Covalently-Bonded Laminar Assembly of Van der Waals Semiconductors with Polymers: Toward High-Performance Flexible Devices.

Van der Waals semiconductors (vdWS) offer superior mechanical and electrical properties and are promising for flexible microelectronics when combined with polymer substrates. However, the self-passivated vdWS surfaces and their weak adhesion to polymers tend to cause interfacial sliding and wrinkling, and thus, are still challenging the reliability of vdWS-based flexible devices. Here, an effective covalent vdWS-polymer lamination method with high stretch tolerance and excellent electronic performance is reported. Using molybdenum disulfide (MoS2 )and polydimethylsiloxane (PDMS) as a case study, gold-chalcogen bonding and mercapto silane bridges are leveraged. The resulting composite structures exhibit more uniform and stronger interfacial adhesion. This enhanced coupling also enables the observation of a theoretically predicted tension-induced band structure transition in MoS2 . Moreover, no obvious degradation in the devices' structural and electrical properties is identified after numerous mechanical cycle tests. This high-quality lamination enhances the reliability of vdWS-based flexible microelectronics, accelerating their practical applications in biomedical research and consumer electronics.

Overexpression of FNDC4 constrains ovarian cancer progression by promoting cell apoptosis and inhibiting cell growth.

Hepatocellular carcinoma is one of the most common malignant tumors in the world. It has been reported that fibronection type III domain containing family plays an important role in the formation and development of a variety of tumors, but the role of FNDC4 is still unclear. In our study, we found that FNDC4 was highly expressed in normal liver tissues but abnormally expressed at low levels in liver cancer tissues. Enhanced apoptosis and decreased proliferation were shown in the FNDC4 overexpression model in HepG2 cells. In addition, FNDC4 was negatively correlated with AFP, a tumor marker of HCC, and other cancer-related genes such as AHSA1, GDF1, GPC3 and MDK. In addition, we found that FNDC4 was associated with the abundance of several tumor-infiltrating lymphocytes and the expression of chemokines and immunostimulators, and FNDC4 was enriched in response to transforming growth factor ß. These results indicated that FNDC4 plays a key role in hepatocellular carcinoma progression and might be a promising biomarker for cancer diagnosis.

Effects of omega-3 polyunsaturated fatty acids on cellular development in human ovarian granulosa tumor cells (KGN).

Emerging research has shown that polyunsaturated fatty acids (PUFAs) benefit human health and exert anti-cancer effects. However, there is little understanding of the specific mechanisms by which PUFAs regulate the cells of the ovarian granulosa tumor. In the current study, we investigate the effects and the possible mechanisms of PUFAs on human ovarian tumor cells development. KGN cells were treated with omega-3. Small interfering (siRNA) and specific activator were used to knock down and overexpress gene expression in KGN cells. The protein content levels were analyzed by Western blot. Cell viability, proliferation and apoptosis assay were performed to examine the cellular development. And the level of glucose uptake in KGN cells were assessed by 2-DG measurement. The results showed that omega-3 treatment reduced cell viability, proliferation and increased cell apoptosis. Further studies showed that omega-3 also reduced GLUT1/4 protein content and cellular glucose uptake. Subsequent knockdown and overexpression of OCT4 using Oct4 siRNA and O4I2 (OCT4 activator) showed that OCT4 was involved in the regulations of omega-3 on GLUT1/4 expression and cell development. Our data demonstrate that omega-3 inhibits cellular development by down-regulating GLUT1/4 expression and glucose uptake in KGN cells, which are mediated through OCT4.

Discovery of Graphene-Water Membrane Structure: Toward High-Quality Graphene Process.

It is widely accepted that solid-state membranes are indispensable media for the graphene process, particularly transfer procedures. But these membranes inevitably bring contaminations and residues to the transferred graphene and consequently compromise the material quality. This study reports a newly observed free-standing graphene-water membrane structure, which replaces the conventional solid-state supporting media with liquid film to sustain the graphene integrity and continuity. Experimental observation, theoretical model, and molecular dynamics simulations consistently indicate that the high surface tension of pure water and its large contact angle with graphene are essential factors for forming such a membrane structure. More interestingly, water surface tension ensures the flatness of graphene layers and renders high transfer quality on many types of target substrates. This report enriches the understanding of the interactions on reduced dimensional material while rendering an alternative approach for scalable layered material processing with ensured quality for advanced manufacturing.

van der Waals Semiconductor Empowered Vertical Color Sensor.

