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The fuel cell hybrid powertrain is a potential power supply system for fuel cell vehicles. The underlying problem is that the fuel cell vehicles encounter exhaustive hydrogen consumption. To effectively manage hydrogen consumption, the aim is to propose fuel cell city bus power and control system. The underlying idea is to determine the target power of fuel cell through simulation study on fuel cell and battery energy management strategy and road test verifications. A half-power prediction energy management strategy is implemented to predict the target power of the fuel cell in the current time step based on the demand power of the vehicle and the state of charge (SOC) of the battery in the previous time steps. This offers better understanding of the correlation between fuel cell power and vehicle drive cycle for enabling effective power supply management. The research results show that the half-power prediction energy management strategy effectively reduces the hydrogen consumption of the vehicle by 7.1% and the number of battery cycle by 6.0%, compared to the stepped management strategy of battery SOC. When applied to a 12-m fuel cell city bus—F12, specially designed and manufactured for the Winter Olympic Games in 2022—the fuel economy of 3.7 kg/100 km is achieved in urban road conditions. This study lays a foundation for providing the powertrain configuration and energy management strategy of fuel cell city bus.

The development of life beyond planet Earth is a long-standing quest of the human race, but whether normal mammalian embryonic development can occur in space is still unclear. Here, we show unequivocally that preimplantation mouse embryos can develop in space, but the rate of blastocyst formation and blastocyst quality are compromised. Additionally, the cells in the embryo contain severe DNA damage, while the genome of the blastocysts developed in space is globally hypomethylated with a unique set of differentially methylated regions. The developmental defects, DNA damage and epigenetic abnormalities can be largely mimicked by the treatment with ground-based low-dose radiation. However, the exposure to simulated microgravity alone does not cause major disruptions of embryonic development, indicating that radiation is the main cause for the developmental defects. This work advances the understanding of embryonic development in space and reveals long-term extreme low-dose radiation as a hazardous factor for mammalian reproduction.

In this work, simple chemical reduction method is used to prepare Pd–Sn nanocatalysts supported on carbon for ethanol electro-oxidation in alkaline environment using ethylene glycol as reductant. The composition, structure and morphologies of PdSn/f-C catalysts are investigated by X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray and transmission electron microscopy. The electro-chemical activity and durability of as-obtained PdSn/f-C nanocatalysts are investigated and determined by cyclic voltammetry and Chronoamperometric measurements. The obtained results demonstrate that as prepared PdSn/f-C nanocatalysts have uniform dispersion and small particle size. In addition to, the as prepared PdSn/f-C nanocatalysts have higher electro-chemical activity and better stability toward EOR in alkaline environment than those of Pd/f-C and commercial Pd/C (JM) nanocatalysts. Specifically, the electro-catalytic activity of Pd 1.5 Sn/f-C nanocatalyst (3413.3 mA mg Pd − 1 ) is almost 8.6 times higher than Pd/C (JM) nanocatalyst (355.2 mA mg Pd − 1 ), which has competitive power among reported Pd–Sn catalysts. These results indicate that the uniform carbon supported PdSn nanostructure are promising electrocatalysts for direct ethanol fuel cells.

The excellent catalyst need to meet low cost, long-time stability and high electrocatalytic activity in direct ethanol fuel cells (DEFC). Here, carbon nanotube-supported Pd-based (Pd/CNT, PdSn/CNT, PdNi/CNT and PdSnNi/CNT) catalysts were synthesized by microwave-assisted polyols and in-situ reduction. Compared with commercial Pd/C (JM), the as-prepared Pd-based catalysts have higher electrocatalytic activity and outstanding long-time durability toward ethanol electro-oxidation reaction in alkaline media. The enhanced electrocatalytic activity of Pd-based catalysts are owning to high electrochemically active surface area (ECSA) and modified electronic structure of Pd. After chronoamperometric test, the current densities of Pd-based catalysts can be reactivated by simple cycle potential scan in 1 M NaOH, which indicated that all of them have excellent resistance to CO poisoning.

Self-recoverable Pd–Ru/TiO2 nanocatalysts have been prepared by electrochemical stripping of Pd–Ru/TiO2 precursors. For the ethanol oxidation reaction (EOR), these Pd–Ru/TiO2 nanocatalysts are used as an anode catalyst. The characterization of catalysts via chronoamperometry has been repeated 15 times. After 15 stability tests, the Pd1Ru0.69/TiO2 nanocatalysts still achieve a factor of 9.4 enhancement at the residual current density (309.42 mA mgPd−1) for the EOR over commercial Pd/C catalysts (33.01 mA mgPd−1). From the 5th to 15th test, when each 10 000 s stability test is performed in a fresh ethanol electrolyte, the initial and residual current density of the catalysts could recover to the original or even better value in a few hours before performing another 10 000 s stability test. Herein, these Pd–Ru/TiO2 nanocatalysts with ultrastability towards ethanol electrooxidation are self-recoverable. Density functional theory calculations reveal that the introduction of oxophilic metal Ru and a TiO2 support into Pd-based catalysts and the synergistic effects between Ru and TiO2 have led to the ultrastability towards the EOR. The introduction of oxophilic metal Ru and a TiO2 support into catalysts can reduce the adsorption energy of OHads on the Pd–Ru/TiO2 nanocatalysts, and it will inhibit the COads produced and adsorbed on the Pd surface.

