The development of logic gate-based fluorescent probes that respond to intracellular hydrogen peroxide and pH in tandem.

Logic gate-based fluorescent probes are powerful tools for the discriminative sensing of multiple signaling molecules that are expressed in concert during the progression of many diseases such as inflammation, cancer, aging, and other disorders. To achieve logical sensing, multiple functional groups are introduced to the different substitution sites of a single fluorescent dye, which increases the complexity of chemical synthesis. Herein, we report a simple strategy that incorporates just one responsive unit into a hemicyanine dye achieving the logic gate-based sensing of two independent analytes. We introduce boronic acid to hemicyanine to quench the fluorescence, and in the presence of hydrogen peroxide (H2O2), the fluorescence is recovered due to removal of the boronate. Interestingly, the subsequent decrease in pH turned the red fluorescence of hemicyanine to green emissive because of protonation of the phenolic alcohol. This unique feature of the probe enables us to construct "INHIBIT" and "AND" logical gates for the accurate measuring of intracellular H2O2 and acidic pH in tandem. This study offers insight into the simple construction of logic-gate based fluorescent probes for the tandem sensing of multiple analytes that are correlatively produced during disease progression.

Bioherbicidal potential of Bacillus altitudinis D30202 on Avena fatua L.: a whole-genome sequencing analysis.

Avena fatua L. (wild oat) is one of the most harmful gramineous weeds that can affect the yield and quality of infiltrating crops. Bacillus altitudinis D30202 exhibits an excellent biocontrol activity against wild oat. To elucidate the biocontrol mechanisms of B. altitudinis D30202, the genome structure of this strain was assessed via whole-genome sequencing analysis. We predicted and analyzed secondary metabolite synthesis gene clusters to elucidate the mechanisms underlying the biocontrol of weeds. The whole-genome sequencing data indicated that B. altitudinis D30202 had the genome size and GC content of 3,777,154 bp and 41.32%, respectively, and 3809 coding genes were identified. Moreover, this strain could generate several compounds with bioherbicidal activity, including 4-hydroxy-3-methoxycinnamic acid and two indole derivatives. Bioinformatics prediction and comparative genomic analysis revealed that the strain had 6 secondary metabolite gene clusters. Furthermore, the taxonomic position of B. altitudinis D30202 was assessed, confirming its uniqueness and novelty within the Bacillus genus. Comparative genomic analysis showed differences in gene distribution, suggesting potential adaptations to different environments. In conclusion, B. altitudinis D30202 possesses a genome with unique characteristics, encoding enzymes and pathways related to herbicidal potential and biocontrol. This study provides a reference basis for understanding the molecular mechanisms of weed inhibition.

Development and validation of the atopic dermatitis and infant skincare knowledge, attitude, and practice (ADISKAP 1.0) scale.

Importance: Preserving skin health is crucial for atopic dermatitis control as well as for the thriving of children. However, a well-developed and validated tool that measures the knowledge, attitude, and practice of skin care is lacking. Objective: To develop and validate the atopic dermatitis and infant skincare knowledge, attitude, and practice (ADISKAP 1.0) scale that measures parental health literacy on atopic dermatitis and skin care. Methods: We conducted a review of the literature, a focus group (two dermatologists and 12 parents), and a panel discussion in order to generate the ADISKAP prototype. Two samples of parents with knowingly superior (dermatologists, n = 59) and inferior (general population, n = 395) knowledge traits participated in the validation of ADISKAP. Cronbach's alpha was reported as a measure of internal consistency, and the intraclass correlation coefficient (ICC) was calculated to assess the test-retest validity. The known-groups technique was used to evaluate construct validity. Results: The ADISKAP scale contained 17 items after content and face validity validation. After removing items that displayed poor test-retest reliability (n = 4) and construct validity (n = 3), 12 items were retained in the ADISKAP 1.0. Interpretation: ADISKAP 1.0 is a reliable and valid tool for assessing parental knowledge, attitude, and practice on infantile atopic dermatitis and skin care.

Short-Term Alternate Feeding between Terrestrially Sourced Oil- and Fish Oil-Based Diets Modulates the Intestinal Microecology of Juvenile Turbot.

