Three-dimensional(3D)bioprinting,specifically direct ink writing(DIW)capable of printing biologically active substances such as growth factors or drugs under low-temperature conditions,is an emerging di-rection in bon...Three-dimensional(3D)bioprinting,specifically direct ink writing(DIW)capable of printing biologically active substances such as growth factors or drugs under low-temperature conditions,is an emerging di-rection in bone tissue engineering.However,limited by the bio-ink mobility and the poor resolution of this printing technology,the lateral pores of current crisscross-stacked scaffolds printed through DIW tend to clog and are inimical to bone growth.Therefore,it is critical to develop DIW printed biologi-cal scaffold structure with high mechanical strength,porosity,and biocompatibility performance.Herein,patterned polylactic acid(PLA)/polycaprolactone(PCL)/nano-hydroxyapatite(n-HA)based scaffold was printed through DIW technological and rolled-up for properties characterization,cytocompatibility test,and bone repair experiment.The result not only shows that the hexagonal patterned scaffolds are me-chanically strong with porosity,but also demonstrated that the hierarchical pore structure formed during rolled-up has the potential to address the clogging problem and stimulates bone growth and repair.展开更多
准确的降水预报对山区小流域防洪减灾具有重要意义。选取浙南山区好溪流域典型降水场次,基于WRF(weather research and forecasting)模式,开展云微物理过程参数化方案和积云对流参数化方案敏感性分析,优选适用于好溪流域的物理过程参数...准确的降水预报对山区小流域防洪减灾具有重要意义。选取浙南山区好溪流域典型降水场次,基于WRF(weather research and forecasting)模式,开展云微物理过程参数化方案和积云对流参数化方案敏感性分析,优选适用于好溪流域的物理过程参数化组合方案,提高好溪流域降水预报精度。研究结果表明:云微物理过程和积云对流参数化过程的方案选择及组合对降水预报影响显著,然而没有某一种组合方案的模拟效果对于所有场次的降水都是最佳的;综合考虑所有的典型降水场次,当云微物理参数化方案选择Lin(Purdue Lin)方案、积云对流过程参数化方案选择KF(Kain-Fritsch)方案时,降水预报精度最高。展开更多
There are a great variety of commercial nickel alloys mainly because nickel is able to dissolve a large amount of alloying elements while maintaining a single ductile austenitic phase. Nickel alloys are generally desi...There are a great variety of commercial nickel alloys mainly because nickel is able to dissolve a large amount of alloying elements while maintaining a single ductile austenitic phase. Nickel alloys are generally designed for and used in highly aggressive environments, for example, those where stainless steels may experience pitting corrosion or environmentally assisted cracking. While nickel alloys are generally resistant to pitting corrosion in chloride-containing environments, they may be prone to crevice corrosion attack. Addition of chromium, molybdenum and tungsten increases the localized corrosion resistance of nickel alloys. This review on the resistance to localized corrosion of nickel alloys includes specific environments such as those present in oil and gas upstream operations, in the chemical process industry and in seawater service.展开更多
In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and en...In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad (Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.展开更多
When partially reproductively isolated species come back into secondary contact, these taxa may diverge in mating preferences and sexual cues to avoid maladaptive hybridization, a process known as reinforcement. This ...When partially reproductively isolated species come back into secondary contact, these taxa may diverge in mating preferences and sexual cues to avoid maladaptive hybridization, a process known as reinforcement. This phenomenon often leads to reproductive character displacement （RCD） between sympatric and allopatric populations of reinforcing species that differ in their exposure to hybridization. Recent discussions have reinvigorated the idea that RCD may give rise to additional speciation between conspecific sympatric and allopatric populations, dubbing the concept ＂cascade reinforcement.＂ Despite some empirical studies supporting cascade reinforcement, we still know very little about the conditions for its evolution. In the present article, we address this question by developing an individual-based population genetic model that explicitly simulates cascade reinforcement when one of the hybridizing species is split into sympatric and allopatric populations. Our results show that when sympatric and allopatric populations reside in the same environment and only differ in their exposure to maladaptive hybridization, migration between them generally inhibits the evolution of cascade by spreading the reinforcement alleles from sympatry into allopatry and erasing RCD. Under these conditions, cascade reinforcement only evolved when migration rate between sympatric and allopatric populations was very low. This indicates that stabilizing sexual selection in allopatry is generally ineffective in preventing the spread of reinforcement alleles. Only when sympatric and allopatric populations experienced divergent ecological selection did cascade reinforcement evolve in the presence of substantial migration. These predictions clarify the conditions for cascade reinforcement and facilitate our understanding of existing cases in nature.展开更多
