Transmission of ultrasonic wave across moisture rocks: Effects of moisture sorption on velocity variation and attenuation

This study focused on investigating the impact of moisture-induced mechanical degradation on three types of rocks. Dynamic moisture sorption experiments were conducted to understand water vapor sorption across different relative humidity (RH) conditions. Ultrasonic tests, performed at various RH levels, revealed the sensitivity of wave velocities and attenuations to changes in moisture content. Subsequent measurements of unconfined compressive strength (UCS) demonstrated how moisture-induced degradation affects the mechanical properties of rocks. This study evaluated the effects of RH on ultrasonic P-/S-wave velocities in three rocks, revealing distinct moisture effects on wave velocity variations. Gray shale and sandstone exhibited similar P-wave behaviors, while black shale differed significantly, showcasing early stiffening effects at lower RH. Saturation heterogeneities at the pore-scale and patchy effects at the large scale highlighted complex interactions between rock, moisture, and wave characteristics. Furthermore, the research assessed the impact of relative humidity on ultrasonic wave attenuations in partially saturated rocks. As RH increased, P-wave attenuation generally rose, influenced by dynamic water saturation and fabric heterogeneity. S-wave attenuation exhibited a similar trend, with noticeable variations among rock types. UCS tests indicated that higher moisture content led to decreased UCS values across various rock specimens. The P- and S-wave velocities during loading further emphasized moisture sensitivity, with S-wave velocity being more responsive to moisture content variations. Dynamic Young's moduli exhibited distinct changes during UCS measurements, highlighting the influence of moisture content on mechanical degradations. These findings underscore the importance of considering moisture effects in understanding and predicting the mechanical behavior of rocks

Precision in medicinal chemistry: Harnessing enzymes for advanced halogenation

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Sex differences in oncogenic mutational processes.

Sex differences have been observed in multiple facets of cancer epidemiology, treatment and biology, and in most cancers outside the sex organs. Efforts to link these clinical differences to specific molecular features have focused on somatic mutations within the coding regions of the genome. Here we report a pan-cancer analysis of sex differences in whole genomes of 1983 tumours of 28 subtypes as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium. We both confirm the results of exome studies, and also uncover previously undescribed sex differences. These include sex-biases in coding and non-coding cancer drivers, mutation prevalence and strikingly, in mutational signatures related to underlying mutational processes. These results underline the pervasiveness of molecular sex differences and strengthen the call for increased consideration of sex in molecular cancer research

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Evaluating the Pressure-Dependent Equivalent Permeability Evolutions for Shale Matrix: Experiments and Modeling

Abstract The ability to model and predict matrix permeability changes during reservoir depletion is critical for accurate analysis of long-term production performance in unconventional gas reservoirs (UGRs), including shale gas and coalbed methane reservoirs. Yet, flow quantification in the nanoporous matrix is still challenging due to the complex pore structure and morphology. To understand the pressure-dependent matrix permeability evolution, this study conducted laboratory permeability measurements using pulverized samples. Equivalent permeability was estimated from the pressure decay profile for the Devonian shale sample. A novel experimental system, a differential volumetric unit, has been established and applied to capture the accurate transient gas flows for the shale sample. The measured permeability of shale exhibited overall decreasing trends with pressure depletion. Due to the presence of slip flow and Knudsen diffusion, low-pore-pressure data did not follow the same decline trend fitted by high-pore-pressure data as observed in the shale sample. This study also utilized methane as the invasion fluid to examine the adsorption effect on matrix permeability, whose value could be up to 40% lower than permeability without correction for adsorption because of the condensation of adsorbed phase at pore surface occupying available pore space. Since these tight rock matrixes are composed of micro- and nanopores, matrix permeability is primarily related to pore structure (e.g., the pore size distribution, porosity and tortuosity). Low-pressure N2 adsorption was conducted to characterize the complex pore structure of the Marcellus shale sample. A multimechanic model was proposed to predict the pressure-dependent matrix permeability based on pore structure information and investigate the effect of gas adsorption on apparent permeability. This model has successfully linked the realistic, complex pore structure with the pressure-dependent matrix permeability of shale and coal. The proposed model could be coupled into the commercially available simulator to forecast long-term production profiles for UGRs wells.</jats:p

Morphology and DNA sequences confirm the first Neotropical record for the Holarctic sepsid species Themira leachi (Meigen) (Diptera: Sepsidae)

Even for the most cosmopolitan of species, climate frequently presents effective barriers for dispersal. For example, many eurytopic and synanthropic species go extinct when introduced into a new climatic zone, and translocated ants remain in sheltered environments reminiscent of their home climate (McGlynn, 1999). Here we report the occurrence of a primarily Holarctic dipteran species, Themira leachi (Meigen), in Neotropical Cuba. This discovery suggests that the species may have a large disjunct distribution, as the next closest record lies almost 3,500 km to the north in Nearctic Newfoundland, Canada (Ozerov, 1998).</jats:p

Why banks take security

This paper aims to understand, through a literature critique, the motivation behind banks to be secured creditors given the current law governing security as well as other factors affecting banks' lending activities. In addition, this paper also analyses the role that securities play in banks' lending decisions