The effect of slight to minor biodegradation on C_6 to C_7 light hydrocarbons in crude oils: a case study from Dawanqi Oilfield in the Tarim Basin,NW China

Light hydrocarbons （LHs） are one of the main petroleum fractions in crude oils, and carry much infor- mation regarding the genetic origin and alteration of crude oils. But secondary alterations--especially biodegrada- tion--have a significant effect on the composition of LHs in crude oils. Because most of the LHs affected in oils underwent only slight biodegradation （rank 1 on the biodegradation scale）, the variation of LHs can be used to describe more the refined features of biodegradation. Here, 23 crude oils from the Dawanqi Oilfield in the Tarim Basin, NW China, eleven of which have been biodegraded to different extents, were analyzed in order to investigate the effect of slight to minor biodegradation on C6--C7 LHs. The study results showed that biodegradation resulted in the prior depletion of straight-chained alkanes, followed by branched alkanes. In slight and minor biodegraded oils, such biodegradation scale could not sufficiently affect C6- C7 cycloalkanes. For branched C6--C7 alkanes, generally, monomethylalkanes are biodegraded earlier than dimethylalkanes and trimethylalkanes, which indicates that branched alkanes are more resistant to biodegradation, with the increase of substituted methyl groups on parent rings. The degree of alkylation is one of the primary controlling factors on the biodegradation of C6-Cv LHs. There is a particular case： although 2,2,3-trimethylbutane has a rela- tive higher alkylation degree, 2,2-dimethylpentane is more resistant to biodegradation than 2,2,3-trimethylbutane. 2,2- Dimethylpentane is the most resistant to biodegradation in branched C6-C7 alkanes. Furthermore, the 2-methylpen- tane/3-methylpentane and 2-methylhexane/3-methylhexane ratios decreased steadily with increasing biodegradation, which implies that isomers of bilateral methyl groups are more prone to bacterial attack relative to mid-chain iso- mers. The position of the alkyls on the carbon skeleton is also one of the critical factors controlling the rate of biodegradation. With increasing biodegradation, Mango＇s LH parameters K1 values decrease and K2 values increase, the values of n-heptane and isoheptane decrease, and the indices of methylcyclohexane and cyclohexane increase. LH parameters should be applied cautiously for the biodegraded oils. Because biodegraded samples belong to slight or minor biodegraded oils, the values of n-heptane and isoheptane from Dawanqi Oilfield can better reflect and determine the ＂Biodegraded＂ zone. When the heptane value is 0-21 and the isoheptane value is 0-2.6, the crude oil in Dawanqi Oilfield is defined as the ＂Biodegraded＂ zone

广义网络上的计算机病毒传播模型

为了研究计算机病毒在广义网络中传播的机制,文章分别提出了计算机病毒传播的非线性和线性模型.理论分析表明,网络的最大特征值是决定计算机病毒传播的重要参数.其次,文章给出非线性和线性模型中的无病毒均衡点全局稳定的充分条件,同时也证明了线性模型的有病毒平衡点的全局吸引性.最后,通过一些数学模拟实验验证了理论分析的主要结论.

Traumatic brain injury induced by exposure to blast overpressure via ear canal

Exposure to explosive shockwave often leads to blast-induced traumatic brain injury in military and civilian populations.Unprotected ears are most often damaged following exposure to blasts.Although there is an association between tympanic membrane perforation and TBI in blast exposure victims,little is known about how and to what extent blast energy is transmitted to the central nervous system via the external ear canal.The present study investigated whether exposure to blasts directed through the ear canal causes brain injury in LongEvans rats.Animals were exposed to a single blast(0–30 pounds per square inch(psi))through the ear canal,and brain injury was evaluated by histological and behavioral outcomes at multiple time-points.Blast exposure not only caused tympanic membrane perforation but also produced substantial neuropathological changes in the brain,including increased expression of c-Fos,induction of a profound chronic neuroinflammatory response,and apoptosis of neurons.The blast-induced injury was not limited only to the brainstem most proximal to the source of the blast,but also affected the forebrain including the hippocampus,amygdala and the habenula,which are all involved in cognitive functions.Indeed,the animals exhibited long-term neurological deficits,including signs of anxiety in open field tests 2 months following blast exposure,and impaired learning and memory in an 8-arm maze 12 months following blast exposure.These results suggest that the unprotected ear canal provides a locus for blast waves to cause TBI.This study was approved by the Institutional Animal Care and Use Committee at the University of Mississippi Medical Center(Animal protocol#0932 E,approval date:September 30,2016 and 0932 F,approval date:September 27,2019).

