500 research outputs found
Quantum Transport with Spin Dephasing: A Nonequilibrium Green's Function Approach
A quantum transport model incorporating spin scattering processes is
presented using the non-equilibrium Green's function (NEGF) formalism within
the self-consistent Born approximation. This model offers a unified approach by
capturing the spin-flip scattering and the quantum effects simultaneously. A
numerical implementation of the model is illustrated for magnetic tunnel
junction devices with embedded magnetic impurity layers. The results are
compared with experimental data, revealing the underlying physics of the
coherent and incoherent transport regimes. It is shown that small variations in
magnetic impurity spin-states/concentrations could cause large deviations in
junction magnetoresistances.Comment: NEGF Formalism, Spin Dephasing, Magnetic Tunnel Junctions,
Magnetoresistanc
Effects of dietary diludine supplementation on growth, proximate composition, muscle and texture structure of rainbow trout juveniles
A feeding trial which lasted for eight weeks was conducted to investigate the effects of diludine, a growth promoter, on feed efficiency, muscle structure and proximate composition of juvenile rainbow trout. Diludine was added at 0.0(D0) 0.2(D1), 0.5(D2) and 1(D3) g kg^-1 to a casein-based diet, and every diet was given to the triplicated groups of juvenile rainbow trout. At the end of experiment, it was determined that a significant improvability existed for both growth and feed utilization in fish fed diets supplemented with diludine (p<0.05). Similarly, different concentrations of diludine affected the densitometric quantification of myofibrillar proteins in fish muscle according to results obtained by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The mean value of fiber diameters significantly increased in skeletal muscle with increasing concentrations of diludine. The histological results also showed hypertrophic adipocytes in skeletal muscle of fish fed D2 and D3 diets. The lowest elasticity values were observed in fish fed the control diet while those fed D3 diet had highest elasticity values. On the other hand, no differences were found between fish fed experimental diets in terms of survival rate and all fish exhibited similar proximate composition for protein, lipid, moisture and ash. Consequently, it may be suggested that dietary diludine supplementation up to 1 g kg^-1 concentration in the diets have positive impacts on growth of rainbow trout juveniles and the better growth in the fish fed with diludine supplements could be arise from muscle characteristics, in particular changes in fibres than proximate composition of the muscles
Neurogenic factor-induced Langerhans cell activation in diabetic mice with mechanical allodynia
Abstract
Background
Langerhans cells (LCs) are antigen-presenting dendritic cells located in the skin. It has been reported that LC activation is associated with painful diabetic neuropathy (PDN); however, the mechanism of LC activation is still unclear.
Methods
The db/db mouse, a rodent model of PDN, was used to study the roles of LCs in the development of PDN in type 2 diabetes. Hind foot pads from db/db and control db/+ mice from 5 to 24 weeks of age (encompassing the period of mechanical allodynia development and its abatement) were collected and processed for immunohistochemistry studies. LCs were identified with immunohistochemistry using an antibody against CD207 (Langerin). The intraepidermal nerve fibers and subepidermal nerve plexus were identified by immunohistochemistry of protein gene product 9.5 (PGP 9.5) and tropomyosin-receptor kinase (Trk) A, the high affinity nerve growth factor receptor.
Results
CD207-positive LCs increased in the db/db mouse during the period of mechanical allodynia, from 8 to 10 weeks of age, in both the epidermis and subepidermal plexus. At 16 weeks of age, when mechanical allodynia diminishes, LC populations were reduced in the epidermis and subepidermal plexus. Epidermal LCs (ELCs) were positive for Trk A. Subepidermal LCs (SLCs) were positive for CD68, suggesting that they are immature LCs. Additionally, these SLCs were positive for the receptor of advanced glycation end products (RAGE) and were in direct contact with TNF-α-positive nerve fibers in the subepidermal nerve plexus during the period of mechanical allodynia. Intrathecal administration of SB203580, a p38 kinase inhibitor, significantly reduced mechanical allodynia, TNF-α expression in the subepidermal plexus, and increased both ELC and SLC populations during the period of mechanical allodynia.
Conclusions
Our data support the hypothesis that increased LC populations in PDN are activated by p38-dependent neurogenic factors and may be involved in the pathogenesis of PDN.http://deepblue.lib.umich.edu/bitstream/2027.42/135942/1/12974_2013_Article_838.pd
Neurogenic factor-induced Langerhans cell activation in diabetic mice with mechanical allodynia
Abstract
Background
Langerhans cells (LCs) are antigen-presenting dendritic cells located in the skin. It has been reported that LC activation is associated with painful diabetic neuropathy (PDN); however, the mechanism of LC activation is still unclear.
