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Aerial recovery，dense flight and aerial refueling of unmanned aerial vehicles（UAVs）all involve flight stability and position control of the vehicle in a close-range interference flow field. In view of the background of UAV lateral recovery and release，adopting interference aerodynamic derivative model，the longitudinal small disturbance equation of motion of the vehicle in the close interference flow field is established，and the method using the rudder deflection to simulate the restoring force to achieve the longitudinal positional stability of the UAV is proposed. By using typical vehicle data，adopting the state space analysis method，the cost function is established，the optimal control design of pitch rudder deflection and variable thrust are completed，and the method of achieving the UAV longitudinal close-range-flight stability control is simulated and verified. The feasibility of close-range-flight stability is preliminarily verified.

Intumescent flame retardant is a halogen-free flame retardant with excellent flame retardancy. It has the characteristics of low smoke, low toxicity and high fire prevention efficiency in the flame retardant process. It is an important direction of flame retardant research. The different classification and composition of intumescent flame retardants and the flame retardant mechanism of intumescent flame retardants are introduced. The research progress of existing intumescent flame retardants is summarized. The surface modification of intumescent flame retardants, the development of single-component intumescent flame retardants, the use of flame retardant synergists and the components of new intumescent flame retardants are elaborated and summarized. The problems that need to be solved in the development of intumescent flame retardants are pointed out. In the future, intumescent flame retardants should be developed in the direction of green and environmental protection. [ABSTRACT FROM AUTHOR]

Both drone swarm intensive flight and drone aerial recovery involve the stability problem of drone/carrier-aircraft flight in close range interference flow field. This paper proposes an aerodynamic derivative model for drone/carrier-aircraft interference based on the above application background, simplifies the longitudinal dynamic equations, and derives the simplified stability criteria for the drone. Numerical simulation and analysis indicate that this simplified criterion reflects the relationship between the drone's motion stability, aerodynamic characteristics, and interference flow field characteristics, and can be used for preliminary analysis and design of flight stability in interference flow fields. Numerical simulation also indicate that the down-wash flow can cause the drone to have short-period motion with slower convergence of amplitude, which increases the difficulty of achieving stable and controllable flight in the interference flow field.

In order to study the effects of microstructure and mechanical properties of 20Cr carburized steel high-speed linear guide under different aging treatment conditions, the microstructure, phase composition and residual stress of linear guide before and after aging treatment were analyzed by scanning electron microscopy (SEM), Х-ray diffractometer (XRD) and X-ray stress tester. The results show that after aging treatment, the martensite structure in the surface layer of 20Cr carburized steel is gradually refined, the fine carbides is precipitated and some residual austenite decompose, the surface hardness of the guide rail increases and the maximum hardness is 729.3HV1/5. Affected by the transformation of residual austenite structure and the change of ferrite content, the residual stress of the carburized layer of the guide rail is eliminated to varying degrees. After heated to 200 °C for 13 h, the residual stress relief effect on the surface of the guide rail is the most obvious, the residual stress value is reduced to -127.17 MPa and the elimination rate is as high as about 54.05%, and there is a polynomial function relationship between the residual stress and the depth of the carburized layer.