Biomimetic artificial vision is receiving significant attention nowadays, particularly for the development of neuromorphic electronic devices, artificial intelligence, and microrobotics. Nevertheless, color recognition, the most critical vision function, is missed in the current research due to the difficulty of downscaling of the prevailing color sensing devices. Conventional color sensors typically adopt a lateral color sensing channel layout and consume a large amount of physical space, whereas compact designs suffer from an unsatisfactory color detection accuracy. In this work, we report a van der Waals semiconductor-empowered vertical color sensing structure with the emphasis on compact device profile and precise color recognition capability. More attractive, we endow color sensor hardware with the function of chromatic aberration correction, which can simplify the design of an optical lens system and, in turn, further downscales the artificial vision systems. Also, the dimension of a multiple pixel prototype device in our study confirms the scalability and practical potentials of our developed device architecture toward the above applications.

The Effect of Melatonin on OCT4 Expression and Granulosa Cell Growth in Female Mice.

Melatonin is mainly secreted by the pineal gland as a neurotransmitter. Moreover, melatonin is also produced by the ovary and plays important roles in female reproduction. However, it is unclear whether melatonin has any effect on the transition from the preantral follicle to the early antral follicle. Octamer-binding transcription factor 4 (OCT4) is important to granulosa cells development, which is regulated by gonadotropin. And these regulations are mediated by the GSK3ß/ß-catenin pathway via the activated PI3K/Akt signaling. The aim of the present study was to determine the effects and the possible mechanisms of melatonin on ovarian cells development. The results showed that melatonin inhibited granulosa cells development, which was accompanied by the downregulation of OCT4 expression. Meanwhile, melatonin also decreased the expression of p-GSK3ß (glycogen synthase kinase 3 beta), p-Akt, ß-catenin, and its translocation to the nucleus in granulosa cells. Moreover, melatonin attenuated the effects of FSH in vitro and eCG in vivo on these regulations. In conclusion, this study shows that melatonin inhibits ovarian cell development by downregulating the OCT4 expression level, which is possibly mediated by inhibiting the PI3K/Akt and GSK3ß/ß-catenin pathway. Melatonin attenuates the effects of gonadotropin on ovarian granulosa cells as a negative regulator.

Mechanisms of OCT4 on 3,5,3'-Tri-iodothyronine and FSH-induced Granulosa Cell Development in Female Mice.

Octamer-binding transcription factor 4 (OCT4) regulates the pluripotency of stem cells and also plays important roles in granulosa cells growth, which is regulated by follicle-stimulating hormone (FSH). Thyroid hormone (TH) is important for the development and maturation of follicles and the maintenance of various endocrine functions. Although 3,5,3'-triiodothyronine (T3) enhances the effects of FSH on the regulation of the growth of granulosa cells and development of follicles, it is unclear whether and, if so, how TH combines with FSH to regulate OCT4 expression in granulosa cells during the preantral to early antral transition stage. Our results showed that T3 enhanced FSH-induced OCT4 expression. However, T3/FSH-induced cellular growth was reduced by OCT4 small interfering RNA. OCT4 knockdown significantly increased the number of apoptotic cell. Moreover, T3 combined with FSH to increase estrogen receptor ß (ERß) expression but did not significantly affect estrogen receptor α expression. ERß knockdown dramatically decreased T3/FSH-induced OCT4 expression and cell development and increased cell apoptosis. The phosphoinositide 3-kinases/protein kinase B pathway was involved in hormones inducing OCT4 and ERß expressions. Furthermore, the hormones regulating OCT4 and ERß expressions were regulated by cytochrome P450 lanosterol 14a-demethylase (CYP51), a key enzyme in sterol and steroid biosynthesis. T3 and FSH cotreatment potentiated cellular development by upregulating OCT4 expression, which is mediated by CYP51 and ERß. These regulatory processes are mediated by the phosphoinositide 3-kinase/protein kinase B signaling pathway. These findings suggest that OCT4 mediates the T3 and FSH-induced development of follicles.

Endosymbiont CLS-HI plays a role in reproduction and development of Haemaphysalis longicornis.

