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Meniscus is a wedge-shaped fibrocartilaginous tissue, playing important roles in maintaining joint stability and function. Meniscus injuries are difficult to heal and frequently progress into structural breakdown, which then leads to osteoarthritis. Regeneration of heterogeneous tissue engineering meniscus (TEM) continues to be a scientific and translational challenge. The morphology, tissue architecture, mechanical strength, and functional applications of the cultivated TEMs have not been able to meet clinical needs, which may due to the negligent attention on the importance of microenvironment

Fifteen undescribed Stemona alkaloids, named as stemarines A-O (1-15), along with 25 known alkaloids (16-40), were isolated and identified from the roots of Stemona mairei (H.Lév.)K.Krause (Stemonaceae). Their structures were elucidated through the analysis of the NMR spectra, mass data, and computational chemistry. All the hitherto undescribed compounds possess a pyrrolo[1,2-α]azepine core structure but differ in important structural features, which reflects their nematocidal activities. Alkaloids 3-6 featured a carboxylic side chain and exhibited significant nematocidal activity against the nematode Caenorhabditis elegans. Transections of fresh roots combined with application of the Dragendorff' reagent on the tissue indicated accumulation of alkaloids mainly in the epidermis and the pith. These results suggest the key pharmacophore of these alkaloids lies in the aliphatic side chain of these compounds and its spatial distribution in the roots indicate protective effects against underground herbivores.

Leptin (Lep) is a key factor for the regulation of food intake and energy homeostasis in mammals. To date, a number of studies have provided evidence for the existence of multiple leptin genes in teleosts, but not much information is available in fish regarding the regulation of leptin genes by sex steriods. As a first step, two leptin genes (lepa and lepb) and a leptin receptor (lepr) gene were cloned from the half-smooth tongue sole (Cynoglossus semilaevis), a representative species of the order Pleuronectiformes. The full-length cDNAs of tongue sole lepa and lepb were 1265 bp and 1157 bp in length, encoding for proteins of 160 aa and 158 aa, respectively. The three-dimensional structures modeling of tongue sole LepA and LepB showed strong conservation of tertiary structure with other vertebrates. The full-length cDNA of tongue sole lepr was 4576 bp, encoding a protein of 1133 aa which contained all functionally important domains conserved among vertebrate LepRs. Tissue distribution analysis showed that tongue sole lepa mRNA was highly detectable in the ovary and brain, while lepb mRNA was ubiquitously expressed in various tissues. Notably, the tongue sole lepr mRNA was most abundant in the ovary. Using a primary hepatocyte culture system, we evaluated the effects of sex steroids on lep/lepr gene expression. Both 17β-estradiol (E2) and testosterone (T) inhibited hepatic lepa and lepr mRNAs without affecting lepb mRNA levels. In addition, T also suppressed growth hormone receptor 1 (ghr1), ghr2, and insulin-like growth factor 2 (igf-2) mRNA levels, and stimulated expression of igf-1 gene. On the other hand, none of these four genes were altered by E2. To the best of our knowledge, this is the first description of a direct and differential regulation of lep/lepr gene expression by sex steroids at the hepatocyte level of a flatfish, supporting that individual leptin peptide may possess different biological roles in teleosts.