Colorful visual signals are important systems for investigating the effects of signaling environ ments and receiver physiology on signal evolution as predicted by the sensory drive hypothesis. Support for the sensory ...Colorful visual signals are important systems for investigating the effects of signaling environ ments and receiver physiology on signal evolution as predicted by the sensory drive hypothesis. Support for the sensory drive hypothesis on color signal evolution is mostly based on document ing correlations between the properties of signals and habitat conditions under which the signals are given （i.e., a correlational approach） and less commonly on the use of mathematical models that integrate representations of visual environments, signal properties, and sensory systems （i.e., a functional approach）. Here, we used an experimental approach in the field to evaluate signal efficacy of colorful lizard throat fans called dewlaps that show geographic variation in the lizard Anolis cristatellus. We used a remote controlled apparatus to display ＂fake dewlaps＂ to wild lizards to test for adaptive divergence in dewlap brightness （i.e., perceived intensity） among populations in situ. We found evidence of local adaptation in dewlap brightness consistent with the sensory drive hypothesis. Specifically, dewlaps that had the brightness characteristics of local lizards were more likely to be detected than those with the brightness characteristics of nonlocal lizards. Our findings indicate that simplified mathematical representations of visual environments may allow robust estimates of relative detectability or conspicuousness in natural habitats. We have shown the feasibility of evaluating color signal efficacy experimentally under natural conditions and dem onstrate the potential advantages of presenting isolated components of signals to an intended re ceiver to measure their contribution to signal function.展开更多
Anthropogenic pollutants have the potential to disrupt reproductive strategies. Little is known about how lead （Pb2＋） exposure disrupts individual-level responses in reproductive behaviors, which are important for ...Anthropogenic pollutants have the potential to disrupt reproductive strategies. Little is known about how lead （Pb2＋） exposure disrupts individual-level responses in reproductive behaviors, which are important for fitness. Drosophila melanogaster was used as a model system to deter- mine the effects of： 1） developmental lead exposure on pre-mating reproductive behaviors （i.e., mate preference）, and 2） lead exposure and mating preferences on fitness in the F0 parental generation and F1 un-exposed offspring. Wild-type strains of D. melanogaster were reared from egg stage to adulthood in control or leaded medium （250 μM PbAc） and tested for differences in： mate preference, male song performance, sex pheromone expression, fecundity, mortality, and body weight. F0 leaded females preferentially mated with leaded males （i.e., asymmetrical positive assortative mating） in 2-choice tests. This positive assortative mating was mediated by the females （and not the males） and was dependent upon context and developmental exposure to Pb. Neither the courtship song nor the sex pheromone profile expressed by control and leaded males medi- ated the positive assortative mating in leaded females. Leaded females did not incur a fitness cost in terms of reduced fecundity, increased mortality, or decreased body weight by mating with leaded males. These results suggest that sublethal exposure to lead during development can alter mate preferences in adults, but not fitness measures once lead exposure has been removed. We suggest that changes in mate preference may induce fitness costs, as well as long-term population and multi-generational implications, if pollution is persistent in the environment.展开更多
Gastroesophageal reflux disease (GERD) is one of the most commonlyencountered digestive diseases in the world, with the prevalence continuing toincrease. Many patients are successfully treated with lifestyle modificat...Gastroesophageal reflux disease (GERD) is one of the most commonlyencountered digestive diseases in the world, with the prevalence continuing toincrease. Many patients are successfully treated with lifestyle modifications andproton pump inhibitor therapy, but a subset of patients require more aggressiveintervention for control of their symptoms. Surgical treatment with fundoplicationis a viable option for patients with GERD, as it attempts to improve the integrityof the lower esophageal sphincter (LES). While surgery can be as effective asmedical treatment, it can also be associated with side effects such as dysphagia,bloating, and abdominal pain. Therefore, a thorough pre-operative assessment iscrucial to select appropriate surgical candidates. Newer technologies arebecoming increasingly available to help clinicians identify patients with true LESdysfunction, such as pH-impedance studies and high-resolution manometry(HRM). Pre-operative evaluation should be aimed at confirming the diagnosis ofGERD, ruling out any major motility disorders, and selecting appropriate surgicalcandidates. HRM and pH testing are key tests to consider for patients with GERDlike symptoms, and the addition of provocative measures such as straight legraises and multiple rapid swallows to HRM protocol can assess the presence ofunderlying hiatal hernias and to test a patient’s peristaltic reserve prior tosurgery.展开更多