Poor dispersibility in aqueous media of polymer functionalized one-dimensional materials including carbon nanotubes (CNTs), inorganic nanoparticles and polymer nanofibers is an inherent challenge to their utilization in several applications. Herein, polydopamine grafted CNTs (PDA-CNTs) are rendered dispersible through chemical crosslinking via bioinspired borate chemistry. Nanolayer coatings of polydopamine are deposited on the side walls of CNTs forming aggregates that lead to highly dense and agglomerated PDA-CNTs sediments in aqueous media. Borate crosslinking facilitates the obtainment of a homogeneous dispersion of borate crosslinked PDA-CNTs (B-PDA-CNTs) by forming strong hydrogen bonds in solution and thus permitting the facile fabrication of B-PDA-CNTs membranes with an interconnected nanoporous structure on a macroporous support. The obtained membranes with a controllable thickness are stable and display good ultrafiltration performances of ferritin molecules (>90%) and high water permeability of more than 2.8 × 103 L m−2 h−1 bar−1. The borate chemical crosslinking highlights a versatile approach for the preparation of stable polydopamine coated nanomaterials for wide applications with bio-macromolecules and in nanocomposite materials.

This work reports the preparation of ternary hollow PdSnNi (H-PdSnNi) catalysts with nanochannels toward the electrooxidation of ethanol in alkaline medium, in which the Pd and Sn nanoparticles grow on the surface of H-Ni microspheres by galvanic replacement method. The reaction is driven by the difference in the equilibrium potential of the Pd/PdCl42−, Sn/Sn2+ and Ni/Ni2+ redox couples. Structural measurements indicate the hollow structure of the H-PdSnNi nanocomposites and the well distribution of nanoparticles. The distinctive Pd NPs and Sn NPs loaded on H-Ni microspheres can efficient prevent Pd NPs from the aggregation and provide a high specific area. Electrochemical tests illustrate that the H-PdSnNi2.5 catalyst has large electrochemically active surface area and prominent activity (1902 A g−1). After the same chronoamperometery test, the residual current density of H-PdSnNi2.5 catalyst remains 1006 A g−1 which is 7.1 times that of Pd/C (JM) (140 A g−1). The superior activity and stability of the H-PdSnNi catalysts toward ethanol electrooxidation are attributed to the hollow structure, the electron effect and bifunctional mechanism due to the addition of Ni and Sn. This work will spur the study of the structure and composition (ternary-metallic) of electrocatalysts toward EOR with superior electrooxidation performance.

In this work, bimetallic NiPd hollow nanoporous (H NiPd) catalysts are prepared by in-situ deposition of Pd nanoparticles (Pd NPs) on hollow Ni (H Ni) microspheres. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) reveal the hollow nanoporous essence of H NiPd catalysts. Meanwhile, using high-angle annular dark-field scanning TEM (HAADF-STEM) and elemental mapping, it is found that tiny dendritic-like NiPd nanocomposites attach on the exterior of microspheres. The content of Pd is easily tailored to constitute H NiPd catalysts with different Ni/Pd atomic ratios. Further electrochemical evaluation vindicates that the as-prepared H NiPd catalysts have a good catalytic activity and stability toward ethanol oxidation reaction (EOR) in alkaline medium. Notably, the peak current density of H Ni3.1Pd catalyst and the chronoamperometric current density of H Ni4.6Pd catalyst are 4 and 2 times of Pd/C (JM) catalyst, respectively, which show that H NiPd catalysts hold great potential in application of alkaline direct ethanol fuel cells (DEFCs).

We have theoretically studied a comprehensive size effect on the spectra of PbSe quantum dot (QD)-doped liquid-core optical fiber, including PbSe QD's particle size and particle number effect, and fiber length and fiber diameter effect. The doping concentration, pump intensity and wavelength were fixed at proper values for comparison. The red shift of emission spectral peak increased with QD diameter, QD number, fiber length and fiber diameter, and reached up to saturation with increasingly QD number which was explained in detail. The evolutions of spectral intensity with the four size parameters were gained, and the related “optimal” (under the certain other parameters) fiber length, diameter and QD number were observed for PbSe QDs of different size as the dopant. Furthermore, each kind of the “optimal” value changed with the other three size parameters. These four size parameters restricted each other, and affected the spectral features together. The calculating results fitted well to the experimental data. This research might be a theoretical basis in the design of optical fiber-based device.