Gonadotropin-inhibitory hormone (GnIH) has been characterized by its ability to inhibit either basal or gonadotropin-releasing hormone (GnRH)-induced gonadotropin synthesis and release in birds and mammals. However, the physiological role of GnIH on the reproductive axis in fish remains inconclusive, with most studies focusing on the orders Cypriniformes and Perciformes. To gain insight into the role of GnIH in the regulation of reproduction in the order Pleuronectiformes, we first cloned the LPXRFa gene, the piscine ortholog of GnIH, in the half-smooth tongue sole. The full-length cDNA of LPXRFa was 918bp in size with an open reading frame (ORF) of 585bp that encoded a 194 amino acids preprohormone with a calculated molecular mass and isoelectric point of 21.73kDa and 6.52, respectively. The LPXRFa precursor encoded two putative peptide sequences that included -MPMRF or -MPQRF motifs at the C-terminal. Tissue distribution analysis showed that LPXRFa transcripts could be detected at high levels in the brains of both sexes and to a lesser extent in the ovary, heart and stomach of females, while a noteworthy expression was observed in the kidney and muscle of males. Furthermore, the expression patterns of LPXRFa mRNA during ovarian maturation were also investigated. In the brain, the mRNA expression of LPXRFa increased significantly at stage III, declined at stage V and reached a maximum at stage VI. In the pituitary, the levels of LPXRFa mRNA remained stable during ovarian maturation and increased significantly to the top level at stage V and then declined back to basal levels. In contrast, the ovarian LPXRFa mRNA levels declined sharply at stage III and remained depressed over the course of ovarian maturation. Taken together, our results provide further evidence for the existence of LPXRFa in the order Pleuronectiformes and suggest its possible involvement in the regulation of reproduction in the female tongue sole.

Hydrogen sulfide (H2S), a novel neuromodulator, is linked to the pathogenesis of several neurodegenerative disorders. Exogenous application of H2S exerts neuroprotection via anti-inflammation and anti-oxidative stress in animal and cellular models of Parkinson's disease (PD). However, the role of endogenous H2S and the contribution of its various synthases in PD remain unclear. In the present study, we found a decline of plasma and striatal sulfide level in 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced PD mouse model. Interestingly, among the three H2S generating enzymes, only cystathionine β-synthase (CBS) expression was largely reduced in the striatum of MPTP-treated mice. The in vitro study confirmed a significant decrease of CBS expression in 1-methyl-4-phenylpyridinium (MPP+)-stimulated astrocytes and microglia, but not in neurons or SH-SY5Y dopaminergic cells. Striatal CBS overexpression, elicited by stereotaxic delivery with Cbs gene using recombinant adeno-associated-virus (rAAV-Cbs), successfully enhanced the sulfide level in the striatum and partially rescued the MPTP-induced dopaminergic neurotoxicity in the midbrain. Specifically, striatal CBS overexpression alleviated the motor deficits and dopaminergic neuron losses in the nigro-striatal pathway, with a concomitant inhibition of glial activation in MPTP-treated mice. Furthermore, compared to rAAV-Vector, rAAV-Cbs injection reduced the aberrant accumulation of nitric oxide and 3-nitrotyrosine (an indicator of protein nitration) in the striatum of MPTP-treated mice. Notably, it also attenuated the increase of nitrated α-synuclein level in MPTP mice. The in vitro study demonstrated that lentivirus-mediated CBS overexpression elevated the sulfide generation in glial cells. Moreover, glial CBS overexpression offered protection to midbrain dopaminergic neurons through repressing nitric oxide overproduction in both glial and neuronal cells induced by MPP+. Taken together, our data suggest that impaired CBS-H2S axis may contribute to the pathogenesis of PD, and that modulation of this axis may become a novel therapeutic approach for PD.

Objective This study examined the association between iron status and a set of breast cancer risk factors among U.S. adult women aged 20–80 years. Methods Data from National Health and Nutrition Examination Survey (2017–2018) were used to examine the relation between serum ferritin, serum iron and transferrin saturation with a set of breast cancer risk factors [body mass index (BMI), waist circumference, glycosylated hemoglobin (HbA1c), fasting plasma glucose, insulin and HOMA-IR]. The multivariable linear regressions were used controlling for age, race/ethnicity, menopause status, education level, smoking status, alcohol consumption, physical activity, high-sensitivity C-reactive protein (hsCRP) and total energy intake. Results HbA1c, BMI and waist circumference data were available for 1902 women with a fasting sample (n = 913) for fasting plasma glucose, insulin and HOMA-IR. Transferrin saturation had significant, inverse associations with BMI, waist circumference and HbA1c. The size of difference observed were that participants in the fourth quartile of transferrin saturation had a 4.50 kg/m2 smaller BMI, a 9.36 cm smaller waist circumference and a 0.1 % lower HbA1c level than participants in the first quartile. Similarly, serum iron concentrations were inversely associated with BMI and waist circumference. In addition, serum iron had significant, inverse associations with insulin and HOMA-IR. Sensitivity analyses among men gave similar results. For serum ferritin, there was a trend towards a positive association between waist circumference, HbA1c and fasting plasma glucose with serum ferritin. However, the associations did not reach statistical significance among women. Conclusions Iron status may impact breast cancer risk via effects on adiposity or glucose metabolism. The findings should be confirmed with further prospective data.