The volatile components of Citri Grandis Exocarpium from Huazhou (CGEH) and Guangxi (CGEG) were analyzed by portable gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF MS) combined with headspace solid-phase microextraction (HS/SPME). Due to its limited separation ability, the portable GC-MS can identify only 8 chemicals in CGEH and 4 chemicals in CGEG and is not able to determine any marker compounds which can distinguish CGEH over CGEG. While the merit of GC×GC-TOF MS is strong separation ability, allowing the identification of 304 chemicals in CGEH and CGEG, of which 261 chemicals are reported for the first time. Among them are 52 compounds only detected in CGEH, 81 ones unique in CGEG, and 171 detected in both CGEH and CGEG. The volatile components in CGEH and CGEG are classified into 17 and 19 types, respectively. The contents of alkene aromatics, hydrocarbons and alcohols in both CGEH and CGEG are relatively high. The principal component analysis (PCA) and orthogonal partial least squares (OPLS-DA) were further performed on the MS data obtained by GC×GC-TOF MS. The results indicated that there is basically no difference from different batches of fruits in the same region, while have obvious differences between CGEH and CGEG. Among these different components, 10 compounds including 3,4-diethyl-1,1'-biphenyl, 1-methyl-4-(1-methylethenyl)-1,2-cyclohexanediol, 1-dodecanol, α-ethylidene-benzeneacetaldehyde, 3,8-dimethyl-undecane, tetradecanal, 2-methyl-tridecane, 5-methyl-2(5H)-furanone, tetraethylene glycol, sabinol in CGEH are screened out with the values of Pearson correlation coefficient |p(corr)|>0.9, |p|>0.06 and variable influence on projection (VIP) value>1.1. On the other hand, several marker compounds, such as cedrane, hibaene, 1,3,5-tris(methylene)-cycloheptane, (E)-longipinane, 1,1,6,6-tetramethylspiro[4.4]nonane, 2-(4a,8-dimethyl-1,2,3,4,4a,8a-hexahydro-2-naphthalenyl)-2-propanol, γ-gurjunene, [1S-(1α,4α,7α)]-1,2,3,4,5,6,7,8-octahydro-1,4,9,9-tetramethyl-4,7-methanoazulene, (2R,5S)-2-methyl-5-(prop-1-en-2-yl)-2-vinyltetrahydrofuran, copaene, spathulenol, β-elemene, sativene, N-[4-bromo-n-butyl]-2-piperidinone, eremophilene, 10α-eremophilane, oleyl alcohol, trifluoroacetate, and selinane are picked up in CGEG. These results proved that GC×GC-TOF MS can identify markers of Citri Grandis Exocarpium, while portable GC-MS can not. These markers can help to distinguish CGEH from others and provide references to quality evaluation of Citri Grandis Exocarpium.

Exosomes are membranous tiny vesicles secreted by cells, which are widely found in the extracellular matrix and various body fluids and carry a variety of biologically functional molecules such as proteins, lipids, messenger RNA （mRNA） and microRNA （miRNA）. Exosomes not only play important biological roles in the field of immunology and oncology, but also have potential application value in the field of forensic medicine. This article reviews the discovery, production and degeneration mechanism, biological functions, isolation and identification methods of exosomes, summarizes the research on exosomes and their significance in the field of forensic science, and discusses their applications in body fluid identification, individual identification, postmortem interval estimation to provide ideas for the application of exosomes in forensic work.

Pyrochlore has been extensively studied as one of the most ideal candidates for nuclear wastes immobilization, due to its excellent geological stability, radiation tolerance, low chemical leaching rate, and high thermal stability. However, the artificial pyrochlore has a relatively high selectivity for curing nuclides, which limits the types and quantity of its target species. To tackle the challenge, a variety of simulated nuclides(Eu, Sm and Nd) were successfully incorporated into the pyrochlore lattice by solid-state reactions. The experimental results show that the multi-pyrochlore exhibits a homogeneous structure with single phase. Leaching tests indicate that the multi-pyrochlore owns excellent leaching resistance and chemical stability, which enables multi-pyrochlore a promising immobilization material for high-level waste.

