Dynamic scaling and stochastic fractal in nucleation and growth processes

A class of nucleation and growth models of a stable phase (S-phase) is investigated for various different growth velocities. It is shown that for growth velocities $v\sim s(t)/t$ and $v\sim x/\tau(x)$, where $s(t)$ and $\tau$ are the mean domain size of the metastable phase (M-phase) and the mean nucleation time respectively, the M-phase decays following a power law. Furthermore, snapshots at different time $t$ are taken to collect data for the distribution function $c(x,t)$ of the domain size $x$ of M-phase are found to obey dynamic scaling. Using the idea of data-collapse we show that each snapshot is a self-similar fractal. However, for $v={\rm const.}$ like in the classical Kolmogorov-Johnson-Mehl-Avrami (KJMA) model and for $v\sim 1/t$ the decay of the M-phase are exponential and they are not accompanied by dynamic scaling. We find a perfect agreement between numerical simulation and analytical results.Comment: 10 pages, 8 captioned figure

Cross-chain Transaction Validation using Lock-and-Key Method for Multi-System Blockchain

Blockchains have profoundly impacted finance and administration, but there are several issues with the current blockchain platforms, including a lack of system interoperability. Currently used blockchain application platforms only work within their networks. Although the underlying concept of all blockchain networks is mainly similar, it involves centralised third-party mediators to transact from other blockchain networks. The current third-party intermediates establish security and trust by keeping track of “account balances” and attesting to the validity of transactions in a centralised ledger. The lack of sufficient inter-blockchain connectivity hinders the mainstream adoption of blockchain. Blockchain technology may be a solid solution for many systems if it grows and works with other systems. For the multi-system blockchain concept to materialise, a mechanism that would connect and communicate with the blockchain systems of various entities in a distributed manner (without any intermediary) while maintaining the property of trust and integrity established by individual blockchains is required. Several methods for verifying cross-chain transactions have been explored in this paper among various blockchains. The efficient verification of cross-chain transactions faces many difficulties, and current research has yet to scratch the surface. In addition to summarising and categorising these strategies, the report also suggests a novel mechanism that gets beyond the existing drawbacks

A study on oxidized-LDL cholesterol in normolipidemic retinal vein occlusion

Background: Oxidized low-density lipoprotein (ox-LDL) has been implicated in atherosclerotic cardiovascular disease. Arteriolosclerosis is an important causative factor for retinal vein occlusion (RVO). Till, date there is dearth of literature on ox-LDL and RVO. Aims and Objectives: The objectives of this study were to see whether ox-LDL cholesterol is an independent risk factor in RVO with normal lipid profile. Materials and Methods: Lipid profiles and ox-LDL levels were assayed in 122 adult unilateral RVO cases and 142 age and sex matched controls in this 1 year old case–control study. Results: ox-LDL cholesterol levels were significantly elevated in RVO cases than controls (54.5±6.1 in cases vs. 36.6±5.6 in controls, P<0.01), although serum lipid profiles were normal in both cases and controls. Conclusion: The ox-LDL-induced atherosclerosis may be responsible for the retinal venous occlusion in absence of other risk factors. Hence, screening for ox-LDL in RVO patients should be worth considering especially in patients with normal lipid profiles

A study to determine the prevalence of oxidised low-density lipoprotein in retinal venous occlusion in a population of West Bengal

Background: Oxidized low-density lipoprotein (ox-LDL) has been implicated in both coronary artery disease and retinal vein occlusion (RVO) because of atherosclerosis. However, there is no study to show the prevalence of ox-LDL in RVO till date. Aims and Objectives: This study aimed to find the prevalence of ox-LDL in RVO in a population of West Bengal. Materials and Methods: A 2-year prospective cross-sectional study of consecutive, unrelated adult patients, with a diagnosis of RVO, attending the outpatient department in a Medical College, was taken up for study. A pilot study was done to determine the expected prevalence of ox-LDL. Sample size was calculated based on the formula n=d2z2pq(z=1.96, d=0.04, p=0.196, q=0.804, n=minimum sample size). ox-LDL was measured in a total of 512 subjects who were selected based on the inclusion and exclusion criteria. Results: In this study, 272 males (aged 50 ± 7.2 years) and 240 females (aged 46 ± 7.7 years) with RVO were screened for ox-LDL. Elevated ox-LDL levels were found in 142 patients out of 512 participants in this study (27.7%). Moreover, 102 cases (19.9%) were found to have both raised LDL and ox-LDL, whereas 40 RVO cases (7.8%) had only elevated ox-LDL among the study participants. 71.8% of 142 RVO cases with elevated ox-LDL levels also had raised LDL levels, whereas remaining 28.2% had normal LDL cholesterol levels. Conclusion: It is high time to look beyond the traditional lipid parameters such as ox-LDL cholesterol levels as a risk factor of RVO. This study proved that ox-LDL cholesterol is highly prevalent in RVO cases. Thereby, proper screening of ox-LDL is a must as a tool for risk reduction of RVO cases, especially in a population with normal LDL cholesterol levels