A nine-week feeding trial was conducted to investigate changes in the intestinal microbiota of turbot in response to alternate feeding between terrestrially sourced oil (TSO)- and fish oil (FO)-based diets. The following three feeding strategies were designed: (1) continuous feeding with the FO-based diet (FO group); (2) weekly alternate feeding between soybean oil (SO)- and FO-based diets (SO/FO group); and (3) weekly alternate feeding between beef tallow (BT)- and FO-based diets (BT/FO group). An intestinal bacterial community analysis showed that alternate feeding reshaped the intestinal microbial composition. Higher species richness and diversity of the intestinal microbiota were observed in the alternate-feeding groups. A PCoA analysis showed that the samples clustered separately according to the feeding strategy, and among the three groups, the SO/FO group clustered relatively closer to the BT/FO group. The alternate feeding significantly decreased the abundance of Mycoplasma and selectively enriched specific microorganisms, including short-chain fatty acid (SCFA)-producing bacteria, digestive bacteria (Corynebacterium and Sphingomonas), and several potential pathogens (Desulfovibrio and Mycobacterium). Alternate feeding may maintain the intestinal microbiota balance by improving the connectivity of the ecological network and increasing the competitive interactions within the ecological network. The alternate feeding significantly upregulated the KEGG pathways of fatty acid and lipid metabolism, glycan biosynthesis, and amino acid metabolism in the intestinal microbiota. Meanwhile, the upregulation of the KEGG pathway of lipopolysaccharide biosynthesis indicates a potential risk for intestinal health. In conclusion, short-term alternate feeding between dietary lipid sources reshapes the intestinal microecology of the juvenile turbot, possibly resulting in both positive and negative effects.

Response of Intestinal Microbiota of Tiger Puffer (Takifugu rubripes) to the Fish Oil Finishing Strategy.

The fish oil finishing (FOF) strategy, that is, re-feeding fish with fish oil (FO)-based diet after a certain period of feeding with alternative lipid source-based diets. On tiger puffer, the present study investigated the response of intestinal microbiota to FOF. Fish were fed four diets based on FO, soybean oil, palm oil and beef tallow as lipid sources, respectively, firstly for 50 days (growing-out period), and then fed the FO-based diet for 30 more days (FOF period). The results showed that dietary terrestrially sourced oils impaired the intestinal function in the growing-out period. However, the activities of amylase, trypsin and anti-oxidative enzymes (SOD, CAT, T-AOC), as well as gene expression of inflammatory cytokines (IL-1ß, TNF-α, TGF-ß) and tight junction protein (Claudin4, Claudin7, Claudin18, JAM, ZO-1) in the intestine were significantly recovered by FOF. The 16S rDNA sequencing analysis showed that FOF improved the similarity of bacterial community among the groups. The MetaStat analysis confirmed that FOF regulated the abundance of butyric acid-producing bacteria (Lachnospiraceae, Eubacterium, Butyricicoccus, Clostridium and Roseburia) and bacteria related to digestion and absorption (Sphingomonas, Romboutsia and Brevibacillus). In conclusion, FOF can recover the intestine function. The intestinal microbiota probably participated in and played a key role in the recovery process.

Use of oral glucose tolerance testing and HbA1c at 6-14 gestational weeks to predict gestational diabetes mellitus in high-risk women.

PURPOSE: To study the prediction of gestational diabetes mellitus (GDM) in high-risk pregnant women by testing fasting blood glucose, 1-h(1hPG) and 2-h plasma glucose (2hPG) after an oral glucose tolerance test, and glycated hemoglobin (HbA1c) in early pregnancy (6-14 weeks). METHODS: We recruited 1311 pregnant women at high risk for diabetes from the Obstetrics Clinic of Daxing District People's Hospital between June 2017 and December 2019. The tests performed during the first trimester included fasting blood glucose (FPG), HbA1c, and 75-g oral glucose tolerance test (OGTT) with 1hPG and 2hPG. Seventy-three pregnant women diagnosed with pregestational diabetes mellitus (PGDM) early in pregnancy and 36 who were missed in the second trimester were excluded. A total of 1202 women were followed up until 24-28 weeks for GDM. The receiver operating characteristic (ROC) and area under the ROC curve (AUC) were calculated to determine the predictive values of FPG, 1hPG, 2hPG, and HbA1c for GDM in early pregnancy in high-risk pregnant women. RESULTS: The AUC for 1hPG for the prediction of GDM in high-risk pregnant women was greater than those for FPG, 2hPG, and HbA1c. All differences were significant. The AUCs for the predictive values of FPG, 1hPG, 2hPG, and HbA1c in high-risk pregnant women were 0.63, 0.76, 0.71, and 0.67, respectively. The prevalence of PGDM among pregnant women at high risk of diabetes was 5.6%. CONCLUSION: First-trimester levels of FPG, 1hPG, 2hPG, and HbA1c in high-risk women are significant predictors of GDM, with 1hPG having the most significant predictive value.

