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A possible anorthositic continent of early Mars and the role of planetary size for the inception of Earth-like life

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Geoscience Frontiers 2018年第4期9卷 1085-1098页

作者： James M.Dohm Shigenori Maruyama Motoyuki Kido Victor R.baker The University Museum The University of Tokyo Earth-Life Science Institute Tokyo Institute of Technology International Research Institute of Disaster Science Tohoku University Lunar and Planetary Laboratory The University of Arizona

The Moon has an anorthositic primordial continental crust. Recently anorthosite has also been discovered on the Martian surface. Although the occurrence of anorthosite is observed to be very limited in Earth＇s extant geological record,both lunar and Martian surface geology suggest that anorthosite may have comprised a primordial continent on the early Earth during the first 600 million years after its formation. We hypothesized that differences in the presence of an anorthositic continent on an Earthlike planet are due to planetary size. Earth likely lost its primordial anorthositic continent by tectonic erosion through subduction associated with a kind of proto-plate tectonics（PPT）. In contrast, Mars and the Moon, as much smaller planetary bodies, did not lose much of their anorthositic continental crust because mantle convection had weakened and/or largely stopped, and with time, they had appropriately cooled down. Applying this same reasoning to a super-Earth exoplanet suggests that, while a primordial anorthositic continent may briefly form on its surface, such a continent will be likely transported into the deep mantle due to intense mantle convection immediately following its formation. The presence of a primordial continent on an Earth-like planet seems to be essential to whether the planet will be habitable to Earth-like life. The key role of the primordial continent is to provide the necessary and sufficient nutrients for the emergence and evolution of life. With the appearance of a ＂trinity＂ consisting of（1） an atmosphere,（2） an ocean, and（3） the primordial continental landmass, material circulation can be maintained to enable a ＂Habitable Trinity＂ environment that will permit the emergence of Earth-like life. Thus, with little likelihood of a persistent primordial continent, a super-Earth affords very little chance for Earth-like life to emerge.

关键词： Anorthosite on Mars Moon Habitable trinity Super-Earth Plate tectonics Origin of life

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Tom Jones

CXCR5 Regulates Neuronal Polarity Development and Migration in the Embryonic Stage via F‑Actin Homeostasis and Results in Epilepsy‑Related Behavior

作者： edited by Sheridan baker.

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Neuroscience Bulletin 2023年第11期39卷 1605-1622页

作者： Zhijuan Zhang Hui Zhang Ana Antonic‑baker Patrick Kwan Yin Yan Yuanlin Ma Department of Neurology Chongqing Key Laboratory of NeurologyThe First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Chongqing Emergency Medical Center The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Neuroscience Central Clinical SchoolMonash UniversityMelbourneAustralia

Epilepsy is a common,chronic neurological disorder that has been associated with impaired neurodevelopment and *** chemokine receptor CXCR5 is involved in seizures via an unknown ***,we first determined the expression pattern and distribution of the CXCR5 gene in the mouse brain during different stages of development and the brain tissue of patients with ***,we found that the knockdown of CXCR5 increased the susceptibility of mice to pentylenetetrazol-and kainic acid-induced seizures,whereas CXCR5 overexpression had the opposite ***5 knockdown in mouse embryos via viral vector electrotransfer negatively influenced the motility and multipolar-to-bipolar transition of migratory *** a human-derived induced an in vitro multipotential stem cell neurodevelopmental model,we determined that CXCR5 regulates neuronal migration and polarization by stabilizing the actin cytoskeleton during various stages of *** experiments demonstrated that the knockdown of CXCR5 induced neuronal hyperexcitability,resulting in an increased number of ***,our results suggested that CXCR5 deficiency triggers seizure-related electrical activity through a previously unknown mechanism,namely,the disruption of neuronal polarity.

关键词： Epilepsy CXCR5 Embryonic neurogenesis Pluripotent stem cells Intrauterine electroporation F-actin Neuronal polarity Neuronal migration

On Modeling Bio-Scaffolds:Structural and Fluid Transport Characterization Based on 3-D Imaging Data

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Tsinghua Science and Technology 2009年第S1期14卷 20-23页

作者： NOTARBERARDINO Bruno baker Matthew TABOR Gavin TURNER Irene YANG Lincoln School of Engineering Computing and Mathematics University of Exeter Exeter EX4 4QF United Kingdom Department of Mechanical Engineering University of Bath Bath BA2 7AY United Kingdom Shanghai Gaitech Scientific Instruments Co. Ltd.