Coxiella-like endosymbiont (CLS-Hl) is a primary endosymbiont of Haemaphysalis longicornis. CLS-Hl infects tick special tissues and its prevalence is 100% in ovaries and Malpighian tubules. Tetracycline was injected into females, which then fed on rabbits also treated with tetracycline. The densities of CLS-Hl were measured by semi-quantitative PCR. CLS-Hl densities in ovaries and Malpighian tubes of H. longicornis had significant effects on engorged weight, feeding time, number of eggs, oviposition period, and hatching period. These findings suggested that CLS-Hl plays a role in the reproduction and development of H. longicornis.

Microbial diversity of the Tibetan tick Haemaphysalis tibetensis (Acari: Ixodidae).

The Tibetan tick Haemaphysalis tibetensis is widely distributed in the Tibetan Plateau, and is recognized as one of the primary parasites affecting domestic and wild animals. No information is available on its microbial diversity. In the current study, the microbiomes in H. tibetensis were explored using Illumina MiSeq sequencing. Results indicate that a total of 28 phyla and 38 genera were characterized from this tick, and most of the microbes were classified in the phylum Proteobacteria. Female and male H. tibetensis harbored similar composition of the microbes, with dominant bacteria from the genus Coxiella accounting for 87.5 and 66.5% in females and males, respectively. The abundance of bacteria belonging to the genus Rickettsia in females and males was 6.9 and 23.7%, respectively. These findings may help understand the relationship between this tick and its symbiontic microorganisms.

Symbiont dynamics of the Tibetan tick Haemaphysalis tibetensis (Acari: Ixodidae).

BACKGROUND: Characterization of the microbial diversity and symbiont dynamics of ticks may help to understand the development of ticks and reveal new strategies to control tick-transmitted pathogens, which has not yet been explored in the Tibetan tick Haemaphysalis tibetensis. This tick species is widely distributed in the Tibetan Plateau, and is recognized as one of the primary parasites affecting domestic and wild animals. METHODS: In the present study, the endosymbionts of H. tibetensis were characterized using diagnostic polymerase chain reaction (diagnostic PCR), and further evaluated for tissue distribution and population dynamics at each developmental stage of ticks and in tissues at different reproductive statuses by real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: Two symbionts were found in H. tibetensis, and named as CLS-Ht (Coxiella-like symbiont in H. tibetensis) and RLS-Ht (Rickettsia-like symbiont in H. tibetensis). They showed 100% infection rate in both females and males of H. tibetensis. CLS-Ht and RLS-Ht can be observed within eggs, larvae, nymphs and adults, which indicates vertical transmission in H. tibetensis. CLS-Ht was specifically distributed in the female ovaries and Malpighian tubules, whereas RLS-Ht was detected within ovaries, Malpighian tubules, salivary glands and midguts of the ticks. Real-time qPCR suggested that adult ticks carried the largest amount of CLS-Ht and RLS-Ht with CLS-Ht having a significantly higher presence in females than in males (P < 0.05), whereas the presence of RLS-Ht showed no significant differences between sexes. In the ovaries, CLS-Ht distribution reached a peak at one day post-engorgement, and then gradually declined to a lower level, whereas no change was observed in RLS-Ht. In Malpighian tubules, the amount of both symbionts displayed an increasing trend with time post-engorgement. In midguts and salivary glands, the amount of RLS-Ht showed no significant differences. CONCLUSION: Two novel endosymbionts (CLS-Ht and RLS-Ht) were characterized in H. tibetensis both showing a high prevalence and stable vertical transmission. The described tissue distribution and population dynamics might imply the important functions of these symbionts during the development and reproduction of ticks.

Two new lignans from Saururus chinensis.

Two new lignans, (Z)-14-bis(3',4'-dimethoxyphenyl)-2,3-dimethylbut-2-ene-1,4-dione (1), threo-2-methyl-3-oxo-1-(3',4',5'-trimethoxyphenyl)butyl-3″,4″-dimethoxybenzoate (2), together with 15 known derivatives (3-17) were isolated from Saururus chinensis. Their structures were determined on the basis of spectral data, including 1D and 2D NMR experiments and HREIMS spectra. The antitumour activity was screened by MTT assay, compounds 1, 2, 3, 5, 9-11 and 13-15 showed no cytotoxic activity against HL-60, SMMC-7721, A549, MCF-7 and SW480 cell lines.

