[Association between early-life factors and pubertal timing in girls]. / ç”Ÿå‘½æ—©æœŸå› ç´ ä¸Žå¥³ç”Ÿé’æ˜¥å‘åŠ¨æ—¶ç›¸çš„å ³è”åˆ†æž.

OBJECTIVES: To study the association between early-life factors (including birth weight, method of birth, gestational age, and history of gestational metabolic disorders) and pubertal timing in girls. METHODS: The stratified cluster sampling method was used to select the girls in grades 2-3 and 7-8 from three primary schools and three middle schools in Guangzhou, China from March to December, 2019, and breast development was examined for all girls. A questionnaire survey was performed to collect the information on early-life factors. The multivariate logistic regression model was used to evaluate the association of gestational metabolic disorders, birth weight, method of birth, and gestational age with pubertal timing in girls. The Bootstrap method was used to assess the mediation effect of body mass index (BMI) (Z score) between high birth weight (≥4 000 g) and pubertal timing. RESULTS: A total of 1 665 girls were enrolled, among whom 280 (16.82%) were judged to have early pubertal timing. The multivariate logistic regression analysis showed that high birth weight was associated with the increased risk of early pubertal timing (OR=2.12, 95%CI: 1.19-3.66, P=0.008). Nevertheless, no significant association was observed between other early-life factors and pubertal timing (P>0.05). The OR for the mediation effect of BMI (Z score) between high birth weight and early pubertal timing was 1.25 (95%CI: 1.09-1.47), accounting for 29.33% of the total effect of high birth weight on early pubertal timing. CONCLUSIONS: High birth weight is associated with the increased risk of early pubertal timing in girls, and overweight/obesity may play a partial mediating role in the association between high birth weight and early pubertal timing in girls.

Nerve growth factor causes epinephrine release dysfunction by regulating phenotype alterations and the function of adrenal medullary chromaffin cells in mice with allergic rhinitis.

The presence of allergic rhinitis (AR) is an increased risk factor for the occurrence of bronchial asthma (BA). Nerve growth factor (NGF), in addition to its key role in the development and differentiation of neurons, may also be an important inflammatory factor in AR and BA. However, the pathogenesis of the progression of AR to BA remains to be elucidated. The present study aimed to investigate the ability of NGF to mediate nasobronchial interactions and explore possible underlying molecular mechanisms. In the present study, an AR mouse model was established and histology of nasal mucosa tissue injury was determined. The level of phenylethanolamine N­methyl transferase in adrenal medulla was determined by immunofluorescence. Primary adrenal medullary chromaffin cells (AMCCs) were isolated and cultured from the adrenal medulla of mice. The expression levels of synaptophysin (SYP), STAT1, JAK1, p38 and ERK in NGF­treated and untreated AMCCs were detected by reverse­transcription­quantitative PCR and western blotting. The epinephrine (EPI) and norepinephrine (NE) concentrations were measured by ELISA. It was found that the expression of SYP in AMCCs was enhanced in the presence of NGF, whereas, the concentration of EPI decreased significantly under the same conditions. Furthermore, NGF mediated the phenotypic and functional changes of AMCCs, resulting in decreased EPI secretion via JAK1/STAT1, p38 and ERK signaling. In conclusion, these findings could provide novel evidence for the role of NGF in regulating neuroendocrine mechanisms.

Antioxidant Activity and the Potential Mechanism of the Fruit From Ailanthus altissima Swingle.

The fruits of Ailanthus altissima Swingle (AS) possess a variety of pharmacological activities. Its antioxidant activity and the potential mode of action have not yet been investigated. In in vitro studies, AS revealed the strong reducing power and DPPH scavenging effect, but hydroxyl radical scavenging activity and ferrous ions-chelating ability were not strong. Meanwhile, the oxidative stress RAW264.7 cell injury model was established, the low and medium-doses of AS showed significant protective effects on the viability of H2O2-treated cells by CCK-8 method. Besides, three doses of AS all increased the activities of SOD, CAT, and GSH-Px and decreased the MDA level compared with the H2O2 group, suggesting it significantly relieved oxidative stress of cells. The active ingredients and related targets of AS were collected by HERB and Swiss Target Prediction database, the common targets of drugs and diseases database were conducted by GeneCards database platform and the Venny platform. We screened the core targets of AS like threonine kinase1 (AKT1), mitogen-activated protein kinase 1 (MAPK1), sirtuin-1 (SIRT1), mechanistic target of rapamycin kinase (MTOR) by STRING database, and the key pathways involved PI3K-AKT and FoxO signaling pathway by KEGG pathway enrichment analysis. Besides, qRT-PCR revealed AS preconditioning significantly up-regulated the expression level of AKT1, SIRT1, MAPK1, and MTOR in model cells, and the effect was related to the regulation of FoxO and PI3K/AKT signaling pathway. In summary, AS showed significant antioxidant activity and its potential mechanism was regulating FoxO and PI3K/AKT signaling pathway.