Self-recoverable Pd-Ru/TiO2 nanocatalysts have been prepared by electrochemical stripping of Pd-Ru/TiO2 precursors. For the ethanol oxidation reaction (EOR), these Pd-Ru/TiO2 nanocatalysts are used as an anode catalyst. The characterization of catalysts via chronoamperometry has been repeated 15 times. After 15 stability tests, the Pd1Ru0.69/TiO2 nanocatalysts still achieve a factor of 9.4 enhancement at the residual current density (309.42 mA mgPd-1) for the EOR over commercial Pd/C catalysts (33.01 mA mgPd-1). From the 5th to 15th test, when each 10 000 s stability test is performed in a fresh ethanol electrolyte, the initial and residual current density of the catalysts could recover to the original or even better value in a few hours before performing another 10 000 s stability test. Herein, these Pd-Ru/TiO2 nanocatalysts with ultrastability towards ethanol electrooxidation are self-recoverable. Density functional theory calculations reveal that the introduction of oxophilic metal Ru and a TiO2 support into Pd-based catalysts and the synergistic effects between Ru and TiO2 have led to the ultrastability towards the EOR. The introduction of oxophilic metal Ru and a TiO2 support into catalysts can reduce the adsorption energy of OHads on the Pd-Ru/TiO2 nanocatalysts, and it will inhibit the COads produced and adsorbed on the Pd surface.

The embryonic surface ectoderm is a simple flat epithelium consisting of cells that express the cytokeratins K8/K18. Before stratification, K5/K14 expression substitutes K8/K18 expression, marking the event called epidermal commitment. Previous studies show that the transcription factor p63 plays an essential role in epidermal commitment. However, detailed expression information of p63 during early epidermal development in mice is still unclear. We systematically studied the expression pattern of p63 in mouse epidermal commitment, together with K8 and K5. We show that p63 expression could be detected as early as E8.5 in mouse embryos preceding epidermal commitment. p63 expression first appears near the newly formed somites and the posterior part of the embryo, further expanding to the whole embryonic surface with particular enrichment in the first branchial arches and the limb buds. ΔNp63 is the major class of isoforms expressed in this period. Relative expression intensity of p63 depends on the embryonic position. In summary, there is a sequential and regular expression pattern of K8, p63 and K5 in mouse epidermal commitment. Our study not only contributes to understanding the early events during epidermal development but also provides a basal tool to study the function of p63 in mammals.

The re-absorption loss in quantum dot optical fibers (QD-OFs) affects the fiber emission and limits the device performance. This is not only related to fiber parameters (fiber length and diameter, QD concentration, etc.), but also depends on the properties of doped materials to a large extent. Therefore, the emission of QD-OFs for two different QD materials (PbSe and CuInS2/ZnS) were theoretically simulated using rate equations and power propagation equations, considering the influence of fluorescence lifetime, absorption and emission cross-section (AECS), Stokes-shift, and full width at half-maximum (FWHM). The parameters that had the greatest influence on emission intensity were the fluorescence lifetime for PbSe QD-OFs and the Stokes-shift for CuInS2/ZnS QD-OFs, when the fibers were relatively long. AECS showed more important in shorter OFs. FWHM had the least influence on emission intensity for any length of fiber. The fluorescence lifetime was more advantageous for the stability of the emission wavelength. Compared with CuInS2/ZnS QD-OFs, the emission intensity of PbSe QD-OFs was lower, which however changed more rapidly with these parameters.

To observe the effect difference between awn-like needle at Tiantu(CV 22) and filiform needle for dysphagia after cerebral infarction.One hundred patients were randomly assigned into an awn-like needle group and a filiform needle group,50 cases in each one. Based on the conventional western medicine for all the patients,awn-like needle was applied at Tiantu(CV 22) in the awn-like needle group;while acupuncture was used at Fengchi(GB 20),Shanglianquan(Extra),Shuigou(GV 26) and Tongli(HT 5) in the filiform needle group,combined with pricking at Jinjin(EX-HN 12), Yuye(EX-HN 13),posterior pharyngeal wall with three-edged needle method. All the treatment was given once a day for two weeks. Standard swallowing assessment scale(SSA) and modified Bathel index for daily life ability(MBI) were used and the efficacy was calculated after treatment.The scores of SSA and MBI were improved after treatment in the two groups(allBased on the conventional western treatment,awn-like needle and filiform needle can both improve dysphagia and daily life after cerebral infarction. But awn-like needle achieves better effect.

Hair follicle stem cells (HFSCs) possess fascinating self-renewal capacity and multipotency, which play important roles in mammalian hair growth and skin wound repair. Although HFSCs from other mammalian species have been obtained, the characteristics of ovine HFSCs, as well as the methods to isolate them have not been well addressed. Here, we report an efficient strategy to obtain multipotent ovine HFSCs. Through microdissection and organ culture, we obtained keratinocytes that grew from the bulge area of vibrissa hair follicles, and even abundant keratinocytes were harvested from a single hair follicle. These bulge-derived keratinocytes are highly positive for Krt15, Krt14, Tp63, Krt19 and Itga6, in addition to their strong proliferation abilities in vitro, these keratinocytes formed new epidermis, hair follicles and sebaceous glands in skin reconstitution experiments, showing that these are HFSCs from the bulge outer root sheath. Taken together, we developed an efficient in vitro system to enrich ovine HFSCs, providing enough HFSCs for the investigations about the ovine hair cycle, aiming to promote wool production in the future.