Preventive Antenatal Educational Program on Allergic Diseases (PAEPAD) versus standard antenatal care for prevention of atopic dermatitis: study protocol for a single-centre, investigator-blinded randomised controlled trial.

INTRODUCTION: Patient education serves an essential purpose in the long-term management of allergic diseases as a secondary prevention approach. However, evidence on using education for primary prevention is limited. This study aims to evaluate the effect of an educational intervention, that is, the Preventive Antenatal Educational Program on Allergic Diseases (PAEPAD), on infantile allergic disease incidences compared with the standard care. METHODS AND ANALYSIS: This is a single-centre randomised controlled trial of expecting mother-children dyads in Daxing Teaching Hospital of Beijing, China. A total of 2266 expecting mothers will be recruited. Expecting mothers enlisted in the birth registry of Daxing Teaching Hospital of Capital Medical University and intend to give birth at this location will be screened for eligibility. Women aged≥18 years with less than 14+6 weeks of pregnancy who intends to remain resident in Daxing district for at least 2 years postpartum will be entered into the run-in phase. Randomisation will take place at 30 weeks of gestation. Women at high risk for miscarriage or intend to have abortions will be excluded. The participants will be allocated into two groups (ie, the PAEPAD and the standard care group) by random allocation (1:1). The PAEPAD group will receive a multidisciplinary education of neonatal care, including standard education as the control group and additional information on skincare of infants, sun protection, topical corticosteroids and an overview of atopic dermatitis (AD), whereas the standard care group will receive the standard neonatal care education carried out by obstetricians. Participants will be followed for 2 years. The primary outcome will be infantile AD cumulative incidence at 2 years postpartum. Secondary outcomes will include other AD outcomes, atopic march outcomes, knowledge outcomes and other maternal and neonatal outcomes. Data collection will be carried out using both electronic and paper questionnaires. Biological samples will also be collected longitudinally. ETHICS AND DISSEMINATION: The study design was approved by the ethical committee of Capital Medical University Daxing Teaching Hospital, Beijing, China. The trial results will be published in peer-reviewed journals and at conferences. TRIAL REGISTRATION NUMBER: ChiCTR registry (Trial ID: ChiCTR2000040463).

Theoretical analysis of a 60 W solar-pumped single crystal fiber laser.

In order to improve the output power of solar-pumped single-crystal fiber (SCF) lasers, we propose a novel solar concentrating system, to the best of our knowledge, consisting of a parabolic mirror, a 3D compound parabolic concentrator, and a hollow-core reflector. By ray tracing with TracePro, the influence of the fiber's diameter and the hollow reflector's shape on the solar absorption efficiency is theoretically investigated. A typical Nd:YAG SCF with a core diameter of 1 mm, length of 150 mm, and doping concentration of 1 at.% is selected for a simulation of laser operation. The output characteristics of the laser are analyzed by solving the rate equation and power transmission equation; the maximum output power and solar-to-laser conversion efficiency are 60.62 W and 4.64%, respectively. The thermal effects of the laser are simulated by Comsol software. When the input solar power is 1307.4 W, the temperature decreases sharply first and then saturates along the SCF fiber, with the maximum value of 69.18°C at the input fiber end. This concentrating system can effectively overcome the limitation of end-launching solar power into SCFs and has great potential in improving the output power of solar fiber lasers.

Dietary lipid levels affected antioxidative status, inflammation response, apoptosis and microbial community in the intestine of juvenile turbot (Scophthalmus maximus L.).

