Tectonic evolution of the Dabashan orocline, central China: Insights from the superposed folds in the eastern Dabashan foreland

The Dabashan orocline is situated in the northwestern margin of the central Yangtze block,central China.Previous studies have defined the orthogonal superposed folds growing in its central-western segment thereby confirming its two-stage tectonic evolution history.Geological mapping has revealed that more types of superposed folds have developed in the eastern segment of the orocline,which probably provides more clues for probing the structure and tectonic history of the Dabashan orocline.In this paper,based on geological mapping,structural measurements and analyses of deformation,we have identified three groups of folds with different trends （e.g.NW-,NE-and nearly E-trending folds） and three types of structural patterns of superposed folds in the eastern Dabashan foreland （e.g.syn-axial,oblique,and conjunctional superposed folds）.In combination with geochronological data,we propose that the synaxial superposed folds are due to two stages of ～N-S shortening in the west and north of the Shennongjia massif,and that oblique superposed folds have been resulted from the superposition of the NW-and NE-trending folds onto the early ～ E-W folds in the east of the Shennongjia massif in the late Jurassic to early Cretaceous.The conjunctional folds are composed of the NW-and NE-trending folds,corresponding to the regional-scale dual-orocline in the eastern Sichuan as a result of the southwestward expansion of the Dabashan foreland during late Jurassic to early Cretaceous,coeval with the northwestward propagation of the Xuefengshan foreland.Integration of the structure and geochronology of the belt shows that the Dabashan orocline is a combined deformation belt primarily experiencing a twostage tectonic evolution history in Mesozoic,initiation of the Dabashan orocline as a foreland basin along the front of the Qinling orogen in late Triassic to early Jurassic due to collisional orogeny,and the final formation of the Dabashan orocline owing to the southwestward propagation of the Qinling orogen during late Jurassic to early Cretaceous intra-continental orogeny.Our studies provide some evidences for understanding the structure and deformation of the Dabashan orocline.

Ages and Hf isotopes of detrital zircons from the Permian strata in the engbatu area(Inner Mongolia) and tectonic implications

The Central Asian Orogenic Belt(CAOB) was built up through protracted accretion and collision of a variety of terranes/micro-continents during Neoproterozoice Mesozoic time. To understand potential links among Paleozoic subduction and accretionary processes that were operative during the development of the southeastern CAOB, we conducted a combined U-Pb and Hf-isotope analysis of detrital zircons from previously defined Devonian, Carboniferous and Early Permian strata in the Bengbatu area,Inner Mongolia. Detrital zircons from(meta-) sandstones in these strata commonly yield major Paleozoic age populations at ca. 300-261 Ma, 351-300 Ma and 517-419 Ma, and also give several Precambrian ages that range from 2687 Ma to 544 Ma. The youngest ages redefine the deposition of all these strata to be in the Middle Permian(Wordiane Capitanian) or later, much younger than previously considered.These ages, coupled with regional magmatic records, support an interpretation of most surrounding areas as possible detritus sources, including the Mongolian arcs to the north, the Northern Accretionary Orogen to the south, and the intervening Erenhote Hegenshan Ophiolite Belt. Zircons with magmatic ages of ca. 500-350 Ma and ca. 300-261 Ma display a large range of εHf(t) values(-13.97 to +15.31),whereas ca. 350-300 Ma zircons are dominated by positive εHf(t) values(+0.14 to +16.00). These results support the occurrence of two significant shifts of the zircon εHf(t) values, which has tectonic implications for the understanding of the Carboniferouse Permian evolution of the southeastern CAOB. A marked shift from mixed to positive zircon εHf(t) values at 350 -330 Ma likely manifests the incipient opening of the Hegenshan Ocean, due to the slab rollback of the subducting Paleo-Asian Oceanic lithosphere. Another shift from positive to mixed zircon εHf(t) values at ca. 300 Ma likely corresponds to a tectonic switch from syn-orogenic subduction-related to post-orogenic extensional setting, genetically related to the tectonic collapse of a formerly overthickened crust.

