[Meta analysis on acceptance rate of HIV pre-exposure prophylaxis among men who have sex with men in China].

Objective: To systematically evaluate the acceptance of pre-exposure prophylaxis (PrEP)among men who have sex with men (MSM) in China, so as to provide reference for the promotion of preventive drug use before human immunodeficiency virus exposure in China. Methods: By searching the databases of China national knowledge infrastructure, VIP database, Wanfan knowledge service platform, PubMed, Web of Science, Embase and The Cochrane Library with key words of "men who have sex with men" "pre-exposure prophylaxis" "PrEP" and "MSM". The literature on the willingness of Chinese MSM population to accept PrEP was systematically collected, and the data of the literature meeting the inclusion criteria were extracted for Meta analysis. Results: A total of 12 articles were selected in this study, including 6 articles in English and 6 in Chinese. The score of bias risk assessment of eligible articles was 14-18, which was more than 70% of the total score. The total number of samples was 11 269. The overall acceptance rate of PrEP was 0.77(95%CI:0.71-0.82). In subgroup analysis, the acceptance rates of different nationalities, marriage, household registration, age, education background, income, sexual orientation, sexual behavior and awareness of PrEP were statistically significant. Conclusion: In general, the acceptance rate of PrEP in MSM population is higher, but the awareness rate is low. There are differences in the acceptance rate among different groups.

High power continuous laser at 461 nm based on a compact and high-efficiency frequency-doubling linear cavity.

A Watt-level continuous and single frequency blue laser at 461 nm is obtained by frequency-doubling an amplified diode laser operating at 922 nm via a LBO crystal in a resonant Fabry-Pérot cavity. We achieved a best optical conversion efficiency equal to 87% with more than 1 W output power in the blue, and limited by the available input power. The frequency-converted beam is characterized in terms of long term power stability, residual intensity noise, and geometrical shape. The blue beam has a linewidth of the order of 1 MHz, and we used it to magneto-optically trap 88Sr atoms on the 5s2 1S0 - 5s5p 1P1 transition. The low-finesse, linear-cavity doubling system is very robust, maintains the lock for several days, and is compatible with a tenfold increase of the power levels which could be obtained with fully-fibered amplifiers and large mode area fibers.

Fast Control of Atom-Light Interaction in a Narrow Linewidth Cavity.

We propose a method to exploit high-finesse optical resonators for light-assisted coherent manipulation of atomic ensembles, overcoming the limit imposed by the finite response time of the cavity. The key element of our scheme is to rapidly switch the interaction between the atoms and the cavity field with an auxiliary control process as, for example, the light shift induced by an optical beam. The scheme is applicable to other atomic species, both in trapped and free fall configurations, and can be adopted to control the internal and/or external atomic degrees of freedom. Our method will open new possibilities in cavity-aided atom interferometry and in the preparation of highly nonclassical atomic states.

Genetic diversity of sea-island cotton (Gossypium barbadense) revealed by mapped SSRs.

In order to evaluate the genetic diversity of sea-island cotton (Gossypium barbadense), 237 commonly mapped SSR markers covering the cotton genome were used to genotype 56 sea-island cotton accessions. A total of 218 polymorphic primer pairs (91.98%) amplified 361 loci, with a mean of 1.66 loci. Polymorphism information content values of the SSR primers ranged from 0.035 to 0.862, with a mean of 0.320. The highest mean polymorphism information content value for the SSR motifs was from a compound motif (0.402), and for the chromosomes it was Chr10 (0.589); the highest ratio of polymorphic primers in Xinjiang accessions was from Chr21 (83.33%). Genetic diversity was high in Xinjiang accessions. AMOVA showed that variation was 8 and 92% among populations and within populations, respectively. The 56 sea-island accessions were divided into three groups in the UPGMA dendrogram: Xinhai5 was in the first group; accessions from Xinjiang, except the five main ones, were in the second group, and the other 34 accessions were in the third group. Accessions from the former Soviet Union and Xinjiang main accessions were closely related. Both PCA and UPGMA confirmed that Xinhai5 was distinct from the other accessions, and accessions from Xinjiang were in an independent group. Given the differences between principal components analysis and UPGMA results, it is necessary to combine molecular markers and pedigree information so that genetic diversity can be objectively analyzed.

A control hardware based on a field programmable gate array for experiments in atomic physics.

Experiments in Atomic, Molecular, and Optical (AMO) physics require precise and accurate control of digital, analog, and radio frequency (RF) signals. We present control hardware based on a field programmable gate array core that drives various modules via a simple interface bus. The system supports an operating frequency of 10 MHz and a memory depth of 8 M (223) instructions, both easily scalable. Successive experimental sequences can be stacked with no dead time and synchronized with external events at any instructions. Two or more units can be cascaded and synchronized to a common clock, a feature useful to operate large experimental setups in a modular way.

Adsorption and desorption of atrazine on carbon nanotubes.