Immune checkpoint inhibitors(ICIs)are a new class of cancer pharmacotherapy consisting of antibodies that block inhibitory immune regulators such as cytotoxic T lymphocyte antigen 4,programmed cell death 1 and program...Immune checkpoint inhibitors(ICIs)are a new class of cancer pharmacotherapy consisting of antibodies that block inhibitory immune regulators such as cytotoxic T lymphocyte antigen 4,programmed cell death 1 and programmed death-ligand 1.Checkpoint blockade by ICIs reactivates a tumor-specific T cell response.Immune-related adverse events can occur in various organs including skin,liver,and gastrointestinal tract.Mild to severe colitis is the most common side effect with some experiencing rapid progression to more serious complications including bowel perforation and even death.Prompt diagnosis and management of ICI-induced colitis is crucial for optimal outcome.Unfortunately,its clinical,endoscopic and histopathologic presentations are non-specific and overlap with those of colitis caused by other etiologies,such as infection,medication,graftversus-host disease and inflammatory bowel disease.Thus,a definitive diagnosis can only be rendered after these other possible etiologies are excluded.Sometimes an extensive clinical,laboratory and radiologic workup is required,making it challenging to arrive at a prompt diagnosis.Most patients experience full resolution of symptoms with corticosteroids and/or infliximab.For ICI-induced colitis that is treatment-refractory,small scale studies offer alternative strategies,such as vedolizumab and fecal microbiota transplantation.In this review,we focus on the clinical features,differential diagnosis,and management of ICIinduced colitis with special attention to emerging treatment options for treatmentrefractory ICI-induced colitis.展开更多
We complete and extend the asymptotic analysis of the spectrum of Jacobi Tau approximations that were first considered by Dubiner. The asymptotic formulas for Jacobi polynomials PN(α ,β ) ,α ,β > -1 are derived...We complete and extend the asymptotic analysis of the spectrum of Jacobi Tau approximations that were first considered by Dubiner. The asymptotic formulas for Jacobi polynomials PN(α ,β ) ,α ,β > -1 are derived and confirmed by numerical approximations. More accurate results for the slowest decaying mode are obtained. We explain where the large negative eigenvalues come from. Furthermore, we show that a large negative eigenvalue of order N2 appears for -1 1 . The eigenvalues for Legendre polynomials are directly related to the roots of the spherical Bessel and Hankel functions that are involved in solving Helmholtz equation inspherical coordinates.展开更多
Based on the thesis that baryons including protons and neutrons are Yang-Mills magnetic monopoles which the author has previously developed and which has been confirmed by over half a dozen empirically-accurate predic...Based on the thesis that baryons including protons and neutrons are Yang-Mills magnetic monopoles which the author has previously developed and which has been confirmed by over half a dozen empirically-accurate predictions, we develop a GUT that is rooted in the SU(4) subgroups for the proton/electron and neutron/neutrino which were used as the basis for these predictions. The SU(8) GUT group so-developed leads following three stages of symmetry breaking to all known phenomenology including a neutrino that behaves differently from other fermions, lepto-quark separation, replication of fermions into exactly three generations, the Cabibbo mixing of those generations, weak interactions which are left-chiral, and all four of the gravitational, strong, weak, and electromagnetic interactions. The next steps based on this development will be to calculate the masses and energies associated with the vacuum terms of the Lagrangian, to see if additional empirical confirmations can be achieved, especially for the proton and neutron and the fermion masses.展开更多