Though there are numerous biological experiments, which have been performed in a space environment, to study the physiological effect of space travel on living organisms, while the potential effect of weightlessness or short-term hypergravity on the reproductive system in most species, particularly in mammalian is still controversial and unclear. In our previous study, we investigated the effect of space microgravity on the development of mouse 4-cell embryos by using Chinese SJ-8. .Unexpectedly, we did not get any developed embryo during the space-flight. Considering that the process of space experiment is quite different from most experiments done on earth in several aspects such as, the vibration and short-term hypergravity during the rock launching and landing. Thus we want to know whether the short-term hypergravity produced by the launch process affect the early embryo development in mice, and howthe early embryos respond to the hypergravity. In present study, we are mimicking the short-term hypergravity during launch by using a centrifuge to investigate its influence on the development of early embryo (2-cell) in mice. We also examined the actin filament distribution in 2-cell embryos by immunostaining to test their potential capacity of development under short-term hypergravity exposure. Our results showed that most 2-cell embryos in the hypergravity exposure groups developed into blastocysts with normal morphology after 72h cultured in vitro, and there is no obvious difference in the development rate of blastocyst formation compared to the control. Moreover, there were no statistically significant differences in birth rates after oviduct transfer of 2-cell mouse embryos exposed on short-term hypergravity compared with 1 g condition. In addition, the well-organized actin distribution appeared in 2-cell embryos after exposed on hypergravity and also in the subsequent developmental blastocysts. Taken together, our data shows that short-term exposure in hypergravity conditions does not affect the normal development and actin filament structures of mouse embryos.

Multipotent skin-derived precursors (SKPs) are dermal stem cells with the capacity to reconstitute the dermis and other tissues, such as muscles and the nervous system. Thus, the easily available human SKPs (hSKPs) hold great promises in regenerative medicine. However, long-term expansion is difficult for hSKPs in vitro. We previously demonstrated that hSKPs senesced quickly under routine culture conditions. To identify the underlying mechanisms so as to find an effective way to expand hSKPs, time-dependent microarray analysis of gene expression in hSKPs during in vitro culture was performed. We found that the senescence of hSKPs had a unique gene expression pattern that differs from reported typical senescence. Subsequent investigation ruled out the role of DNA damage and classical p53 and p16INK4a signaling in hSKP senescence. Examination of cyclin-dependent kinase inhibitors revealed the involvement of p15INK4b and p27KIP1. Further exploration about upstream signals indicated the contribution of Akt hypo-activity and FOXO3 to hSKP senescence. Forced activation of Akt and knockdown of FOXO3, p15INK4b and p27KIP1 effectively inhibited hSKP senescence and promoted hSKP proliferation. The unique senescent phenotype of human dermal stem cells and the role of Akt-FOXO3-p27KIP1/p15INK4b signaling in regulating hSKP senescence provide novel insights into the senescence and self-renewal regulation of adult stem cells. The present study also points out a way to propagate hSKPs in vitro so as to fulfill their promises in regenerative medicine.

Stem cells are undifferentiated progenitor cells that are accepted as a source of seed cells for therapeutic applications in tissue regeneration and as a model to investigate the lineage-specific differentiation of stem cells. Outstanding research in recent years has shed light on the role of micro-environment of stem cells in the proliferation and differentiation. Although studies have indicated that soluble mediators such as cytokines and growth factors play a significant role in proliferation and differentiation of stem cells, a critical role for mechanical force and mechanotransduction in controlling self-renewal, differentiation, aging and apoptosis of stem cells has also been revealed. In this review, we summarize and discuss the mechanisms of cells response to mechanical stimuli, the biomechanical force as a regulator for stem cell self-renewal and differentiation, and the putative mechanisms of mechanotransduction.

Recently, physical factors in the local cellular microenvironment have been confirmed with strong influences on regulating stem cell fate. Despite the recent identification of the rotary cell culture system (RCCS) as a bioreactor for culturing stem cells, the underlying biological role provided by RCCS in the lineage differentiation of embryonic stem cells (ESCs) remains largely undefined. Here, we explored the embryoid body (EB) formation and subsequent differentiation of mouse ESCs in RCCS. We demonstrated that EBs formed in RCCS were more homogeneous and bigger in size compared with those in the static condition. Further, we determined that mesendoderm differentiation was prominently enhanced, while neuroectodermal differentiation was significantly suppressed in RCCS. Surprisingly, we found that Wnt/β-catenin signaling was greatly enhanced mainly due to the increased expression of Wnt3 during ESC differentiation in RCCS. Inhibition of Wnt/β-catenin signaling by DKK1 decreased the expression of Brachyury and attenuated mesendoderm differentiation in RCCS. Intriguingly, Wnt3a markedly increased Brachyury expression under static condition rather than in RCCS. Taken together, our findings uncover a new role of rotary suspension culture in initializing the early differentiation of ESCs.