Bio-scaffolds which are most commonly open celled porous structures are increasingly used for tissue engineering and regenerative medicine. A number of studies have shown that the bulk properties of such irregular structures are poorly modeled using idealized unit cell approaches. The paper therefore uses novel image based meshing techniques to explore both fluid flow and bulk structural properties of a bone scaffold, as accurate modeling of bio-scaffolds with non-uniform cellular structures is very important for the development of optimal scaffolds for tissue engineering application. In this study, a porous hydroxyapatite/tricalcium phosphate (HA/TCP) bone scaffold has been scanned in a Micro-CT scanner, and converted into a volumetric mesh using image processing software developed by the authors. The resulting mesh was then exported to commercial FEA and CFD solvers for analysis. Initial FEA and CFD studies have shown promising results and have highlighted the importance of accurate modeling to understand how microstructures influence the mechanical property of the scaffold, and to analyze flow regimes through the sample. The work highlights the potential use of image based meshing for the ad hoc characterization of scaffolds as well as for assisting in the design of scaffolds with tailored strength, stiffness, and transport properties.

关键词： bio-scaffolds material characterization finite element computational fluid dynamics dynamics microstructures

Drug Repurposing for the Treatment of Mycobacterium abscessus Infections

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感染微生物与疾病(英文) 2023年第3期5卷 101-110页

作者： Emily J.baker Antonia Molloy Jonathan A.G.Cox School of Life and Health Sciences Aston UniversityAston TriangleBirminghamUK.

With the ever-increasing burden of antimicrobial resistance,the demand to introduce countermeasures becomes increasingly *** urgency of this need is intensified by the void in antibiotic discovery,with the identification of novel compounds declining with *** increasing concern is Mycobacterium abscessus,which displays high levels of intrinsic resistance that lead to poor success rates,even after lengthy drug *** tackling these issues is now focused on the repurposing of preexisting drugs for antimycobacterial use,facilitating the discovery of antimicrobial compounds amidst a crisis where novel antibiotics are *** of this includes the use of combination treatments,whereby coadministration of synergistic compounds can reduce dose requirements and slow the progression of antimicrobial resistance in the long *** this review,we will introduce the current therapeutic options for *** and provide insight into why treatment is so *** will also compile the current updates within drug repurposing for this pathogen,including the use of unconventional agents such as antimalarial drugs,the repositioning of antitubercu-losis candidates and the repurposing of preexisting antibiotics,including the application of combination *** addition,the in vitro drug screening platforms used in their discovery will be appraised,with the view of highlighting potential future perspectives that may help increase physiological *** review provides a timely appraisal of the future of *** treatment.

关键词： drug repurposing Mycobacterium abscessus antimycobacterial drug discovery antimicrobials

Relationship between seminal plasma zinc concentration and spermatozoa-zona pellucida binding and the ZP-induced acrosome reaction in subfertile men

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Asian Journal of Andrology 2009年第4期11卷 499-507页

作者： De-Yi Liu Boon-Shih Sie Ming-Li Liu Franca Agresta HW Gordon baker Department of Obstetrics and Gynaecology University of Melbourne Royal Women ＇s Hospital Parkville 3052 Australia Reproductive Services and Melbourne IVF Royal Women＇s Hospital Parkville 3052 Australia

The aim of this study was to determine the relationship between seminal zinc concentration and spermatozoazona pellucida （ZP） binding and the ZP-induced acrosome reaction （ZPIAR） in subfertile men. Semen analyses and seminal zinc concentration assessments were carried out according to the World Health Organization manual for 458 subfertile men. A spermatozoa-ZP interaction test was carried out by incubating 2 × 10^6 motile spermatozoa with a group of four unfertilized oocytes obtained from a clinical in vitro fertilization programme. After 2 h of incubation, the number of spermatozoa bound per ZP and the ZPIAR of ZP-bound spermatozoa were examined. The effect of adding 0.5 mmol L^-1 zinc to the media on the ZPIAR of spermatozoa from normozoospermic men was also tested in vitro. Seminal zinc concentration positively correlated with sperm count and duration of abstinence, but negatively correlated with semen volume. On analysis of data from all participants, both spermatozoa-ZP binding and the ZPI- AR were significantly correlated with sperm motility and normal morphology, but not with seminal zinc concentration. However, in men with normozoospermic semen, the seminal zinc concentration was significantly higher in men with defective ZPIAR （〈 16%） than in those with normal ZPIAR （ ≥ 16% ）（P 〈 0.01）. The addition of 0.5 mmol L^-1 zinc to the culture media had no effect on spermatozoa-ZP binding, but significantly reduced the ZPIAR in vitro （P 〈 0. 001）. In conclusion, seminal zinc concentration is correlated with sperm count and the duration of abstinence in subfertile men. In men with normozoospermic semen, high seminal zinc concentration may have an adverse effect on the ZPIAR.