In an earlier paper, the author employed the thesis that baryons are Yang-Mills magnetic monopoles and that proton and neutron binding energies are determined based on their up and down current quark masses to predict...In an earlier paper, the author employed the thesis that baryons are Yang-Mills magnetic monopoles and that proton and neutron binding energies are determined based on their up and down current quark masses to predict a relationship among the electron and up and down quark masses within experimental errors and to obtain a very accurate relationship for nuclear binding energies generally and for the binding of 56Fe in particular. The free proton and neutron were understood to each contain intrinsic binding energies which confine their quarks, wherein some or most (never all) of this energy is released for binding when they are fused into composite nuclides. The purpose of this paper is to further advance this thesis by seeing whether it can explain the specific empirical binding energies of the light 1s nuclides, namely, 2H, 3H, 3He and 4He, with high precision. As the method to achieve this, we show how these 1s binding energies are in fact the components of inner and outer tensor products of Yang-Mills matrices which are implicit in the expressions for these intrinsic binding energies. The result is that the binding energies for the 4He, 3He and 3H nucleons are respectively, independently, explained to less than four parts in one million, four parts in 100,000, and seven parts in one million, all in AMU. Further, we are able to exactly relate the neutron minus proton mass difference to a function of the up and down current quark masses, which in turn enables us to explain the 2H binding energy most precisely of all, to just over 8 parts in ten million. These energies have never before been theoretically explained with such accuracy, which leads to the conclusion that the underlying thesis provides the strongest theoretical explanation to date of what baryons are, and of how protons and neutrons confine their quarks and bind together into composite nuclides. As is also reviewed in Section 9, these results may lay the foundation for more easily catalyzing nuclear fusion energy release.展开更多
We show how the Koide relationships and associated triplet mass matrices can be generalized to derive the observed sum of the free neutron and proton rest masses in terms of the up and down current quark masses and th...We show how the Koide relationships and associated triplet mass matrices can be generalized to derive the observed sum of the free neutron and proton rest masses in terms of the up and down current quark masses and the Fermi vev to six parts in 10,000. This sum can then be solved for the separate neutron and proton masses using the neutron minus proton mass difference derived by the author in a recent, separate paper. The oppositely-signed charges of the up and down quarks are responsible for the appearance of a complex phase exp(iδ) and real rotation angle θ which leads on an independent basis to mass and mixing matrices similar to that of Cabibbo, Kobayashi and Maskawa (CKM). These can then be used to specify the neutron and proton mass relationships to unlimited accuracy using θ as a nucleon fitting angle deduced from empirical data. This fitting angle is then shown to be related to an invariant of the CKM mixing angles within experimental errors. Also developed is a master mass and mixing matrix which may help to interconnect all baryon and quark masses and mixing angles. The Koide generalizations developed here enable these neutron and proton mass relationships to be given a Lagrangian formulation based on neutron and proton field strength tensors that contain vacuum-amplified and current quark wavefunctions and masses. In the course of development, we also uncover new Koide relationships for the neutrinos, the up quarks, and the down quarks.展开更多
Nanodielectric composites have been developed in recent years attempting to improve the dielectric properties such as dielectric constant, dielectric strength and voltage endurance. Among various investigations, nanop...Nanodielectric composites have been developed in recent years attempting to improve the dielectric properties such as dielectric constant, dielectric strength and voltage endurance. Among various investigations, nanoparticle dispersion was particularly emphasized in this work. General Electric Global Research Center in Niskayuna NY USA has investigated various nanoparticles, nanocomposites and nanocomposite synthesis methods intending to understand particle dispersion and their impact on the nanocomposite dielectric properties. The breakdown strength and microstructures of the nanocomposites containing different particles were studied for projects related to capacitor and electrical insulation technologies. The nanocomposite synthesis methods either employed commerical nanoparticles or utilized nanoparticles that were self-assembled (in-situ precipitation) in a matrix. Our investigations have shown that nanocomposites prepared with solution chemistry were more favorable for producing uniform dispersion of nanoparticles. Structural information of nanocomposites was studied with transmission electron microscopy and the interection between particles and matrix polymers were tentatively probed using dielectric spectroscopy. In these new class of materials high energy densities on the order of 15J/cc were achievable in nanocomposites.展开更多