Serum­derived exosomes from house dust mite­sensitized guinea pigs contribute to inflammation in BEAS­2B cells via the TLR4­NF­κB pathway.

Airway epithelial cells, which are the first physical defense barrier against allergens, play a pivotal role in immunity, airway inflammation and airway remodeling. The damage and dysfunction of these cells trigger the development of airway inflammatory diseases. Exosomes, which exist in various bodily fluids, mediate cell­cell communication and participate in the immune response process. The present study aimed to investigate whether serum exosomes play a pro­inflammatory role in bronchial epithelial cells (BEAS­2B cells) and, if so, explore the underlying molecular mechanisms. A guinea pig model of House dust mite (HDM)­induced asthma was established by sensitizing the rodents with HDM and PBS, and serum­derived exosomes were harvested. It was found that serum­derived exosomes from HDM­sensitized guinea pigs displayed higher levels of exosomal markers than those from controls. Additionally, western blot analysis and reverse transcription­quantitative PCR indicated that serum­derived exosomes from HDM­sensitized guinea pigs carried heat shock protein 70 and triggered an inflammatory response in BEAS­2B cells via the toll­like receptor 4 (TLR4)­NF­κB pathway. However, TAK­242, an inhibitor of the expression of TLR4, blocked the activation of the TLR4­NF­κB pathway. These findings provided a novel mechanism for exosome­mediated inflammatory responses and a new perspective for the intervention of inflammatory airway disorders.

A Novel PCR Method for Detecting ACE Gene Insertion/Deletion Polymorphisms and its Clinical Application.

BACKGROUND: Angiotensin-converting enzyme (ACE) plays a major role in blood pressure regulation and cardiovascular homeostasis. The wide distribution and multifunctional properties of ACE suggest it's involvement in various pathophysiological conditions. RESULTS: In this study, a novel visual detection method for ACE I/D polymorphisms was designed by integrating direct PCR without the need for DNA extraction using gold magnetic nanoparticles (GMNPs)-based lateral flow assay (LFA) biosensor. The entire detection procedure could enable the genotyping of clinical samples in about 80 min. The detection limit was 0.75 ng and results could be obtained in 5 min using the LFA device. Three hundred peripheral blood samples were analyzed using the direct PCR-LFA system and then verified by sequencing to determine accuracy and repeatability. A clinical preliminary study was then performed to analyze a total of 633 clinical samples. CONCLUSIONS: After grouping based on age, we found a significant difference between the genotypes and the age of patients in the CHD group. The introduction of this method into clinical practice may be helpful for the diagnosis of diseases caused by large fragment gene insertions/deletions.

Ultra-high synergetic intensity for humic acid removal by coupling bubble discharge with activated carbon.

Humic acid (HA) removal research focuses on the global water treatment industry. In this work, efficient HA degradation with an ultra-high synergetic intensity is achieved by combined bubble discharge with activated carbon (AC). Adding AC to the discharge greatly improves HA removal efficiency and degradation speed; the synergetic intensity reaches 651.52% in the combined system, and the adsorption residual on AC is 4.52%. After 90 min of treatment, the HA removal efficiency reaches 98.90%, 31.29%, and 7.61% in the plasma-AC combined, solo bubble discharge, and solo AC adsorption systems, respectively. During the plasma process, the number of pore structures and active sites and the amount of oxygen-containing functional groups on the AC surface increase, resulting in a higher adsorption capacity to reactive species (H2O2 and O3) and HA and promoting interactions on the AC surface. For HA mineralization, the presence of AC greatly promotes the destruction of aromatic structures and chromophoric HA functional groups.

