322 research outputs found
Managing the Service Supply Chain in the Department of Defense: An Empirical Study of Current Management Practices
Sponsored Report (for Acquisition Research Program)This paper presents the results of our ongoing research on the management of services acquisition in the Department of Defense. In this empirical study we developed and used a web-based survey to collect data on the acquisition strategy, procurement methods, and contract types used at Air Force and Navy installations. Specifically, we studied the current management practices in such areas as life cycle approach, project management, organization/management structure, and training provided to services acquisition personnel. We find that the majority of the services contracts awarded and administered conformed to our expectation. For example, most service contracts are competitively bid, fixed-priced awards without any type of contract incentive. However, we found that the Air Force and Navy use different contracting approaches''specifically in the areas of organizational level of acquisition offices (regional versus installation), the use of project teams, leaders of the acquisition effort (program personnel versus contracting officers), and managers of the services requirement (program personnel, contracting officers, and customer organizations). We analyzed the implications and impact of different approaches on the effectiveness of the contract management process and make recommendations on improving the management of services acquisition in the Department of Defense.Naval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited
Lateritic Plateaus in the Northern Western Ghats, India; a Review of Bauxite Mining Restoration Practices
In global consequences of rapidly changing climate and increased amphibian population decline, mapping amphibian diversity in biodiversity hotspots is essential. In this study we have systematically studied anurans of Phansad Wildlife Sanctuary in terms of species diversity, population structure, threat status and distribution. We recorded a total of 22 anuran species, of which 11 species are endemic to Western Ghats biodiversity hotspot. Family Dicroglossidae was found to be more species-rich. Spatial and temporal variation in anuran diversity was observed by using Shannon diversity and evenness indices. Most of the endemic and threatened anuran species are found to be associated with evergreen undisturbed forest patches. Habitat parameters like humidity, forest type, canopy coverage, riparian canopy coverage, stream persistence and litter depth are found to be major variables governing species diversity and distribution. Major anthropogenic threats to amphibians of Phansad Wildlife Sanctuary are discussed along with future conservation objectives. With range extension of species like Fejervarya caperata and Minervarya sahyadris further north in the Western Ghats, taxonomic ambiguities recorded during study are discussed briefly
Loss of stearoyl-CoA desaturase 2 disrupts inflammatory response in macrophages
Macrophages are innate immune cells that patrol tissues and are the first responders to detect infection. They orchestrate the host immune response in eliminating invading pathogens and the subsequent transition from inflammation to tissue repair. Macrophage dysfunction contributes to age-related pathologies, including low-grade inflammation in advanced age that is termed inflammaging. Our laboratory has previously identified that macrophage expression of a fatty acid desaturase, stearoyl-CoA desaturase 2 (SCD2), declines with age. Herein, we delineate the precise cellular effects of SCD2 deficiency in murine macrophages. We found that deletion o
High-spatial-resolution mapping and source apportionment of aerosol composition in Oakland, California, using mobile aerosol mass spectrometry
We investigated spatial and temporal patterns in the concentration and
composition of submicron particulate matter (PM1) in Oakland,
California, in the summer of 2017 using an aerosol mass spectrometer mounted
in a mobile laboratory. We performed  ∼ 160 h of mobile sampling in the
city over a 20-day period. Measurements are compared for three adjacent
neighborhoods with distinct land uses: a central business district
(downtown), a residential district (West Oakland), and a major
shipping port (port). The average organic aerosol (OA) concentration is
5.3 µg m−3 and contributes  ∼ 50 % of the PM1
mass. OA concentrations in downtown are, on average,
1.5 µg m−3 higher than in West Oakland and port. We
decomposed OA into three factors using positive matrix factorization:
hydrocarbon-like OA (HOA; 20 % average contribution), cooking OA (COA;
25 %), and less-oxidized oxygenated OA (LO-OOA; 55 %). The collective
45 % contribution from primary OA (HOA + COA) emphasizes the
importance of primary emissions in Oakland. The dominant source of primary OA
shifts from HOA-rich in the morning to COA-rich after lunchtime. COA in
downtown is consistently higher than West Oakland and port due to a large
number of restaurants. HOA exhibits variability in space and time. The
morning-time HOA concentration in downtown is twice that in port, but port
HOA increases more than two-fold during midday, likely because trucking
activity at the port peaks at that time. While it is challenging to
mathematically apportion traffic-emitted OA between drayage trucks and cars,
combining measurements of OA with black carbon and CO suggests that while
trucks have an important effect on OA and BC at the port, gasoline-engine
cars are the dominant source of traffic emissions in the rest of Oakland.