In this study, CuO films with hollow cubic cages were prepared by a facile two-step procedure consisting of electrodeposition synthesis and subsequent direct calcination. First, Cu2O nanocubes were fabricated on ITO substrate through a simple electrodeposition procedure. Then, Cu2O nanocubes were converted to CuO hollow cubic cages without obvious morphological change through direct calcination. The obtained CuO cubic cages serving as active materials illustrated a favorable performance for nonenzymatic glucose sensing with high sensitivity of [Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text] at a low applied potential of 0.50[Formula: see text]V, fast-response time (less than 3[Formula: see text]s), low detection limit of 1.0[Formula: see text][Formula: see text]M and wide linear range up from 2.0[Formula: see text][Formula: see text]M to 1.0[Formula: see text]mM ([Formula: see text]). Moreover, the good selectivity of the CuO cubic cages-based nonenzymatic glucose sensor against electroactive compounds such as ascorbic acid, uric acid and dopamine were also demonstrated. These good features indicate that the as-prepared CuO cubic cages can be used as promising electrode materials, which have a great potential in the development of sensitive and selective nonenzymatic glucose sensors.

The uterine natural killer cells (uNK cells) are the major immune cells in pregnant uterus and the number of uNK cells is dramatically increased during placentation and embryo development. The uNK cells are necessary for the immune tolerance, cytokine secretion and angiogenesis of placenta. Former studies indicated that the population expansion of uNK cells was accomplished through recruitment of NK cell precursors from the spleen and bone marrow, but not proliferation of NK cells. However, the necessary molecules within this process were little understood. Here in our study, we found the co-localized expression of Cxcl14 protein with uNK cells in E13.5 pregnant uterus. Moreover, we used Cxcl14 knockout mice to examine uNK cells in mesometrial lymphoid aggregate of pregnancy (MLAp) and decidua basalis (DB) of E13.5 pregnant uterus and found significantly decreased uNK cells in Cxcl14−/− pregnant uteri compared with Cxcl14+/− pregnant uteri. To further explorer the molecular change in MLAp and DB after Cxcl14 knockout, we isolated the MLAp and DB from Cxcl14+/+ and Cxcl14−/− pregnant uteri and performed microarray analysis. We found many genes were up and down regulated after Cxcl14 knockout. In conclusion, our results suggested the important function of Cxcl14 in uNK cells and the proper level of Cxcl14 protein were required to recruit NK cells to pregnant uterus.

Hair follicle stem cells (HFSCs) are considered one of the useful donor cell types for skin regenerative medicine owing to their robust proliferative capacity and multipotency. However, methods for easily and effectively obtaining HFSCs from a limited skin biopsy are still lacking. Here we report a novel approach for obtaining a subpopulation of HFSCs from a small skin sample from the rat tail, which uses the sebaceous glands (SGs) to capture the adjacent HFSCs. By means of organ culture, keratinocytes were expanded from the detached SGs, which also included adherent HFSCs from the hair follicle that could be passaged at the single-cell level. These SG-captured keratinocytes strongly expressed the basal layer markers K14, integrin α6, and p63; the bulge stem cell marker K15; and the upper isthmus stem cell marker Plet1. Furthermore, we reconstituted new epidermis, hair follicles, and SGs from the SG-captured keratinocytes using an easily operated, modified skin reconstitution assay based on silicone gel sheeting. This study suggests that the SGs could be an accessible capturer to harvest the adjacent HFSC subpopulation, particularly when the donor tissue is limited.

R-spondin proteins are novel Wnt/β-catenin agonists, which signal through their receptors leucine-rich repeat-containing G-protein coupled receptor (LGR) 4/5/6 and substantially enhance Wnt/β-catenin activity. R-spondins are reported to function in embryonic development. They also play important roles in stem cell functions in adult tissues, such as the intestine and mammary glands, which largely rely on Wnt/β-catenin signaling. However, in the skin epithelium and hair follicles, the information about R-spondins is deficient, although the expressions and functions of their receptors, LGR4/5/6, have already been studied in detail. In the present study, highly-enriched expression of the R-spondin family genes (Rspo1/2/3/4) in the hair follicle dermal papilla is revealed. Expression of Rspo1 in the dermal papilla is specifically and prominently upregulated before anagen entry, and exogenous recombinant R-spondin1 protein injection in mid-telogen leads to precocious anagen entry. Moreover, R-spondin1 activates Wnt/β-catenin signaling in cultured bulge stem cells in vitro, changing their fate determination without altering the cell proliferation. Our pioneering study uncovers a role of R-spondin1 in the activation of cultured hair follicle stem cells and the regulation of hair cycle progression, shedding new light on the governance of Wnt/β-catenin signaling in skin biology and providing helpful clues for future treatment of hair follicle disorders.

