Gas hydrate recycling is an important process in natural hydrate systems worldwide and frequently leads to the high gas hydrate saturations found close to the base of the gas hydrate stability zone ...(GHSZ). However, to date it remains enigmatic how, and under which conditions, free gas invades back into the GHSZ. Here we use a 1D compositional multi-phase flow model that accounts for sedimentation to investigate the dominant mechanisms that control free gas flow into the GHSZ using a wide-range of parameters i.e. hydrate formation kinetics, sediment permeability, and capillary pressure. In the first part of this study, we investigate free gas invasion into the GHSZ without any sedimentation, and analyse the dynamics of hydrate formation in the vicinity of the base of GHSZ. This helps establish plausible initial conditions for the main part of the study, namely, hydrate recycling due to rapid and continuous sedimentation. For the case study, we apply our numerical model to the Green Canyon Site 955 in the Gulf of Mexico, where the reported high hydrate saturations are likely a result of hydrate recycling driven by rapid sedimentation. In the model, an initial hydrate layer forms due to the invasion of a specified volume of rising free gas. This hydrate layer is consistent with the local pressure, temperature and salinity state. This hydrate layer is then thermally de-stabilised by sedimentation resulting in free gas formation and hydrate recycling. A key finding of our study is that gas hydrate recycling is a cyclic process which can be divided into three phases of 1) gas hydrate melting and free gas nozzling through the hydrate layer, 2) formation of a new gas hydrate layer as the old layer vanishes, and 3) fast uninhibited grow of a new hydrate layer. High hydrate saturations of about 80% can be attained purely through physical, burial-driven recycling of gas hydrates, without any additional gas input from other sources. Hydrate recycling is, therefore, highly dynamic with its own inherent cyclicity rather than a gradual process paced by the rate of sediment deposition.
•Sedimentation-driven gas hydrate recycling is cyclic in nature with time scales set by reactive multi-phase transport.•Each cycle can be divided into three distinct phases: 1) gas accumulation phase, 2) gas breakthrough phase and 3) uninhibited hydrate build-up phase.•In the presence of sufficient accumulated gas, convex deposition of hydrate acts like a mechanical nozzle for the ascending gas flow.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Distant metastases are frequent in head and neck squamous cell carcinomas (HNSCC), but they are limited to some organs like lungs, bone, mediastinum, liver and brain. Peritoneal metastases (PMs) from ...HNSCC are extremely rare. A 28-year-old chronic smoker and alcoholic was diagnosed with squamous cell carcinoma of oropharynx. Patient was admitted and was given six cycles of concurrent chemo and radiotherapy (CCRT) and was discharged. Two months later, he presented with abdominal pain and lump. Contrast-enhanced CT revealed ascites, peritoneal implants and subcutaneous deposit which were proved to be metastases by histopathology. The present case is the seventh reported case of PM from HNSCC. • Patients of HNSCC shall be screened for distant metastases. • Differential diagnosis of HNSCC needs consideration when encountered with peritoneal metastases. • Research is required to understand the basis of PM in HNSCC while on CCRT to suggest management modifications.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Essential trace metals like zinc (Zn), iron (Fe), and copper (Cu) play an important physiological role in the metabolomics and healthy functioning of body organs, including the brain. However, ...abnormal accumulation of trace metals in the brain and dyshomeostasis in the different regions of the brain have emerged as contributing factors in neuronal degeneration, Aβ aggregation, and Tau formation. The link between these essential trace metal ions and the risk of AD has been widely studied, although the conclusions have been ambiguous. Despite the absence of evidence for any clinical benefit, therapeutic chelation is still hypothesized to be a therapeutic option for AD. Furthermore, the parameters like bioavailability, ability to cross the BBB, and chelation specificity must be taken into consideration while selecting a suitable chelation therapy. The data in this review summarizes that the primary intervention in AD is brain metal homeostasis along with brain metal scavenging. This review evaluates the impact of different trace metals (Cu, Zn, Fe) on normal brain functioning and their association with neurodegeneration in AD. Also, it investigates the therapeutic potential of metal chelators in the management of AD. An extensive literature search was carried out on the “Web of Science, PubMed, Science Direct, and Google Scholar” to investigate the effect of trace elements in neurological impairment and the role of metal chelators in AD. In addition, the current review highlights the advantages and limitations of chelation therapies and the difficulties involved in developing selective metal chelation therapy in AD patients.
At the cellular level, cancer is the disease of both the genome and the epigenome, and the interplay between genetic mutations and epigenetic states may occur at the level of elementary chromatin ...units, the nucleosomes. They are formed by a segment of DNA wrapped around an octamer of histone proteins. In this review, we survey various mechanisms of cancer etiology and progression mediated by histones and nucleosomes. In particular, we discuss the effects of mutations in histones, changes in their expression and slicing on epigenetic dysregulation and carcinogenesis. The links between cancer phenotypes and differential expression of histone variants and isoforms are summarized. Finally, we discourse the geometric and steric effects of DNA compaction in nucleosomes on DNA mutation rate, interactions with transcription factors, including pioneer transcription factors, and prospects of cancer cells’ genome and epigenome editing.
