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Investigating neurogenic bowel in experimental spinal cord injury: where to begin?

Neural Regeneration Research 2019年第2期14卷 222-226页

作者： Amanda R.White gregory m.holmes Department of Neural & Behavioral Sciences Penn State University College of Medicine

The devastating losses following traumatic spinal cord injury(SCI) encompass the motor, sensory and autonomic nervous systems. Neurogenic bowel is a slow transit colonic dysfunction marked by constipation, rectal evacuation difficulties, decreased anorectal sensation, fecal incontinence or some combination thereof. Furthermore, neurogenic bowel is one of the most prevalent comorbidities of SCI and is recognized by afflicted individuals and caregivers as a lifelong physical and psychological challenge that profoundly affects quality of life. The restoration of post-injury control of movement has received considerable scientific scrutiny yet the daily necessity of voiding the bowel and bladder remains critically under-investigated. Subsequently, physicians and caregivers are rarely presented with consistent, evidence-based strategies to successfully address the consequences of dysregulated voiding reflexes. Neurogenic bowel is commonly believed to result from the interruption of the supraspinal control of the spinal autonomic circuits regulating the colon. In this mini-review, we discuss the clinical challenges presented by neurogenic bowel and emerging pre-clinical evidence that is revealing that SCI also initiates functional remodeling of the colonic wall concurrent with a decrease in local enteric neurons. Since the enteric input to the colonic smooth muscle is the final common pathway for functional contractions of the colon, changes to the neuromuscular interface must first be understood in order to maximize the efficacy of therapeutic interventions targeting colonic dysfunction following SCI.

关键词： colon enteric nervous system parasympathetic sympathetic autonomic nervous system defecationreflexes gastrointestinal inflammation constipation incontinence

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Altered physiology of gastrointestinal vagal afferents following neurotrauma

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Neural Regeneration Research 2021年第2期16卷 254-263页

作者： Emily N.Blanke gregory m.holmes Emily m.Besecker Department of Health Sciences Gettysburg CollegeGettysburgPAUSA Department of Neural and Behavioral Sciences Penn State University College of MedicineHersheyPAUSA

The adaptability of the central nervous system has been revealed in several model systems.Of particular interest to central nervous system-injured individuals is the ability for neural components to be modified for regain of function.In both types of neurotrauma,traumatic brain injury and spinal cord injury,the primary parasympathetic control to the gastrointestinal tract,the vagus nerve,remains anatomically intact.However,individuals with traumatic brain injury or spinal cord injury are highly susceptible to gastrointestinal dysfunctions.Such gastrointestinal dysfunctions attribute to higher morbidity and mortality following traumatic brain injury and spinal cord injury.While the vagal efferent output remains capable of eliciting motor responses following injury,evidence suggests impairment of the vagal afferents.Since sensory input drives motor output,this review will discuss the normal and altered anatomy and physiology of the gastrointestinal vagal afferents to better understand the contributions of vagal afferent plasticity following neurotrauma.

关键词： gastrointestinal functions microbiome neurotrauma nodose ganglia sensory neuropathy spinal cord injury traumatic brain injury vagal afferents visceral reflexes

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Nonuniform Dependence on the Initial Data for Solutions of Conservation Laws

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Communications on Applied mathematics and Computation 2024年第1期6卷 489-500页

作者： John m.holmes Barbara Lee Keyfitz Department of mathematics The Ohio State UniversityColumbusOH43210USA

In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results appl... 详细信息

关键词： Conservation laws Data-to-solution map Nonuniform dependence

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Electrobiocorrosion by microbes without outer-surface cytochromes

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mLife 2024年第1期3卷 110-118页

作者： Dawn E.holmes Trevor L.Woodard Jessica A.Smith Florin musat Derek R.Lovley Department of microbiology University of Massachusetts AmherstAmherstMassachusettsUSA Department of Physical and Biological Science Western New England UniversitySpringfieldMassachusettsUSA Department of Biomolecular Sciences Central Connecticut State UniversityNew BritainConnecticutUSA Department of Biology Section for MicrobiologyAarhus UniversityAarhusDenmark Department of molecular Biology and Biotechnology Facuity of Biology and GeologyBabes-Bolyai UniversityCluj-NapocaRomania

Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage.Some microbes are capable of direct metal-to-microbe electron transfer(electrobiocorrosion),but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation.Previous studies have suggested that respiration with 316L stainless steel as the electron donor is indicative of electrobiocorrosion,because,unlike pure Fe^(0),316L stainless steel does not abiotically generate H2 as an intermediary electron carrier.Here,we report that all of the methanogens(methanosarcina vacuolata,methanothrix soehngenii,and methanobacterium strain Im1)and acetogens(Sporomusa ovata and Clostridium ljungdahli)evaluated respired with pure Fe^(0)as the electron donor,but only m.vacuolata,mx.soehngeni,and S.ovata were capable of stainless steel electrobiocorrosion.The electrobiocorrosive methanogens re-quired acetate as an additional energy source in order to produce methane from stainless steel.Cocultures of S.ovata and mx.soehngeni demonstrated how acetogens can provide acetate to methanogens during corrosion.Not only was meth-anobacterium strain Im1 not capable of electrobiocorrosion,but it also did not accept electrons from Geobacter metal-lireducens,an effective electron-donating partner for direct interspecies electron transfer to all methanogens that can directly accept electrons from Fe^(0).The finding that m.vacuolata,mx.soehngeni,and S.ovata are capable of electrobiocorrosion,despite a lack of the outer-surface c-type cytochromes previously found to be important in other electrobiocorrosive microbes,demonstrates that there are multiple microbial strategies for making electrical contact with Fe^(0).

关键词： acetogen corrosion Fe^(0) methanogen stainless steel

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Integrins and their potential roles in mammalian pregnancy

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Journal of Animal Science and Biotechnology 2024年第1期15卷 1-19页

作者： gregory A.Johnson Robert C.Burghardt Fuller W.Bazer Heewon Seo Joe W.Cain Department of Veterinary Integrative Biosciences School of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTX 77843‑4459USA Department of Animal Science College of Agriculture and Life SciencesTexas A&M UniversityCollege StationTX 77843‑2471USA

Integrins are a highly complex family of receptors that, when expressed on the surface of cells, can mediate reciprocal cell-to-cell and cell-to-extracellular matrix(ECm) interactions leading to assembly of integrin adhesion complexes(IACs) that initiate many signaling functions both at the membrane and deeper within the cytoplasm to coordinate processes including cell adhesion, migration, proliferation, survival, differentiation, and metabolism. All metazoan organisms possess integrins, and it is generally agreed that integrins were associated with the evolution of multicellularity, being essential for the association of cells with their neighbors and surroundings, during embryonic development and many aspects of cellular and molecular biology. Integrins have important roles in many aspects of embryonic development, normal physiology, and disease processes with a multitude of functions discovered and elucidated for integrins that directly influence many areas of biology and medicine, including mammalian pregnancy, in particular implantation of the blastocyst to the uterine wall, subsequent placentation and conceptus(embryo/fetus and associated placental membranes) development. This review provides a succinct overview of integrin structure, ligand binding, and signaling followed with a concise overview of embryonic development, implantation, and early placentation in pigs, sheep, humans, and mice as an example for rodents. A brief timeline of the initial localization of integrin subunits to the uterine luminal epithelium(LE) and conceptus trophoblast is then presented, followed by sequential summaries of integrin expression and function during gestation in pigs, sheep, humans, and rodents. As appropriate for this journal, summaries of integrin expression and function during gestation in pigs and sheep are in depth, whereas summaries for humans and rodents are brief. Because similar models to those illustrated in Fig. 1, 2, 3, 4, 5 and 6 are present throughout the scientific literature, the illustrations in this m

关键词： Humans Implantation Integrins Pigs Pregnancy Rodents Sheep

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High Temperature Iron Ethylene Polymerization Catalysts Bearing N,N,N'-2-(1-(2,4-Dibenzhydryl-6-fluorophenylimino)ethyl)-6-(1-(arylphenylimino)ethyl)pyridines

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Chinese Journal of Polymer Science 2024年第2期42卷 188-201,I0007页

作者： Chantsalnyam Bariashir Qiu-Yue Zhang Bayasgalan Ulambayar gregory A.Solan Tong-Ling Liang Wen-Hua Sun Institute of Chemistry and Chemical Technology Mongolian Academy of SciencesUlaanbaatar13330Mongolia Key Laboratory of Engineering Plastics and Beijing National Laboratory for molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China Department of Chemistry University of LeicesterUniversity RoadLeicesterLE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

