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Search Results: 1 - 10 of 153634 matches for " Justin H. Berger "
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Major Facilitator Superfamily Domain-Containing Protein 2a (MFSD2A) Has Roles in Body Growth, Motor Function, and Lipid Metabolism
Justin H. Berger, Maureen J. Charron, David L. Silver
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050629
Abstract: The metabolic adaptations to fasting in the liver are largely controlled by the nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARα), where PPARα upregulates genes encoding the biochemical pathway for β-oxidation of fatty acids and ketogenesis. As part of an effort to identify and characterize nutritionally regulated genes that play physiological roles in the adaptation to fasting, we identified Major facilitator superfamily domain-containing protein 2a (Mfsd2a) as a fasting-induced gene regulated by both PPARα and glucagon signaling in the liver. MFSD2A is a cell-surface protein homologous to bacterial sodium-melibiose transporters. Hepatic expression and turnover of MFSD2A is acutely regulated by fasting/refeeding, but expression in the brain is constitutive. Relative to wildtype mice, gene-targeted Mfsd2a knockout mice are smaller, leaner, and have decreased serum, liver and brown adipose triglycerides. Mfsd2a knockout mice have normal liver lipid metabolism but increased whole body energy expenditure, likely due to increased β-oxidation in brown adipose tissue and significantly increased voluntary movement, but surprisingly exhibited a form of ataxia. Together, these results indicate that MFSD2A is a nutritionally regulated gene that plays myriad roles in body growth and development, motor function, and lipid metabolism. Moreover, these data suggest that the ligand(s) that are transported by MFSD2A play important roles in these physiological processes and await future identification.
DlgS97/SAP97, a Neuronal Isoform of Discs Large, Regulates Ethanol Tolerance
Rajani Maiya,Seonok Lee,Karen H. Berger,Eric C. Kong,Justin B. Slawson,Leslie C. Griffith,Kogo Takamiya,Richard L. Huganir,Ben Margolis,Ulrike Heberlein
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048967
Abstract: From a genetic screen for Drosophila melanogaster mutants with altered ethanol tolerance, we identified intolerant (intol), a novel allele of discs large 1 (dlg1). Dlg1 encodes Discs Large 1, a MAGUK (Membrane Associated Guanylate Kinase) family member that is the highly conserved homolog of mammalian PSD-95 and SAP97. The intol mutation disrupted specifically the expression of DlgS97, a SAP97 homolog, and one of two major protein isoforms encoded by dlg1 via alternative splicing. Expression of the major isoform, DlgA, a PSD-95 homolog, appeared unaffected. Ethanol tolerance in the intol mutant could be partially restored by transgenic expression of DlgS97, but not DlgA, in specific neurons of the fly’s brain. Based on co-immunoprecipitation, DlgS97 forms a complex with N-methyl-D-aspartate (NMDA) receptors, a known target of ethanol. Consistent with these observations, flies expressing reduced levels of the essential NMDA receptor subunit dNR1 also showed reduced ethanol tolerance, as did mutants in the gene calcium/calmodulin-dependent protein kinase (caki), encoding the fly homolog of mammalian CASK, a known binding partner of DlgS97. Lastly, mice in which SAP97, the mammalian homolog of DlgS97, was conditionally deleted in adults failed to develop rapid tolerance to ethanol’s sedative/hypnotic effects. We propose that DlgS97/SAP97 plays an important and conserved role in the development of tolerance to ethanol via NMDA receptor-mediated synaptic plasticity.
On the Milankovitch sensitivity of the Quaternary deep-sea record
W. H. Berger
Climate of the Past Discussions , 2013, DOI: 10.5194/cpd-9-1237-2013
Abstract: The response of the climate system to external forcing has become an item of prime interest in the context of global warming, especially with respect to the rate of melting land-based ice masses. The deep-sea record of ice-age climate change has been useful in assessing the sensitivity of the climate system to such forcing, notably to orbital forcing, which is well-known for the last several million years. When comparing response and forcing, one finds that sensitivity varies greatly through time, apparently in dependence on the state of the system. The changing stability of ice masses presumably is the underlying cause for the changing state of the system. A buildup of vulnerable ice masses within the latest Tertiary, when going into the ice ages, is conjectured to cause a stepwise increase of climate variability since the early Pliocene.