A nine-week feeding trial was conducted to comprehensively investigate the effects of different levels of dietary lipid on intestinal physiology of juvenile turbot. Three diets with different lipid levels (8%, 12% and 16%) were formulated, which were designated as the low-lipid group (LL), medium-lipid group (ML) and high-lipid group (HL), respectively. Each diet was fed to six replicate tanks, and each tank was stocked with 35 fish. The results revealed that medium dietary lipid (12%) increased the activities of intestinal digestive enzymes and brush border enzymes. Excessive dietary lipid (16%) decreased the intestinal antioxidative enzyme levels and increased the lipid peroxidation pressure. In addition, HL stimulated the occurrence of intestinal inflammation and significantly up-regulated the mRNA expression level of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interferon-γ (IFN-γ) and transforming growth factor-ß (TGF-ß). Dietary LL and HL induced the apoptosis of intestinal epithelial cells. Sequencing of bacterial 16 s rRNA V4 region indicated that the abundance and diversity of intestinal microflora in fish fed with medium lipid diet (12%) were significantly higher than those in other groups, indicating the intestinal microflora ecology in group ML was more balanced. MetaStat analysis indicated that both low- and high-lipid diets significantly reduced the relative abundance of intestinal beneficial bacteria. In conclusion, results of this study demonstrated the sensitivity of intestinal health and microbiota to dietary lipid levels. From the perspective of microecological balance, medium dietary lipid (12%) was more conducive to maintaining the intestinal microflora stability of turbot.

Patient Education Programs in Pediatric Atopic Dermatitis: A Systematic Review of Randomized Controlled Trials and Meta-Analysis.

INTRODUCTION: Patient education is crucial for improving disease outcomes in atopic dermatitis (AD). This review aims to summarize evidence about the effectiveness of educational programs for parents of pediatric AD patients. METHODS: PubMed and Embase (inception to Feb 2020) were searched and randomized controlled trials (RCTs) in English were included. Risk of bias was assessed using Cochrane risk of bias tools and quality of evidence was assessed by Grading of Recommendations Assessment, Development and Evaluation (GRADE). Pooled standardized mean difference (SMD) and 95% confidence intervals (CIs) were calculated for the disease severity instrument (Scoring of Atopic Dermatitis, SCORAD) and quality of life (QoL) instruments using the random-effects model. RESULTS: A total of 13 RCTs were included in the systematic review. The meta-analysis of SCORAD contained seven studies with a total of 1853 patients. The reduction in disease severity (SCORAD) was larger in the treatment group (SMD = - 8.22, 95% CI = - 11.29, - 5.15; P < 0.001; I2 = 78.6%). Subgroup analyses revealed that the association was modified by the frequency of sessions (P for Cochran Q < 0.01) and the duration of follow-up (P for Cochran Q < 0.01). No significant effect-modification was observed for disease severity and borderline significance was observed for session delivery (individual vs group session). The pooled effect sizes for QoL measures including Dermatitis Family Index (SMD = - 0.65, 95% CI = - 1.49, 0.18), Children's Dermatology Life Quality Index (SMD = - 1.61, 95% CI = - 3.76, 0.55; I2= 89.0%) and Infants' Dermatology Quality of Life Index (SMD = 0.30, 95% CI = - 1.04, 1.63; I2= 63.1%) were not significant. CONCLUSIONS: Structured patient education is beneficial and should be implemented for the management of AD patients. However, an optimal delivery mode needs to be determined.

The prevalence of CGG repeat expansion mutation in FMR1 gene in the northern Chinese women of reproductive age.

BACKGROUND: The prevalence of CGG repeat expansion mutation in FMR1 gene varies among different populations. In this study, we investigated the prevalence of this mutation in women of reproductive age from northern China. METHODS: A total of 11,891 pre-conceptional or pregnant women, including 5037 pregnant women and 7357 women with the history of spontaneous abortion or induced abortion due to delayed growth of the embryos, were recruited. The number of CGG repeats in FMR1 was measured by the TRP-PCR method. We also offered genetic counseling and prenatal diagnosis to the women carrying pre-mutation or full mutation alleles. RESULTS: The prevalence of pre-mutation in reproductive women in northern China was 1/410, higher than that in southern China and Korea but lower than that in western countries. We also found that the prevalence of pre-mutation was relatively high (1/320) in women with abortion history. CONCLUSION: Screening for CGG repeat expansion mutation in FMR1 should be recommended to the women with the history of spontaneous abortion or induced abortion due to delayed growth of the embryos.

Analysis of energy monitoring for a double-pulsed CO2 integrated path differential absorption lidar at 1.57 µm.