Author(s): Zhang, Yunfang; Zhang, Ying; Shi, Junchao; Zhang, He; Cao, Zhonghong; Gao, Xuan; Ren, Wanhua; Ning, Yunna; Ning, Lina; Cao, Yujing; Chen, Yongchang; Ji, Weizhi; Chen, Zi-Jiang; Chen, Qi; Duan, Enkui

Basal plane bending is a structural defect in SiC single crystals caused mainly by the thermal mismatch between seed and holder, which deteriorates the quality of the wafers and blocks their applications. In this paper, basal plane bending was detected by high-resolution X-ray diffractometry (HRXRD) and transmission synchrotron white-beam X-ray topography (SWBXT). HRXRD reveals that the (0001) Si face is a concave sphere and SWBXT shows that the shapes of the Laue spots are different from that of the cross section of the synchrotron radiation beam. On the basis of a spherical curvature model for a (0001) 6H-SiC single crystal, the shapes of the Laue spots were simulated. The results are in good agreement with the experimental observations. Thus, SWBXT is an effective method for detecting basal plane bending.

Well-controlled trophoblast invasion into uterine decidua is a critical process for the normal development of placenta, which is tightly regulated by various factors produced within the trophoblast-endometrial microenvironment. CXCL14 is involved in tumor growth and metastasis, and its expression in placenta is temporally regulated during pregnancy. However, the role of CXCL14 in trophoblast function during human pregnancy is not clear. In this study, by using RT-PCR through human pregnancy, we found that CXCL14 was selectively expressed at early but not late pregnancy. Immunostaining revealed that CXCL14 proteins were strongly expressed in villous cytotrophoblasts and moderately in decidualized stromal cells but very weakly in syncytiotrophoblasts and extravillous trophoblasts. The effect of CXCL14 on trophoblast invasion were examined by using human villous explants cultured on Matrigel and further proved by invasion and migration assay of primary trophoblast cells and trophoblast cell line HTR-8/SVneo. Our data showed that CXCL14 significantly inhibited outgrowth of villous explant in vitro; this effect is due to suppression of trophoblast invasion and migration through regulating matrix metalloproteinases activities, whereas the trophoblast proliferation was not affected. Moreover, because a receptor for CXCL14 has not been identified, we performed further cell-specific CXCL14 binding activities with regard to different cell types within the maternal-fetal interface. Our data revealed that CXCL14 could specifically bind to trophoblast cells but not decidual cells from the maternal-fetal interface. These results suggest that CXCL14 plays an important role in regulating trophoblast invasion through an autocrine/paracrine manner during early pregnancy.

6H-SiC single crystals were grown by sublimation method. It is found that foreign grains occur frequently on the facets of the crystals. To characterize the foreign grain, a longitudinal and a sectional cut samples were prepared by standard mechanical processing method. Raman spectrum confirms that the foreign grain is actually a mis-oriented 6H-SiC grain. The surface structure of the foreign grain was studied by chemical etching and optical microscopy. It is shown that etch pits in foreign grain region take the shape of isosceles triangle, which are different from those in mono-crystalline region, and high density stacking faults are observed on the surface of the foreign grain. The orientation of foreign grain surface is determined to be (10\( \bar 1 \)4) plane by back-scattering X-ray Laue image. The X-ray powder diffraction reveals that the powder is partly graphitized after a long crystal growth run. Therefore it is believed that the loss of Si results in the formation of C inclusions, which is responsible for the nucleation of foreign grain in the facet region.

The nature of the micropipe, a fatal defect in SiC-based device applications, is still not fully understood. In this work, the birefringence images of micropipes in 6H-SiC crystals along thecaxis have been observed and simulated in detail. Based on Frank's theory, the intensity contours of birefringence images for micropipes viewed end-on in 6H-SiC crystals have been derived by considering the photoelastic anisotropy of silicon carbide. The results are in good agreement with experimental observations.

Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration.

G protein-coupled receptors (GPCRs) mediate multiple key biological processes in the body. The orphan receptor GPR39 has been reported to be involved in various pathophysiological events. However, the function of GPR39 in skin biology remains unknown. Using a genetically engineered mouse strain in which lacZ expression faithfully replaced endogenous Gpr39 expression, we discovered a unique expression pattern of Gpr39 in the sebaceous gland (SG). Using various methods, we confirmed that GPR39 marked a specific cell population at the opening of the SG and colocalised with the SG stem cell marker Blimp1. Further investigations showed that GPR39 was spatiotemporally expressed during skin wound repair. Although it was dispensable for skin development and homeostasis, GPR39 contributed positively to skin wound healing: its loss led to a delay in wound healing during the intermediate stage. The present study reveals a novel role of GPR39 in both dermatology and stem cell biology that has not been previously recognised.