Point spreads and money lines from sports wagering markets are used to evaluate the impressiveness of team streaks. Sports wagering data have previously been useful in assessing competitive balance in sports. Our appr...Point spreads and money lines from sports wagering markets are used to evaluate the impressiveness of team streaks. Sports wagering data have previously been useful in assessing competitive balance in sports. Our approach was motivated by the amount of media scrutiny that accompanied the winning streak of the NBA’s Miami Heat and the point streak of the NHL’s Chicago Blackhawks which occurred simultaneously for the most part in 2013. The topic came to the forefront again with the 2014-2015 winning streak of the Atlanta Hawks. Three streaks are highlighted in our paper. The length of the streaks, the quality of the competition, injuries, and a variety of other factors were mentioned in the media but the discussion was limited to subjective opinions as no way of properly weighing relative influence of the factors was identified. Wagering markets provide an excellent source of information for making these judgments. Several complementary measures are described and the most impressive team streaks within and across professional baseball, basketball, football, and ice hockey are identified.展开更多
Anomalies of the epididymis are most commonly associated with an undescended testis but also found occasionally in a normally descended testis. Our 11- year-old patient presented with an acute scrotum and Doppler ultr...Anomalies of the epididymis are most commonly associated with an undescended testis but also found occasionally in a normally descended testis. Our 11- year-old patient presented with an acute scrotum and Doppler ultrasound that suggested epididymitis. Painful symptoms required scrotal exploration with the finding of a torsion and infarction of the epididymis. The etiology of the torsion was an abnormal attachment of the epididymis to the testis. Torsion of the epididymis has not previously been reported.展开更多
基金supported by the China NSFC project(No.32171338)the Key Science and Technology Special Project of Sichuan Province(No.2020ZDZX0008)the Innovation and Reform Project of Postgraduate Education of Sichuan University in 2021,and the Experimental Technology Research Project of Sichuan University(No.SCU221099).
文摘Three-dimensional(3D)bioprinting,specifically direct ink writing(DIW)capable of printing biologically active substances such as growth factors or drugs under low-temperature conditions,is an emerging di-rection in bone tissue engineering.However,limited by the bio-ink mobility and the poor resolution of this printing technology,the lateral pores of current crisscross-stacked scaffolds printed through DIW tend to clog and are inimical to bone growth.Therefore,it is critical to develop DIW printed biologi-cal scaffold structure with high mechanical strength,porosity,and biocompatibility performance.Herein,patterned polylactic acid(PLA)/polycaprolactone(PCL)/nano-hydroxyapatite(n-HA)based scaffold was printed through DIW technological and rolled-up for properties characterization,cytocompatibility test,and bone repair experiment.The result not only shows that the hexagonal patterned scaffolds are me-chanically strong with porosity,but also demonstrated that the hierarchical pore structure formed during rolled-up has the potential to address the clogging problem and stimulates bone growth and repair.
文摘准确的降水预报对山区小流域防洪减灾具有重要意义。选取浙南山区好溪流域典型降水场次,基于WRF(weather research and forecasting)模式,开展云微物理过程参数化方案和积云对流参数化方案敏感性分析,优选适用于好溪流域的物理过程参数化组合方案,提高好溪流域降水预报精度。研究结果表明:云微物理过程和积云对流参数化过程的方案选择及组合对降水预报影响显著,然而没有某一种组合方案的模拟效果对于所有场次的降水都是最佳的;综合考虑所有的典型降水场次,当云微物理参数化方案选择Lin(Purdue Lin)方案、积云对流过程参数化方案选择KF(Kain-Fritsch)方案时,降水预报精度最高。
文摘There are a great variety of commercial nickel alloys mainly because nickel is able to dissolve a large amount of alloying elements while maintaining a single ductile austenitic phase. Nickel alloys are generally designed for and used in highly aggressive environments, for example, those where stainless steels may experience pitting corrosion or environmentally assisted cracking. While nickel alloys are generally resistant to pitting corrosion in chloride-containing environments, they may be prone to crevice corrosion attack. Addition of chromium, molybdenum and tungsten increases the localized corrosion resistance of nickel alloys. This review on the resistance to localized corrosion of nickel alloys includes specific environments such as those present in oil and gas upstream operations, in the chemical process industry and in seawater service.
文摘In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad (Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.