Despite the expectation of being spatially uniform, LO-OOA also exhibits
spatial differences. Morning-time LO-OOA in downtown is roughly 25 %
( ∼ 0.6 µg m−3) higher than the rest of Oakland. Even as
the entire domain approaches a more uniform photochemical state in the
afternoon, downtown LO-OOA remains statistically higher than West Oakland and
port, suggesting that downtown is a microenvironment with higher
photochemical activity. Higher concentrations of particulate sulfate (also of
secondary origin) with no direct sources in Oakland further reflect higher
photochemical activity in downtown. A combination of several factors (poor
ventilation of air masses in street canyons, higher concentrations of
precursor gases, higher concentrations of the hydroxyl radical) likely
results in the proposed high photochemical activity in downtown. Lastly,
through Van Krevelen analysis of the elemental ratios (H ∕ C, O ∕ C)
of the OA, we show that OA in Oakland is more chemically reduced than several
other urban areas. This underscores the importance of primary emissions in
Oakland. We also show that mixing of oceanic air masses with these primary
emissions in Oakland is an important processing mechanism that governs the
overall OA composition in Oakland.</p
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family
The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future
Functional Data Analysis Applied to Modeling of Severe Acute Mucositis and Dysphagia Resulting From Head and Neck Radiation Therapy.
Purpose Current normal tissue complication probability modeling using logistic regression suffers from bias and high uncertainty in the presence of highly correlated radiation therapy (RT) dose data. This hinders robust estimates of dose-response associations and, hence, optimal normal tissue-sparing strategies from being elucidated. Using functional data analysis (FDA) to reduce the dimensionality of the dose data could overcome this limitation.Methods and materials FDA was applied to modeling of severe acute mucositis and dysphagia resulting from head and neck RT. Functional partial least squares regression (FPLS) and functional principal component analysis were used for dimensionality reduction of the dose-volume histogram data. The reduced dose data were input into functional logistic regression models (functional partial least squares-logistic regression [FPLS-LR] and functional principal component-logistic regression [FPC-LR]) along with clinical data. This approach was compared with penalized logistic regression (PLR) in terms of predictive performance and the significance of treatment covariate-response associations, assessed using bootstrapping.Results The area under the receiver operating characteristic curve for the PLR, FPC-LR, and FPLS-LR models was 0.65, 0.69, and 0.67, respectively, for mucositis (internal validation) and 0.81, 0.83, and 0.83, respectively, for dysphagia (external validation). The calibration slopes/intercepts for the PLR, FPC-LR, and FPLS-LR models were 1.6/-0.67, 0.45/0.47, and 0.40/0.49, respectively, for mucositis (internal validation) and 2.5/-0.96, 0.79/-0.04, and 0.79/0.00, respectively, for dysphagia (external validation). The bootstrapped odds ratios indicated significant associations between RT dose and severe toxicity in the mucositis and dysphagia FDA models. Cisplatin was significantly associated with severe dysphagia in the FDA models. None of the covariates was significantly associated with severe toxicity in the PLR models. Dose levels greater than approximately 1.0Â Gy/fraction were most strongly associated with severe acute mucositis and dysphagia in the FDA models.Conclusions FPLS and functional principal component analysis marginally improved predictive performance compared with PLR and provided robust dose-response associations. FDA is recommended for use in normal tissue complication probability modeling
Chronic hyperglycemia induces trans-differentiation of human pancreatic stellate cells and enhances the malignant molecular communication with human pancreatic cancer cells
BACKGROUND:
Diabetes mellitus is linked to pancreatic cancer. We hypothesized a role for pancreatic stellate cells (PSC) in the hyperglycemia induced deterioration of pancreatic cancer and therefore studied two human cell lines (RLT-PSC, T3M4) in hyperglycemic environment.
METHODOLOGY/PRINCIPAL FINDINGS:
The effect of chronic hyperglycemia (CHG) on PSCs was studied using mRNA expression array with real-time PCR validation and bioinformatic pathway analysis, and confirmatory protein studies. The stress fiber formation (IC: αSMA) indicated that PSCs tend to transdifferentiate to a myofibroblast-like state after exposure to CHG. The phosphorylation of p38 and ERK1/2 was increased with a consecutive upregulation of CDC25, SP1, cFOS and p21, and with downregulation of PPARγ after PSCs were exposed to chronic hyperglycemia. CXCL12 levels increased significantly in PSC supernatant after CHG exposure independently from TGF-β1 treatment (3.09-fold with a 2.73-fold without TGF-β1, p<0.05). The upregualtion of the SP1 transcription factor in PSCs after CHG exposure may be implicated in the increased CXCL12 and IGFBP2 production. In cancer cells, hyperglycemia induced an increased expression of CXCR4, a CXCL12 receptor that was also induced by PSC's conditioned medium. The receptor-ligand interaction increased the phosphorylation of ERK1/2 and p38 resulting in activation of MAP kinase pathway, one of the most powerful stimuli for cell proliferation. Certainly, conditioned medium of PSC increased pancreatic cancer cell proliferation and this effect could be partially inhibited by a CXCR4 inhibitor. As the PSC conditioned medium (normal glucose concentration) increased the ERK1/2 and p38 phosphorylation, we concluded that PSCs produce other factor(s) that influence(s) pancreatic cancer behaviour.