For double-pulsed 1.57 µm integrated path differential absorption lidar, the transmitted pulse energy measurement is an important factor that can influence the uncertainty of CO2 concentration measurement. An energy monitoring experiment was performed to determine how to improve the measurement precision of the transmitted pulse energy. Ground glass diffusers were used to reduce the speckle effect during energy monitoring. The roughness and rotational speed of the ground glass diffusers were considered and compared. The normalized energy ratios between on-line and off-line echo pulses and on-line and off-line energy monitoring pulses were analyzed, and the Allan deviation was used to evaluate the energy monitoring results. Averaging 148 shots, the standard deviation of the normalized energy ratio reached 0.0757%, whereas the correlation between the energy ratio of the on-line and off-line energy monitoring pulses and the energy ratio of the on-line and off-line echo pulses was higher than 90%.

Sensitive determination of aldehyde metabolites in exhaled breath condensate using capillary electrophoresis with laser-induced fluorescence detection.

A novel capillary electrophoresis with laser-induced fluorescence detection method has been developed for the analysis of aldehyde metabolism biomarkers for oxidative stress in exhaled breath condensate (EBC), and fluorescein 5-thiosemicarbazide was used as a derivatization reagent. In a simple capillary zone electrophoresis mode, ten low molecular weight aldehydes (LMWAs) could be well separated within 30 min. The reaction efficiency was doubled by increasing sample solution pH and magnetic stirring, and the LODs of this method reached 0.16-3.4 nM (S/N = 3). Acceptable recoveries (82.1-115%) were obtained for EBC samples, and the RSD data were within 7.9%. This developed method has been applied for the analyses of EBC samples and evaluation of the correlation between smoking and the contents of aldehyde metabolites in EBC. Due to no need of buffer additives and sample preconcentration, this proposed method may provide an appealing alternative for the trace analyses of LMWAs in noninvasive biofluids. Graphical abstract ᅟ.

Optimal iodine absorption line applied for spaceborne high spectral resolution lidar.

Spaceborne high spectral resolution lidar (HSRL) provides a wide range of observations, e.g., measurements of aerosol backscattering and extinction coefficients and aerosol depolarization ratio with high accuracy, which are of great significance to the study of air pollution monitoring and climate change. With different cells and finger temperatures, the transmittance of the different absorption lines of the iodine vapor filter at 532 nm wavelength was measured. The 1064 nm fundamental frequency pulse energy and the 532 nm frequency-doubled pulse energy output of different seeder laser wavelengths were measured. Based on the relationship among the laser output power, the absorption line shape of the iodine vapor filter, and the atmospheric model, the echo power was calculated and compared. The 1110 iodine absorption line was selected as the optimized filter for the HSRL, which could increase in 22% and 14% efficiency compared with the traditional 1109 line, and a new proposed 1105 line at the 532 nm HSRL channel at 5 km altitude with an enhanced aerosol model, respectively.

Double-pulse 1.57 µm integrated path differential absorption lidar ground validation for atmospheric carbon dioxide measurement.

A ground-based double-pulse integrated path differential absorption (IPDA) instrument for carbon dioxide (CO2) concentration measurements at 1572 nm has been developed. A ground experiment was implemented under different conditions with a known wall located about 1.17 km away acting as the scattering hard target. Off-/offline testing of a laser transmitter was conducted to estimate the instrument systematic and random errors. Results showed a differential absorption optical depth (DAOD) offset of 0.0046 existing in the instrument. On-/offline testing was done to achieve the actual DAOD resulting from the CO2 absorption. With 18 s pulses average, it demonstrated that a CO2 concentration measurement of 432.71±2.42 ppm with 0.56% uncertainty was achieved. The IPDA ranging led to a measurement uncertainty of 1.5 m.

Liquid-based endometrial cytology associated with curettage in the investigation of endometrial carcinoma in a population of 1987 women.

PURPOSE: The aim of this study was to investigate the diagnostic accuracy of liquid-based endometrial cytology, in comparison with histology. METHODS: 1987 patients scheduled for hysteroscopy were enrolled in this study. All patients proceeded sequentially through endometrial cytology, hysteroscopy and then dilatation and curettage (D&C). Cytology sampling was performed by brushing the uterus cavity using SAP-1 and the sample was prepared to liquid-based smear using SurePath technology. The slides were stained by Papanicolaou method. All cytological diagnosis was correlated with the D&C histological diagnosis. RESULTS: Cyto-histological correlations were possible in 1672 (89.3%) patients: in 254 (12.8%) patients the D&C was inadequate, in 75 (3.8%) patients the cytology was inadequate, and in 14 (0.7%) patients both were inadequate. In postmenopausal women, 758 of 790 cytologies (96.0%) were adequate, while 586 of 790 histologies (74.2%) were adequate. SAP-1 provided more sufficient materials for cytology than D&C for histology (P < 0.001). Taking atypical hyperplasia or worse as a positive result, the diagnostic accuracy of liquid-based endometrial cytology was 86.1%, sensitivity was estimated at 70.3%, specificity at 88.5%, positive predictive value at 48.0% and negative predictive value at 95.2%. Taking endometrial carcinoma as a positive result, the diagnostic accuracy of liquid-based endometrial cytology was 94.4%; sensitivity was estimated at 53.2%, specificity at 98.6%, positive predictive value at 79.8% and negative predictive value at 95.3%. CONCLUSIONS: Liquid-based endometrial cytology can be considered a useful method for detecting of endometrial pathology as a first-line approach.