Kisspeptin (Kiss) plays a critical role in mediating gonadal steroid feedback to the gonadotropin-releasing hormone (GnRH) neurons in mammals. However, little information regarding the regulation of kisspeptin gene by sex steroids is available in teleosts. In this study, we examined the direct actions of estradiol (E2) and testosterone (T) on hypothalamic expression of kisspeptin and other key factors involved in reproductive function of half-smooth tongue sole. As a first step, a partial-length cDNA of kiss2 was identified from the brain of tongue sole and kiss2 transcript levels were shown to be widely expressed in various tissues, notably in the ovary. Then, the actions of sex steroids on kiss2 and other reproduction-related genes were evaluated using a primary hypothalamus culture system. Our results showed that neither kiss2 nor its receptor kiss2r mRNA levels were significantly altered by sex steroids. Moreover, sex steroids did not modify hypothalamic expression of gonadotropin-inhibitory hormone (gnih) and its receptor gnihr mRNAs, either. However, E2 markedly stimulated both gnrh2 and gnrh3 mRNAs levels. Overall, this study provides insights into the role of sex steroids in the reproductive function of Pleuronectiform teleosts.

Kisspeptin (Kiss) acts as a positive regulator of reproduction by acting on gonadotropes and gonadotropin-releasing hormone (GnRH) neurons. Despite its functional significance, the intricate web of intracellular signal transduction pathways in response to Kiss is still far from being fully understood in teleosts. Accordingly, we investigated the molecular mechanism of Kiss action and its possible interaction with LPXRFa signaling in this study. In vitro functional analysis revealed that synthetic tongue sole Kiss2 decapeptide increased the cAMP responsive element-dependent luciferase (CRE-luc) activity in COS-7 cells transfected with its cognate receptor, while this stimulatory effect was markedly reduced by two inhibitors of the adenylate cyclase (AC)/protein kinase A (PKA) pathway. Similarly, Kiss2 also significantly stimulated serum responsive element-dependent luciferase (SRE-luc) activity, whereas this stimulatory effect was evidently attenuated by two inhibitors of the phospholipase C (PLC)/protein kinase C (PKC) pathway. In addition, LPXRFa-2 suppressed Kiss2-elicited CRE-luc activity in a dose-dependent manner. Taken together, Kiss2 utilizes both AC/PKA and PLC/PKC pathways to exert its functions via its cognate receptor and LPXRFa may antagonize the action of Kiss2 by inhibiting kisspeptin signaling. As far as we know, this study is the first to characterize the half-smooth tongue sole kisspeptin and LPXRFa signaling pathway in COS-7 cells transfected with their cognate receptors and provides novel information on the interaction between LPXRFa system and kisspeptin system in teleosts.

Kisspeptin (Kiss) and its receptor, KissR (previously known as GPR54), play a critical role in the control of reproduction and puberty onset in mammals. Additionally, a number of studies have provided evidence of the existence of multiple Kiss/KissR systems in teleosts, but the physiological relevance and functions of these kisspeptin forms (Kiss1 and Kiss2) still remain to be investigated. To this end, we examined the direct actions of Kiss2 on hypothalamic functions in the half-smooth tongue sole (Cynoglossus semilaevis), a representative species of the order Pleuronectiformes. As a first step, the full-length cDNA for kiss2r was identified and kiss2r transcripts were shown to be widely expressed in various tissues, notably in the brain of tongue sole. Then, the effects of Kiss2 decapeptide on reproduction-related gene expression were evaluated using a primary hypothalamus culture system. Our results showed that neither gnrh2 nor gnrh3 mRNA levels were altered by Kiss2. However, Kiss2 significantly increased the amounts of gnih and kiss2 mRNAs. In contrast, Kiss2 elicited an evident inhibitory effect on both gnihr and kiss2r mRNA levels. To the best of our knowledge, this is the first description of a direct and differential regulation of reproduction-related gene expression by Kiss2 at the hypothalamus level of a teleost fish. Overall, this study provides novel information on the role of Kiss2/Kiss2R system in the reproductive function of teleosts.