Degradation of trimethoprim in aqueous by persulfate activated with nanosecond pulsed gas-liquid discharge plasma.

The persulfate activation by nanosecond pulsed gas-liquid discharge (NPG-LD) is employed to degrade the trimethoprim (TMP) in water. The results show that persulfate addition enhances the degradation of TMP by NPG-LD through an obvious synergetic effect. With treatment time of 50 min, the high removal efficiency and energy yield reach 94.6% and 0.57 gkWh-1 in air NPG-LD with the addition of persulfate, respectively, which is 13.5% and 0.09 gkWh-1 higher than that in solo air NPG-LD, respectively. Correspondingly, the calculated synergetic factor achieves 1.62, indicating the synergetic effect is established. The activation mechanism of persulfate by NPG-LD is analyzed by the measurement of reactive species and the effects of radical scavenger addition on TMP removal. It is found that the synergetic effect between NPG-LD and persulfate is attributed to the increased production of OH, H2O2, and . Besides, the TMP degradation by NPG-LD and persulfate synergetic system is influenced by discharge working gas, pulse voltage, addition dosage of persulfate, initial TMP concentration, and initial pH value. Subsequently, the degradation pathway of TMP is analyzed using LC-MS/MS.

High birth weight and its interaction with physical activity influence the risk of obesity in early school-aged children.

BACKGROUND: High birth weight (HBW) is associated with childhood obesity, but with inconsistent results. This study investigated the relationship between HBW and childhood obesity, and further explored the interaction of HBW with behavioral and socio-economic determinants of obesity. METHODS: This cross-sectional study enrolled 1906 grade-two children of Guangzhou, China, from June to November, 2016. Overweight/obesity corresponded to a body mass index higher than the sex-age-specific criteria. Abdominal obesity was assessed using the sex-specific waist-height ratio cutoffs. The association of HBW with obesity was evaluated in multivariable logistic regression model. The relative excess risk due to interaction (RERI) and the attributable proportion of interaction (AP) indices were used to measure additive interaction, while applying the interaction of OR index for multiplicative interaction assessment. RESULTS: Children with HBW had an increased risk of overweight/obesity [odds ratio (OR) = 2.42, 95% confidence interval (CI) = 1.56-3.76] compared with those without HBW. Significant additive interaction of HBW with physical activity was found for overweight/obesity [relative excess risk due to interaction (RERI) = 2.69, 95% CI = 0.62-4.75; attributable proportion of interaction (AP) = 0.72, 95% CI = 0.42-1.02]. The HBW children with insufficient activity had higher odds of overweight/obesity compared to the non-HBW children with sufficient activity (OR = 3.75, 95% CI = 2.06-6.83). In addition, we identified a significant interaction of HBW with household income for abdominal obesity (RERI = 1.20, 95% CI = 0.02-2.37; AP = 0.76, 95% CI = 0.16-1.36). CONCLUSIONS: HBW confers an increased risk for childhood overweight/obesity. Physical activity attenuates the effect of HBW on overweight/obesity, and HBW possibly synergistically interacts with high household income to promote abdominal obesity in childhood.

[Breeding of new Artemisia annua variety "Kehao No.1"].

As a natural plant source of artemisinin,a first-line drug against malaria,Artemisia annua directly affects the extraction process of artemisinin and the source of artemisinin. At present,traditional breeding methods combined with tissue culture are often used to breed high-yield artemisinin-containing new varieties of A. annua. However,the breeding method has the disadvantages of low efficiency and continuous selection. In this study,heavy ion beam irradiation technology was used to observe the specific germplasm resources of A. annua,and the morphological characteristics,agronomic traits and artemisinin content were used as indicators to observe the selection materials and materials. The cultivated new varieties were compared with trials and regional trials. In addition,the new variety of A. annua was identified by SRAP molecular marker technology. The results showed that the new variety of A. annua, " Kehao No.1",had an average yield of 235. 0 kg of dry leaf per mu,which was more than 20% higher than that of the control. Especially,the average artemisinin content was 2. 0%,which was 45% higher than that of the control,and the " Kehao No.1" has high anti-white powder disease,high-yield and high-quality new varieties. Therefore,mutagenic breeding of heavy ion beam irradiation can significantly improve the yield and artemisinin content of the " Kehao No. 1" and it has a good promotion value.

