Positive carbon isotope excursions:global correlation and genesis in the Middle-Upper Ordovician in the northern Tarim Basin,Northwest China

Stable carbon isotope ratio （δ13Ccarb） analysis has been widely applied to the study of the inter-conti- nental or global marine carbonate correlation. Large-scale Cambrian-Ordovician carbonate platforms were developed in the Tarim Basin. But research on fluctuation character- istics and global correlation of δ13Ccarb is still weak. Based on conodont biostratigraphy and whole-rock δ13Ccarb data in the Tahe oil-gas field of the northern Tarim Basin, the global correlation and genesis of positive carbon isotope excursions in the Darriwilian--Early Katian was exam- ined. Three positive excursions were identified in the Tahe oil-gas field including the middle Darriwilian carbon iso- tope excursion （MDICE）, the Guttenberg carbon isotope excursion （GICE）, and a positive excursion within the Pygodus anserinus conodont zone which is named the Early Sandbian carbon isotope excursion （ESICE） in this paper. Furthermore, these positive excursions had no direct relation with sea level fluctuations. MDICE and GICE could be globally correlated. The Middle-Upper Ordovi- cian Saergan Formation source rocks of the Kalpin outcrops were in accordance with the geological time of MDICE and ESICE. GICE had close relationship with the source rock of the Lianglitag Formation in the basin.Massive organic carbon burial was an important factor controlling the genesis of these positive excursions.

Effects of environmental hypothermia on hemodynamics and oxygen dynamics in a conscious swine model of hemorrhagic shock

BACKGROUND:Hypothermia is associated with poor outcome in trauma patients;however,hemorrhagic shock(HS)model with anesthetized swine was different from that of clinical reality.To identify the effects of environmental hypothermia on HS,we investigated hemodynamics and oxygen dynamics in an unanesthetized swine model of HS under simulating hypothermia environment.METHODS:Totally 16 Bama pigs were randomly divided into ambient temperature group(group A)and low temperature group(group B),8 pigs in each group.Venous blood(30 mL/kg)was continuously withdrawn for more than 15 minutes in conscious swine to establish a hemorrhagic shock model.Pulmonary arterial temperature(Tp),heart rate(HR),mean arterial pressure(MAP),pulmonary arterial pressure(PAP),pulmonary arterial wedge pressure(PAWP),central venous pressure(CVP),cardiac output(CO),hemoglobin(Hb),saturation of mixed venous blood(SvO_2)and blood gas analysis were recorded at the baseline and different hemorrhagic shock time(HST).The whole body oxygen delivery indices,DO_2l and VO_2l,and the O_2 extraction ratio(O_2ER)were calculated.RESULTS:Core body temperature in group A decreased slightly after the hemorrhagic shock model was established,and environmental hypothermia decreased in core body temperature.The mortality rate was significantly higher in group B(50%)than in group A(0%).DO_2l and VO_2l decreased significantly after hemorrhage.No difference was found in hemodynamics,DO_2l and VO_2l between group A and group B,but the difference in pH,lactic acid and O_2ER was significant between the two groups.CONCLUSION:Environmental hypothermia aggravated the disorder of oxygen metabolism after hemorrhagic shock,which was associated with poor prognosis.

Novel m.4268T>C mutation in the mitochondrial tRNA^(Ile) gene is associated with hearing loss in two Chinese families

BACKGROUND Herein,we report the genetic,clinical,molecular and biochemical features of two Han Chinese pedigrees with suggested maternally transmitted non-syndromic hearing loss.AIM To investigate the pathophysiology of hearing loss associated with mitochondrial tRNA mutations.METHODS Sixteen subjects from two Chinese families with hearing loss underwent clinical,genetic,molecular,and biochemical evaluations.Biochemical characterizations included the measurements of tRNA levels using lymphoblastoid cell lines derived from five affected matrilineal relatives of these families and three control subjects.RESULTS Three of the 16 matrilineal relatives in these families exhibited a variable seriousness and age-at-onset(8 years)of deafness.Analysis of mtDNA mutation identified the novel homoplasmic tRNA^(Ile) 4268T>C mutation in two families both belonging to haplogroup D4j.The 4268T>C mutation is located in a highly conserved base pairing(6U–67A)of tRNA^(Ile).The elimination of 6U–67A basepairing may change the tRNA^(Ile) metabolism.Functional mutation was supported by an approximately 64.6%reduction in the level of tRNA^(Ile) observed in the lymphoblastoid cell lines with the 4268T>C mutation,in contrast to the wild-type cell lines.The reduced level of tRNA was below the proposed threshold for normal respiration in lymphoblastoid cells.However,genotyping analysis did not detect any mutations in the prominent deafness-causing gene GJB2 in any members of the family.CONCLUSION These data show that the novel tRNA^(Ile) 4268T>C mutation was involved in maternally transmitted deafness.However,epigenetic,other genetic,or environmental factors may be attributed to the phenotypic variability.These findings will be useful for understanding families with maternally inherited deafness.

Mitochondria-targeted nano-AIEgens as a powerful inducer for evoking immunogenic cell death

AIEgens can serve as an effective platform for the construction of photosensitizer-based immunogenic cell death(ICD)inducers.To date,several mitochondria or endoplasmic reticulum(ER)-targeted aggregationinduced emission(AIE)molecules have been developed and have evoked massive ICD in cells.However,due to the complex physicochemical environment in cells,these small AIE molecules cannot maintain a stable aggregate state,which not only affects the fluorescence intensity of the photosensitizer but also decreases the generation of reactive oxygen species(ROS),and thus reducing the effect of the photosensitizer to elicit ICD.AIEgen-based nanomicelles,which maintain a stable micellar structure,can prevent defects of AIE molecules in photodynamic therapy(PDT)applications.Therefore,in this study,a mitochondria-targeted AIE nanophotosensitizer was synthesized and used as a highly potent ICD inducer for vaccine preparation and tumor prevention.

Coarse-Grained Cloud Synchronization Mechanism Design May Lead to Severe Traffic Overuse

In recent years, cloud sync（hronization） services such as GoogleDrive and Dropbox have provided Internet users with convenient and reliable data storing/sharing functionality. The cloud synchronization mechanism （in particular, how to deliver the user-side data updates to the cloud） plays a critical role in cloud sync services because it greatly affects the cloud operation cost （in terms of sync traffic） and user experience （in terms of sync delay）. By comprehensively measuring tens of popular cloud sync services, we find that their cloud sync mechanisms differ greatly in sync performance and design granularity. Quite surprisingly, some very popular services （like GoogleDrive and 115 SyncDisk） utilize a quite coarse-grained cloud sync mechanism that may lead to severe traffic overuse. For example, updating 1-MB data may sometimes result in 260-MB sync traffic. In this paper, we conduct a comparative study of various cloud sync mechanisms by analyzing their respective pros and cons under different situations, unravel the pathological processes for their traffic overuse problems, and finally provide insights/solutions for better choosing/designing a cloud sync service.