The Compound Cheqian Tablets are derived from Cheqian Power in Comprehensive Recording of Divine Assistance, and they are made by modern technology with the combination of Plantago asiatica and Coptis chinensis. To investigate the material basis of Compound Cheqian Tablets in the treatment of diabetic nephropathy, in this study, the chemical components of Compound Cheqian Tablets were characterized and analyzed by UPLC-Q-TOF-MS/MS, and a total of 48 chemical components were identified. The identified chemical compounds were analyzed by network pharmacology. By validating with previous literature, six bioactive compounds including acteoside, isoacteoside, coptisine, magnoflorine, palmatine, and berberine were confirmed as the index components for qua-lity evaluation. Furthermore, the content of the six components in the Compound Cheqian Tablets was determined by the "double external standards" quantitative analysis of multi-components by single marker(QAMS), and the relative correction factor of isoacteoside was calculated as 1.118 by using acteoside as the control; the relative correction factors of magnoflorine, palmatine, and berberine were calculated as 0.729, 1.065, and 1.126, respectively, by using coptisine as the control, indicating that the established method had excellent stability under different conditions. The results obtained by the "double external standards" QAMS approximated those obtained by the external standard method. This study qualitatively characterized the chemical components in the Compound Cheqian Tablets by applying UPLC-Q-TOF-MS/MS and screened the pharmacodynamic substance basis for the treatment of diabetic nephropathy via network pharmacology, and primary pharmacodynamic substance groups were quantitatively analyzed by the "double external stan-dards" QAMS method, which provided a scientific basis for clarifying the pharmacodynamic substance basis and quality control of Compound Cheqian Tablets.

The response of leaf functional traits to forest fire is one of the research hotspots in the forest fire ecology. Studying post-fire changes in leaf functional traits of Pinus tabuliformis can reveal its growth strategies to adapt to fire environment and provide reference for the post-fire recovery. We analyzed the changes of leaf functional traits in burned areas with different fire severities (unburned, light burn and moderate burn) in Qinyuan County burned area of Shanxi Province, and studied the variation characteristics of leaf economic spectrum in different burned areas. The results showed that there were significant differences in burned areas with different fire severities for all leaf functional traits except N/P. Among them, the difference of leaf area was the most obvious, which was the most sensitive trait. With the increases of fire severity in burned areas, leaf area, leaf thickness, leaf dry matter content, leaf nitrogen content and leaf phosphorus content increased, while specific leaf area and leaf organic carbon content decreased. There were significant correlations among some leaf functional traits, with the correlations being distinct in burned areas with different fire severities. The leaf economic spectrum moved from 'unburned-light burn-mode-rate burn' to the resource trade-off strategy of 'rapid investment-return type' along the fire environment. The recovery of P. tabuliformis would be accelerated in burned area with low fire severity.

Currently available drugs for complex diseases have such limitations as unsatisfactory efficacy, drug resistance, and toxic side effects. Complexity of biological systems is a determinant of drug efficacy. It is not an effective approach to find disturbance strategies for the complicated biological network for complex diseases based on the static topological structures, as biological systems undergo dynamic changes all the time. Supported by profound theoretical basis and rich clinical experience, traditional Chinese medicine(TCM) emphasizes systematic and dynamic treatment depending on changes. Guided by TCM theory in practical treatment, Chinese medicine dynamically and comprehensively regulates the overall state. Therefore, if the dynamic factors are taken into consideration in design, the resultant drugs will be more effective. This study proposes state-regulating(SR) medicine from the perspective of system dynamics, elaborating the concept in terms of the connotations and principle and verifying the feasibility of SR medicine design with the attractor method. Thus, SR medicine is a new concept for drug discovery and design from the aspect of system dynamics, which integrates the TCM focusing on holistic dynamic regulation with biomedicine that features local microscopic research such as molecular mechanisms. The attractor method is a feasible techinical way for SR medicine design.

