460 research outputs found
Modeling and Analysis of Perishable Inventory System with Retrial demands in Supply Chain
In this article, we consider a continuous review perishable inventory system with poisson demands. The maximum storage capacity at lower echelon (retailer) is S and the upper Echelon (Distribution Center) is M (= nQ). The life time of each item is assumed to be exponential. The operating policy is (s, S) policy, that is, whenever the inventory level drops to s, an order for Q = (S - s > s) item is placed. The ordered items are received after a random time which is distributed as exponential. We assume that demands occurring during the stock-out period enter into the orbit. These orbiting demands send out signal to complete for their demand which is distributed as exponential. The joint probability distribution of the inventory level at retailer, inventory level at DC and the number of demands in the orbit are obtained in the steady state case. Various system performance measures are derived and the results are illustrated numerically
Changes in Two Point Discrimination and the law of mobility in Diabetes Mellitus patients
<p>Abstract</p> <p>Background</p> <p>Diabetic neuropathy is a family of nerve disorders with progressive loss of nerve function in 15% of diabetes mellitus (DM) subjects. Two-point discrimination (TPD) is one method of quantitatively testing for loss of nerve function. The law of mobility for TPD is known for normal subjects in earlier studies but has not been studied for diabetic subjects. This is a pilot study to evaluate and plot the law of mobility for TPD among DM subjects.</p> <p>Methods</p> <p>The Semmes Weinstein monofilament (SWMF) was used to measure the loss of protective sensation. An Aesthesiometer was used to find the TPD of several areas in upper and lower extremities for normal and diabetic subjects. All the subjects were screened for peripheral artery occlusive disease with ankle brachial pressure index (0.9 or above).</p> <p>Results</p> <p>TPD of normal and diabetic subjects for different areas of hands and legs from proximal to distal is evaluated for 18 subjects. TPD values decrease from proximal to distal areas. Vierodt's law of mobility for TPD holds good for normal subjects in the hand and foot areas. The law of mobility for TPD in DM subjects holds well in the hand but doesn't hold well in foot areas with or without sensation.</p> <p>Conclusion</p> <p>TPD is a quantitative and direct measure of sensory loss. The TPD value of diabetic subjects reveals that the law of mobility do not hold well for Diabetic subjects in foot areas. The significance of this result is that the TPD of the diabetic subjects could provide direct, cost effective and quantitative measure of neuropathy.</p
Assessment of Safety and Interference Issues of Radio Frequency Identification Devices in 0.3 Tesla Magnetic Resonance Imaging and Computed Tomography
The objective of this study was to evaluate two issues regarding magnetic resonance imaging (MRI) including device functionality and image artifacts for the presence of radio frequency identification devices (RFID) in association with 0.3 Tesla at 12.7 MHz MRI and computed tomography (CT) scanning. Fifteen samples of RFID tags with two different sizes (wristband and ID card types) were tested. The tags were exposed to several MR-imaging conditions during MRI examination and X-rays of CT scan. Throughout the test, the tags were oriented in three different directions (axial, coronal, and sagittal) relative to MRI system in order to cover all possible situations with respect to the patient undergoing MRI and CT scanning, wearing a RFID tag on wrist. We observed that the tags did not sustain physical damage with their functionality remaining unaffected even after MRI and CT scanning, and there was no alternation in previously stored data as well. In addition, no evidence of either signal loss or artifact was seen in the acquired MR and CT images. Therefore, we can conclude that the use of this passive RFID tag is safe for a patient undergoing MRI at 0.3 T/12.7 MHz and CT Scanning
What doesn't kill you makes you stranger: Dipeptidyl peptidase-4 (CD26) proteolysis differentially modulates the activity of many peptide hormones and cytokines generating novel cryptic bioactive ligands
Dipeptidyl peptidase 4 (DPP4) is an exopeptidase found either on cell surfaces where it is highly regulated in terms of its expression and surface availability (CD26) or in a free/circulating soluble constitutively available and intrinsically active form. It is responsible for proteolytic cleavage of many peptide substrates. In this review we discuss the idea that DPP4-cleaved peptides are not necessarily inactivated, but rather can possess either a modified receptor selectivity, modified bioactivity, new antagonistic activity, or even a novel activity relative to the intact parent ligand.