Distinguishing between parenchymal and anastomotic leakage at duct-to-mucosa pancreatic reconstruction in pancreaticoduodenectomy
Justin H Nguyen
World Journal of Gastroenterology , 2008,
Abstract: AIM: To distinguish anastomotic from parenchymal leakage at duct-to-mucosa reconstruction of the pancreatic remnant.METHODS: We reviewed the charts of 68 pancreaticod-uodenectomies performed between 5/2000 and 12/2005 with end-to-side duct-to-mucosa pancreatojejunostomy (PJ). The results of pancreatography, as well as peripancreatic drain volumes, and amylase levels were analyzed.RESULTS: Of 68 pancreatojejunostomies, 48 had no leak by pancreatography and had low-drain amylase (normal); eight had no pancreatographic leak but had elevated drain amylase (parenchymal leak); and 12 had pancreatographic leak and elevated drain amylase (anastomotic leak). Although drain volumes in the parenchymal leak group were significantly elevated at postoperative day (POD) 4, no difference was found at POD 7. Drain amylase level was not significantly different at POD 4. In contrast, at POD 7, the anastomotic-leak group had significantly elevated drain amylase level compared with normal and parenchymal-leak groups (14158 ± 24083 IU/L vs 89 ± 139 IU/L and 1707 ± 1515 IU/L, respectively, P = 0.012).CONCLUSION: For pancreatic remnant reconstruction after pancreaticoduodenectomy, a combination of pancreatogram and peripancreatic drain amylase levels can be used to distinguish between parenchymal and anastomotic leakage at pancreatic remnant reconstruction.
Effect of Land Use Change on Carbon Content and CO2 Flux of Cloud Forest Soils, Santa Elena, Costa Rica  [PDF]
Lawrence H. Tanner, David L. Smith, Jessica Curry, Justin Twist
Open Journal of Soil Science (OJSS) , 2014, DOI: 10.4236/ojss.2014.42009
Abstract:

We investigated the effects of land-use changes on soil carbon storage and soil CO2 flux by comparing soils from mature cloud forest and 31-year-old secondary forest, both in the Santa Elena Forest Reserve, a municipallyowned reserve at an elevation of 1600 to 1700 m near the town of Monteverde, and a clear-cut pasture near the reserve. Soils in the mature forest exhibit only weak horizonation but typically thick A horizons; they also consistently yield the highest carbon contents in the upper 30 cm. Soil CO2 flux was the highest in these soils, but also displayed the highest spatial variability. Secondary forest soils contain substantially less soil carbon than mature forest soils, but more than pasture soils. CO2 flux in the secondary forest soils was more similar to that of the mature forest, but displayed lower spatial variability. The pasture soils contain less soil carbon and produced lower CO2 flux levels than either of the forest soils. The pasture soils typically contain a well-defined coarse sandy layer 10 to 20 cm below the surface that we interpret as a sediment layer deposited across much of the landscape following a widespread erosion event, likely a consequence of the clear-cutting. Soil nitrogen concentrations are more than an order of magnitude lower than soil carbon concentrations, and display no trends between the different landscapes examined. Our preliminary results suggest that reforestation does restore soil carbon to clear-cut landscapes, but returning soil carbon levels to pre-land use levels occurs at a time scale of centuries, rather than decades.

Spatial heterogeneity of satellite derived land surface parameters and energy flux densities for LITFASS-area
A. Tittebrand,F. H. Berger
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2009,
Abstract: Based on satellite data in different temporal and spatial resolution, the current use of frequency distribution functions (PDF) for surface parameters and energy fluxes is one of the most promising ways to describe subgrid heterogeneity of a landscape. Objective of this study is to find typical distribution patterns of parameters (albedo, NDVI) for the determination of the actual latent heat flux (L.E) determined from highly resolved satellite data within pixel on coarser scale. Landsat ETM+, Terra MODIS and NOAA-AVHRR surface temperature and spectral reflectance were used to infer further surface parameters and radiant- and energy flux densities for LITFASS-area, a 20×20 km2 heterogeneous area in Eastern Germany, mainly characterised by the land use types forest, crop, grass and water. Based on the Penman-Monteith-approach L.E, as key quantity of the hydrological cycle, is determined for each sensor in the accordant spatial resolution with an improved parametrisation. However, using three sensors, significant discrepancies between the inferred parameters can cause flux distinctions resultant from differences of the sensor filter response functions or atmospheric correction methods. The approximation of MODIS- and AVHRR- derived surface parameters to the reference parameters of ETM (via regression lines and histogram stretching, respectively), further the use of accurate land use classifications (CORINE and a new Landsat-classification), and a consistent parametrisation for the three sensors were realized to obtain a uniform base for investigations of the spatial variability. The analyses for 4 scenes in 2002 and 2003 showed that for forest clear distribution-patterns for NDVI and albedo are found. Grass and crop distributions show higher variability and differ significantly to each other in NDVI but only marginal in albedo. Regarding NDVI-distribution functions NDVI was found to be the key variable for L.E-determination.