The development of 1D porous electrodes with high-rate capability and long cycle-life is a central issue for electrochemical energy storage. Herein, the 1D highly porous Li3V2(PO4)3/C nanofibers for lithium-ion batteries cathode have been designed and successfully fabricated via a facile electrospinning-assisted solid-state method. Benefiting from the well-defined 1D porous structure, the as-fabricated product displays excellent electrochemical performance when used as cathode for lithium-ion batteries in the potential range of 3.0 and 4.8 V. It exhibits high reversible capacity of 191 mAh g− 1 at a low rate of 0.1 C, superior rate performance (110 mAh g− 1 at 20 C) and good cycle-life stability (94.5% capacity retention over 120 cycles at 20 C). Therefore, this 1D porous Li3V2(PO4)3/C is a promising cathode material for high-performance lithium-ion batteries and the synthetic strategy presented in this work can be further used to prepare other electrodes in energy storage.

This paper addresses the total mechanical energy and equivalent differential equation of motion for single degree of freedom fractional oscillators. Based on the energy storage and dissipation properties of the Caputo fractional derivatives, the expression for total mechanical energy in the single degree of freedom fractional oscillators is firstly presented. The energy regeneration due to the external exciting force and the energy loss due to the fractional damping force during the vibratory motion are analyzed. Furthermore, based on the mean energy dissipation and storage in the fractional damping element in steady-state vibration, two new concepts, namely mean equivalent viscous damping and mean equivalent stiffness are suggested and the above coefficient values are evaluated. By this way, the fractional differential equations of motion for single-degree-of-freedom fractional oscillators are equivalently transformed into integer-order ordinary differential equations.

Naringenin (NR), a flavonoid abundant in citrus fruits has been reported to possess anti-inflammatory properties. The present study aimed to investigate the protective of naringenin in rats after spinal cord injury (SCI) and the underlying mechanisms associated with neuroinflammation. Adult male Sprague-Dawley rats were subjected to laminectomy at T9-T11 and compression with a vascular clip. The spinal cords spanning the injury site about 0.8cm were collected for testing. There were five groups (n=7 in each group): (a) Control group; (b) sham group group; (c) SCI+saline; (d) SCI+NR (50mg/kg, p.o.) group and (e) SCI+NR (100mg/kg, p.o.) group. Different doses of NR (50mg/kg, p.o. and 100mg/kg, p.o.) or saline were administered once daily for 11 consecutive days, from 3days prior to surgery to 7days after surgery. The expression level of miR-223, NLRP3 and IL-1β were measured by RT- qPCR. The accumulation of neutrophils at the site of compression, as evaluated by measuring the tissue myeloperoxidase activity, significantly increased with time following the compression, peaking at 24h post compression. The expression of miR-223 was significant elevated in (b). However, spinal cord myeloperoxidase activity and the expression of miR-223 did not increase in sham-operated animals. NR significantly inhibited a SCI-induced activation of neutrophils through repressed miR-223 in group (d) and (e). There was a better effect in group (e) than group (d). miR-223 is thought to act as a fine-tuner of granulocyte production and the inflammatory response. Our findings suggested that repeated administration of naringenin (100mg/kg, p.o) may provide the protective effect of the spinal cord injury in rats, possibly through inhibiting neuroinflammation.