Identification, Distribution and Population Dynamics of Francisella-like Endosymbiont in Haemaphysalis doenitzi (Acari: Ixodidae).

Francisella-like endosymbionts (FLEs) with significant homology to Francisella tularensis (γ-proteobacteria) have been characterized in several tick species, whereas knowledge on their distribution and population dynamics in ticks remains meager. Hence, in the current study, we identified a novel Francisella-like endosymbiont (FLEs-Hd) from the tick Haemaphysalis doenitzi and evaluated the putative functions of this symbiont. Results indicated that FLEs-Hd had 100% infection rate and a perfect vertical transmission in H. doenitzi, and that it is distributed in ovaries, malpighian tubules, salivary glands and midguts of the ticks, suggesting that FLEs-Hd presumably is a crucial symbiont of the host without specific tissue tropism. To further explore the function of the symbiont, the population dynamics of FLEs-Hd at each developmental stage of ticks and in tissues at different reproductive statuses were determined by real-time quantitative polymerase chain reaction (real-time qPCR). Results showed that the high density and regular population dynamics of FLEs-Hd appeared in female ovaries, suggesting that the symbiont may provide necessary nutrients or regulators to ensure normal ovary development of ticks.

Characterization of the life cycle of the tick Haemaphysalis tibetensis under field conditions in Qinghai-Tibet plateau.

The tick Haemaphysalis tibetensis Hoogstraal is found uniquely in the Qinghai-Tibet plateau of Tibet and Gansu of China. Not much is known of this tick. Therefore, in this study we investigated the life cycle of H. tibetensis under field conditions from March 2014 to March 2015 in Damxung County, north Lhasa City in Tibet (Autonomous Region in China). The results of the study demonstrated that the tick H. tibetensis requires an average of 177.8 days (range 129-202 days) to complete a life cycle, with rabbits supplied as hosts in the field plot. Under natural lighting and climate conditions, the feeding period of females was an average of 7.7 days, and the pre-oviposition period was 9.4 days, followed by 28.2 days for oviposition. The premolting period of nymphs lasted 52.7 days, which was the longest life cycle phase. The average weight ratio of engorged to unfed females was 58.2. Additionally, there was a highly positive correlation between the weight of engorged and the number of the eggs that were laid (r = 0.83, P < 0.05). The reproductive efficiency index and reproductive fitness index in females were 5.1 and 4.7, respectively.

Abundance and seasonal activity of Haemaphysalis concinna (Acari: Ixodidae) at the border between China and Russia in Northern Inner Mongolia, China.

BACKGROUND: Haemaphysalis concinna, a three-host tick vector of several pathogens, poses a high risk to the health of humans and livestock. However, knowledge of the seasonal activities, relative density and other ecological characteristics of this tick is quite limited and fragmentary. This knowledge gap represents a bottleneck in our understanding of the health risks associated with tick-borne pathogens. METHODS: We conducted a two-year study from April 2012 to March 2014 in Northern Inner Mongolia situated on the China-Russia border, China, to investigate the seasonal activities and relative density of the three developmental stages of H. concinna. During the study period, feeding ticks were removed weekly from domestic sheep and their attachment sites were recorded. Questing ticks were collected weekly from five habitats (broadleaf forest, coniferous forest, shrubs, grassland and mixed coniferous forest) using the flagging-dragging method of capture. Rodents were captured and examined on two consecutive nights each week from June to September in 2012. RESULTS: H. concinna ticks were found mainly in shrubs and grasslands habitats. Adults were encountered from February to October with the major peak occurring in June. Larvae, which were observed mainly from late April to late September, reached peak numbers in late July. Nymphs were observed mainly from March to October, and their numbers peaked in early July. H. concinna adults and nymphs were found attached to sheep and their most favored sites of attachment were the face and ears. H. concinna larvae were found on two rodent species, Apodemus peninsulae and Eutamias sibiricus. CONCLUSION: The relative density and seasonal activities of H. concinna have been systematically reported for Northern Inner Mongolia, China. The information about the hosts infested by H. concinna and its preferred attachment sites on sheep will help efforts to control this tick and the tick-borne diseases carried by it.