关键词： semen analysis seminal zinc spermatozoa-zona pellucida interaction subfertile men

Evaluation and assessment of semen for IVF/ICSI

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Asian Journal of Andrology 2002年第4期4卷 281-285页

作者： D.Y. Liu H.W.G. baker University of Melbourne Department of Obstetrics and Gynaecology and Melbourne IVF and Reproductive Services Royal Women's Hospital Carlton Victoria 3053 AustraliaUniversity of Melbourne Department of Obstetrics and Gynaecology and Melbourne IVF and Reproductive Services Royal Women's Hospital Carlton Victoria 3053 Australia

Evaluation and assessment of semen is very important for both diagnosis of male infertility and selection of patients for treatment with IVF or ICSI. In standard IVF, sperm function is essential for normal fertilization: sperm must be able to bind to zona pellucida (ZP), undergo the acrosome reaction and penetrate the ZP and fuse with the oolemma before fertilization takes place. In contrast, most sperm functions are not required for fertilization in ICSI since sperm bypass the ZP and oolemma by injection of a single sperm directly into cytoplasm of oocyte. Therefore, the clinical decision on treatment of patients with either IVF or ICSI is mostly dependent on results of sperm tests. However, conventional semen analyses do not provide accurate information about sperm fertilizing ability since many patients with subtle sperm defects can not be detected. More advanced sperm function tests are required to detect sperm defects that may lead to failure of fertilization in standard IVF. In the last 15 years we performed extensive studies on relationship between sperm functions and fertilization rates by logistic regression analysis in large numbers of IVF patients including 370 patients with zero fertilization rate by IVF. We confirmed sperm morphology assessed strictly was strongly related to fertilisation rate with standard IVF. Thus sperm morphology assessment is very useful for selection of patients for ICSI. We also developed a number of new tests including sperm-ZP binding, sperm-ZP penetration and the ZP-induced AR and evaluated the clinical value of these tests. Sperm-ZP binding and sperm-ZP penetration tests are the most powerful indicators for sperm fertilizing ability in vitro. The ZP-induced AR is highly correlated with sperm-ZP penetration. We discovered a condition we call disordered ZP-induced AR which causes serve infertility in up to 25% men with otherwise idiopathic infertility In conclusion, the combination of semen analysis with advanced sperm function

关键词： male infertility sperm function tests sperm-oocyte interactions IVF/ICSI

Nucleotide sequence conservation of novel and established cis-regulatory sites within the tyrosine hydroxylase gene promoter

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Frontiers in Biology 2015年第1期10卷 74-90页

作者： Meng WANG Kasturi BANERJEE Harriet baker John W. CAVE Burke Medical Research Institute White Plains NY 10605 USA Weill Cornell Medical College Brain and Mind Research Institute NY 10065 USA

Tyrosine hydroxylase （TH） is the rate-limiting enzyme in catecholamine biosynthesis and its gene proximal promoter （〈 1 kb upstream from the transcription start site） is essential for regulating transcription in both the developing and adult nervous systems. Several putative regulatory elements within the TH proximal promoter have been reported, but evolutionary conservation of these dements has not been thoroughly investigated. Since many vertebrate species are used to model development, function and disorders of human catecholaminergic neurons, identifying evolutionarily conserved transcription regulatory mechanisms is a high priority. In this study, we align TH proximal promoter nucleotide sequences from several vertebrate species to identify evolutionarUy conserved motifs. This analysis identified three elements （a TATA box, cyclic AMP response element （CRE） and a 5＇-GGTGG-3＇ site） that constitute the core of an ancient vertebrate TH promoter. Focusing on only eutherian mammals, two regions of high conservation within the proximal promoter were identified： a -250 bp region adjacent to the transcription start site and a -85 bp region located approximately 350 bp further upstream. Within both regions, conservation of previously reported cis-regulatory motifs and human single nucleotide variants was evaluated. Transcription reporter assays in a TH-expressing cell line demonstrated the functionality of highly conserved motifs in the proximal promoter regions and electromobility shift assays showed that brain-region specific complexes assemble on these motifs. These studies also identified a non-canonical CRE binding （CREB） protein recognition element in the proximal promoter. Together, these studies provide a detailed analysis of evolutionary conservation within the TH promoter and identify potential cisregulatory motifs that underlie a core set of regulatory mechanisms in mammals.

关键词： catecholamine dopamine transcription evolution

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In Memoriam:*** ***

International Soil and Water Conservation Research 2021年第4期9卷 485-489页

作者： Dennis C.Flanagan Richard M.Cruse James L.baker Paige Chyu USDA-Agricultural Research Service National Soil Erosion Research LaboratoryWest LafayetteINUSA Department of Agronomy Iowa State UniversityAmesIAUSA Department of Agricultural&Biosystems Engineering Iowa State UniversityAmesIAUSA International Research and Training Center on Erosion and Sedimentation BeijingChina

The soil erosion research and soil and water conservation global community lost a treasured member on November 20,2020,when *** Matthew Laflen(Fig.1)*** one with a friendly welcoming smile,John had hundreds of friends,both personally and professionally throughout the *** article includes many of his professional and scientific contributions,and impacts from his research and outreach activities.

关键词： soil hundreds professional