Addition of peroxiredoxin 6 (PRDX6) to IVF fertilization medium maintains motility and longevity of human spermatozoa

This study aims to investigate the protective effects of peroxiredoxin 6 on the total motility and progressive motility of human spermatozoa.Semen samples with normal parameters were collected from 23 males and supplemented with different concentrations of peroxiredoxin 6.All the semen samples were measured according to the WHO 5th manual,and the motile spermatozoa were extracted using IVF fertilization medium supplemented with different peroxiredoxin 6 concentrations.Total motility and progressive motility were observed at different time-points of culture at room temperature.After peroxiredoxin 6 supplementation,all groups had a significant increase in total motility and progressive motility compared to the control group.The difference in total motility and progressive motility between the 0 and 10−7 mM groups was observed at 24 and 48 h of culture at room temperature.At 24 h,the total motility increased by 30%in the control group(16.03±11.91 vs.11.51±7.84),and progressive motility increased by 21%(10.53±9.4 vs.8.31±6.04).A similar trend was observed in the 48 h group.In addition,we also found that peroxiredoxin 6 had a well protective effect on sperm kinetic parameters at 10−7 mM.The findings of this study suggest that peroxiredoxin 6 can enhance sperm total motility and progressive motility in IVF fertilization medium.Peroxiredoxin 6 may have potential benefits for sperm preparation in assisted reproductive technology.

Study on Lateral Aerodynamic Characteristics of Hypersonic Lifting-Configuration

To have a deep understanding of the lateral stability of hypersonic lifting-configurations, wind-tunnel tests of roll static and dynamic stability for typical hypersonic lifting-configurations are carried out. The results show the roll is static unstable in small angles; the roll dynamic test curves present obvious non-linearity characteristics, and the model vibrates violently even When the angle of attack is small, which may be provoked by the non-symmetry transition from the small transverse flow around the nose of model. Subsequent research adopts longitudinal trips to generate symmetry transition at the fore-body of the model. As a result, the lateral stability of the aircrafts is apparently improved. The results show that the lateral stability of hypersonic aircrafts is very weak, and the main reason for this is lateral perturbation of flow over the nose, among which asymmetric transition weighs the most. Adoption of longitudinal trips could spur fixed transition of lateral flow, reduce the transition asymmetry of lateral flow, and strengthen the lateral stability of hypersonic aircrafts at the same time.

Assessment of Random Recruitment Assumption in Respondent-Driven Sampling in Egocentric Network Data

One of the key assumptions in respondent-driven sampling (RDS) analysis, called “random selection assumption,” is that respondents randomly recruit their peers from their personal networks. The objective of this study was to verify this assumption in the empirical data of egocentric networks. Methods: We conducted an egocentric network study among young drug users in China, in which RDS was used to recruit this hard-to-reach population. If the random recruitment assumption holds, the RDS-estimated population proportions should be similar to the actual population proportions. Following this logic, we first calculated the population proportions of five visible variables (gender, age, education, marital status, and drug use mode) among the total drug-use alters from which the RDS sample was drawn, and then estimated the RDS-adjusted population proportions and their 95% confidence intervals in the RDS sample. Theoretically, if the random recruitment assumption holds, the 95% confidence intervals estimated in the RDS sample should include the population proportions calculated in the total drug-use alters. Results: The evaluation of the RDS sample indicated its success in reaching the convergence of RDS compositions and including a broad cross-section of the hidden population. Findings demonstrate that the random selection assumption holds for three group traits, but not for two others. Specifically, egos randomly recruited subjects in different age groups, marital status, or drug use modes from their network alters, but not in gender and education levels. Conclusions: This study demonstrates the occurrence of non-random recruitment, indicating that the recruitment of subjects in this RDS study was not completely at random. Future studies are needed to assess the extent to which the population proportion estimates can be biased when the violation of the assumption occurs in some group traits in RDS samples.