A carefully performed phytochemical investigation of the roots of Stemona mairei (Stemonaceae) led to the discovery of six so far undescribed dihydrostilbene dimers maistilbene A–F and four monomers maistilbene G–J. This is the first report of stilbenoids of this plant species and the first report of dimeric dihydrostilbenes from this plant family. The absolute configuration of these compounds was determined by a combination of Mo2(AcO)4-induced ECD spectra and quantum chemical calculation of NMR chemical shift, ECD and spin-spin coupling constants. Maistilbene G could increase the glucose consumption in L6 myotubes, disclosing a new hypoglycemic candidate.

This study fabricated the integral-structure flexible inter/intra-ply hybrid composites, composed of HRBP cushioning layer and inter/intra-ply hybrid laminates surface-reinforcements through needle-punching and thermal-treating. Effects of the factors, including HRBP/CHP blending ratio, needle punching frequency and laminating sequence, on the compression, puncture resistance and electromagnetic interference shielding effectiveness (EMI SE) of flexible inter/intra-ply hybrid composites were investigated. An integral memory model on the compressive loading of non-woven structure was designed based on Poisson distribution, on which the numerical analysis was based to predict the compressive resistance and hysteresis loss. The support factor was greater than 8.2, and the highest value was recorded at a fiber blending ratio of 7H/3C and needle-punching frequency of 100 S/minute. The predicted compression energy loss was in good agreement with the actual value. The puncture resistance was enhanced with an increase in HRBP fiber blending ratio and a decrease in needle-punching frequency. With an electromagnetic wave frequency ranging from 2.0 to 2.5 GHz, the hybrid composites had excellent electromagnetic shielding effect. The EMI SE of the hybrid composites exhibited similar curve in different wave band when needle-punching frequency was enhanced. The hybrid composites with a cushioning center-ply and double hybrid-laminates cover-plies exhibited the highest EMI SE.

Methanogenic crude oil degradation is a significant process in subsurface environments and degradation of crude oil n-alkanes has been well documented. However, little is known about the biodegradability of the resulting heavy oil. In this study, a methanogenic consortium enriched from Shengli oilfield generated 1.3–1.9 mmol CH4/g of heavy oil at a rate of 2.9–8.8 μmol CH4/g of oil/day. Four SARA fractions (saturates, aromatics, resins and asphaltenes) of oils experienced a loss in linear aliphatic structures. n-Alkylcyclohexanes, methyl-n-alkylcyclohexanes, n-alkyldecalins, n-alkylbenzenes, n-alkyltoluenes and n-alkylxylenes with alkyl side chains longer than 14 carbons were degraded over 50% compared to the undegraded oil. In addition, the extent of degradation of these hydrocarbons increased with increasing carbon length. Correspondingly, n-fatty acids and naphthenic acids with 1–3 naphthenic rings accumulated over time. 16S rRNA gene analysis revealed that aceticlastic Methanosarcina and Methanothrix dominated in the archaeal domain, and bacterial members related to Dehalococcoidia and Soehngenia were consistently present in the successive transfer cultures. However, neither assA/masD-like genes nor alkyl-substituted succinate metabolites were detected, indicating an alternative degradation pathway, rather than addition to fumarate. This study provides novel insights into methanogenic degradation of long-chain alkyl substituted hydrocarbons in heavy oil, which also extends our understanding of anaerobic degradation of crude oil in subsurface sedimentary environments.

Continued interest in bioactive alkaloids led to the isolation of four undescribed alkaloids along with 74 known ones from the aerial parts of Tabernaemontana bufalina Lour. The structures of the yet undescribed alkaloids were elucidated based on NMR, IR, UV, MS and CD spectroscopic data and X-ray crystal diffraction and, according to the plant source, named as taberhaines A–D (1–4). The known compounds comprised of 66 monoterpenoid indole, three carboline and five isoquinoline alkaloids. Among them, the known apparicine inhibited significantly the activity of xanthine oxidase, which plays an important role for gout, with an IC50 value of 0.65 μM, compared to the standard drug allopurinol (IC50 = 0.60 μM).