Evaluation of Computed Tomography Perfusion Imaging in a Rat Acute Cerebral Ischemia-Reperfusion Model.

AIM: This study aims to apply computed tomography perfusion imaging (CTPI) technology under in vivo conditions in order to explore its reliability and accuracy in evaluating the rat acute cerebral ischemia-reperfusion model (RACIRM). MATERIAL AND METHODS: The thread embolism method was used in 48 rats to create the RACIRM. Rats were divided into 2 groups as ischemia group and ischemia-reperfusion group. We then compared and evaluated the results of CTPI, 2,3,5-triphenyl tetrazolium chloride (TTC) staining, and hematoxylin and eosin (HE) staining of both groups. RESULTS: There were no significant differences in the volumes of hypoperfusion regions in the cerebral blood flow (CBF) and cerebral blood volume (CBV) of each group at each CTPI time point and these volumes were not significantly different from the corresponding findings on the TTC-stained infarct regions. The mean transit time (MTT) did show a significant difference, as did the volumes observed in both the MTT ischemic region and TTC-stained infarct region. The CTPI parameters exhibited correlation with the infarct volumes calculated in TTC staining, among which CBV exhibited the highest correlation. CONCLUSION: CTPI could rapidly, accurately, and non-invasively evaluate the site, size, and hemodynamic changes in the cerebral ischemia-reperfusion animal model.

Liquid-based endometrial cytology associated with curettage in the investigation of endometrial carcinoma in postmenopausal women.

OBJECTIVE: The aim of this study was to investigate the diagnostic accuracy of liquid-based endometrial cytology in postmenopausal women, in comparison with histology. MATERIALS AND METHODS: There were 790 postmenopausal women scheduled for hysteroscopy enrolled in this study. After providing informed consent, all patients proceeded sequentially through endometrial cytology, hysteroscopy, and then dilatation and curettage (D&C). Cytology sampling was performed by brushing the uterus cavity using SAP-1 and the sample was prepared to liquid-based smear using SurePath technology. The slides were stained by Papanicolaou method. All cytological diagnoses were correlated with the D&C histological diagnoses. RESULTS: Cytohistological correlations were possible in 567 (71.8%) patients: the D&C was inadequate in 204 (25.8%) patients; the cytology was inadequate in 32 (4.1%) patients; and both were inadequate in 13 (1.6%) patients. SAP-1 provided more sufficient material for cytology than D&C can for histology (p < 0.001). Taking atypical hyperplasia and endometrial carcinoma as a positive result, the diagnostic accuracy of liquid-based endometrial cytology was 81.5%; sensitivity was estimated at 75.9%, specificity at 83.3%, positive predictive value at 59.1% and negative predictive value at 91.6%. CONCLUSION: Liquid-based endometrial cytology can be considered a useful method in the detection of endometrial pathology in postmenopausal women.

Serotypes, antibiotic susceptibilities, and multi-locus sequence type profiles of Streptococcus agalactiae isolates circulating in Beijing, China.

BACKGROUND: To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections. METHODS: All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles. RESULTS: In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB. CONCLUSION: S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.

Injection seeded single-frequency pulsed Nd:YAG laser resonated by an intracavity phase modulator.

A reliable single frequency Q-switched Nd:YAG laser is developed by using a lithium niobate crystal as the intracavity phase modulator. Successful injection seeding is performed by adopting an electro-optic crystal in an effectively simplified cavity arrangement. The laser is capable of producing 4.8 mJ pulse-energy at 400 Hz repetition rate with nearly Fourier-transform-limited spectral linewidth. The pulse duration is approximately 25 ns, and the beam quality factor M2 is less than 1.3.