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast exposure induces damage to the vestibular end organs in the inner ear.However,the underlying mechanisms remain to be elucidated.In this report,single vestibular afferent activity and the vestibuloocular reflex(VOR)were investigated before and after exposure to blast shock waves(~20 PSI)delivered into the left external ear canals of anesthetized rats.Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure.Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents.Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5e2Hz.Blast exposure,however,resulted in few changes in the VOR responses to sinusoidal head rotation and translation.To the best of our knowledge,this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model.These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.

Autonomic responses to blast overpressure can be elicited by exclusively exposing the ear in rats

Blast overpressure has become an increasing cause of brain injuries in both military and civilian populations. Though blast＇s direct effects on the cochlea and vestibular organs are active areas of study, little attention has been given to the ear＇s contribution to the overall spectrum of blast injury. Acute auto- nomic responses to blast exposure, including bradycardia and hypotension, can cause hypoxia and contribute to blast-induced neurotrauma. Existing literature suggests that these autonomic responses are elicited through blast impacting the thorax and lungs. We hypothesize that the unprotected ear also provides a vulnerable locus for blast to cause autonomic responses. We designed a blast generator that delivers controlled overpressure waves into the ear canal without impacting surrounding tissues in order to study the ear＇s specific contribution to blast injury. Anesthetized adult rats＇ left ears were exposed to a single blast wave ranging from 0 to 110 PSI （0-758 kPa）. Blast exposed rats exhibited decreased heart rates and blood pressures with increased blast intensity, similar to results gathered using shock tubes and whole-body exposure in the literature. While rats exposed to blasts below 50 PSI （345 kPa） exhibited increased respiratory rate with increased blast intensity, some rats exposed to blasts higher than 50 PSI （345 kPa） stopped breathing immediately and ultimately died. These autonomic responses were significantly reduced in vagally denervated rats, again similar to whole-body exposure literature. These results support the hypothesis that the unprotected ear contributes to the autonomic responses to blast.

Numerical Simulation of PRHR System Based on CFD

In this paper numerical simulation of PRHR HX and IRWST is demonstrated using FLUENT, and different numbers of C-type heat transfer tubes and coolant inlet temperature’s effects for the residual heat removal capacity of PRHR HX, IRWST thermal stratification and natural circulation have been researched. It’s found that at a constant flow area when heat transfer tubes’ number increased outlet temperature of PRHR HX is lower, the whole water temperature of IRWST is higher, thermal stratification and natural circulation are more oblivious. At a constant mass flow when inlet temperature of PRHR HX increased, inlet flow velocity increases and outlet temperature is higher. But on the other hand the cooling rate increases at the same time, the average temperature of IRWST is higher, the range of thermal stratification expands and the velocity of natural circulation increases.

Analysis of Changing Factors on Airborne Allergenic Pollens Distribution in Taiyuan Downtown, North China

To study and analyse 2 surveys on airborne allergenic pollens distribution in Taiyuan Downtown, North China 30 years apart, the surveys focused on the phenomenon and the influence factors on types, counts, drift patterns, growth and decline rhythm and distribution features of airborne pollen with the same methods in the region in March 1977 to February 1978 and July 2008 to June 2009, respectively. The data of two airborne pollens surveys were treated with statistics, comparation and analysis, and the influence factors of pollen distribution in Taiyuan Downtown were explored. In the 2 surveys, 24 species and 35 species of pollen were collected in the region, respectively. Two pollen drift peaks were formed in spring and autumn in the two surveys. Artemisia L. is still the absolute dominant allergy airborne pollen. The types, counts, drift patterns and composition of pollen in air could be changed by the plants variation. Climate warming might affect pollen peak appearing time and lasting time, climate warming and Poplar & Willow contents changes in spring and autumn reversed the airborne pollen peak. It was found that Humulus L. had become the region’s main allergic pollen. Invasive strong allergen ragweed was spread to the inland city Taiyuan. Allergists should focus on exotic invasive harmful plants in the region.