The N,N,N'-ferrous chloride complexes,[2-{CmeN(2,4-(CHPh)_(2)-6-FC_(6)H_(2))}-6-(CmeNAr)C_(5)H_(3)N]FeCl_(2)(Ar=2,6-me_(2)C_(6)H_(3) Fe1,2,6-Et_(2)C_(6)H_(3)Fe2,2,6-^(i)Pr_(2)C_(6)H_(3) Fe3,2,4,6-me_(3)C_(6)H_(2) Fe4 and 2,6-Et_(2)-4-meC_(6)H_(2) Fe5),each possessing one N-2,4-dibenzhydryl-6-fluorophenyl group,were readily synthesized from their respective unsymmetrical bis(imino)pyridines,L1-L5.Structural identification of Fe2 highlighted the variation in the steric properties provided by the dissimilar N-aryl groups.Following pre-treatment with either mAO or mmAO,complexes Fe1-Fe5 all displayed,at an operating temperature of 80℃,high activities for ethylene polymerization with levels falling in the order:Fe4> Fe1> Fe5> Fe2> Fe3.Notably,Fe4/mAO displayed the highest activity of 1.94×10^(7) g_(PE)·mol_(Fe)^(-1)·h^(-1) of the study with only a modest loss in performance at 90℃.Generally,the resulting polyethylenes were highly linear(T_(m) range:122-132℃),narrowly disperse and of low molecular weight(m_(w) range:6.73-46.04kg·mol^(-1)),with the most sterically hindered Fe3 forming the highest molecular weight polymer of the series.End-group analysis by ^(1)H-and ^(13)CNmR spectroscopy revealed saturated alkyl(n-propyl and i-propyl) and unsaturated vinyl chain ends indicative of the role of both β-H elimination and chain transfer to aluminum as termination pathways.By comparison with previou sly reported iron precatalysts with similar tridentate ligand skeletons,it is evident that the introduction of a large benzhydryl group in combination with a fluorine as the ortho-substituents of one N-aryl group has the effect of enhancing thermal stability of the iron polymerization catalyst whilst maintaining appreciable polymer molecular weight.

关键词： Iron catalyst Ethylene polymerization Linear polyethylene Fluoride effect Thermal stability

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Synthesis of phosphonated graphene oxide by electrochemical exfoliation to enhance the performance and durability of high-temperature proton exchange membrane fuel cells

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Journal of Energy Chemistry 2023年第1期76卷 448-458,I0011页

作者： Jianuo Chen Zunmin Guo maria Perez-Page Yifeng Jia Ziyu Zhao Stuart m.holmes Department of Chemical Engineering and Analytical Science University of ManchesterOxford RoadManchester M139PLUnited Kingdom Chemistry Research Laboratory Department of ChemistryUniversity of Oxford12 Mansfield RoadOxford OX13TAUnited Kingdom

The doping of functionalized graphene oxide(GO)in the membranes becomes a promising method for improving the performance of high-temperature proton exchange membrane fuel cells(HT-PEmFC).Phosphonated graphene oxide(PGO)with a P/O ratio of 8.5%was quickly synthesised by one-step electrochemical exfoliation based on a three-dimensiaonal(3D)printed reactor and natural graphite flakes.Compared with the GO prepared by the two-step electrochemical exfoliation method,the PGO synthesized by the one-step electrochemical exfoliation can better improve the performance of the membrane-electrode-assembly(mEA)based on the polybenzimidazole(PBI)membrane in the HTPEmFC.The doping of 1.5 wt%GO synthesised by electrochemical exfoliation with the 2-step method or reactor method in PBI increased the peak power density by 17.4%or 35.4%compared to mEA based on pure PBI membrane at 150℃,respectively.In addition,the doping of PGO in PBI improves its durability under accelerated stress test(AST).

关键词： Electrochemical exfoliation Phosphonated graphene oxide High-temperature fuel cells

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High-performance polymer electrolyte membranes incorporated with 2D silica nanosheets in high-temperature proton exchange membrane fuel cells

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Journal of Energy Chemistry 2022年第1期31卷 323-334,I0009页

作者： Zunmin Guo Jianuo Chen Jae Jong Byun Rongsheng Cai maria Perez-Page madhumita Sahoo Zhaoqi Ji Sarah J.Haigh Stuart m.holmes Department of Chemical Engineering and Analytical Science The University of ManchesterM139PLUnited Kingdom Department of materials The University of ManchesterM139PLUnited Kingdom