Significance of Heavy-Ion Beam Irradiation-Induced Avermectin B1a Production by Engineered Streptomyces avermitilis.

Heavy-ion irradiation technology has advantages over traditional methods of mutagenesis. Heavy-ion irradiation improves the mutation rate, broadens the mutation spectrum, and shortens the breeding cycle. However, few data are currently available regarding its effect on Streptomyces avermitilis morphology and productivity. In this study, the influence of heavy-ion irradiation on S. avermitilis when cultivated in approximately 10 L stirred-tank bioreactors was investigated. The specific productivity of the avermectin (AVM) B1a-producing mutant S. avermitilis 147-G58 increased notably, from 3885 to 5446 µg/mL, approximately 1.6-fold, compared to the original strain. The mycelial morphology of the mutant fermentation processes was microscopically examined. Additionally, protein and metabolite identification was performed by using SDS-PAGE, 2- and 3-dimensional electrophoresis (2DE and 3DE). The results showed that negative regulation gene deletion of mutants led to metabolic process upregulating expression of protein and improving the productivity of an avermectin B1a. The results showed that the heavy-ion beam irradiation dose that corresponded to optimal production was well over the standard dose, at approximately 80 Gy at 220 AMeV (depending on the strain). This study provides reliable data and a feasible method for increasing AVM productivity in industrial processes.

Bortezomib Relieves Immune Tolerance in Nasopharyngeal Carcinoma via STAT1 Suppression and Indoleamine 2,3-Dioxygenase Downregulation.

Radiotherapy is the primary treatment for nasopharyngeal carcinoma (NPC). Patients with intermediate and advanced stage NPC receiving only radiotherapy have limited survival, so newer immunotherapeutic approaches are sought. The major impediment to better clinical outcomes is tumor immune tolerance. Indoleamine 2,3-dioxygenase (IDO), an IFNγ-inducible enzyme, is a major inducer of immune tolerance during tumor development; therefore, inhibition of the IDO pathway is an important modality for cancer treatment. We show that bortezomib, a proteasomal inhibitor, inhibited the pathways leading to STAT1 and IRF-1 activation, both of which are necessary for IDO expression. Bortezomib downregulated IFNγ-induced IDO expression via inhibition of STAT1 phosphorylation and nuclear translocation, thereby suppressing STAT1-driven IDO transcription in NPC cells. Bortezomib also promoted IκB-α phosphorylation-ubiquitination, which released NF-κB from IκB-α. However, the released NF-κB could not enter the nucleus to conduct its biological effects and accumulated in the cytoplasm. Negative feedback inhibited the transcription of NF-κB, which is important for activating IRF-1 expression. IDO expression is regulated by two important transcription factor binding sites, ISREs, which bind STAT1 and IRF-1, and GASs, which binds STAT1. Bortezomib upregulated IRF-1 protein by inhibiting its proteasome-dependent degradation, but it also inhibited STAT1 phosphorylation, which directly inhibited the activation of GAS and indirectly inhibited the activation of ISRE, which needs both STAT1 and IRF-1. These discoveries provide a mechanism for the antitumor action of bortezomib and have implications for the development of clinical cancer immunotherapy for preventing and treating NPC. Cancer Immunol Res; 5(1); 42-51. ©2016 AACR.

The acquisition of Clostridium tyrobutyricum mutants with improved bioproduction under acidic conditions after two rounds of heavy-ion beam irradiation.

End-product inhibition is a key factor limiting the production of organic acid during fermentation. Two rounds of heavy-ion beam irradiation may be an inexpensive, indispensable and reliable approach to increase the production of butyric acid during industrial fermentation processes. However, studies of the application of heavy ion radiation for butyric acid fermentation engineering are lacking. In this study, a second (12)C(6+) heavy-ion irradiation-response curve is used to describe the effect of exposure to a given dose of heavy ions on mutant strains of Clostridium tyrobutyricum. Versatile statistical elements are introduced to characterize the mechanism and factors contributing to improved butyric acid production and enhanced acid tolerance in adapted mutant strains harvested from the fermentations. We characterized the physiological properties of the strains over a large pH value gradient, which revealed that the mutant strains obtained after a second round of radiation exposure were most resistant to harsh external pH values and were better able to tolerate external pH values between 4.5 and 5.0. A customized second round of heavy-ion beam irradiation may be invaluable in process engineering.

