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Progesterone modulates m TOR in the hippocampus of mice after traumatic brain injury

Neural Regeneration Research 2018年第3期13卷 434-439页

作者： richard justin garling Lora Talley Watts Shane Sprague Murat Digicaylioglu Department of Neurosurgery Wayne State University Detroit MI USA School of Medicine The University of Texas Health Science Center at San Antonio San Antonio TX USA Department of Neurosurgery The University of Texas Health Science Center at San Antonio San Antonio TX USA

Spinal cord injury results in the loss of motor and sensory pathways and spontaneous regeneration of adult mammalian spinal cord neurons is limited. Chitosan and sodium alginate have good biocompatibility, biodegradability, and are suitable to assist the recovery of damaged tissues, such as skin, bone and nerve. Chitosan scaffolds, sodium alginate scaffolds and chitosan-sodium alginate scaffolds were separately transplanted into rats with spinal cord hemisection. Basso-Beattie-Bresnahan locomotor rating scale scores and electrophysiological results showed that chitosan scaffolds promoted recovery of locomotor capacity and nerve transduction of the experimental *** days after surgery, chitosan scaffolds retained the original shape of the spinal cord. Compared with sodium alginate scaffolds- and chitosan-sodium alginate scaffolds-transplanted rats, more neurofilament-H-immunoreactive cells （regenerating nerve fibers） and less glial fibrillary acidic protein-immunoreactive cells （astrocytic scar tissue） were observed at the injury site of experimental rats in chitosan scaffold-transplanted rats. Due to the fast degradation rate of sodium alginate, sodium alginate scaffolds and composite material scaffolds did not have a supporting and bridging effect on the damaged tissue. Above all, compared with sodium alginate and composite material scaffolds, chitosan had better biocompatibility, could promote the regeneration of nerve fibers and prevent the formation of scar tissue,and as such, is more suitable to help the repair of spinal cord injury.

关键词： nerve regeneration spinal cord injury chitosan sodium alginate functional recovery scaffold neurofilament-H glial fibrillary acidic protein scar tissue locomotor capacity neural regeneration

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Does progesterone show neuroprotective effects on traumatic brain injury through increasing phosphorylation of Akt in the hippocampus?

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Neural Regeneration Research 2014年第21期9卷 1891-1896页

作者： richard justin garling Lora Talley Watts Shane Sprague Lauren Fletcher David F.Jimenez Murat Digicaylioglu Department of Neurosurgery University of Texas Health Science CenterSan AntonioTXUSA Research Imaging Institute University of Texas Health Science CenterSan AntonioTXUSA Department of Cellular and Structural Biology University of Texas Health Science CenterSan AntonioTXUSA Department of Neurology University of Texas Health Science CenterSan AntonioTXUSA

There are currently no federally approved neuroprotective agents to treat traumatic brain injury. Progesterone, a hydrophobic steroid hormone, has been shown in recent studies to exhibit neu-roprotective effects in controlled cortical impact rat models. Akt is a protein kinase known to play a role in cell signaling pathways that reduce edema, inlfammation, apoptosis, and promote cell growth in the brain. This study aims to determine if progesterone modulates the phosphor-ylation of Aktvia its threonine 308 phosphorylation site. Phosphorylation at the threonine 308 site is one of several sites responsible for activating Akt and enabling the protein kinase to carry out its neuroprotective effects. To assess the effects of progesterone on Akt phosphorylation, C57BL/6 mice were treated with progesterone （8 mg/kg） at 1 （intraperitonally）, 6, 24, and 48 hours （subcutaneously） post closed-skull traumatic brain injury. The hippocampus was harvest-ed at 72 hours post injury and prepared for western blot analysis. Traumatic brain injury caused a signiifcant decrease in Akt phosphorylation compared to sham operation. However, mice treat-ed with progesterone following traumatic brain injury had an increase in phosphorylation of Akt compared to traumatic brain injury vehicle. Our ifndings suggest that progesterone is a viable treatment option for activating neuroprotective pathways after traumatic brain injury.