We examine in detail five different major DPP4 substrates: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide tyrosine-tyrosine (PYY), and neuropeptide Y (NPY), and stromal derived factor 1 (SDF-1 aka CXCL12). We note that discussion of the cleaved forms of these five peptides are underrepresented in the research literature, and are both poorly investigated and poorly understood, representing a serious research literature gap. We believe they are understudied and misinterpreted as inactive due to several factors. This includes lack of accurate and specific quantification methods, sample collection techniques that are inherently inaccurate and inappropriate, and a general perception that DPP4 cleavage inactivates its ligand substrates.
Increasing evidence points towards many DPP4-cleaved ligands having their own bioactivity. For example, GLP-1 can work through a different receptor than GLP-1R, DPP4-cleaved GIP can function as a GIP receptor antagonist at high doses, and DPP4-cleaved PYY, NPY, and CXCL12 can have different receptor selectivity, or can bind novel, previously unrecognized receptors to their intact ligands, resulting in altered signaling and functionality. We believe that more rigorous research in this area could lead to a better understanding of DPP4’s role and the biological importance of the generation of novel cryptic ligands. This will also significantly impact our understanding of the clinical effects and side effects of DPP4-inhibitors as a class of anti-diabetic drugs that potentially have an expanding clinical relevance. This will be specifically relevant in targeting DPP4 substrate ligands involved in a variety of other major clinical acute and chronic injury/disease areas including inflammation, immunology, cardiology, stroke, musculoskeletal disease and injury, as well as cancer biology and tissue maintenance in aging
LRH-1 drives colon cancer cell growth by repressing the expression of the <i>CDKN1A</i> gene in a p53-dependent manner
Liver receptor homologue 1 (LRH-1) is an orphan nuclear receptor that has been implicated in the progression of breast, pancreatic and colorectal cancer (CRC). To determine mechanisms underlying growth promotion by LRH-1 in CRC, we undertook global expression profiling following siRNA-mediated LRH-1 knockdown in HCT116 cells, which require LRH-1 for growth and in HT29 cells, in which LRH-1 does not regulate growth. Interestingly, expression of the cell cycle inhibitor p21 (CDKN1A) was regulated by LRH-1 in HCT116 cells. p21 regulation was not observed in HT29 cells, where p53 is mutated. p53 dependence for the regulation of p21 by LRH-1 was confirmed by p53 knockdown with siRNA, while LRH-1-regulation of p21 was not evident in HCT116 cells where p53 had been deleted. We demonstrate that LRH-1-mediated p21 regulation in HCT116 cells does not involve altered p53 protein or phosphorylation, and we show that LRH-1 inhibits p53 recruitment to the p21 promoter, likely through a mechanism involving chromatin remodelling. Our study suggests an important role for LRH-1 in the growth of CRC cells that retain wild-type p53
Is a cooperative approach to seaweed farming effectual? An analysis of the seaweed cluster project (SCP), Malaysia
Seaweed (Kappaphycus spp.) farming has been practised in Malaysia since the late 1970s following government policy incentives (training and farming inputs). However, numerous governance, economic, environmental, technological and sociocultural challenges have limited the industry from achieving its full potential. The Seaweed Cluster Project (SCP) was introduced in 2012 to address some of these challenges. We sought to evaluate the effectiveness of the SCP in delivering its central objectives of increasing seaweed production, optimising the farming area, improving seaweed quality and farming efficiency, raising farmers’ income, and reducing the environmental impact of seaweed farming. Community and industry perceptions of the SCP were obtained from seven communities using a mixed-methods approach based on face-to-face semi-structured interviews, focus group discussions, household surveys, observation and secondary data. Views on the SCP outcomes were