Curcumin combined with FAPαc vaccine elicits effective antitumor response by targeting indolamine-2,3-dioxygenase and inhibiting EMT induced by TNF-α in melanoma.

Fibroblast activation protein α (FAPα) is a potential target for cancer therapy. However, elimination of FAPα+ fibroblasts activates secretion of IFN-γ and TNF-α. IFN-γ can in turn induce expression indolamine-2,3-dioxygenase (IDO), thereby contributing to immunosuppression, while TNF-α can induce EMT. These two reactive effects would limit the efficacy of a tumor vaccine. We found that curcumin can inhibit IDO expression and TNF-α-induced EMT. Moreover, FAPαc vaccine and CpG combined with curcumin lavage inhibited tumor growth and prolonged the survival of mice implanted with melanoma cells. The combination of FAPαc vaccine, CpG and curcumin stimulated FAPα antibody production and CD8+ T cell-mediated killing of FAPα-expressing stromal cells without adverse reactive effects. We suggest a combination of curcumin and FAPαc vaccine for melanoma therapy.

Efficacy and safety of domestic leuprorelin in girls with idiopathic central precocious puberty: a multicenter, randomized, parallel, controlled trial.

BACKGROUND: In central precocious puberty (CPP), the pulse secretion and release of gonadotropin-releasing hormone (GnRH) are increased due to early activation of the hypothalamic-pituitary-gonadal axis, resulting in developmental abnormalities with gonadal development and appearance of secondary sexual characteristics. The CPP without organic disease is known as idiopathic CPP (ICPP). The objective of the study was to evaluate the clinical efficacy and safety of domestic leuprorelin (GnRH analog) in girls with ICPP. METHODS: A total of 236 girls with ICPP diagnosed from April 2012 to January 2014 were selected and were randomized into two groups. One hundred fifty-seven girls in the test group were treated with domestic leuprorelin acetate, 79 girls in the control group were treated with imported leuprorelin acetate. They all were treated and observed for 6 months. After 6-month treatment, the percentage of children with peak luteinizing hormone (LH) ≤3.3 U/L, the percentage of children with peak LH/peak follicle stimulating hormone (FSH) ratio <0.6, the improvements of secondary sexual characteristics, gonadal development and sex hormone levels, the change of growth rate of bone age (BA) and growth velocity, and drug adverse effects between two groups were compared. RESULTS: After the treatment, the percentage of children with a suppressed LH response to GnRH, defined as a peak LH ≤3.3 U/L, at 6 months in test and control groups were 96.80% and 96.20%, respectively, and the percentage of children with peak LH/FSH ratio ≤0.6 at 6 months in test and control groups were 93.60% and 93.70%, respectively. The sizes of breast, uterus and ovary of children and the levels of estradiol (E 2 ) were significantly reduced, and the growth rate of BA was also reduced. All the differences between pre- and post-treatment in each group were statistically significant (P < 0. 05), but the differences of the parameters between two groups were not significant (P > 0.05). CONCLUSIONS: Domestic leuprorelin is effective and safe in the treatment of Chinese girls with ICPP. Its effectiveness and safety are comparable with imported leuprorelin.

Synthesis and biological evaluation of new pleuromutilin derivatives as antibacterial agents.

Several pleuromutilin derivatives possessing thiadiazole moieties were synthesized via acylation reactions under mild conditions. The in vitro antibacterial activities of the derivatives against methicillin-resistant S. aureus, methicillin-resistant S. epidermidis, S. aureus, S. epidermidis, E. coli, and B. cereus were tested by the agar dilution method and Oxford cup assay. All the screened compounds displayed potent activity. Compound 6d was the most active antibacterial agent because of its lowest MIC value and largest inhibition zone. Docking experiments were performed to understand the possible mode of the interactions between the derivatives and 50S ribosomal subunit. Moreover, the absorption, distribution, metabolism, excretion and toxicity properties of the synthesized compounds were analyzed after prediction using the Advanced Chemistry Development/Percepta Platform available online.