Methods
The db/db mouse, a rodent model of PDN, was used to study the roles of LCs in the development of PDN in type 2 diabetes. Hind foot pads from db/db and control db/+ mice from 5 to 24 weeks of age (encompassing the period of mechanical allodynia development and its abatement) were collected and processed for immunohistochemistry studies. LCs were identified with immunohistochemistry using an antibody against CD207 (Langerin). The intraepidermal nerve fibers and subepidermal nerve plexus were identified by immunohistochemistry of protein gene product 9.5 (PGP 9.5) and tropomyosin-receptor kinase (Trk) A, the high affinity nerve growth factor receptor.
Results
CD207-positive LCs increased in the db/db mouse during the period of mechanical allodynia, from 8 to 10 weeks of age, in both the epidermis and subepidermal plexus. At 16 weeks of age, when mechanical allodynia diminishes, LC populations were reduced in the epidermis and subepidermal plexus. Epidermal LCs (ELCs) were positive for Trk A. Subepidermal LCs (SLCs) were positive for CD68, suggesting that they are immature LCs. Additionally, these SLCs were positive for the receptor of advanced glycation end products (RAGE) and were in direct contact with TNF-α-positive nerve fibers in the subepidermal nerve plexus during the period of mechanical allodynia. Intrathecal administration of SB203580, a p38 kinase inhibitor, significantly reduced mechanical allodynia, TNF-α expression in the subepidermal plexus, and increased both ELC and SLC populations during the period of mechanical allodynia.
Conclusions
Our data support the hypothesis that increased LC populations in PDN are activated by p38-dependent neurogenic factors and may be involved in the pathogenesis of PDN.http://deepblue.lib.umich.edu/bitstream/2027.42/112392/1/12974_2013_Article_838.pd
Organ-targeted high-throughput in vivo biologics screen identifies materials for RNA delivery
Therapies based on biologics involving delivery of proteins, DNA, and RNA are currently among the most promising approaches. However, although large combinatorial libraries of biologics and delivery vehicles can be readily synthesized, there are currently no means to rapidly characterize them in vivo using animal models. Here, we demonstrate high-throughput in vivo screening of biologics and delivery vehicles by automated delivery into target tissues of small vertebrates with developed organs. Individual zebrafish larvae are automatically oriented and immobilized within hydrogel droplets in an array format using a microfluidic system, and delivery vehicles are automatically microinjected to target organs with high repeatability and precision. We screened a library of lipid-like delivery vehicles for their ability to facilitate the expression of protein-encoding RNAs in the central nervous system. We discovered delivery vehicles that are effective in both larval zebrafish and rats. Our results showed that the in vivo zebrafish model can be significantly more predictive of both false positives and false negatives in mammals than in vitro mammalian cell culture assays. Our screening results also suggest certain structureâactivity relationships, which can potentially be applied to design novel delivery vehicles.National Institutes of Health (U.S.) (Transformative Research Award R01 NS073127)National Institutes of Health (U.S.) (Director's Innovator Award DP2 OD002989)David & Lucile Packard Foundation (Award in Science and Engineering)Sanofi Aventis (Firm)Foxconn International Holdings Ltd.Hertz Foundation (Fellowship)University Grants Committee (Hong Kong, China) (Early Career Award 125012)National Natural Science Foundation (China) (81201164)ITC (ITS/376/13)Chinese University of Hong Kong (Grant 9610215)Chinese University of Hong Kong (Grant 7200269
MEDICAL WASTE MANAGEMENT AT SAMUEL J. MOEDA NAVAL HOSPITAL KUPANG, NUSA TENGGARA TIMUR
Background: Hospital is a public health service agency that produces daily medical waste, especially solid waste that must be handled properly. Although the Indonesian Naval Hospital Samuel J. Moeda has implemented waste management and disposal, management is still ineffective in light of the lack of managerial resources, basic management processes, and incinerator unavailability as a final waste management tool. This study aimed to analyze the management of medical waste starting from input, process, and output, at Samuel J. Moeda Naval Hospital, Kupang, Nusa Tenggara Timur.
Subjects and Method: This study was descriptive with qualitative approach. It was conducted at Samuel J. Moeda Naval Hospital, Kupang, Nusa Tenggara Timur. A sample of 14 informants were selected for this study. The data were collected by in-depth interview, direct obesrvation, and document review. Checklist sheets were used to assist direct observation.
Results: Waste management was not well-performed with limited facilities and infrastructure, unspecified and inadequate budgeting. The process of solid medical waste management was not optimally performed, and there were some errors found during the process. Similarly, the output of solid medical waste management did not meet the standards set by the Minister of Health Regulation No. 1204/ 2004. It appears that waste management issues received little attention from the hospital management.