文摘When partially reproductively isolated species come back into secondary contact, these taxa may diverge in mating preferences and sexual cues to avoid maladaptive hybridization, a process known as reinforcement. This phenomenon often leads to reproductive character displacement （RCD） between sympatric and allopatric populations of reinforcing species that differ in their exposure to hybridization. Recent discussions have reinvigorated the idea that RCD may give rise to additional speciation between conspecific sympatric and allopatric populations, dubbing the concept ＂cascade reinforcement.＂ Despite some empirical studies supporting cascade reinforcement, we still know very little about the conditions for its evolution. In the present article, we address this question by developing an individual-based population genetic model that explicitly simulates cascade reinforcement when one of the hybridizing species is split into sympatric and allopatric populations. Our results show that when sympatric and allopatric populations reside in the same environment and only differ in their exposure to maladaptive hybridization, migration between them generally inhibits the evolution of cascade by spreading the reinforcement alleles from sympatry into allopatry and erasing RCD. Under these conditions, cascade reinforcement only evolved when migration rate between sympatric and allopatric populations was very low. This indicates that stabilizing sexual selection in allopatry is generally ineffective in preventing the spread of reinforcement alleles. Only when sympatric and allopatric populations experienced divergent ecological selection did cascade reinforcement evolve in the presence of substantial migration. These predictions clarify the conditions for cascade reinforcement and facilitate our understanding of existing cases in nature.
文摘Colorful visual signals are important systems for investigating the effects of signaling environ ments and receiver physiology on signal evolution as predicted by the sensory drive hypothesis. Support for the sensory drive hypothesis on color signal evolution is mostly based on document ing correlations between the properties of signals and habitat conditions under which the signals are given （i.e., a correlational approach） and less commonly on the use of mathematical models that integrate representations of visual environments, signal properties, and sensory systems （i.e., a functional approach）. Here, we used an experimental approach in the field to evaluate signal efficacy of colorful lizard throat fans called dewlaps that show geographic variation in the lizard Anolis cristatellus. We used a remote controlled apparatus to display ＂fake dewlaps＂ to wild lizards to test for adaptive divergence in dewlap brightness （i.e., perceived intensity） among populations in situ. We found evidence of local adaptation in dewlap brightness consistent with the sensory drive hypothesis. Specifically, dewlaps that had the brightness characteristics of local lizards were more likely to be detected than those with the brightness characteristics of nonlocal lizards. Our findings indicate that simplified mathematical representations of visual environments may allow robust estimates of relative detectability or conspicuousness in natural habitats. We have shown the feasibility of evaluating color signal efficacy experimentally under natural conditions and dem onstrate the potential advantages of presenting isolated components of signals to an intended re ceiver to measure their contribution to signal function.
文摘Anthropogenic pollutants have the potential to disrupt reproductive strategies. Little is known about how lead （Pb2＋） exposure disrupts individual-level responses in reproductive behaviors, which are important for fitness. Drosophila melanogaster was used as a model system to deter- mine the effects of： 1） developmental lead exposure on pre-mating reproductive behaviors （i.e., mate preference）, and 2） lead exposure and mating preferences on fitness in the F0 parental generation and F1 un-exposed offspring. Wild-type strains of D. melanogaster were reared from egg stage to adulthood in control or leaded medium （250 μM PbAc） and tested for differences in： mate preference, male song performance, sex pheromone expression, fecundity, mortality, and body weight. F0 leaded females preferentially mated with leaded males （i.e., asymmetrical positive assortative mating） in 2-choice tests. This positive assortative mating was mediated by the females （and not the males） and was dependent upon context and developmental exposure to Pb. Neither the courtship song nor the sex pheromone profile expressed by control and leaded males medi- ated the positive assortative mating in leaded females. Leaded females did not incur a fitness cost in terms of reduced fecundity, increased mortality, or decreased body weight by mating with leaded males. These results suggest that sublethal exposure to lead during development can alter mate preferences in adults, but not fitness measures once lead exposure has been removed. We suggest that changes in mate preference may induce fitness costs, as well as long-term population and multi-generational implications, if pollution is persistent in the environment.