Comparison of the effects of high energy carbon heavy ion irradiation and Eucommia ulmoides Oliv. on biosynthesis butyric acid efficiency in Clostridium tyrobutyricum.

Clostridium tyrobutyricum is well documented as a fermentation strain for the production of butyric acid. In this work, using high-energy carbon heavy ion irradiated C. tyrobutyricum, then butyric acid fermentation using glucose or alkali and acid pretreatments of Eucommia ulmoides Oliv. as a carbon source was carried out. Initially, the modes at pH 5.7-6.5 and 37°C were compared using a model medium containing glucose as a carbon source. When the 72gL(-1) glucose concentration was found to be the highest yield, the maximum butyric acid production from glucose increased significantly, from 24gL(-1) for the wild type strains to 37gL(-1) for the strain irradiated at 126AMeV and a dose of 35Gy and a 10(7)ions/pulse. By feeding 100gL(-1) acid pretreatments of E. ulmoides Oliv. into the fermentations, butyrate yields (5.8gL(-1)) and butyrate/acetate (B/A) ratio (4.32) were achieved.

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch.

BACKGROUND: Butyric acid as a renewable resource has become an increasingly attractive alternative to petroleum-based fuels. Clostridium tyrobutyricum ATCC 25755T is well documented as a fermentation strain for the production of acids. However, it has been reported that butyrate inhibits its growth, and the accumulation of acetate also inhibits biomass synthesis, making production of butyric acid from conventional fermentation processes economically challenging. The present study aimed to identify whether irradiation of C. tyrobutyricum cells makes them more tolerant to butyric acid inhibition and increases the production of butyrate compared with wild type. RESULTS: In this work, the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 3.6, 7.2 and 10.8 g·L-1 equivalents were studied. The results showed that, regardless of the irradiation used, there was a gradual inhibition of cell growth at butyric acid concentrations above 10.8 g·L-1, with no growth observed at butyric acid concentrations above 3.6 g·L-1 for the wild-type strain during the first 54 h of fermentation. The sodium dodecyl sulfate polyacrylamide gel electrophoresis also showed significantly different expression levels of proteins with molecular mass around the wild-type and irradiated strains. The results showed that the proportion of proteins with molecular weights of 85 and 106 kDa was much higher for the irradiated strains. The specific growth rate decreased by 50% (from 0.42 to 0.21 h-1) and the final concentration of butyrate increased by 68% (from 22.7 to 33.4 g·L-1) for the strain irradiated at 114 AMeV and 40 Gy compared with the wild-type strains. CONCLUSIONS: This study demonstrates that butyric acid production from glucose can be significantly improved and enhanced by using 12C6+ heavy ion-irradiated C. tyrobutyricum. The approach is economical, making it competitive compared with similar fermentation processes. It may prove useful as a first step in a combined method employing long-term continuous fermentation of acid-production processes.

The effect of microdosimetric 12C6+ heavy ion irradiation and Mg2+ on canthaxanthin production in a novel strain of Dietzia natronolimnaea.