CONCLUSIONS:
Hyperglycemia induces increased CXCL12 production by the PSCs, and its receptor, CXCR4 on cancer cells. The ligand-receptor interaction activates MAP kinase signaling that causes increased cancer cell proliferation and migration
Betacellulin Induces Increased Retinal Vascular Permeability in Mice
BACKGROUND: Diabetic maculopathy, the leading cause of vision loss in patients with type 2 diabetes, is characterized by hyper-permeability of retinal blood vessels with subsequent formation of macular edema and hard exudates. The degree of hyperglycemia and duration of diabetes have been suggested to be good predictors of retinal complications. Intervention studies have determined that while intensive treatment of diabetes reduced the development of proliferative diabetic retinopathy it was associated with a two to three-fold increased risk of severe hypoglycemia. Thus we hypothesized the need to identify downstream glycemic targets, which induce retinal vascular permeability that could be targeted therapeutically without the additional risks associated with intensive treatment of the hyperglycemia. Betacellulin is a 32 kD member of the epidermal growth factor family with mitogenic properties for the retinal pigment epithelial cells. This led us to hypothesize a role for betacellulin in the retinal vascular complications associated with diabetes. METHODS AND FINDINGS: In this study, using a mouse model of diabetes, we demonstrate that diabetic mice have accentuated retinal vascular permeability with a concomitant increased expression of a cleaved soluble form of betacellulin (s-Btc) in the retina. Intravitreal injection of soluble betacellulin induced retinal vascular permeability in normoglycemic and hyperglycemic mice. Western blot analysis of retinas from patients with diabetic retinopathy showed an increase in the active soluble form of betacellulin. In addition, an increase in the levels of A disintegrin and metalloproteinase (ADAM)-10 which plays a role in the cleavage of betacellulin was seen in the retinas of diabetic mice and humans. CONCLUSIONS: These results suggest that excessive amounts of betacellulin in the retina may contribute to the pathogenesis of diabetic macular edema
Lack of significant association of an insertion/deletion polymorphism in the angiotensin converting enzyme (ACE) gene with tropical calcific pancreatitis
BACKGROUND: The genetic basis of tropical calcific pancreatitis (TCP) is different and is explained by mutations in the pancreatic secretory trypsin inhibitor (SPINK1) gene. However, mutated SPINK1 does not account for the disease in all the patients, neither does it explain the phenotypic heterogeneity between TCP and fibro-calculous pancreatic diabetes (FCPD). Recent studies suggest a crucial role for pancreatic renin-angiotensin system during chronic hypoxia in acute pancreatitis and for angiotensin converting enzyme (ACE) inhibitors in reducing pancreatic fibrosis in experimental models. We investigated the association of ACE gene insertion/deletion (I/D) polymorphism in TCP patients using a case-control approach. Since SPINK1 mutations are proposed a modifier role, we also investigated its interaction with the ACE gene variant. METHODS: We analyzed the I/D polymorphism in the ACE gene (g.11417_11704del287) in 171 subjects comprising 91 TCP and 80 FCPD patients and compared the allelic and genotypic frequency in them with 99 healthy ethnically matched control subjects. RESULTS: We found 46% and 21% of TCP patients, 56% and 19.6% of FCPD patients and 54.5% and 19.2% of the healthy controls carrying the I/D and D/D genotypes respectively (P>0.05). No significant difference in the clinical picture was observed between patients with and without the del allele at the ACE in/del polymorphism in both categories. No association was observed with the presence or absence of N34S SPINK1 mutation in these patients. CONCLUSION: We conclude that the ACE insertion/deletion variant does not show any significant association with the pathogenesis, fibrosis and progression of tropical calcific pancreatitis and the fibro-calculous pancreatic diabetes
Structural and Functional Changes of the Human Macula during Acute Exposure to High Altitude
Background: This study aimed to quantify structural and functional changes at the macula during acute exposure to high altitude and to assess their structure/function relationship. This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study. Methodology/Principal Findings: Spectral domain optical coherence tomography and microperimetry were used to quantify changes of central retinal structure and function in 14 healthy subjects during acute exposure to high altitude (4559 m). High-resolution volume scans and fundus-controlled microperimetry of the posterior pole were performed in addition to best-corrected visual acuity (BCVA) measurements and assessment of acute mountain sickness. Analysis of measurements at altitude vs. baseline revealed increased total retinal thickness (TRT) in all four outer ETDRS grid subfields during acute altitude exposure (TRTouter = 2.8061.00 mm; mean change695%CI). This change was inverted towards the inner four subfields (TRT inner = 21.8960.97 mm) with significant reduction of TRT in the fovea (TRT foveal = 26.6260.90 mm) at altitude. BCVA revealed no significant difference compared to baseline (0.0660.08 logMAR). Microperimetry showed stable mean sensitivity in all but the foveal subfield (MSfoveal = 21.1260.68 dB). At baseline recordings before and.2 weeks after high altitude exposure, all subjects showed equal levels with no sign of persisting structural or functional sequels. Conclusions/Significance: During acute exposure to high altitude central retinal thickness is subject to minor, ye
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