To explore the temporal and spatial intrusion process of runoffs and the response of water quality during the flood season in the Jinpen Reservoir (JPR) in Xi'an. Continuous in-situ monitoring was carried out on the water quality indexes (WQI) from the upstream river channel to the reservoir of two runoffs in early August and mid-September 2019. The single factor WQI and comprehensive WQI were used to assess the water quality vertically. Different inflow conditions of rain storm runoffs evolved into different intrusions. The initial inflow of the two runoffs was small, the runoff experienced a full-section intrusion, bottom intrusion, and mid-intrusion process along the way; the position of mid-intrusion in reservoir changed from 545-565 m at the beginning of the runoff to 535-580 m at the end in early August, and developed from 540-575 m of mid-intrusion to 575 m below the bottom of the intrusion in mid-September. The continuous inflow weakened the thermal stratification structure and replenished the DO in the reservoir. Meanwhile, mass particulate pollutants sank into the reservoir, and vertically, the nutrients of middle and bottom parts were higher than at the surface. The single factor WQI showed that the TP and permanganate index values of underflow location increased to some extent, and both exceeded the class Ⅲ water quality standard of surface water at the end. The comprehensive WQI showed that the middle layer of runoff was moderately polluted in early August, while the bottom layer was heavily polluted due to the dual effects of anaerobic and particle deposition, and reached the peak after one week of runoff, while the bottom intrusion of below 575 m directly caused heavy pollution in the middle layer, and bottom layer was medium polluted due to the supplement of dissolved oxygen in mid-September. The discharge of the spillway tunnel and the intake of stratified water could effectively guarantee the safety of the water supply during the flood season.

In this study, the relative molecular weight distribution and fluorescent characteristics of the organic matter in sediments during the thermal stratification of a drinking water reservoir were studied. The nitrogen removal, growth performance, and carbon removal ability of an aerobic denitrifier were investigated when the organic matter in sediments was used as a carbon source. The results found that:① during the stratification period in the drinking water reservoir, the organic matter in sediments has a larger proportion of relative molecular mass>100×10 3 . It can be observed that compared with the relative molecular weight distribution in different months, the percentage of macromolecular organic matter in sediments is the lowest in July (44.62%), showing a characteristic of smaller relative molecular weight; ② the organic matter in sediments of the drinking water reservoir was composed of terrestrial humic-like substance component C1 (250 nm, 425 nm), tryptophan and amino acid-like substances component C2 (230 nm/280 nm, 322 nm), and traditional microbial humic-like substances component C3 (250 nm, 340 nm). Component C2 accounted for a higher percentage, and the organic matter in July showed a higher total fluorescence intensity; ③ during the aerobic denitrification process, organic matter in May displayed better characteristics as an electron donor, while organic matter in July exhibited excellent performance as an energy substance and better denitrification characteristics of the strain WGX-9; ④ the aerobic denitrification performance of the strain WGX-9 can be significantly promoted when the organic matter in sediments is a carbon source, compared with natural organic matter, algae organic matter, and actual water of the drinking water reservoir. This study clarifies the characteristics of the organic matter in sediments during the thermal stratification period of the drinking water reservoir and its effect on an aerobic denitrifier. This will provide a scientific basis for the research of nitrogen pollution control in micro-polluted water sources.

Olfactory microorganisms mainly include actinomycetes, algae, and myxobacteria, and are widely found in typical water ecosystems such as water source reservoirs, lakes, streams, and oceans. Biologically-derived taste and odor compounds can cause severe off-flavor problems at trace concentrations, threatening the safety of water supplies. Physical and chemical methods have been implemented, but they need to be improved and optimized. Microbial methods show attractive prospects due to their environmentally friendly characteristics. This article reviews the literature regarding the types, biological sources, detection methods, control measures, influencing factors, and odor-producing mechanisms of microbial methods. Future research directions and fields of investigation are discussed in order to promote the related research of taste and odor compounds and ensure the safety of urban water supplies.