Conclusion: Medical waste management at Samuel J. Moeda, Naval Hospital, Kupang has not been well-performed. The hospital can pay attention to the potential of medical waste recycle for extended hospital purposes. Recruitment, education, and training, of medical waste management staff are urgently needed. Routine waste management evaluation is also needed to help create a healthy hospital environment.
Keywords: solid medical waste, management, hospita
A Thioacetal Photocage Designed for Dual Release: Application in the Quantitation of Therapeutic Release by Synchronous Reporter Decaging
Despite the immense potential of existing photocaging technology, its application is limited by the paucity of advanced caging tools. Here, we report on the design of a novel thioacetal orthoânitrobenzaldehyde (TNB) dual arm photocage that enabled control of the simultaneous release of two payloads linked to a single TNB unit. By using this cage, which was prepared in a single step from commercial 6ânitroverataldehyde, three drugâfluorophore conjugates were synthesized: TaxolâTNBâfluorescein, TaxolâTNBâcoumarin, and doxorubicinâTNBâcoumarin, and longâwavelength UVA lightâtriggered release experiments demonstrated that dual payload release occurred with rapid decay kinetics for each conjugate. In cellâbased assays performed in vitro, dual release could also be controlled by UV exposure, resulting in increased cellular fluorescence and cytotoxicity with potency equal to that of unmodified drug towards the KB carcinoma cell line. The extent of such dual release was quantifiable by reporter fluorescence measured in situ and was found to correlate with the extent of cytotoxicity. Thus, this novel dual arm cage strategy provides a valuable tool that enables both active control and realâtime monitoring of drug activation at the delivery site.Binary photocage: An orthoânitrobenzaldehydeâderived dual arm photocage was developed for realâtime monitoring of the simultaneous release of two payloads linked to a single cage unit. Lightâcontrolled uncaging of the drugâfluorophore conjugate resulted in increased cellular fluorescence, which was found to correlate with cytotoxicity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135367/1/cbic201600494.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135367/2/cbic201600494-sup-0001-misc_information.pd
High-throughput in vivo vertebrate screening
We demonstrate a high-throughput platform for cellular-resolution in vivo chemical and genetic screens on zebrafish larvae. The system automatically loads zebrafish from reservoirs or multiwell plates, and positions and rotates them for high-speed confocal imaging and laser manipulation of both superficial and deep organs within 19 s without damage. We performed small-scale test screening of retinal axon guidance mutants and neuronal regeneration assays in combination with femtosecond laser microsurgery.National Institutes of Health (U.S.) (Directorâs Innovator Award 1-DP2-OD002989â01)David & Lucile Packard Foundation (Award in Science and Engineering)Alfred P. Sloan Foundation (Award)Broad Institute of MIT and Harvard (Sparc Grant)National Science Foundation (U.S.) (Fellowship)Foxconn (Sponsorship
Electromagnetically Induced Transparency and Slow Light with Optomechanics
Controlling the interaction between localized optical and mechanical
excitations has recently become possible following advances in micro- and
nano-fabrication techniques. To date, most experimental studies of
optomechanics have focused on measurement and control of the mechanical
subsystem through its interaction with optics, and have led to the experimental
demonstration of dynamical back-action cooling and optical rigidity of the
mechanical system. Conversely, the optical response of these systems is also
modified in the presence of mechanical interactions, leading to strong
nonlinear effects such as Electromagnetically Induced Transparency (EIT) and
parametric normal-mode splitting. In atomic systems, seminal experiments and
proposals to slow and stop the propagation of light, and their applicability to
modern optical networks, and future quantum networks, have thrust EIT to the
forefront of experimental study during the last two decades. In a similar
fashion, here we use the optomechanical nonlinearity to control the velocity of
light via engineered photon-phonon interactions. Our results demonstrate EIT
and tunable optical delays in a nanoscale optomechanical crystal device,
fabricated by simply etching holes into a thin film of silicon (Si). At low
temperature (8.7 K), we show an optically-tunable delay of 50 ns with
near-unity optical transparency, and superluminal light with a 1.4 microseconds
signal advance. These results, while indicating significant progress towards an
integrated quantum optomechanical memory, are also relevant to classical signal
processing applications. Measurements at room temperature and in the analogous
regime of Electromagnetically Induced Absorption (EIA) show the utility of
these chip-scale optomechanical systems for optical buffering, amplification,
and filtering of microwave-over-optical signals.Comment: 15 pages, 9 figure
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