Stress Analysis for Reactor Coolant Pump Nozzle of Nuclear Reactor Pressure Vessel

Integrated reactor structural design makes the pressure vessel itself and loads more complicated, so stress concentration makes strength failure easier at reactor coolant pump nozzle. The general purpose finite element program ANSYS/ WORKBENCH was used for 3D stress and fatigue analysis and the results of the evaluation are based on RCC-M criteria. The integrated reactor structural design is evaluated to demonstrate with applicable criteria and ANSYS/WORK- BENCH has better operability than ANSYS APDL on stress analysis of reactor pressure vessel.

DMSS:An Attention-Based Deep Learning Model for High-Quality Mass Spectrometry Prediction

Accurate prediction of peptide spectra is crucial for improving the efficiency and reliability of proteomic analysis,as well as for gaining insight into various biological processes.In this study,we introduce Deep MS Simulator(DMSS),a novel attention-based model tailored for forecasting theoretical spectra in mass spectrometry.DMSS has undergone rigorous validation through a series of experiments,consistently demonstrating superior performance compared to current methods in forecasting theoretical spectra.The superior ability of DMSS to distinguish extremely similar peptides highlights the potential application of incorporating our predicted intensity information into mass spectrometry search engines to enhance the accuracy of protein identification.These findings contribute to the advancement of proteomics analysis and highlight the potential of the DMSS as a valuable tool in the field.

Emerging roles and potential clinical applications of translatable circular RNAs in cancer and other human diseases

Circular RNAs (circRNAs) are a special class of single-stranded RNA molecules with covalently closed loops widely expressed in eukaryotic organisms. CircRNAs have long been considered to play important roles in various physiological and pathological processes as non-coding RNAs. However, circRNAs have recently garnered considerable attention due to their ability to be translated into peptides/proteins via internal ribosome entry site- or N6-methyladenosine-mediated pathways or rolling translation mechanisms. Furthermore, dysregulation of translatable circRNAs and their encoded proteins has been associated with developing and progressing diseases such as cancer. This review aims to summarize the driving mechanisms of circRNA translation and the available strategies in circRNA translation research. The main focus is on the emerging biological functions of translatable circRNAs, their regulatory mechanisms, and potential clinical applications in human diseases to provide new perspectives on disease diagnosis, prognosis, and targeted therapy.

Influence of mass-flow ratio of inner to outer secondary air on gas-particle flow near a swirl burner

The influence of mass-flow-rate ratio of inner to outer secondary air on gas-particle flow characteristics was determined in the near-burner region of a centrally fuel-rich swirl coal combustion burner, Velocity and particle volume flux profiles and normalized particle number concentrations were obtained. Peaks in tangential mean velocity and three-dimensional root-mean-square fluctuation velocities were found to decrease as the mass-flow-rate ratio increased. Moreover, the peaks in the mean axial velocities and parti- cle volume flux near the wall increased, whereas those near the chamber axis decreased. Simultaneously, both recirculation zone and swirl number decreased as the mass-flow-rate ratio increased.

Variable selection procedures from multiple testing

Variable selection has played an important role in statistical learning and scienti?c discoveries during the past ten years, and multiple testing is a fundamental problem in statistical inference and also has wide applications in many scienti?c ?elds. Signi?cant advances have been achieved in both areas. This study attempts to ?nd a connection between the adaptive LASSO(least absolute shrinkage and selection operator) and multiple testing procedures in linear regression models. We also propose procedures based on multiple testing methods to select variables and control the selection error rate, i.e., the false discovery rate. Simulation studies demonstrate that the proposed methods show good performance relative to controlling the selection error rate under a wide range of settings.

Empirical likelihood inference in autoregressive models with time-varying variances

This paper develops the empirical likelihood(EL)inference procedure for parameters in autore-gressive models with the error variances scaled by an unknown nonparametric time-varying function.Compared with existing methods based on non-parametric and semi-parametric esti-mation,the proposed test statistic avoids estimating the variance function,while maintaining the asymptotic chi-square distribution under the null.Simulation studies demonstrate that the proposed EL procedure(a)is more stable,i.e.,depending less on the change points in the error variances,and(b)gets closer to the desired confidence level,than the traditional test statistic.