In response to the annual hypolimnetic anoxia in stratified reservoirs, water-lifting aerators (WLAs) were used in Jinpen Reservoir to supplement the dissolved oxygen in the bottom water and suppress the release of reduced pollutants from sediment. However, due to the influence of geomorphic characteristics at the bottom of the reservoir, there were some differences in the efficiency of artificial mixing and aeration. After the deactivation of WLAs, the dissolved oxygen in the bottom water of some deeper areas was rapidly depleted, resulting in the re-release of pollutants. To explore the release mechanisms and diffusion intensity of iron and manganese during this period, the representative samples in the main reservoir area were collected to measure the distribution of dissolved iron and manganese in the pore water and overlying water and calculate the diffusive flux of dissolved iron and manganese across the sediment-water interface. The results showed that the bottom water of the lower terrain rapidly entered the anaerobic condition after the system was deactivated, resulting in the release of a large amount of dissolved manganese into the overlying water, the maximum concentration of which was 0.42 mg·L -1 . However, the bottom water of the higher terrain briefly entered a state of hypoxia, after which the dissolved oxygen concentration increased rapidly, so the dissolved manganese concentration increased moderately to 0.17 mg·L -1 . The distribution of iron and manganese in the pore-water-overlying water showed that the dissolved manganese was released more easily into the overlying water than the iron under anaerobic conditions and constant accumulation in the upper sediments and overlying water. However, the release of dissolved iron was not only suppressed by dissolved oxygen but also by other oxidants such as manganese oxide. The diffusion flux of dissolved manganese declined after the system was deactivated. A mass balance calculation demonstrated that the accumulation of dissolved manganese in the anaerobic layer was not only related to the diffusion flux but also to the sedimentation flux and the thickness of the anaerobic layer. Therefore, the biogeochemical cycle of iron and manganese in the anaerobic layer requires further study.

Aerobic anoxygenic photosynthesis bacteria (AAPB) play a significant role in the material circulation of the hydrosphere, with diverse community structure and unique metabolic functions. To investigate the spatial and temporal succession characteristics of AAPB abundance and community structure in Jinpen Reservoir, a quantitative real-time polymerase chain reaction and Illumina MiSeq high-throughput sequencing technique targeting the pufM gene were applied. Furthermore, redundancy analysis was used to determine the influence of environmental factors on their community structure. The results showed that the AAPB abundance ranged from (6.70±0.43)×10 3 to (2.69±0.15)×10 4 copies·mL -1 , with the maximum value appearing in October, and decreased with an increase in water depth. Samples were mainly classified into 19 genera (except for the unclassified genus); the most abundant AAPB genera were Bradyrhizobium sp. and Methylobacterium sp., which were affiliated to the α -Proteobacteria, and the proportion of the Bradyrhizobium sp. was highest in November, accounting for more than 60% (except 10 m). Furthermore, Rubrivivax sp., belonging to β -Proteobacteria, was found to have a low proportion. There was a strong interaction relationship between AAPB genera. For example, Rhodobacter sp. was positively correlated with Rhodovulum sp., while Hydrogenophaga sp. was negatively correlated with Bradyrhizobium sp.. The community structure composition and distribution of AAPB were significantly different, mainly affected by temperature ( T ), total nitrogen (TN), NO 3 - -N, and light intensity and comprehensively regulated by environmental factors. For instance, T , TN, and total phosphorus had a significant impact on the AAPB community structure of water samples at 0, 5, and 15 m in October, whereas light intensity, pH, DO, and chlorophyll-a were major structuring factors in the AAPB assemblages of water samples at 5 m in December. The results have guiding significance for parsing the spatial and temporal variability of AAPB abundance and diversity in stratified reservoirs, and simultaneously provide a theoretical basis for exploring the driving factors of AAPB population structure.

