and plasma diagnostics to the generated electron spectrum.An ensemble of trained networks was used to predict the electron spectrum and to provide an estimation of the uncertainty of that prediction.It is anticipated that this approach will be useful for inferring the electron spectrum prior to undergoing any process that can alter or destroy the beam.In addition,the model provides insight into the scaling of electron beam properties due to stochastic fluctuations in the laser energy and plasma electron density.
基金support from the UK STFC grants ST/V001639/1 with the XFEL Physical Sciences Hub and ST/P002021/1the UK EPSRC grants EP/V049577/1 and EP/R006202/1+5 种基金as well as the U.S.DOE Office of Science,Fusion Energy Sciences under FWP No.100182in part by the National Science Foundation under Grant No.1632708 and Award No.PHY–1903414M.J.V.S.acknowledges support from the Royal Society URFR1221874support from the DOE NNSA SSGF program under DE-NA0003960support from the U.S.DOE grant DESC0016804support from the project‘Advanced research using high-intensity laser-produced photons and particles’(CZ.02.1.01/0.0/0.0/16_019/0000789)from the European Regional Development Fund(ADONIS)。
文摘The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter space.This limits the utility of sequential 1D scanning of experimental parameters for the optimization of secondary radiation,although to-date this has been the accepted methodology due to low data acquisition rates.High repetition-rate(HRR)lasers augmented by machine learning present a valuable opportunity for efficient source optimization.Here,an automated,HRR-compatible system produced high-fidelity parameter scans,revealing the influence of laser intensity on target pre-heating and proton generation.A closed-loop Bayesian optimization of maximum proton energy,through control of the laser wavefront and target position,produced proton beams with equivalent maximum energy to manually optimized laser pulses but using only 60%of the laser energy.This demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.