DEVELOPMENT AND EVALUATION OF FREEZING RESISTANT INTRAVENOUS FLUID

Objectives: Hemorrhagic or hypovolemic shocks accounts for a large portion of civilian and military trauma deaths due to life-threatening blood loss which requires intravenous fluid infusion to prevent essential deficiencies of fluids. However, at low temperature (-150C) fluid bottles freeze out and can not be used in emergency. In view of that, objective of the present work is to develop a freezing resistant intravenous formulation (FRIV) and its in vivo safety and efficacy evaluation. Methods: FRIV formulations were developed using standardized ringer lactate (RL) formulation protocol, in which varying concentrations of ethanol and glycerol were added to induce desired physiochemical properties. Efficacy of FRIV was evaluated in terms of survival percentage of hemorrhagic animal models (Swiss albino strain mice). Acute toxicity studies were carried out through an infusion at dose levels (0, 20 and 40 ml/Kg b. wt.). Results: In vitro data showed that optimized FRIV (F-10) takes more time (360 ± 21 min) for freezing and less time in thawing (50 ± 4.50 min) in comparison to control which takes (110 ± 15 min) in freezing and (80 ± 7.25 min) in thawing. Formulations were found to be stable and sterile up to six months. In vivo efficacy data showed ≥ 75% survival in animals infused with FRIV as compared to control group in hemorrhagic animal models and no treatment related toxic effects of optimized formulation in terms of hematological, serum biochemistry and histopathological analysis. Conclusion: Pre-clinical safety and efficacy data of the present study indicated that developed FRIV formulation could be used for fluid recovery during the hemorrhagic shocks conditions in the combat scenario

Cationic Amino Acid Transporters and Salmonella Typhimurium ArgT Collectively Regulate Arginine Availability towards Intracellular Salmonella Growth

Cationic amino acid transporters (mCAT1 and mCAT2B) regulate the arginine availability in macrophages. How in the infected cell a pathogen can alter the arginine metabolism of the host remains to be understood. We reveal here a novel mechanism by which Salmonella exploit mCAT1 and mCAT2B to acquire host arginine towards its own intracellular growth within antigen presenting cells. We demonstrate that Salmonella infected bone marrow derived macrophages and dendritic cells show enhanced arginine uptake and increased expression of mCAT1 and mCAT2B. We show that the mCAT1 transporter is in close proximity to Salmonella containing vacuole (SCV) specifically by live intracellular Salmonella in order to access the macrophage cytosolic arginine pool. Further, Lysosome associated membrane protein 1, a marker of SCV, also was found to colocalize with mCAT1 in the Salmonella infected cell. The intra vacuolar Salmonella then acquire the host arginine via its own arginine transporter, ArgT for growth. The argT knockout strain was unable to acquire host arginine and was attenuated in growth in both macrophages and in mice model of infection. Together, these data reveal survival strategies by which virulent Salmonella adapt to the harsh conditions prevailing in the infected host cells

TLR 9 Activation in Dendritic Cells Enhances Salmonella Killing and Antigen Presentation via Involvement of the Reactive Oxygen Species

Synthetic CpG containing oligodeoxynucleotide Toll like receptor-9 agonist (CpG DNA) activates innate immunity and can stimulate antigen presentation against numerous intracellular pathogens. It was observed that Salmonella Typhimurium growth can be inhibited by the CpG DNA treatment in the murine dendritic cells. This inhibitory effect was mediated by an increased reactive oxygen species production. In addition, it was noted that CpG DNA treatment of dendritic cells during Salmonella infection leads to an increased antigen presentation. Further this increased antigen presentation was dependent on the enhanced reactive oxygen species production elicited by Toll like receptor-9 activation. With the help of an exogenous antigen it was shown that Salmonella antigen could also be cross-presented in a better way by CpG induction. These data collectively indicate that CpG DNA enhance the ability of murine dendritic cells to contain the growth of virulent Salmonella through reactive oxygen species dependent killing

Modulation of the Arginase Pathway in the Context of Microbial Pathogenesis: A Metabolic Enzyme Moonlighting as an Immune Modulator

Arginine is a crucial amino acid that serves to modulate the cellular immune response during infection. Arginine is also a common substrate for both inducible nitric oxide synthase (iNOS) and arginase. The generation of nitric oxide from arginine is responsible for efficient immune response and cytotoxicity of host cells to kill the invading pathogens. On the other hand, the conversion of arginine to ornithine and urea via the arginase pathway can support the growth of bacterial and parasitic pathogens. The competition between iNOS and arginase for arginine can thus contribute to the outcome of several parasitic and bacterial infections. There are two isoforms of vertebrate arginase, both of which catalyze the conversion of arginine to ornithine and urea, but they differ with regard to tissue distribution and subcellular localization. In the case of infection with Mycobacterium, Leishmania, Trypanosoma, Helicobacter, Schistosoma, and Salmonella spp., arginase isoforms have been shown to modulate the pathology of infection by various means. Despite the existence of a considerable body of evidence about mammalian arginine metabolism and its role in immunology, the critical choice to divert the host arginine pool by pathogenic organisms as a survival strategy is still a mystery in infection biology

Global delivery models: the role of talent, speed and time zones in the global outsourcing industry

Global delivery models (GDMs) are transforming the global IT and business process outsourcing industry. GDMs are a new form of client-specific investment promoting service integration with clients by combining client proximity with time-zone spread for 24/7 service operations. We investigate antecedents and contingencies of setting up GDM structures. Based on comprehensive data we show that providers are likely to establish GDM location configurations when clients value access to globally distributed talent and speed of service delivery, in particular when services are highly commoditized. Findings imply that coordination across time zones increasingly affects international operations in business-to-business and born-global industries