Origin and phylogenetic analysis of Tibetan Mastiff based on the mitochondrial DNA sequence

At present, the Tibetan Mastiff is the oldest and most ferocious dog in the world. However, the origin of the Tibetan Mastiff and its phylogenetic relationship with other large breed dogs such as Saint Bernard are unclear. In this study, the primers were designed accord- ing to the mitochondrial genome sequence of the domestic dog, and the 2,525 bp mitochondrial sequence, containing the whole sequence of Cytochrome b, tRNA-Thr, tRNA-Pro, and control region of the Tibetan Mastiff, was obtained. Using grey wolves and coyotes as out- groups, the Tibetan Mastiff and 12 breeds of domestic dogs were analyzed in phylogenesis. Tibetan Mastiff, domestic dog breeds, and grey wolves were clustered into a group and coyotes were clustered in a group separately. This indicated that the Tibetan Mastiff and the other domestic dogs originated from the grey wolf, and the Tibetan Mastiff belonged to Carnivora, Canidae, Canis, Canis lupus, Canis lupus familiaris on the animal taxonomy. In domestic dogs, the middle and small breed dogs were clustered at first; German Sheepdog, Swedish Elkhound, and Black Russian Terrier were clustered into one group, and the Tibetan Mastiff, Old English Sheepdog, Leonberger, and Saint Bernard were clustered in another group. This confirmed the viewpoint that many of the famous large breed dogs worldwide such as Saint Bernard possibly had the blood lineage of the Tibetan Mastiff, based on the molecular data. According to the substitution rate, we concluded that the approximate divergence time between Tibetan Mastiff and grey wolf was 58,000 years before the present （YBP）, and the approximate divergence time between other domestic dogs and grey wolf was 42,000 YBP, demonstrating that the time of origin of the Tibetan Mastiff was earlier than that of the other domestic dogs.

High-Transconductance,Highly Elastic,Durable and Recyclable All-Polymer Electrochemical Transistors with 3D Micro-Engineered Interfaces

Organic electrochemical transistors(OECTs)have emerged as versatile platforms for broad applications spanning from flexible and wearable integrated circuits to biomedical monitoring to neuromorphic computing.A variety of materials and tailored micro/nanostructures have recently been developed to realized stretchable OECTs,however,a solid-state OECT with high elasticity has not been demonstrated to date.Herein,we present a general platform developed for the facile generation of highly elastic all-polymer OECTs with high transconductance(up to 12.7 mS),long-term mechanical and environmental durability,and sustainability.Rapid prototyping of these devices was achieved simply by transfer printing lithium bis(trifluoromethane)sulfonimide doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS/LiTFSI)microstructures onto a resilient gelatin-based gel electrolyte,in which both depletion-mode and enhancement-mode OECTs were produced using various active channels.Remarkably,the elaborate 3D architectures of the PEDOT:PSS were engineered,and an imprinted 3D-microstructured channel/electrolyte interface combined with wrinkled electrodes provided performance that was retained(>70%)through biaxial stretching of 100%strain and after 1000 repeated cycles of 80%strain.Furthermore,the anti-drying and degradable gelatin and the self-crosslinked PEDOT:PSS/LiTFSI jointly enabled stability during>4 months of storage and on-demand disposal and recycling.This work thus represents a straightforward approach towards high-performance stretchable organic electronics for wearable/implantable/neuromorphic/sustainable applications.

Self-Healing All-in-One Energy Storage for Flexible Self-Powering Ammonia Smartsensors

Self-healable and flexible all-in-one self-powering smartsensing devices have recently attracted great attention.Herein,a flexible all-in-one solid-state electronic system of polyvinyl alcohol(PVA)hydrogel-based supercapacitors for self-powering ammonia smartsensors has been fabricated.Self-healing supercapacitors are prepared by integrating polypyrrole(PPy)and boron crosslinked PVA/KCl hydrogel as a sandwich configuration,exhibiting large specific capacitance of 244.81 mF cm^(-2)at 0.47 mA cm^(-2),and good charging/discharging stability of 2000 cycles,while ammonia sensors are realized by a SnO_(2)/PPy-modified conductive PVA hydrogel film,demonstrating an excellent sensing behavior toward NH_(3) vapor under 50 ppb–500 ppm.As a result,selfhealing supercapacitors could well store energy and then self-power sensing unit for remotely real-time detection via a smartphone,acquiring high flexibility of energy-sensing system.With attractive biocompatibility and selfhealing performance toward various environment,this all-in-one flexible energy-smartsensor system would pave the way to novel fabrication process in realization of wearable self-healing smart devices.

Current Advances in Epigenetic Modification and Alteration during Mammalian Ovarian Folliculogenesis

During the growth and development of mammalian ovarian follicles, the activation and deactivation of mass genes are under the synergistic control of diverse modifiers through genetic and epigenetic events. Many factors regulate gene activity and functions through epigenetic modification without altering the DNA sequence, and the common mechanisms may include but are not limited to： DNA methylation, histone modifications （e.g., acetylation, deacetylation, phosphorylation, methylation, and ubiquitination）, and RNA- associated silencing of gene expression by noncoding RNA. Over the past decade, substantial progress has been achieved in studies involving the epigenetic alterations during mammalian germ cell development. A number of candidate regulatory factors have been identified. This review focuses on the current available information of epigenetic alterations （e.g., DNA methylation, histone modification, noncoding-RNA-mediated regulation） during mammalian folliculogenesis and recounts when and how epigenetic patterns are differentially established, maintained, or altered in this process. Based on different types of epigenetic regulation, our review follows the temporal progression of events during ovarian folliculogenesis and describes the epigenetic changes and their contributions to germ cell-specific functions at each stage （i.e,, primordial folliculogenesis （follicle formation）, follicle maturation, and follicular atresia）.

Terabit FSO communication based on a soliton microcomb

Free-space optical(FSO)communication technology is a promising approach to establish a secure wireless link,which has the advantages of excellent directionality,large bandwidth,multiple services,low mass and less power requirements,and easy and fast deployments.Increasing the communication capacity is the perennial goal in both scientific and engineer communities.In this paper,we experimentally demonstrate a Tbit/s parallel FSO communication system using a soliton microcomb as a multiple wavelength laser source.Two communication terminals are installed in two buildings with a straight-line distance of~1 km.102 comb lines are modulated by10 Gbit/s differential phase-shift keying signals and demodulated using a delay-line interferometer.When the transmitted optical power is amplified to 19.8 dBm,42 optical channels have optical signal-to-noise ratios higher than 27 dB and bit error rates less than 1×10^(-9).Our experiment shows the feasibility of a wavelength-division multiplexing FSO communication system which suits the ultra-high-speed wireless transmission application scenarios in future satellite-based communications,disaster recovery,defense,last mile problems in networks and remote sensing,and so on.