Multipotent skin-derived precursors (SKPs) are dermal stem cells with the capacity to reconstitute the dermis and other tissues, such as muscles and the nervous system. Thus, the easily available human SKPs (hSKPs) hold great promises in regenerative medicine. However, long-term expansion is difficult for hSKPs in vitro. We previously demonstrated that hSKPs senesced quickly under routine culture conditions. To identify the underlying mechanisms so as to find an effective way to expand hSKPs, time-dependent microarray analysis of gene expression in hSKPs during in vitro culture was performed. We found that the senescence of hSKPs had a unique gene expression pattern that differs from reported typical senescence. Subsequent investigation ruled out the role of DNA damage and classical p53 and p16(INK4a) signaling in hSKP senescence. Examination of cyclin-dependent kinase inhibitors revealed the involvement of p15(INK4b) and p27(KIP1). Further exploration about upstream signals indicated the contribution of Akt hypo-activity and FOXO3 to hSKP senescence. Forced activation of Akt and knockdown of FOXO3, p15(INK4b) and p27(KIP1) effectively inhibited hSKP senescence and promoted hSKP proliferation. The unique senescent phenotype of human dermal stem cells and the role of Akt-FOXO3-p27(KIP1)/p15(INK4b) signaling in regulating hSKP senescence provide novel insights into the senescence and self-renewal regulation of adult stem cells. The present study also points out a way to propagate hSKPs in vitro so as to fulfill their promises in regenerative medicine.

Self-seeded growth of aluminum nitride single crystals in BN crucible was conducted by sublimation method. It was found that the growth temperature played a critical role in the determination of the crystal morphologies and the appearance crystalline planes. The (0 0 0 1) and pseudo ( 1 1 2 ¯ 0 ) planes were often present at low and high temperature, respectively. The self-seeded crystals possess high structural quality which were assessed by high resolution X-ray diffractometry with a full-width at half-maximum of 35.76 arcsec. Step flow mechanism for the growth of AlN similar to SiC growth was confirmed with the aid of atomic force microscopy.

The chemical mechanical polishing (CMP) of the Si face (0 0 0 1), the C face ( 0 0 0 1 ¯ ), the a face ( 1 1 2 ¯ 0 ) and the m face ( 1 1 ¯ 0 0 ) of silicon carbide (SiC) wafers was investigated. It was found that the removal rate and surface quality varied greatly with the different crystal face orientations during the CMP. Surface quality was characterized with atomic force microscopy (AFM) in terms of root mean square (RMS) roughness and high-resolution X-ray diffractometry (HRXRD). The optimum CMP process yielded a superior Si face finish with 0.096 nm RMS roughness, while no polishing action was observed on the C face. Results were explained in light of the atomic structure. CMP mechanisms of four faces were analyzed based on different polishing results.

Skin-derived precursors (SKPs) are multipotent cells with dermal stem cell properties. These easily available cells possess the capacity to reconstitute the skin in vivo, as well as a broader differentiation potential in vitro, which endows them with great prospects in regenerative medicine. However, the present authors’ group and others previously found that adult human SKPs (hSKPs) expanded deficiently in vitro, which largely counteracted their research and practical values. Taking the physiological micro-environment of hSKPs into consideration, the authors sought to establish a hydrogel scaffold-based three-dimensional (3-D) culture system for hSKPs in the present study. After comparing their morphology, growth characteristics, signature gene expression and differentiation potential in different hydrogels, the present authors found that a chemically defined hyaluronic acid and denatured collagen-based hydrogel system that mimicked the natural niche of hSKPs in the dermis could alleviate hSKP senescence, support hSKP proliferation as spheres, while largely retaining their properties and potential. This study suggested that recapitulating the in vivo stem cell niche by providing them with 3-D extracellular matrix environments could help them achieve better self-renewal in vitro. In addition, the animal-origin-free and biocompatible 3-D hydrogel system will certainly benefit fundamental research and clinical applications of hSKPs in the near future.

This paper presents an image mosaic algorithm and its application to the microimage of grass seeds. The following main steps are involved, firstly in the registration stage, the scale invariant feature transform (SIFT) is employed to obtain initial matches. Then the Random Sample Consensus (RANSAC) is used to remove incorrect matches effectively. Finally in the fusion stage, fade-in and fade-out method is applied to smooth seams which exist in the stitched image. Since the effect is not obvious, the adaptive Gamma correction method is used to weaken illumination effect on image quality to obtain a stitched image, which contains more information than each of the original images. Experimental results demonstrate that the proposed approach achieves good performance for grass seeds microimage mosaic in both subjective and objective evaluations.