关键词： nerve regeneration Akt traumatic brain injury progesterone apoptosis neuroprotec-tion brain injury western blotting controlled cortical impact neural regeneration

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Contaminated open fracture and crush injury: a murine model

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Bone Research 2015年第1期3卷 31-39页

作者： Shawn R Gilbert justin Camara richard Camara Lynn Duffy Ken Waites Hyunki Kim Kurt Zinn Department of Surgery University of Alabama at Birmingham AL USA Loma Linda School of Medicine Loma LindaCAUSA Departments of Pathology University of Alabama at BirminghamAL USA Department of Radiology University of Alabama at BirminghamAL USA

Modern warfare has caused a large number of severe extremity injuries, many of which become infected. In more recent conflicts, a pattern of co-infection with Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus has emerged. We attempted to recreate this pattern in an animal model to evaluate the role of vascularity in contaminated open fractures. Historically, it has been observed that infected bones frequently appear hypovascular, but vascularity in association with bone infection has not been examined in animal models. Adult rats underwent femur fracture and muscle crush injury followed by stabilization and bacterial contamination with A. baumannii complex and methicillin-resistant Staphylococcus *** and perfusion were assessed by micro CT angiography and SPECT scanning, respectively, at 1, 2 and 4 weeks after injury. Quantitative bacterial cultures were also obtained. Multi-bacterial infections were successfully created, with methicillin-resistant S. aureus predominating. There was overall increase in blood flow to injured limbs that was markedly greater in bacteria-inoculated limbs. Vessel volume was greater in the infected group. Quadriceps atrophy was seen in both groups, but was greater in the infected group. In this animal model, infected open fractures had greater perfusion and vascularity than non-infected limbs.

关键词： MRSA Contaminated open fracture and crush injury a murine model

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Exact Dynamic Modeling of PWM DC-to-DC Power Converters—Part II: Discontinuous Conduction Mode

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Journal of Power and Energy Engineering 2021年第5期9卷 48-62页

作者： justin Simmons richard Tymerski Maseeh College of Engineering and Computer Science Portland State University Portland USA

This paper follows on from the first paper, Part I, where a general formulation of a describing function approach to frequency response determination of switched linear networks, such as PWM converters, was simplified and updated. The models assume a piecewise linear state space equation description of the system and results in a closed form solution for the sought after frequency response. In Part I, model derivation was demonstrated for the case of PWM converters operating in the continuous conduction mode (CCM). This operating mode does not feature any state dependent switching times. In this paper, Part II, frequency response models for any transfer function for PWM converters operating in discontinuous conduction mode (DCM) are derived based on the theory presented in Part I. This operating model features state dependent switching times. The describing function models developed are exact and therefore, in terms of accuracy, are to be preferred over averaged models which are widely used. The example of a boost dc-to-dc converter operating in DCM is simulated to obtain the control to output and input to output frequency responses and are compared with the models derived here. Excellent agreement between the simulated and model responses was found. Matlab code implementing the analytical models is also presented which the user can adapt for any other PWM converter topology. The models derived here may be used as a basis from which simplified models may be derived while still preserving required accuracy.

关键词： Describing Function DC-to-DC Switching Power Converter Small-Signal Modeling Frequency Response

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Exact Dynamic Modeling of PWM DC-to-DC Power Converters—Part I: Continuous Conduction Mode

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Journal of Power and Energy Engineering 2021年第5期9卷 26-47页

作者： justin Simmons richard Tymerski Maseeh College of Engineering and Computer Science Portland State University Portland USA

A general approach is presented by which the exact frequency response of any transfer function of switched linear networks can be determined. This is achieved with a describing function approach using a state space equation formulation. This work presents a somewhat simplified set of equations to one previously given by one of the authors. To demonstrate application of the general formulation, the frequency responses of switched networks used as PWM DC-to-DC converters operating in continuous conduction mode (CCM) under voltage mode control are derived. (The accompanying paper, Part II, will present results for converters operating in discontinuous conduction mode (DCM)). From the general sets of equations developed here, both the control to output and input source variation to output frequency responses are derived. The describing function approach enables exact frequency response determination, even at high frequencies where the accuracy using average models may be compromised. Confirmation of the accuracy of the derived models is provided by comparing the responses with those obtained using the commercial simulator PSIM on a PWM boost converter. The magnitude and phase responses are shown to match perfectly over the full range of frequencies up to close to half the switching frequency. Matlab code that implements the models is given such that the user can easily adapt for use with other PWM converter topologies.

关键词： Describing Function DC-to-DC Switching Power Converter Small-Signal Modeling Frequency Response

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Design and Control of an Alternative Buck PWM DC-to-DC Converter

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Journal of Power and Energy Engineering 2021年第6期9卷 43-61页

作者： justin Simmons richard Tymerski Department of Electrical & Computer Engineering Portland State University Portland Oregon USA

The second order dc-to-dc buck converter with input LC filter is widely used in industry. An alternative 4th order converter which has advantages in terms of control design leading to better transient performance is presented. A complete DC (steady state average and ripple quantities) and AC small-signal analyses of this converter for both uncoupled and coupled inductor cases is provided. Conditions for achieving, in a lossless manner, a minimum phase control-to-output transfer function are found, which ameliorates regulator design while maximizing loop bandwidth. A closed loop regulator design procedure is presented and the performance of a design example is examined with a prototype. It is believed that this converter is a good alternative in applications where the second order buck converter augmented with an input filter has been traditionally utilized.