Silica nanosheets(SN)derived from natural vermiculite(Verm)were successfully incorporated into polyethersulfone-polyvinylpyrrolidone(PES-PVP)polymer to fabricate high-temperature proton exchange membranes(HT-PEms).The content of SN filler was varied(0.1-0.75 wt%)to study its influence on proton conductivity,power density and durability.Benefiting from the hydroxyl groups of SN that enable the formation of additional proton-transferring pathways,the inorganic-organic membrane displayed enhanced proton conductivity of 48.2 mS/cm and power density of 495 mW/cm^(2) at 150℃ without humidification when the content of SN is 0.25 wt%.Furthermore,exfoliated SN(E-SN)and sulfonated SN(S-SN),which were fabricated by a liquid-phase exfoliation method and silane condensation,respectively,were embedded in PES-PVP polymer matrix by a simple blending method.Due to the significant contribution from sulfonic groups in S-SN,the membrane with 0.25 wt%S-SN reached the highest proton conductivity of51.5 mS/cm and peak power density of 546 mW/cm^(2) at150℃,48%higher than the pristine PES-PVP membranes.Compared to unaltered PES-PVP membrane,SN added hybrid composite membrane demonstrated excellent durability for the fuel cell at 150℃.Using a facile method to prepare 2D SN from natural clay minerals,the strategy of exfoliation and functionalization of SN can be potentially used in the production of HT-PEms.

关键词： Silica nanosheets Vermiculite High-temperature proton exchange membrane Proton conductivity

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Geriatric assessment for oncologists

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Cancer Biology & medicine 2015年第4期12卷 261-274页

作者： Beatriz Korc-Grodzicki Holly m.holmes Armin Shahrokni memorial Sloan Kettering Cancer Center Weill Cornell Medical CollegeNew York Division of Geriatric and Palliative medicine The University of Texas Health Science Center at Houston

The world is experiencing aging of its population. Age-specific incidence rates of cancer are higher and cancer is now recognized as a part of aging. Treating older patients can be challenging. The clinical behavior of some tumors changes with age and the aging process itself brings physiological changes leading to decline in the function of organs. It is essential to identify those patients with longer life expectancy, potentially more likely to benefit from aggressive treatment vs. those that are more vulnerable to adverse outcomes. A primary determination when considering therapy for an older cancer patient is a patient's physiologic, rather than chronologic age. In order to differentiate amongst patients of the same age, it is useful to determine if a patient is fit or frail. Frail older adults have multiple chronic conditions and difficulties maintaining independence. They may be more vulnerable to therapy toxicities, and may not have substantial lasting benefits from therapy. Geriatric assessment(GA) may be used as a tool to determine reversible deficits and devise treatment strategies to mitigate such deficits. GA is also used in treatment decision making by clinicians, helping to risk stratify patients prior to potentially high-risk therapy. An important practical aspect of GA is the feasibility of incorporating it into a busy oncology practice. Key considerations in performing the GA include: available resources, patient population, GA tools to use, and who will be responsible for using the GA results and develop care plans. Challenges in implementing GA in clinical practice will be discussed.

关键词：临床医生健康评估肿瘤癌症患者遗传算法生理变化器官功能衰老过程

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Doped graphene/carbon black hybrid catalyst giving enhanced oxygen reduction reaction activity with high resistance to corrosion in proton exchange membrane fuel cells

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Journal of Energy Chemistry 2022年第5期31卷 143-153页

作者： Zhaoqi Ji Jianuo Chen maría Pérez-Page Zunmin Guo Ziyu Zhao Rongsheng Cai maxwell T.P.Rigby Sarah J.Haigh Stuart m.holmes School of Automotive Engineering Harbin Institute of TechnologyWeihai264209ShandongChina Department of Chemical Engineering and Analytical Science The University of ManchesterManchester M139PLUK Department of materials The University of ManchesterManchester M139PLUK

Nitrogen doping of the carbon is an important method to improve the performance and durability of catalysts for proton exchange membrane fuel cells by platinum–nitrogen and carbon–nitrogen bonds. This study shows that p-phenyl groups and graphitic N acting bridges linking platinum and the graphene/carbon black(the ratio graphene/carbon black = 2/3) hybrid support materials achieved the average size of platinum nanoparticles with(4.88 ± 1.79) nm. It improved the performance of the lower-temperature hydrogen fuel cell up to 0.934 W cm^(-2) at 0.60 V, which is 1.55 times greater than that of commercial Pt/C. Doping also enhanced the interaction between Pt and the support materials, and the resistance to corrosion, thus improving the durability of the low-temperature hydrogen fuel cell with a much lower decay of 10 mV at 0.80 A cm^(-2) after 30 k cycles of an in-situ accelerated stress test of catalyst degradation than that of 92 mV in Pt/C, which achieves the target of Department of Energy(mV). meanwhile,Pt/Nr EGO_(2)-CB_(3) remains 78% of initial power density at 1.5 A cm^(-2) after 5 k cycles of in-situ accelerated stress test of carbon corrosion, which is more stable than the power density of commercial Pt/C, keeping only 54% after accelerated stress test.

关键词： Nitrogen doped graphene Low-temperature hydrogen fuel cell Catalyst degradation Carbon corrosion

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