generally negative, including low take-up rates by indigenous people, poor stakeholder participation in decision-making, limited acceptance of new technologies, economic vulnerability, a complex marketing system, and low social cohesion of seaweed farming communities. Positive perceptions included recognition that the SCP confers high social status upon a community, reduces operating costs, and facilitates the production of certified seaweed. The SCP’s problems are linked to poor multi-level governance, weak market mechanisms and unintegrated community development. The study concludes with five recommendations to improve the SCP: promote the participation of indigenous people; legalise existing migrant farmers; strengthen local seaweed cooperative organisations; provide entrepreneurship skills to farmers; and fully integrate stakeholders into decision-making
Sinteza i farmakološka evaluacija 3-cikloheksil-2-supstituiranih hidrazino-3H-kinazolin-4-ona kao analgetika i antiinflamatorika
A series of novel 3-cyclohexyl-2-substituted hydrazino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 3-cyclohexyl-2-hydrazino quinazolin-4(3H)-one with a variety of aldehydes and ketones. The starting material, 3-cyclohexyl-2-hydrazino quinazolin-4(3H)-one, was synthesized from cyclohexyl amine. Title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic behavior. The compound 3-cyclohexyl-2-(1-methylbutylidene-hydrazino)-3H-quinazolin-4-one (4c) emerged as the most active compound of the series and is moderately more potent in its analgesic and anti-inflammatory activities compared to the reference standard diclofenac sodium. Interestingly, test compounds showed only mild ulcerogenic potential when compared to acetylsalicylic acid.Reakcijom amino skupine 3-cikloheksil-2-hidrazino kinazolin-4(3H)-ona s različitim aldehidima i ketonima sintetizirani su novi 3-cikloheksil-2-supstituirani hidrazino-kinazolin-4(3H)-oni. Početni spoj 3-cikoheksil-2-hidrazino kinazolin-4(3H)-on pripravljen je iz cikloheksilamina. Sintetizirani spojevi testirani su na analgetsko i protuupalno djelovanje te ulcerogena svojstva. Spoj 3-cikloheksil-2-(1-metilbutiliden-hidrazino)-3H-kinazolin-4-on (4c) imao je najjače analgetsko i protuupalno djelovanje, nešto jače nego referentni spoj diklofenak natrij. Osim toga, testirani spojevi imaju samo blago ulcerogeno djelovanje u usporedbi s acetilsalicilnom kiselinom
Aristolochic Acid I Induced Autophagy Extenuates Cell Apoptosis via ERK 1/2 Pathway in Renal Tubular Epithelial Cells
Autophagy is a lysosomal degradation pathway that is essential for cell survival and tissue homeostasis. However, limited information is available about autophagy in aristolochic acid (AA) nephropathy. In this study, we investigated the role of autophagy and related signaling pathway during progression of AAI-induced injury to renal tubular epithelial cells (NRK52E cells). The results showed that autophagy in NRK52E cells was detected as early as 3–6 hrs after low dose of AAI (10 µM) exposure as indicated by an up-regulated expression of LC3-II and Beclin 1 proteins. The appearance of AAI-induced punctated staining of autophagosome-associated LC3-II upon GFP-LC3 transfection in NRK52E cells provided further evidence for autophagy. However, cell apoptosis was not detected until 12 hrs after AAI treatment. Blockade of autophagy with Wortmannin or 3-Methyladenine (two inhibitors of phosphoinositede 3-kinases) or small-interfering RNA knockdown of Beclin 1 or Atg7 sensitized the tubular cells to apoptosis. Treatment of NRK52E cells with AAI caused a time-dependent increase in extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity, but not c-Jun N-terminal kinase (JNK) and p38. Pharmacological inhibition of ERK1/2 phosphorylation with U0126 resulted in a decreased AAI-induced autophagy that was accompanied by an increased apoptosis. Taken together, our study demonstrated for the first time that autophagy occurred earlier than apoptosis during AAI-induced tubular epithelial cell injury. Autophagy induced by AAI via ERK1/2 pathway might attenuate apoptosis, which may provide a protective mechanism for cell survival under AAI-induced pathological condition
- …