To explore the effect mechanism of the artificial mixing process on the temporal and spatial succession of algae community structure in a water body, this study used water-lifting aerators to induce in-situ artificial mixing of the water body of Jinpen Reservoir, and in-situ spot physical-chemical parameters and algae of the water body of the reservoir were observed during an artificial mixing process. A total of 51 species of 28 genera of 6 families of algae were identified in the water body of the Jinpen Reservoir. The artificial mixing effect of the water-lifting aerators significantly inhibited the growth of algae in the water, and had a significant impact on the community structure. Before activation of the water-lifting aerators, algae were mainly distributed in the surface water body, and Chlorella vulgaris was the dominant species. With the operation of the water-lifting aerators, the algal density of surface water body decreased significantly, and the vertical distribution of the algae density in the water body tended to be uniform. The dominant species tended to succeed in Cyclotella sp. This study used the method of redundancy analysis, combined with critical depth theory and the characteristics of algae growth, to analyze the relationship between the spatial-temporal succession of algae community structure and the changes in the main physical-chemical parameters in Jinpen Reservoir during the artificial process. The analysis results showed that the artificial mixing of the water-lifting aerators mainly affects the temporal and spatial succession of the algae community structure by rapidly destroying the thermal stratification stability of the water body and significantly increasing the water mixing depth.

To examine the effects of pig manure application on dry matter production, nitrogen accumulation and distribution, grain yield and nitrogen use efficiency of rice and wheat, the field trial was conducted with wheat 863 and rice 498. Fertilization treatments consisted of seven rates of organic manure supply: control (CK, no chemical nitrogen fertilizer, no pig manure), conventional fertilizing (T 1 , no pig manure), 2500 kg·hm -2 pig manure with 75% conventional fertilizing (T 2 ), 5000 kg·hm -2 pig manure with 50% conventional fertilizing (T 3 ), 10000 kg·hm -2 pig manure (T 4 ), 15000 kg·hm -2 pig manure (T 5 ) and 20000 kg·hm -2 pig manure (T 6 ). Combined application of pig manure with chemical fertilizer promoted dry matter accumulation of rice and wheat throughout the growing season. At the maturity stage of rice and wheat, the highest aboveground dry matter accumulation presented under highest pig manure input (T 6 ). The dry matter accumulation and nitrogen distribution were enriched in stem or leaf. The dry matter accumulation and nitrogen distribution rate in grain at T 6 was significantly lower than T 2 treatment. The high-est nitrogen fertilizer partial productivity, fertilizer agronomic efficiency and grain yield of rice pre-sented at T 3 treatment, which increased by 11.4%, 55.4%, 11.4% than that of conventional chemical fertilizer treatment, respectively. These vaules for wheat were at T 2 , which was 14.0%, 29.1%, 14.0% higher than that of conventional fertilizer treatment, respectively. The combined application of pig manure with appropriate rates of chemical fertilizer (T 2 and T 3 ) could promote dry matter accumulation, the migration of nitrogen to grains, the increase of yield and the nitrogen use efficiency. Too much pig manure input (15000-20000 kg·hm -2 ) could lead to excessive supply of nitrogen for crops. In this case, the transportation of dry matter to economic organs would be blocked and the nitrogen enriched to stem. The late-maturing phenomenon occurred, resulting in significant decrease of grain yield.

The biogeochemical cycle of nitrogen in the aquatic environment is the research hotspot in the world all the time. Nitrification and denitrification are the special processes of the microorganisms, and also the key steps in the nitrogen biogeochemical cycle possessing great significance in the freshwater ecosystem. In the processes of outbreaks of cyanobacterial blooms, total nitrogen, chlorophyll a, dissolved oxygen and pH decreased sharply, whilst dissolved organic carbon and ammonium nitrogen increased. The results of simulation of outbreaks of cyanobacterial blooms using micro-universe system in lab showed that the amoA gene abundance was reduced in the early stage and AOA was replaced by AOB gradually. Our results also showed that the amount of denitrifiers with nirS/nirK was elevated by also 100 times during the bloom outbreak, which can explain the promoted denitrification in the water during cyanobacterial bloom.