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IJS, KILJ, NUK, PNG, UL, UM
Chronic suppurative otitis media is a serious health problem worldwide. It has been a general view that the hearing loss increases with the size of the perforation, more so if it is in the postero- ...inferior quadrant. The present study is an effort to test the validity of above concepts. With Institutional ethical committee clearance, an observational study was carried at SMS medical college, Jaipur. A total of 90 cases were studied. All cases between the age group 15–50 years with dry tympanic membrane perforations were divided into 3 groups Group I (0–9 mm²), Group II (9–30 mm²), Group III (>30 mm²) with 30 in each group based on size of perforation. Hearing loss was calculated as average of hearing loss at 500, 1000, 2000 Hz. Similarly the site of perforation was grouped as perforation involving anterior quadrant, posterior quadrant and multiple quadrant as Group A, Group B, Group C respectively. At the end of study, data was compiled systematically and analyzed using Post Hoc test. The age group ranges between 15 and 50 years with mean age of 25.6 years. Hearing loss was found to be directly proportional to the size of perforation in our study. (
p
= 0.000, highly significant). We also observed that hearing loss was more in posterior and multiple perforations than in anterior perforations. (
p
= 0.000, highly significant). Overall this study has shown significant correlation between the size and the site of the perforation to the degree of hearing loss.
Family social capital (FSC) encompasses the positive relationships and effective functioning within a family that positively influences psychological well-being (PWB) of working women. This work ...investigates the complex relationship between well-being and FSC. Self-esteem (SE) and a sense of coherence (SOC) are critical concepts between working women’s FSC and well-being. The methodology of this cross-sectional study was carefully designed to explore complex relationships among multiple factors affecting the PWB of employed women in the Northern region of India. Three hundred fifteen usable questionnaires were obtained after a meticulous data cleansing process. The findings demonstrate that FSC enhances SE, which further positively influences PWB. Moreover, results shows that SE plays a significant role in mediating the relationship between FSC and well-being. The data also indicates a moderating role of SOC between FSC and well-being. The current study contributes significantly to the existing literature with theoretical implications by providing additional conceptual insights that can expand the overall understanding of FSC, particularly in the context of non-Western countries.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
The optimization of β-turns has been used as a strategy to increase protein thermal stability. One example is the S48P mutation in Ribonuclease Sa, introduced to optimize a β-turn, which increases ...the stability of the protein as determined experimentally. Here, we have studied 48SYGY51 β-turn and its S48P mutant from RNase Sa, as a peptide and as part of the protein, using molecular dynamics simulations. The turn propensity of the region 48SYGY51 shows an increase in both the peptide and protein models on S48P mutation. The mutant protein shows an overall decrease in conformational dynamics and a decrease in conformational heterogeneity as compared to the wildtype protein. A comparatively restricted sampling of the φ-ψ region of GLN47, a pre PRO48 residue, in the mutant protein and some local changes in hydrogen bonding patterns involving residues 20–24 might be contributing to the mutant protein stability. In addition, some long-range hydrogen bonding interactions involving the 60s loop and the salt-bridge interaction involving ASP17-ARG63 could also be contributing to the increase in rigidity and stability of the mutant protein.
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•S48P mutation at the first position of type II β-turn 48SYGY51 in RNase Sa leads to an increase in turn propensity.•The mutant protein is structurally rigidified in comparison to the wildtype.•Conformational restrictions due to GLN47-PRO48 contribute to loss of flexibility observed in the S48P mutant.•Salt-bridge between ASP17 and ARG63 might play a role in increased rigidity and stability of the mutant protein.•Long-range hydrogen bonds involving 60s loop and 20-24 segment might also lead to greater rigidity and stability in mutant.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The rate-limiting step for the folding of the helix-turn-helix (HTH) protein, Z34C, involves β-turn region 20DPNL23. This reverse turn has been observed to be part of the transition state in the ...folding process for Z34C, influencing its folding rates. Molecular dynamics simulations were performed on this turn peptide and its two mutants, D20A and P21A, to study turn formation using GROMOS54A7 force field. We find that this region has a turn propensity of its own, and the highest turn propensity is observed for the wild-type, which correlates well with available experimental results. We also find that a slight unfavorable change in ΔG turn folding causes a drastic change in the folding rates of HTH motif and a mechanistic interpretation is given. Implications of these observations for the folding of the HTH protein Z34C are discussed.
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IJS, KILJ, NUK, PNG, UL, UM
How can we explain the broad and uneven spatial effects of Machine Learning (ML) algorithms that mediate the everyday lives of smart city residents? The discriminatory impacts of civic algorithms ...remain opaque to city inhabitants and experts alike. Current Explainable AI (XAI) approaches, while influential, are limited in their ability to explain the inequitable algorithmic spatial effects in an accessible, critical, and grounded manner. My thesis explores the potential of participatory mapping as a critical and collaborative technique to address these limits. My work draws on (1) scholarship on critical data and algorithmic studies, (2) qualitative research with domain experts from history and criminology, and (3) participatory mapping sessions with city residents and ML practitioners. Ultimately, my research will inform the design of a toolkit to help people in classrooms and community centers collaboratively reflect on how city residents may unevenly experience the impact of artificially intelligent systems guiding contemporary urban life.
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