A morphogenesis method is proposed for the topology and shape optimization of framed structures subject to spatial constraints. This combines direct elemental addition, or elimination, and free nodal shift, or restricted nodal shift related to the structures geometry. The optimization is based on elemental and nodal sensitivity information to generate or amend the structural topology and adjust the nodal positions to achieve a structure with minimum strain energy. In this method, the design parameters, such as supporting conditions, spatial constraints, etc, have significant influence on the final structural form; so various structural forms can be obtained by changing these design parameters in the project design phase. Several numerical examples are provided to illustrate the validity of this method and the mechanical behaviour of these structures. Results show that this can effectively reduce the structural bending moments and ensure sufficient structural stiffness.

Epidemiological studies have evaluated the association between interleukin-6 (IL-6) gene -174 G/C polymorphism and type 1 diabetes mellitus (T1DM) risk, but results of different studies have been inconsistent. The present meta-analysis was therefore designed to clarify these controversies. PubMed, Embase and Web of Science were searched from the first available year to March 25, 2012, as well as hand searching of the references of identified articles were performed. All studies investigating the association between IL-6 gene -174 G/C polymorphism and T1DM risk were included. Data analyses were carried out by Review Manager 5.1.2 and Stata 11.0. Seven studies were included in the final meta-analysis, covering a total of 9697 T1DM cases and 8455 controls. The results showed no evidence for significant association between IL-6 gene -174 G/C polymorphism and T1DM risk (for C/C+C/G vs. G/G: OR=1.30, 95% CI=0.84-2.00, p=0.24; for C/C vs. C/G+G/G: OR=1.10, 95% CI=0.75-1.60, p=0.63; for C/C vs. G/G: OR=1.34, 95% CI=0.75-2.42, p=0.33; for C allele vs. G allele: OR=1.16, 95% CI=0.88-1.53, p=0.30). In addition, the similar results were obtained in the subgroup analysis based on ethnicity. In summary, the present meta-analysis suggests that IL-6 gene -174 G/C polymorphism is not associated with T1DM risk. However, due to the small sample size in most of the included studies and the selection bias existed in some studies, the results should be interpreted with caution.

It remains controversial regarding the association between interleukin-8 (IL-8) gene −251 T/A polymorphism and peptic ulcer disease (PUD) risk. Thus, a large-scale meta-analysis evaluating the precise association between this gene variant and PUD risk is required. We searched the PubMed, Embase, Web of Science, and Google Scholar until April 25, 2012. Additionally, hand searching of the references of identified articles were performed. All the statistical tests were performed using Stata 11.0. A total of eight studies (3105 subjects) were included in this meta-analysis. Overall, no significant association was found between IL-8 gene −251 T/A polymorphism and PUD risk (for A allele vs. T allele: OR = 1.17, 95% CI = 0.97–1.41, p = 0.094; for A/A vs. T/T: OR = 1.33, 95% CI = 0.94–1.90, p = 0.108; for A/A vs. A/T + T/T: OR = 1.22, 95% CI = 0.97–1.52, p = 0.083; for A/A + A/T vs. T/T: OR = 1.26, 95% CI = 0.95–1.67, p = 0.113). However, in the subgroup analyses by ethnicity, H. pylori infection and the subtype of PUD, significant associations were found between IL-8 gene −251 T/A polymorphism and PUD risk in Asians, H. pylori+, duodenal ulcer disease (DUD) and gastric ulcer disease (GUD), respectively. In summary, the present meta-analysis suggests that IL-8 gene −251 T/A polymorphism is associated with increased PUD risk among Asians, and especially for the subgroups of H. pylori+, DUD and GUD.