文摘Gastroesophageal reflux disease (GERD) is one of the most commonlyencountered digestive diseases in the world, with the prevalence continuing toincrease. Many patients are successfully treated with lifestyle modifications andproton pump inhibitor therapy, but a subset of patients require more aggressiveintervention for control of their symptoms. Surgical treatment with fundoplicationis a viable option for patients with GERD, as it attempts to improve the integrityof the lower esophageal sphincter (LES). While surgery can be as effective asmedical treatment, it can also be associated with side effects such as dysphagia,bloating, and abdominal pain. Therefore, a thorough pre-operative assessment iscrucial to select appropriate surgical candidates. Newer technologies arebecoming increasingly available to help clinicians identify patients with true LESdysfunction, such as pH-impedance studies and high-resolution manometry(HRM). Pre-operative evaluation should be aimed at confirming the diagnosis ofGERD, ruling out any major motility disorders, and selecting appropriate surgicalcandidates. HRM and pH testing are key tests to consider for patients with GERDlike symptoms, and the addition of provocative measures such as straight legraises and multiple rapid swallows to HRM protocol can assess the presence ofunderlying hiatal hernias and to test a patient’s peristaltic reserve prior tosurgery.
文摘Immune checkpoint inhibitors(ICIs)are a new class of cancer pharmacotherapy consisting of antibodies that block inhibitory immune regulators such as cytotoxic T lymphocyte antigen 4,programmed cell death 1 and programmed death-ligand 1.Checkpoint blockade by ICIs reactivates a tumor-specific T cell response.Immune-related adverse events can occur in various organs including skin,liver,and gastrointestinal tract.Mild to severe colitis is the most common side effect with some experiencing rapid progression to more serious complications including bowel perforation and even death.Prompt diagnosis and management of ICI-induced colitis is crucial for optimal outcome.Unfortunately,its clinical,endoscopic and histopathologic presentations are non-specific and overlap with those of colitis caused by other etiologies,such as infection,medication,graftversus-host disease and inflammatory bowel disease.Thus,a definitive diagnosis can only be rendered after these other possible etiologies are excluded.Sometimes an extensive clinical,laboratory and radiologic workup is required,making it challenging to arrive at a prompt diagnosis.Most patients experience full resolution of symptoms with corticosteroids and/or infliximab.For ICI-induced colitis that is treatment-refractory,small scale studies offer alternative strategies,such as vedolizumab and fecal microbiota transplantation.In this review,we focus on the clinical features,differential diagnosis,and management of ICIinduced colitis with special attention to emerging treatment options for treatmentrefractory ICI-induced colitis.
文摘We complete and extend the asymptotic analysis of the spectrum of Jacobi Tau approximations that were first considered by Dubiner. The asymptotic formulas for Jacobi polynomials PN(α ,β ) ,α ,β > -1 are derived and confirmed by numerical approximations. More accurate results for the slowest decaying mode are obtained. We explain where the large negative eigenvalues come from. Furthermore, we show that a large negative eigenvalue of order N2 appears for -1 1 . The eigenvalues for Legendre polynomials are directly related to the roots of the spherical Bessel and Hankel functions that are involved in solving Helmholtz equation inspherical coordinates.
文摘Based on the thesis that baryons including protons and neutrons are Yang-Mills magnetic monopoles which the author has previously developed and which has been confirmed by over half a dozen empirically-accurate predictions, we develop a GUT that is rooted in the SU(4) subgroups for the proton/electron and neutron/neutrino which were used as the basis for these predictions. The SU(8) GUT group so-developed leads following three stages of symmetry breaking to all known phenomenology including a neutrino that behaves differently from other fermions, lepto-quark separation, replication of fermions into exactly three generations, the Cabibbo mixing of those generations, weak interactions which are left-chiral, and all four of the gravitational, strong, weak, and electromagnetic interactions. The next steps based on this development will be to calculate the masses and energies associated with the vacuum terms of the Lagrangian, to see if additional empirical confirmations can be achieved, especially for the proton and neutron and the fermion masses.