Spatial heterogeneity of satellite derived land surface parameters and energy flux densities for LITFASS-area
A. Tittebrand,F. H. Berger
Atmospheric Chemistry and Physics Discussions , 2008,
Abstract: Remote sensing data provide area integrated information of surface properties in different spatial or temporal resolutions according to different sensor features. Landsat ETM+, Terra MODIS and NOAA-AVHRR surface temperature and spectral reflectance were used to infer further surface parameters and radiant- and energy flux densities for LITFASS-area, a 20×20 km2 heterogeneous area in Eastern Germany, mainly characterized by the land use types forest, crop, grass and water. Based on the Penman-Monteith-approach the actual latent heat flux (L.E), as key quantity of the hydrological cycle, is determined for each sensor in the accordant spatial resolution with an improved parametrization. However, using three sensors, significant discrepancies between the inferred parameters can cause flux distinctions resultant from differences of the sensor filter response functions or atmospheric correction methods. The approximation of MODIS- and AVHRR- derived surface parameters to the reference parameters of ETM (via regression lines and histogram stretching, respectively), further the use of accurate land use classifications (CORINE and a new Landsat-classification), and a consistent parametrization for the three sensors were realized to obtain a uniform base for investigations of the spatial variability. For the target area the spatial heterogeneity is analysed investigating frequency distribution functions (PDF) for surface parameters and energy fluxes. PDF is the most promising way to describe subgrid heterogeneity due to the given data in different spatial resolution. Aim of this study is to find typical distribution pattern of parameters (albedo, NDVI) for the determination of L.E determined from the highly resolved ETM data within pixel on coarser scale (MODIS, AVHRR). The analyses for 4 scenes in 2002 and 2003 showed that clear distribution-pattern for forest for NDVI and albedo are found. Grass and crop distributions show higher variability and differ significantly to each other in NDVI but only marginal in albedo. Regarding NDVI-distribution functions NDVI was found to be the key variable for L.E-determination.
Breakdown of the coherent state path integral: two simple examples
Justin H. Wilson,Victor Galitski
Physics , 2010, DOI: 10.1103/PhysRevLett.106.110401
Abstract: We show how the time-continuous coherent state path integral breaks down for both the single-site Bose-Hubbard model and the spin path integral. Specifically, when the Hamiltonian is quadratic in a generator of the algebra used to construct coherent states, the path integral fails to produce correct results following from an operator approach. As suggested by previous authors, we note that the problems do not arise in the time-discretized version of the path integral.
Kinderwunsch Online Coaching - ein webbasiertes Selbsthilfeprogramm
H?mmerli K,Znoj H,Berger T
Journal für Reproduktionsmedizin und Endokrinologie , 2009,
Abstract: Immer mehr Paare bleiben ungewollt kinderlos. Obschon sich infertile Patienten generell bezüglich psychopathologischer Auff lligkeiten nicht von der Allgemeinbev lkerung unterscheiden, stellt die Zeit des Bangens und Hoffens auf ein Kind, die Behandlung und die Verarbeitung der Kinderlosigkeit eines der stressreichsten Lebensereignisse dar. Insbesondere w hrend der reproduktionsmedizinischen Behandlung wurden kurzfristig erh hte Werte in Depressivit t und ngstlichkeit bei infertilen Frauen best tigt. Da oftmals psychologische Unterstützung fehlt und ein offener Umgang mit Infertilit t für die Paare h ufig schwierig ist, sucht eine Vielzahl infertiler Patienten aus dem Internet Informationen und Austausch heute existieren unz hlige Informationsseiten und Selbsthilfeforen zu Infertilit t. Gleichzeitig besteht ein Mangel an empirisch und theoretisch fundierten psychologischen Unterstützungsans tzen. In diesem Beitrag wird das erste deutschsprachige webbasierte Selbsthilfebehandlungsprogramm für infertile Patienten vorgestellt. Erfahrungen einer ersten Evaluation des Programms werden diskutiert.
The Crucial Role of Bilateral Infraclavicular Nerve Blocks in the Anesthetic Management of a Trauma Patient  [PDF]
Eric P. Chiang, Paul Dangerfield, Jaideep H. Mehta, Marian Sherman, Jeffrey S. Berger
Open Journal of Anesthesiology (OJAnes) , 2012, DOI: 10.4236/ojanes.2012.24026
Abstract: Bilateral brachial plexus blocks and regional anesthesia in trauma patients are rarely performed due to potential complications when using these techniques. We illustrate a case in which bilateral infraclavicular nerve blocks were placed as part of a multimodal approach to pain management in a trauma patient. We discuss potential hazards, important considerations, and rationale for attempting this procedure. Ultimately, performing bilateral brachial plexus nerve blocks in trauma patients is a viable option when choosing pain management techniques.
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