The etiology,clinical features and medical treatment of somatotroph adenomas

Somatotroph adenomas lead to hypersecretion of growth hormones(GH)and may cause mass effects.Patients with somatotroph adenomas may present with acral and soft tissue enlargement,joint pain,heart and respiratory failure,diabetes mellitus and hypertension,resulting in increased morbidity and mortality.Early diagnosis and treatment are therefore important in prolonging life and improving quality of life.Recent studies depicted the landscape of genetic and epigenetic changes in sporadic somatotroph adenomas.New approaches are being developed for genetic testing,diagnosis and surveillance,which are helpful in early diagnosis,treatment and disease control of somatotroph adenomas.Data suggest that patients with somatotroph adenomas are best treated with multidisciplinary teams composed of neuro-endocrinologists,neurosurgeons,radiation oncologists and other specialists.This mini-review summarizes in a concise way the up-to-date discussion on the etiology,new diagnostic techniques and novel treatments of somatotroph adenomas.

Characteristics of Rock Mechanics Response and Energy Evolution Regime of Deep Reservoirs in the Bozhong Sag,Bohai Bay Basin

Hydraulic fracturing is a mature and effectivemethod for deep oil and gas production,which provides a foundation for deep oil and gas production.One of the key aspects of implementing hydraulic fracturing technology lies in understanding mechanics response characteristics of rocks in deep reservoirs under complex stress conditions.In this work,based on outcrop core samples,high-stress triaxial compression tests were designed to simulate the rock mechanics behavior of deep reservoirs in Bozhong Sag.Additionally,this study analyzes the deformation and damage law for rock under different stress conditions.Wherein,with a particular focus on combining energy dissipation theory to further understand damage law for deep reservoirs.The experimental results show that regardless of stress conditions,the process of deformation/failure of deep-seated reservoirs goes through five stages:Fracture compaction,newfracture formation,stable fracture expansion,unstable fracture expansion,and post-peak residual deformation.Under different stress conditions,the energy change laws of specimens are similar.The energy dissipation process of rocks corresponds closely to the trend of deformation-failure curve,then displays distinctive stage characteristics.Wherein,in stage of rock fracture compaction,the input energy curve is approximately coincident with the elastic strain energy curve,while the dissipation energy curve remains near zero.With the increase of strain,the growth rate of elastic strain energy increases gradually,but with the deformation entering the crack propagation stage,the growth rate of elastic strain energy slows down and the dissipation energy increases gradually.Finally,in the post-peak stage,rock fracture releases a lot of energy,which leads to the sharp decline of elastic strain energy curve.In addition,the introduction of damage variable D quantifies the analysis of the extent of failure for rocks.During the process of increasing strain,rock damage exhibits nonlinear growth with increasing stress.

磁性固体酸催化剂Fe_(3)O_(4)/C-SO_(3)H制备及表征

以四氧化三铁为磁核,生物质碳(葡萄糖、淀粉、蔗糖)为原料,采用先制备Fe_(3)O_(4)/C,再对其进行磺化的方法制备磁性碳基固体酸催化剂Fe_(3)O_(4)/C-SO_(3)H。以辛基葡萄糖苷的合成反应为探针,考察生物质碳种类、碳化温度、碳化时间、酸种类、磺化温度和磺化时间等因素对葡萄糖转化率和催化剂酸含量的影响。利用FT-IR、XRD、TG、SEM和振动样品磁强计(简称VSM)等对催化剂进行表征。结果表明Fe_(3)O_(4)/C-SO_(3)H的最佳制备条件为:以淀粉为生物质碳源,其用量为m(Fe_(3)O_(4))∶m(淀粉)=1∶10,碳化温度为190℃,碳化时间为8 h,以对甲苯磺酸为磺酸源,其质量比为m(Fe_(3)O_(4)/C)∶m(对甲苯磺酸)=1∶0.6,磺化温度为250℃,磺化时间为4 h。在上述条件下,催化剂酸含量为1.17 mmol/g,葡萄糖转化率为97.9%。表征结果也表明,具有良好晶型结构的Fe_(3)O_(4)在后续的碳化和磺化过程中,结构没有发生明显的变化,仍保留着良好的磁学性能。催化剂Fe_(3)O_(4)/C-SO_(3)H具备一定的孔道结构,热稳定性能良好。