Author(s): Peng, Hongying; Shi, Junchao; Zhang, Ying; Zhang, He; Liao, Shangying; Li, Wei; Lei, Li; Han, Chunsheng; Ning, Lina; Cao, Yujing; Zhou, Qi; Chen, Qi; Duan, Enkui

Sublimation method was used to grow bulk SiC by J.A. Lely for the first time in 1955 (Lely, 1955). It was improved then by Tairov and Tsvetkov and became the most mature method for bulk SiC growth. In this chapter, we will introduce the growth of hexagonal SiC. Although the bulk growth method is well known and used widely, there are still plenty of details which are different and unique for different groups. The growth of 4H-SiC is not as stable as that of 6H-SiC. That is to say the growth of 4H-SiC needs a harsh growth conditions. In order to grow high quality 4H polytype, the polytype transition of 4H-SiC single crystals had been studied. Although single crystals of SiC are commercially available, owing to the specific structures of SiC, there are still some structural defects, such as micropipes, mis-orientations, dislocations, stacking faults, basal plane dislocations, particle inclusions, precipitates and so on, which hinder its applications. So in this chapter we also introduce the recent progress in research of structural defects in 6H-SiC single crystals. Three kinds of typical structural defects in 6H-SiC single crystals were investigated. First, we describe the strain field of a micropipe by the theory of screw dislocation. Stress birefringence images from micropipes with different Burgers vectors have been simulated. The results are compared with polarized optical microscopic observations. Second, elementary screw dislocations were observed by back-reflection synchrotron radiation topography (BRSRT). Based on the reflection geometry, the image of an elementary screw dislocation was simulated. Elementary screw dislocation is a pure screw dislocation with Burger vector lc. Finally, Basal plane bending was detected by high resolution X-ray diffractometry (HRXRD) and transmission synchrotron white-beam x-ray topography (SWBXT). The observation and investigation of the structural defects helped us to understand their formation mechanisms. This makes it possible for us to further decrease or eventually eliminate them.

The skin is susceptible to different injuries and diseases. One major obstacle in skin tissue engineering is how to develop functional three-dimensional (3D) substitute for damaged skin. Previous studies have proved a 3D dynamic simulated microgravity (SMG) culture system as a "stimulatory" environment for the proliferation and differentiation of stem cells. Here, we employed the NASA-approved rotary bioreactor to investigate the proliferation and differentiation of human epidermal stem cells (hEpSCs). hEpSCs were isolated from children foreskins and enriched by collecting epidermal stem cell colonies. Cytodex-3 micro-carriers and hEpSCs were co-cultured in the rotary bioreactor and 6-well dish for 15 days. The result showed that hEpSCs cultured in rotary bioreactor exhibited enhanced proliferation and viability surpassing those cultured in static conditions. Additionally, immunostaining analysis confirmed higher percentage of ki67 positive cells in rotary bioreactor compared with the static culture. In contrast, comparing with static culture, cells in the rotary bioreactor displayed a low expression of involucrin at day 10. Histological analysis revealed that cells cultured in rotary bioreactor aggregated on the micro-carriers and formed multilayer 3D epidermis structures. In conclusion, our research suggests that NASA-approved rotary bioreactor can support the proliferation of hEpSCs and provide a strategy to form multilayer epidermis structure.

Pregnancy loss is a serious social and medical issue, with one important cause associated with aberrant embryo implantation during early pregnancy. However, whether and how the process of embryo implantation is affected by environmental factors such as stress-induced sympathetic activation remained elusive. Here we report an unexpected, transient effect of β(2)-adrenoreceptor (β(2)-AR) activation (day 4 postcoitus) in disrupting embryo spacing at implantation, leading to substantially increased midterm pregnancy loss. The abnormal embryo spacing could be prevented by pretreatment of β(2)-AR antagonist or genetic ablation of β-AR. Similar β(2)-AR activation at day 5 postcoitus, when implantation sites have been established, did not affect embryo spacing or pregnancy outcome, indicating that the adverse effect of β(2)-AR activation is limited to the preimplantation period before embryo attachment. In vitro and in vivo studies demonstrated that the transient β(2)-AR activation abolished normal preimplantation uterine contractility without adversely affecting blastocyst quality. The contractility inhibition is mediated by activation of the cAMP-PKA pathway and accompanied by specific down-regulation of lpa3, a gene previously found to be critical for uterine contraction and embryo spacing. These results indicated that normal uterine contraction-mediated correct intrauterine embryo distribution is crucial for successful ongoing pregnancy. Abnormal β(2)-AR activation at early pregnancy provided a molecular clue in explaining how maternal stress at early stages could adversely affect the pregnancy outcome.

Objectives To define the expression pattern of the putative zinc receptor GPR39 at different regions of the mouse prostate. Methods We used a mouse strain harboring a LacZ reporter at 1 allele of gpr39 (gpr39+/LacZ). LacZ staining of adult prostate was performed by whole-mount staining followed by tissue section. The expression results were also confirmed at protein level by immunohistochemistry staining using GPR39 antibody in adult male mice. Results Whole-mount LacZ staining and tissue sections clearly revealed that GPR39 mRNA is intensely expressed at the epithelial cells of dorsal and anterior prostates, with lower intensity at the lateral prostate and very low or no expression in the ventral prostate. Immunohistochemistry staining results were consistent with those for LacZ staining. Conclusions These data demonstrate that the putative zinc receptor GPR39 is spatially expressed at different regions of the mouse prostate with various intensities, suggesting that GPR39 might play an important role in mediating zinc function for normal prostate health in a region-specific manner. GPR39 expression in human prostate under normal and pathologic conditions is an interesting issue that warrants further investigation.