文摘In an earlier paper, the author employed the thesis that baryons are Yang-Mills magnetic monopoles and that proton and neutron binding energies are determined based on their up and down current quark masses to predict a relationship among the electron and up and down quark masses within experimental errors and to obtain a very accurate relationship for nuclear binding energies generally and for the binding of 56Fe in particular. The free proton and neutron were understood to each contain intrinsic binding energies which confine their quarks, wherein some or most (never all) of this energy is released for binding when they are fused into composite nuclides. The purpose of this paper is to further advance this thesis by seeing whether it can explain the specific empirical binding energies of the light 1s nuclides, namely, 2H, 3H, 3He and 4He, with high precision. As the method to achieve this, we show how these 1s binding energies are in fact the components of inner and outer tensor products of Yang-Mills matrices which are implicit in the expressions for these intrinsic binding energies. The result is that the binding energies for the 4He, 3He and 3H nucleons are respectively, independently, explained to less than four parts in one million, four parts in 100,000, and seven parts in one million, all in AMU. Further, we are able to exactly relate the neutron minus proton mass difference to a function of the up and down current quark masses, which in turn enables us to explain the 2H binding energy most precisely of all, to just over 8 parts in ten million. These energies have never before been theoretically explained with such accuracy, which leads to the conclusion that the underlying thesis provides the strongest theoretical explanation to date of what baryons are, and of how protons and neutrons confine their quarks and bind together into composite nuclides. As is also reviewed in Section 9, these results may lay the foundation for more easily catalyzing nuclear fusion energy release.
文摘We show how the Koide relationships and associated triplet mass matrices can be generalized to derive the observed sum of the free neutron and proton rest masses in terms of the up and down current quark masses and the Fermi vev to six parts in 10,000. This sum can then be solved for the separate neutron and proton masses using the neutron minus proton mass difference derived by the author in a recent, separate paper. The oppositely-signed charges of the up and down quarks are responsible for the appearance of a complex phase exp(iδ) and real rotation angle θ which leads on an independent basis to mass and mixing matrices similar to that of Cabibbo, Kobayashi and Maskawa (CKM). These can then be used to specify the neutron and proton mass relationships to unlimited accuracy using θ as a nucleon fitting angle deduced from empirical data. This fitting angle is then shown to be related to an invariant of the CKM mixing angles within experimental errors. Also developed is a master mass and mixing matrix which may help to interconnect all baryon and quark masses and mixing angles. The Koide generalizations developed here enable these neutron and proton mass relationships to be given a Lagrangian formulation based on neutron and proton field strength tensors that contain vacuum-amplified and current quark wavefunctions and masses. In the course of development, we also uncover new Koide relationships for the neutrinos, the up quarks, and the down quarks.
文摘Nanodielectric composites have been developed in recent years attempting to improve the dielectric properties such as dielectric constant, dielectric strength and voltage endurance. Among various investigations, nanoparticle dispersion was particularly emphasized in this work. General Electric Global Research Center in Niskayuna NY USA has investigated various nanoparticles, nanocomposites and nanocomposite synthesis methods intending to understand particle dispersion and their impact on the nanocomposite dielectric properties. The breakdown strength and microstructures of the nanocomposites containing different particles were studied for projects related to capacitor and electrical insulation technologies. The nanocomposite synthesis methods either employed commerical nanoparticles or utilized nanoparticles that were self-assembled (in-situ precipitation) in a matrix. Our investigations have shown that nanocomposites prepared with solution chemistry were more favorable for producing uniform dispersion of nanoparticles. Structural information of nanocomposites was studied with transmission electron microscopy and the interection between particles and matrix polymers were tentatively probed using dielectric spectroscopy. In these new class of materials high energy densities on the order of 15J/cc were achievable in nanocomposites.
文摘Point spreads and money lines from sports wagering markets are used to evaluate the impressiveness of team streaks. Sports wagering data have previously been useful in assessing competitive balance in sports. Our approach was motivated by the amount of media scrutiny that accompanied the winning streak of the NBA’s Miami Heat and the point streak of the NHL’s Chicago Blackhawks which occurred simultaneously for the most part in 2013. The topic came to the forefront again with the 2014-2015 winning streak of the Atlanta Hawks. Three streaks are highlighted in our paper. The length of the streaks, the quality of the competition, injuries, and a variety of other factors were mentioned in the media but the discussion was limited to subjective opinions as no way of properly weighing relative influence of the factors was identified. Wagering markets provide an excellent source of information for making these judgments. Several complementary measures are described and the most impressive team streaks within and across professional baseball, basketball, football, and ice hockey are identified.
文摘Anomalies of the epididymis are most commonly associated with an undescended testis but also found occasionally in a normally descended testis. Our 11- year-old patient presented with an acute scrotum and Doppler ultrasound that suggested epididymitis. Painful symptoms required scrotal exploration with the finding of a torsion and infarction of the epididymis. The etiology of the torsion was an abnormal attachment of the epididymis to the testis. Torsion of the epididymis has not previously been reported.