磁性碳基固体酸制备及其在糖苷合成中的应用研究

以四氧化三铁为磁核,可溶性淀粉为基质,对甲苯磺酸为磺酸基来源,分别采用分步法和一步法制得磁性碳基固体酸催化剂Fe_(3)O_(4)/C-SO_(3)H(A)和Fe_(3)O_(4)/C-SO_(3)H(B)。利用SEM、XRD、FT-IR、TG、振动样品磁强计(简称VSM)等手段对催化剂进行表征,并将两种催化剂的活性进行比较,活性好的催化剂应用于辛基葡萄糖苷的合成。结果发现,Fe_(3)O_(4)/C-SO_(3)H(A)为核壳结构,粒径大小约为30 nm;Fe_(3)O_(4)/C-SO_(3)H(B)表现为具有一定多孔结构的无定形颗粒物;两种催化剂均具有较好的热稳定性和磁学性能。相比于Fe_(3)O_(4)/C-SO_(3)H(B),Fe_(3)O_(4)/C-SO_(3)H(A)在酸含量、葡萄糖转化率上表现更佳,因此选用Fe_(3)O_(4)/C-SO_(3)H(A)作为辛基葡萄糖苷的合成催化剂。当Fe_(3)O_(4)/C-SO_(3)H(A)用量为葡萄糖质量7%,正辛醇和葡萄糖的摩尔比为9∶1,反应温度为140℃时,葡萄糖转化率可达到98.5%。催化剂可通过简单的磁场分离进行重复利用,重复使用3次后,葡萄糖的转化率仍在92%以上。

Phylogenetic placement of Cynomorium in Rosales inferred from sequences of the inverted repeat region of the chloroplast genome

Cynomorium is a herbaceous holoparasite that has been placed in Santalales, Saxifragales, Myrtales, or Sapindales. The inverted repeat （IR） region of the chloroplast genome region is slow evolving and, unlike mitochondrial genes, the chloroplast genome experiences few horizontal gene transfers between the host and parasite. Thus, in the present study, we used sequences of the IR region to test the phylogenetic placements of Cynomorium. Phylogenetic analyses of the chloroplast IR sequences generated largely congruent ordinal relationships with those from previous studies of angiosperm phylogeny based on single or multiple genes. Santalales was closely related to Caryophyllales and asterids. Saxifragales formed a clade where Peridiscus was sister to the remainder of the order, whereas Paeonia was sister to the woody clade of Saxifragales. Cynomorium is not closely related to Santalales, Saxifragales, Myrtales, or Sapindales; instead, it is included in Rosales and sister to Rosaceae. The various placements of the holoparasite on the basis of different regions of the mitochondrial genome may indicate the heterogeneous nature of the genome in the parasite. However, it is unlikely that the placement of Cynomorium in Rosales is the result of chloroplast gene transfer because Cynomorium does not parasitize on rosaceous plants and there is no chloroplast gene transfer between Cynomorium and Nitraria, a confirmed host of Cynomorium and a member of Sapindales.

Sequences of low-copy nuclear gene support the monophyly of Ostrya and paraphyly of Carpinus （Betulaceae）

Coryloideae consists of four genera: Corylus, Ostryopsis, Carpinus, and Ostrya. While both molecular and non-molecular data support the close relationship of Carpinus and Ostrya, the monophyly of the two genera has remained controversial. In this study, sequences of the nuclear nitrate reductase (Nia) were used to test the naturalness of the two genera. Ostrya species form a robust clade, supporting the monophyly of the genus. The clade, however, is located between Carpinus cordata and the remaining species of Carpinus, indicating that Carpinus is paraphyletic, and Ostrya has evolved from within Carpinus. Within Carpinus, section Distegocarpus is polyphyletic, whereas section Carpinus is a clade where subsections Polyneurae and Carpinus are more closely related to each other than either is to subsection Monbeigianae.