BACKGROUND: Dietzia natronolimnaea is one of the most important bacterial bioresources for high efficiency canthaxanthin production. It produces the robust and stable pigment canthaxanthin, which is of special interest for the development of integrated biorefineries. Mutagenesis employing 12C6+ irradiation is a novel technique commonly used to improve microorganism productivity. This study presents a promising route to obtaining the highest feasible levels of biomass dry weight (BDW), and total canthaxanthin by using a microdosimetric model of 12C6+ irradiation mutation in combination with the optimization of nutrient medium components. RESULTS: This work characterized the rate of both lethal and non-lethal dose mutations for 12C6+ irradiation and the microdosimetric kinetic model using the model organism, D. natronolimnaea svgcc1.2736. Irradiation with 12C6+ ions resulted in enhanced production of canthaxanthin, and is therefore an effective method for strain improvement of D. natronolimnaea svgcc1.2736. Based on these results an optimal dose of 0.5-4.5 Gy, Linear energy transfer (LET) of 80 keV µm-1and energy of 60 MeV u-1 for 12C6+ irradiation are ideal for optimum and specific production of canthaxanthin in the bacterium. Second-order empirical calculations displaying high R-squared (0.996) values between the responses and independent variables were derived from validation experiments using response surface methodology. The highest canthaxanthin yield (8.14 mg) was obtained with an optimized growth medium containing 21.5 g L-1 D-glucose, 23.5 g L-1 mannose and 25 ppm Mg2+ in 1 L with an irradiation dose of 4.5 Gy. CONCLUSIONS: The microdosimetric 12C6+ irradiation model was an effective mutagenic technique for the strain improvement of D. natronolimnaea svgcc1.2736 specifically for enhanced canthaxanthin production. At the very least, random mutagenesis methods using 12C6+ions can be used as a first step in a combined approach with long-term continuous fermentation processes. Central composite design-response surface methodologies (CCD-RSM) were carried out to optimize the conditions for canthaxanthin yield. It was discovered D-glucose, Mg2+ and mannose have significant influence on canthaxanthin biosynthesis and growth of the mutant strain.

[Correlation of resistance to peer pressure and risky decision-making with adolescent health risk behaviors].

OBJECTIVE: To explore possible interrelationships among resistance to peer pressure, risky decision-making and health risk behaviors among young adolescents. METHODS: Based on the cluster sampling method, the participants who were recruited from 5 junior middle schools in Guangzhou and 3 junior middle schools in Shenyang city on October, 2010, were administered to complete the questionnaire concerned with their experiences with drinking and smoking during the past 30 days preceding the survey, and the hours using computer daily both in weekdays and in weekend. The level of resistance to peer influence and risky decision-making were assessed by Resistance to peer influence scale (RPIS) and Youth decision-making questionnaire (YDMQ). Logistic regression was used to explore possible interrelationships among resistance to peer influence, risky decision-making and health risk behaviors among young adolescents. RESULTS: A total of 1985 questionnaires were valid, including 1001(50.4%) boys and 984 (49.6%) girls. About 27.1% (537/1985) junior middle school students reported having health risk behaviors, boys' (30.7%, 307/1001) was higher than girls' (23.4%, 230/984) with significant gender difference (P < 0.05). The prevalence of smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekdays and in weekend were 5.1% (102/1985), 14.3% (284/1985), 3.5% (70/1985) and 13.7% (272/1985), respectively. The rate of drinking, using computer over 3 hours daily in weekdays and in weekend were higher in males (16.4% (164/1001), 4.5% (45/1001), 16.2% (162/1001)) than those in females (12.2% (120/984), 2.5% (25/984), 11.2% (110/984)) (P < 0.05). The scores of RPIS and YDMQ of the two cities adolescents were 2.82 ± 0.39 and 1.68 ± 0.62. The students reported smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekend gained lower RPIS scores (2.43 ± 0.40, 2.61 ± 0.41, 2.77 ± 0.40) than their counterparts who didn't report these kind of health risk behaviors (2.84 ± 0.38, 2.85 ± 0.38, 2.82 ± 0.39)(P < 0.05). And those reported smoking, drinking during the past 30 days before the survey and using computer over 3 hours daily in weekdays and in weekend gained higher YDMQ scores (2.38 ± 0.66, 2.06 ± 0.66, 1.97 ± 0.72, 1.84 ± 0.64, respectively) than their counterparts who didn't report these kind of health risk behaviors (1.64 ± 0.38, 1.61 ± 0.58, 1.67 ± 0.61, 1.65 ± 0.61, respectively) (P < 0.05). After adjusting gender, area, parental education degree, self-reported family economic condition, multi-variant logistic regression analysis indicated that the low and middle level of resistance to peer influence (low and middle level vs high level, had odds ratios of 2.97 (1.96 - 4.50) and 1.51 (1.05 - 2.16)), and also the middle and high level of risky decision-making (middle and high level vs low level, had odds ratios of 1.62 (1.19 - 2.22) and 3.43 (2.39 - 4.90)) were all the risk factors of adolescent health risk behaviors. CONCLUSION: Adolescents with poor ability of resistance to peer pressure and high risky decision-making were both the risk factors of adolescent health risk behaviors.