关键词： DC-to-DC Converter Buck Converter

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Spectral matching techniques (SMTs) and automated cropland classification algorithms (ACCAs) for mapping croplands of Australia using MODIS 250-m time-series (2000–2015) data

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International Journal of Digital Earth 2017年第9期10卷 944-977页

作者： Pardhasaradhi Teluguntla Prasad S.Thenkabail Jun Xiong Murali Krishna Gumma Russell G.Congalton Adam Oliphant justin Poehnelt Kamini Yadav Mahesh Rao richard Massey U.S.Geological Survey(USGS) Western Geographic Science CenterFlagstaffAZUSA Bay Area Environmental Research Institute(BAERI) PetalumaCAUSA International Crops Research Institute for the Semi-Arid Tropics(ICRISAT) PatancheruHyderabadIndia Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA Department of Forestry and Wildland Resources Humboldt State UniversityArcataCAUSA School of Earth Science and Environmental Sustainability Northern Arizona UniversityFlagstaffAZUSA

Mapping croplands,including fallow areas,are an important measure to determine the quantity of food that is produced,where they are produced,and when they are produced(***).Furthermore,croplands are known as water guzzlers by consuming anywhere between 70%and 90%of all human water use *** these facts and the increase in global population to nearly 10 billion by the year 2050,the need for routine,rapid,and automated cropland mapping year-after-year and/or season-after-season is of great *** overarching goal of this study was to generate standard and routine cropland products,year-after-year,over very large areas through the use of two novel methods:(a)quantitative spectral matching techniques(QSMTs)applied at continental level and(b)rule-based Automated Cropland Classification Algorithm(ACCA)with the ability to hind-cast,now-cast,and *** was chosen for the study given its extensive croplands,rich history of agriculture,and yet nonexistent routine yearly generated cropland products using multi-temporal remote *** research produced three distinct cropland products using Moderate Resolution Imaging Spectroradiometer(MODIS)250-m normalized difference vegetation index 16-day composite time-series data for 16 years:2000 through *** products consisted of:(1)cropland extent/areas versus cropland fallow areas,(2)irrigated versus rainfed croplands,and(3)cropping intensities:single,double,and continuous *** accurate reference cropland product(RCP)for the year 2014(RCP2014)produced using QSMT was used as a knowledge base to train and develop the ACCA algorithm that was then applied to the MODIS time-series data for the years 2000–2015.A comparison between the ACCA-derived cropland products(ACPs)for the year 2014(ACP2014)versus RCP2014 provided an overall agreement of 89.4%(kappa=0.814)with six classes:(a)producer’s accuracies varying between 72%and 90%and(b)user’s accuracies varying between 79%and 90%.ACPs

关键词： Croplands food security automated cropland classification algorithms machine learning algorithms quantitative spectral matching techniques Australia

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Cyclophilins A and B oppositely regulate renal tubular epithelial cell phenotype

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Journal of Molecular Cell Biology 2020年第7期12卷 499-514页

作者： Eduard Sarró Mónica Durán Ana Rico Diana Bou-Teen Vanesa Fernández-Majada Anthony J.Croatt Karl A.Nath Maria Teresa Salcedo justin H.Gundelach Daniel Batlle richard J.Bram Anna Meseguer Renal Physiopathology Group CIBBIM-NanomedicineVall d’Hebron Research Institute08035 BarcelonaSpain Cardiovascular Diseases Group Vall d’Hebron Research Institute08035 BarcelonaSpain Biomimetic Systems for Cell Engineering Laboratory Institute for Bioengineering of Catalonia(IBEC)The Barcelona Institute of Science and Technology(BIST)08028 BarcelonaSpain Division of Nephrology and Hypertension and Department of Medicine Mayo ClinicRochesterMN 55905USA Department of Pathology Hospital Universitari Vall d’Hebron08035 BarcelonaSpain Department of Pediatric and Adolescent Medicine College of MedicineMayo ClinicRochesterMN 55905USA Department of Biochemistry and Molecular Biology College of MedicineMayo ClinicRochesterMN 55905USA Division of Nephrology and Hypertension Northwestern University Feinberg School of MedicineChicagoIL 60611USA Department of Immunology College of MedicineMayo ClinicRochesterMN 55905USA Departament de Bioquímica i Biologia Molecular Unitat de Bioquímica de MedicinaUniversitat Autònoma de Barcelona08193 BellaterraSpain Red de Investigación Renal(REDINREN) Instituto de Salud Carlos III-FEDER28040 MadridSpain

Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial–mesenchymal transition(pEMT),proliferation,and further redifferentiation into specialized tubule epithelial cells(TECs).Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase(PPIase)activity of cyclophilin(Cyp)proteins,we hypothesized that cyclophilins could regulate TEC *** we demonstrate that in cultured TECs,CypA silencing triggers loss of epithelial features and enhances transforming growth factorβ(TGFβ)-induced EMT in association with upregulation of epithelial repressors Slug and *** pro-epithelial action of CypA relies on its PPIase *** contrast,CypB emerges as an epithelial repressor,because CypB silencing promotes epithelial differentiation,prevents TGFβ-induced EMT,and induces tubular structures in 3D *** addition,in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction,inflammatory and pro-fibrotic events were *** silencing/knockout leads to Slug,but not Snail,*** support of Slug expression depends on its endoplasmic reticulum location,where it interacts with calreticulin,a calcium-buffering chaperone related to Slug *** CypB silencing reduces ionomycin-induced calcium release and Slug upregulation,we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium *** conclusion,this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair.

关键词： cyclophilins epithelial phenotype Slug TGFβ UUO fibrosis

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Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators:Outcome analysis using telemetry review

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World Journal of Gastrointestinal Endoscopy 2012年第3期4卷 87-93页

作者： justin R Cuschieri Mohammed N Osman richard CK Wong Amitabh Chak Gerard A Isenberg Division of Gastroenterology Department of MedicineAlbert Einstein Medical Center5401 Old York RoadKlein building suite 363PhiladelphiaPA 19141United States Division of Cardiology Department of MedicineUniversity Hospitals Case Medical Center11100 Euclid AvenueClevelandOH 44106United States Division of Gastroenterology and Liver Disease Department of MedicineUniversity Hospitals Case Medical Center11100 Euclid AvenueClevelandOH 44016United States

AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METHODS:Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from *** searched for unexplained electrocardiogram (ECG) findings,changes in CP andICD set parameters,any abnormality in transmitted capsule data,and adverse clinical ***:There were no adverse events or hemodynamically significant arrhythmias *** and ICD set parameters were *** majority of ECG abnormalities were also found in pre-or post-SBCE ECG tracings and the CP behavior during arrhythmias appeared *** patients seemed to have episodes of undersensing by the ***,similar findings were documented in ECGs taken outside the time frame of the *** patient was observed to have a low signal encountered from the capsule resulting in lack of localization,but no images were ***:Capsule-induced EMI remains a possibility but is unlikely to be clinically *** interference of SBCE is also possible,but is infrequent and does not result in loss of images transmitted by the capsule.

关键词： Small bowel capsule endoscopy Cardiac pacemakers Implantable cardioverter defibrillators Electromagnetic interference Telemetry review

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The acute and chronic effect of low temperature on survival, heart rate and neural function in crayfish (<i>Procambarus clarkii</i>) and prawn (<i>Macrobrachium rosenbergii</i>) species

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Open Journal of Molecular and Integrative Physiology 2012年第3期2卷 75-86页

作者： Yoo Sun Chung richard M. Cooper justin Graff Robin L. Cooper Department of Biology University of Kentucky Lexington USA

The effect of acute and chronic cold exposure on heart rate (HR) and neuronal function in crayfish Procambarus clarkii and prawns Macrobrachium rosenbergii was addressed. This is particularly important since prawn farms of this species are used for aquaculture in varied climates world wide. The success of P. clarkii as an invasive species throughout the world may in part be due to their ability to acclimate to cold and warm habitats. A set of experiments was devised to address the physiological abilities of these species in managing rapid changes to cold environments as well as their ability to respond to sensory stimuli by using behavior and a bioindex of HR. Prawns died within 2 hrs when moved from 21℃ to 5℃. Crayfish reduced their HR but survived for at least a week with this rapid change. Changes in temperature of 5℃ each week resulted in death of the prawns when 10℃ was reached. Some died at 16℃ and some lasted at 10℃ for 1 day before dying. Crayfish remained responsive to sensory stimuli and survived with either rapid or slow changes in temperature from 21℃ to 5℃. Primary sensory neurons were rapidly inhibited in prawns with an acute change to 5℃, where as in crayfish the activity was reduced but not completely inhibited. An induced sensory-CNS-motor circuit elicited activity at neuromuscular junctions in prawns and crayfish at 21℃ but with acute changes to 5℃only in crayfish was the circuit functionally intact. The ability to survive rapid environmental temperature changes will impact survival and in time the distribution of a species. The significance of these findings is that they may account, in part, for the wide ecological distribution of P. clarkii as compared to M. rosenbergii. The invasiveness of organisms, as for P. clarkii, is likely linked to the physiological robustness to acute and chronic temperature changes of habitats.

关键词： Acclimate Adaptation Crustacean Heart Rate

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