Phylogeny of Catalpa （Bignoniaceae） inferred from sequences of chloroplast ndhF and nuclear ribosomal DNA

Phylogenetics of Chilopsis and Catalpa (Bignoniaceae) was elucidated based on sequences of chloro-plast ndhF and the nrDNA ITS region. In Bignoniaceae, Chilopsis and Catalpa are most closely related as sister genera. Our data supported section Macrocatalpa of the West Indies and section Catalpa of eastern Asian and North American continents. Within section Catalpa, Catalpa ovata of eastern Asia form a clade with North American species, C. speciosa and C. bignonioides, while the other eastern Asian species comprise a clade where C. duclouxii is sister to the clade of C. bungei and C. fargesii. The Caribbean species of Catalpa diverged early from the continental species. More studies are needed to test whether the phylogenetic pattern is common in eastern Asian-North American disjunct genera with species in the West Indies.

δ13C and δ15N in Humboldt squid beaks: understanding potential geographic population connectivity and movement

We quantified theδ^13C andδ^15N values in the lower beaks of Humboldt squid,Dosidicus gigas,collected from international waters off Costa Rica,Ecuador,Peru and Chile by Chinese squid jigging vessels during 2009,2010 and 2013.There was a significant difference in the isotopic values among regions with the lowest value off Ecuador and the highest off Chile,which were interpreted as a function of trophic effects as well as baseline values.However,constant trophic level of D.gigas across its geographic range showed that spatial variation in the baseline of primary production is the main driver responsible for the observed geographic isotope variability.Inter-regional difference and intra-regional convergence of isotope values indicated squid off Costa Rica,Ecuador and Chile belong to different geographically segregated populations,which were previously proved by integrated population identifying method.In contrast,the higher variations inδ^13C andδ^15N values in a given size group suggest the squid off Peru move and forage in different places.Moreover,potential population exchange could be responsible for the overlap of the isotope values between the squid off Peru and off Chile.On the whole,the spatial difference in isotopic values of Humboldt squid beaks improves our understanding of potential geographic population connectivity and movement.

Nerve growth factor in muscle afferent neurons of peripheral artery disease and autonomic function

In peripheral artery disease patients,the blood supply directed to the lower limbs is reduced.This results in severe limb ischemia and thereby enhances pain sensitivity in lower limbs.The painful perception is induced and exaggerate during walking,and is relieved by rest.This symptom is termed by intermittent claudication.The limb ischemia also amplifies autonomic responses during exercise.In the process of pain and autonomic responses originating exercising muscle,a number of receptors in afferent nerves sense ischemic changes and send signals to the central nervous system leading to autonomic responses.This review integrates recent study results in terms of perspectives including how nerve growth factor affects muscle sensory nerve receptors in peripheral artery disease and thereby alters responses of sympathetic nerve activity and blood pressure to active muscle.For the sensory nerve receptors,we emphasize the role played by transient receptor potential vanilloid type 1,purinergic P2X purinoceptor 3 and acid sensing ion channel subtype 3 in amplified sympathetic nerve activity responses in peripheral artery disease.

Phylogenetics and biogeography of eastern Asian–North American disjunct genus Pachysandra (Buxaceae) inferred from nucleotide sequences

Pachysandra is an eastern Asian-North American disjtunct genus with three species, two in eastern Asia （Pachysandra axillaris and Pachysandra terminalis） and one in eastern North America （Pachysandra procurnbens）. Although morphological and cytological studies suggest a close affinity of Pprocumbens with P axillaris, molecular data from nuclear and chloroplast DNA regions have provided conflicting signals. In this study, we tested previous phylogenetic hypotheses using sequences of nuclear ribosomal DNA internal transcribed spacers and chloroplast ndhF gene from multiple individuals of each of the three species. We also estimated the time of divergence between eastem Asia and eastern North America. Our results support the morphological and cytological conclusion that P procumbens is more closely related to P axillaris than to P terminalis. The estimated time of divergence of P axillaris and P procumbens was 14.6±5.5 mya, consistent with estimates from many other eastern Asian-North American disjunct genera. The migration of Pachysandra populations from eastern Asia to North America might have occurred by way of the North Atlantic land bridge.