Increasing evidence suggests a regulatory role for the IGF system in teleost oocyte maturation (OM). Our objectives were to determine if IGF-I and IGF-II regulate different stages of OM in southern flounder (Paralichthys lethostigma) and to identify the likely maturation-inducing steroid (MIS) in this species. The most abundant final product of ovarian steroidogenesis assays eluted at the position of 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S). 20β-S was also more potent in inducing germinal vesicle breakdown (GVBD) of maturationally-competent oocytes than other teleost MISs. IGF-II (100 nM) induced maturational competence (OMC), as greater GVBD was induced after incubation with IGF-II+20β-S compared to that of the 20β-S+20β-S or IGF-II+no treatment group. Incubation with IGF-II (100 nM) for 4-8 h significantly increased ovarian membrane progestin receptor alpha (mPRα or Paqr7b) mRNA levels 12-15% and mPRα protein levels 75-101%. Further, the IGF-II-induced increase in mPRα protein concentrations was partially blocked by pretreatment with Wortmannin, a Pik3 inhibitor, and PD 098,059, a Mapk inhibitor. Both IGF-I and -II (100 nM) induced GVBD of maturationally-competent oocytes was blocked by incubation with cycloheximide. Incubation with D,L-Aminoglutethimide decreased IGF-II-induced GVBD but had no effect on IGF-I-induced GVBD. IGF-I and -II were also able to induce GVBD of maturationally-incompetent oocytes, and elicited 75% and 135% greater GVBD, respectively, than hCG+20β-S at 100 nM. In conclusion, we show that 20β-S is the likely MIS in this species and that IGF-I and -II are also able to induce GVBD. Further, IGF-II not only induces OMC but also up-regulates ovarian mPRα mRNA and protein through Pik3- and Mapk-dependent pathways. This is the first demonstration of mPRα regulation by an IGF in any vertebrate species.

This paper is concerned with the controllability of a kind of nonlinear stochastic impulsive functional systems. Sufficient conditions for the complete controllability of the nonlinear stochastic impulsive functional systems are obtained by using Schauder fixed-point theorem. A numerical example is given to illustrate the effectiveness of the theoretical results.

D * (Detectivity), an important figure of merit for photodetectors, is limited by zero bias resistance–area product ( R 0 A ) . R 0 A is determined by Auger recombination mechanism, depending on the composition, temperature, carrier concentration and other parameters of the photodetectors. To investigate R 0 A of In1−xGaxAs infrared photodetectors, in this paper, theoretical analysis of Auger recombination mechanism was carried out in the room temperature, by taking CCCH, CHHL and CHHS into account. The calculated results show that there are significant influences on R 0 A for various parameters in both p- and n-type regions of the devices. With carrier concentration around 1017 to 1018 cm−3, R 0 A of 108 Ω cm2 (n-region) and 106 Ω cm2 (p-region) are obtained for x = 0.47 , when thickness and surface recombination velocity of the sample are 5 μm and 100 m/s, respectively.

The existence of direct progestin actions on teleost sperm to stimulate hypermotility is not widely acknowledged because it has only been demonstrated in members of the family Sciaenidae. In the present study, progestin stimulation of sperm hypermotility was investigated in a non-sciaenid, southern flounder, and the potential role of membrane progestin receptor alpha (mPRα or Paqr7b) in mediating this action was examined. The major progestin produced in vitro by flounder testicular fragments co-migrated with 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S) during thin-layer chromatography. Treatment of flounder sperm with 5 nM-100 nM 20β-S significantly increased sperm velocity in vitro , whereas 17,20β-dihydroxy-4-pregnen-3-one and other steroids were ineffective. A single class of high affinity ( K d 22.95 nM), saturable, limited-capacity binding sites ( B max 0.013 nM) specific for 20β-S was identified on sperm membranes. Treatment of sperm membranes with guanosine 5′-(3- O -thio)triphosphate reduced [ 3 H]-20β-S binding, suggesting the 20β-S receptor couples to a G protein. The membrane adenylyl cyclase inhibitor 2′,5′-dideoxyadenosine blocked 20β-S-induced sperm hypermotility, indicating 20β-S activates stimulatory G proteins. Finally, flounder paqr7b was cloned and characterized from testicular tissues. The Paqr7b protein is expressed on the midpiece of flounder sperm and is more abundant in individuals with high sperm motility than low motility donors. These findings suggest that 20β-S stimulates sperm hypermotility in flounder through activation of stimulatory G proteins, likely through Paqr7b. The finding that progestins directly stimulate sperm hypermotility in a flatfish, a highly derived species not belonging to the teleost family Sciaenidae, suggests this phenomenon is widespread among advanced fishes.