Objective: To study the impact of the water extract from Codonopsis thalictrifolia Wall (CTW) on the reproductive, Methods: We divided 32 male SD infant rats into four groups of equal number to be treated intragastrical-system of male infant rats. ly with distilled water (control) and CTW at 10 g/kg (low dose) , 20 g/kg (medium dose), and 40 g/kg (high dose), respectively, twice a day for 2 weeks. Then we killed the rats, measured the levels of testosterone (T), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the serum, obtained the testis weight, body weight, testis visceral coefficient and sperm concentration, and detected sperm viability, sperm motility and the level of cyclic adenosine monophosphate (cAMP) in the Leydig cells, followed by, Results: Compared with the control group, the low-dose, me-analysis of differences among different groups using the SPSS software. Medium-dose and high-dose CTW groups showed significant decreases in the serum T level ([3.09 +/-0.42] vs [1.22 +/-0. 32] , [1.06 +/- 0.29] and [0.57 +/-0.18] nmol/L, P<0.01), testis weight ([1.40 +/-0.16] vs [0.96 +/-0.09], [0.92 +/-0.11] and [0.91 +/- 0.08] g, P <0.01), and sperm concentration ([1.03 +/-0.16] vs [0.19 +/-0.07], [0.17 +/-0.08] and [0.16 +/-0.07] x 10(6)/ml, P <0.01), but a dramatic elevation in the testis visceral coefficient ([42.22 +/- 3.02] vs [51.39 +/- 3.09], [52.28 +/- 4.86] and [54.13 +/-6.06] mg/10 g, P <0.01); the medium- and high-dose CTW groups exhibited remarkable increases in the levels of serum LH ([13.62+/-0.89] vs [14.69 +/-0.12] and [14.93 +/-0.28] ng/L, P<0.01) and FSH ([4.32 +/-0.18] vs [4.77 +/-0.23] and [4.89 +/-0. 38] IU/L, P <0.05); all the three CTW groups showed markedly inhibited serum T secretion ([1.85 +/- 0.18] vs [1.42 +/-0.15], [1.12+/-0.18] and [0.88 +/-0.21] nmol/L, P<0.01) and intracellular cAMP ([5.51 +/-0.12] vs [4.39+/-0.06], [4.28 +/-0.07] and [4.11 +/- 0.10] nmol/L, P <0.01) in the Leydig cells., Conclusion: The water extract from CTW may reduce the synthesis of testosterone in the serum of male infant rats through the PKA pathway and consequently inhibit their testicular development and sperm production and affect the development of their reproductive system.

Stimulated by retinoic acid gene 8 (STRA8) is specifically expressed in mammalian germ cells before their transition from mitosis to meiosis. STRA8 expression is observed only in the postnatal testis. Single nucleotide polymorphisms but no mutations were identified in the coding or proximal promoter region of STRA8 in some gonadal dysgenesis patients. Studies on the teratocarcinoma cells and embryonic stem cells (ESC) transfected with STRA8-EGFP, a fusion construct harboring the promoter and coding region of the enhanced green fluorescence protein, have shown that the STRA8-EGFP positive cells may undergo meiosis, develop into sperm and generate live offspring mice. STRA8-EGFP positive cells derived from the bone marrow are able to differentiate into spermatogenic cells, but arrest in the premeiotic stage, and those from the adult mouse testis, when cultured in ESC culture conditions, may acquire ESC properties, pluripotency and redifferentiation capacity and act as a new stem cell source for tissue regeneration. The presence of oocytes renewed in postnatal mouse ovaries calls in question the absence of STRA8 in postnatal mouse ovaries.