Analysis of isolation of cerebral cortical neurons in rats by different methods

The aim of this study was to find a way to efficiently separate neuronal cells from the cerebral cortex of adult rats,providing a reference method for rapid acquisition of neuronal cells from the adult rat brain.Fifteen SD rats were randomly divided into three groups,with five SD rats in each group.Then,neuron cells were isolated from the adult rat cerebral cortex by the grinding method,the trypsin method,and the collagenase II method,respectively.The expression of anti-NeuN in the neurons of each group was analyzed by flow cytometry.The acquisition rates and morphology of neurons of each group were observed by immunofluorescence staining.The grinding or collagenase II method is more suitable for rapid acquisition of neuronal cells from an adult rat’s cerebral cortex.The number of neuron cells obtained by the trypsin method were very few,so it is not convenient for later experiments.

A Robotic System with Robust Remote Center of Motion Constraint for Endometrial Regeneration Surgery

Surgical robots have been widely used in diferent procedures to improve and facilitate the surgery.However,there is no robot designed for endometrial regeneration surgery,which is a new therapy for restoring fertility in women using stem cells.Endometrial regeneration surgery requires processing of the endometrium and transplantation of stem cells with minimal trauma to the uterus.In this paper,we introduce a surgical robotic system that consists of a dexterous hysteroscope,supporting arm,and additional novel instruments to facilitate the operation and decrease trauma to the uterus.Remote center of motion(RCM)constraint is required to protect the cervix of the uterus.First,the supporting arm and hysteroscope are controlled separately in kinematics to ensure that the RCM constraint and hysteroscope’s shape and posture are predictable.Then,a task-decoupled method is used to improve the robustness of the RCM constraint.Experiments confrm that the proposed method is more robust and achieves higher RCM accuracy.In addition,the master-slave control of a robot with RCM constraint is also verifed.This study proposes the realization of a robot with robust RCM control for endometrial regeneration surgery.

Stem cell microencapsulation maintains stemness in inflammatory microenvironment

Maintaining the stemness of the transplanted stem cell spheroids in an inflammatory microenvironment is challenging but important in regenerative medicine. Direct delivery of stem cells to repair periodontal defects may yield suboptimal effects due to the complexity of the periodontal inflammatory environment. Herein, stem cell spheroid is encapsulated by interfacial assembly of metal-phenolic network(MPN) nanofilm to form a stem cell microsphere capsule. Specifically, periodontal ligament stem cells(PDLSCs) spheroid was coated with FeⅢ/tannic acid coordination network to obtain spheroid@[FeⅢ-TA] microcapsules. The formed biodegradable MPN biointerface acted as a cytoprotective barrier and exhibited antioxidative, antibacterial and anti-inflammatory activities, effectively remodeling the inflammatory microenvironment and maintaining the stemness of PDLSCs. The stem cell microencapsulation proposed in this study can be applied to multiple stem cells with various functional metal ion/polyphenol coordination, providing a simple yet efficient delivery strategy for stem cell stemness maintenance in an inflammatory environment toward a better therapeutic outcome.

A Genetic-Algorithm-Based Information Evolution Model for Social Networks

the existing information diffusion models focus on analyzing the spatial distribution of certain pieces of messages in social networks. However, these conventional models ignored another important characteristic of diffusion: gradually changing of message contents due to the ‘new' and ‘comment' mechanisms. A novel genetic-algorithm-based information evolution model is proposed to reproduce both the diffusion and development process of information in social networks. This model firstly proposes a five-tuple to represent three types of topics: independent, competitive and mutually exclusive. Furthermore, it adopts mutation operator and forms new crossover and mutation rules to simulate four typical interactions between individuals, which bring the advantage of reproducing the information evolution process in both popularity and content.A series of experiments tested on public datasets demonstrate that: 1) independent and competitive topics of information rarely affect each other while mutually exclusive topics significantly suppress the diffusion processes of each other; 2) lower mutation probability leads to decreasing of final information amount. The experimental results show that our evolution model is more reasonable and feasible in demonstrating the evolution of information in social networks.