Fluorescence microscopic self-ordered ring (SOR) technique with microwave heating is proposed for minocycline based on the capillary flow of solvent on the surface of hydrophobic glass slide and applied to residues detection of the antibiotics in milks of Inner Mongolia. In the reaction medium of hexahydropyridine containing polyvinyl alcohol-124 (PVA-124), a SOR of minocycline with the outer diameter of 1.54 mm and the ring belt width of 22.6 microm can be formed. When a 0.30 microL droplet of minocycline mixture was spotted on the solid surface, minocycline in the range of 4.2 x 10(-2)-1.8 x 10(-11) mol x ring(-1) (1.4 x 10(-6)-0.60 x 10(-5) mol x L(-1)) can be detected, the maximum fluorescence intensity was found to be proportional to the minocycline concentration, and the limit of detection can reach 4.2 x 10(-13) mol x ring(-1) (1.4 x 10(-7) mol x L(-1)) with three times of signal to noise ratio. With the present method, the contents of minocycline in milk samples of Inner Mongolia and minocycline hydrochloride capsule sample were satisfactorily determined with recoveries of 97.2%-103% and 99.4%-102%, respectively, and RSD lower than 1.2%, correspondingly. Therefore, a highly sensitive and selective analysis method for detecting content of trace drug contaminations was established. The method provided theory basis to quantificational analysis of the residues of the antibiotics in milks which was Inner Mongolia' preponderant resource products. It has important realistic meaning and broad application prospect.

Stra8 (stimulated by retinoic acid gene 8) is a specific expression gene in mammalian germ cells' transition from mitosis to meiosis. Stra8 expresses in an anterior to posterior wave from embryonic days 12.5 to 16.5 in germ cells of XX gonads in mice. Meiosis germ cells are observed 1 day after Stra8 expression, which begins in the testis after birth and triggers meiosis entry. Germ cell sex determination is directed by a difference in the timing of entry into meiosis in embryonic gonads. The position of retinoic acid production and CYP26b1 expression that metabolizes RA to an inactive form regulates Stra8 expression. Although cytoplasmic protein Stra8 is necessary for the entry of germ cells into meiotic prophase, the function of the protein remains unknown.

The present study aimed to investigate the effect of proto-oncogene c-src on the viability of rat spermatogonial stem cells from 9 day-old rat in vitro. MTT method was used to observe the viability of the spermatogonial stem cells treated with antisense c-src oligodeoxynucleotides (ODNs) in vitro; RT-PCR was utilized to observe the expression of c-src mRNA and Western blot was used to observe the protein expressions of pp60c-src and phosphorylated signal transducer and activator of transcription-3 (p-STAT3). Compared with that in control group, the viability of spermatogonial stem cells decreased by 8.1% (P<0.05) and the expression of c-src mRNA decreased significantly after treatment with 10 μmol/L antisense c-src ODNs for 12 h. Compared with that in the control group, the protein expressions of pp60c-src and p-STAT3 decreased by 33.8% and 45.3% (both P<0.01), respectively, in the spermatogonial stem cells after being transfected with antisense c-src ODNs. The results suggest that proto-oncogene c-src regulates the viability of rat spermatogonial stem cells through p-STAT3.

This article reviews the specific expression of many proto-oncogenes during male germ cell development. The normal expression of proto-oncogenes plays an important role in the regulation of spermatogonial mitosis, spermatocyte meiosis as well as spermiogenesis and sperm maturation.

Apoptosis is necessary for the development and maturation of Leydig cells. However, increased apoptosis results the decline of testosterone production, which may increase germ cell apoptosis and the possibility of infertility. There are several aspects contributing to Leydig cell apoptosis such as ethane dimethanesulphonate (EDS), glucocorticoid, developmental stage and some hormones including FSH, LH/hCG and testosterone. A number of genes are involved in the regulation of Leydig cells apoptosis. It was reported that SCF/c-kit, Bcl-2 and Bcl-xl inhibited the apoptosis while caspase-3, Fas, Bax and clusterine stimulated it.

In recent years, people have paid more attention to the spermatogonial stem cells that have the capacity for self renewal and multilineage differentiation and produce daughter cells that can expand and differentiate into spermatozoa under the adjustment of self genes and external signal. This article reviews recent advances in studies of enrichment and original selection of the spermatogonial stem cells. This review also summarizes some control factors in proliferation and transplantation techniques.