The potential impact of carbon nanotubes (CNTs) on human health and the environment is receiving more and more attention. The high surface area of CNTs tends to adsorb a large variety of toxic chemicals, which may enhance the toxicity of CNTs and/or toxic chemicals. In this study, adsorption and desorption of atrazine on carbon nanotubes from aqueous solution were studied through batch reactors. The adsorption equilibrium isotherms were nonlinear and were fitted by Freundlich, Langmuir, and Polanyi-Manes models. It was found that the Polanyi-Manes model described the adsorption process better than other two isotherm models. Together with the "characteristic curve," the Polanyi adsorption potential theory is applicable to describe the adsorption process of atrazine on CNTs. Thermodynamic calculations indicated that the adsorption reaction of atrazine on CNTs is spontaneous and exothermic. The desorption data showed that no significant desorption hysteresis occurred. High adsorption capacity and adsorption reversibility of atrazine on CNTs suggest that CNTs have high health and environmental risks, whereas they have potential applications for atrazine removal from water.

Nutritional effects on operant visual learning in Drosophila melanogaster.

The nutritional effects on operant visual learning behavior were investigated in a flight simulator. Operant visual learning and memory formation were normal in Drosophila (S-flies) reared on standard medium, but absent in flies (P-flies) raised on Peking medium. S- and P-flies were transferred to the alternative medium soon after hatching and their progeny was also raised on corresponding medium for several generations. respectively. S-flies transferred showed significantly reduced learning acquisition and 20 min memory retention, and operant visual learning along with memory formation was abolished in their progeny within three generations. Transferred P-flies recovered slowly their learning acquisition and memory formation to normal levels within five generations. Further studies suggested that low protein and minerals or high carbohydrate contents in Peking medium might be related to abnormal performance of P-flies. These results confirm the feasibility of affecting learning behavior by dietary regimens and developing an insect model of maternal malnutrition for pre- or post-natal malnutrition in Drosophila.

Temporary amnesia induced by cold anesthesia and hypoxia in Drosophila.

Memory consolidation in Drosophila was investigated using cold anesthesia- and hypoxia-induced amnesia. Individual flies were operantly trained to avoid the specific flight orientations with respect to the landmarks surrounding them when paired with heat reinforcement at a flight simulator. Cold anesthesia, introduced immediately after training, exerted a significantly diminishing effect on memory between 15 and 150 min after training. Hypoxia delivered immediately after training had a significantly diminishing effect on memory between 30 and 150 min after training. In addition, cold anesthesia disrupted memory only when introduced within the first 20 min, while hypoxia worked only when delivered within the first 2 min after training. When interpreted in the context of a four-phase model of memory consolidation, the results suggest that 1) cold anesthesia disrupts both short-term memory (STM) and anesthesia-resistant memory (ARM), 2) hypoxia disrupts ARM specifically, 3) both of them leave long-term memory (LTM) intact, and 4) LTM may be independent of availability of STM and ARM in flies.

Principal component analysis. A factor analytical technique for the determination of interobserver variation in histomorphologic tumor grading.

The insufficient interobserver reproducibility limits the practical use of histomorphological tumor grading in daily routine pathology. In this study, the reasons for the quite low rates of agreement between different observers have been investigated by the application of a factor analytical technique, i.e. principal component analysis with varimax rotation, on a tumor grading system. Grading results from 44 cases of G1 and G2 giant cell tumors of the bone (GCT), graded by three different observers according to the five criteria of Jaffe, were taken as an example. It could be proven that the single criteria were used in an observer-specific way. Two criteria, for example, which are scored highly correlated by one observer, may be used independently by another. The resulting observer-specific different recognition patterns may provide an explanation for their quite different grading results, which were identical in only 48.6% to 54.1% (mean: 50.9%) of the cases. No correlation of GCT grading with recurrence was found in 31 cases which had been treated by intralesional surgery.

Multiple-phase model of memory consolidation confirmed by behavioral and pharmacological analyses of operant conditioning in Drosophila.

Previous work on classical olfactory learning and memory in flies has suggested at least four distinct phases of memory consolidation. Similarly, our behavioral and pharmacological analyses also provided clear evidence for at least four pharmacologically distinct memory phases in flies after operant conditioning. Anesthesia-resistant memory (ARM) is present between about 20 and 120 min after training, and susceptible to disruption by the ATPase deactivating chemicals such as ouabain and ethacrynic acid (EA). Long-term memory (LTM) is activated at least 150 min after training, and can be disrupted by protein synthesis inhibitors such as cycloheximide (CXM). In addition, a very short-term memory (pre-STM) is demonstrated by feeding flies with potassium chloride (KCl), which has been shown to disrupt the short-term memory. These observations confirm our previous argument that memory formation in flies involves an intricate, multiple-phase pathway of consolidation.

Contrast study on multinucleated giant cells in giant cell tumors of bone and other multinucleated cells.

By means of tissue culture, electron microscopy, cytochemistry, indirect immunofluorescence and immunohistochemistry, the multinucleated giant cells(MGCs) in 12 giant cell tumors of bone (GCT) were studied in contrast with osteoclasts (OCs), foreign body giant cells (FGCs) and inflammatory giant cells (IGCs). The findings in the majority of MGCs were identical with those in OCs, suggesting that they most probably derived from the same precursor. Continuous in vitro culture revealed two kinds of MGCs, which were designated preliminarily as short-lived MGCs and long-lived MGCs for their difference in morphology and in several biological features, which suggests two kinds of MGCs exist in GCT. We conclude that the short-lived conform to the typical MGCs known generally to the pathologists, while the long-lived are deemed to be closely related to the neoplastic elements of the tumor.

A study of Chinese knee joint geometry for prosthesis design.

This study for the first time provides the geometric parameters of the knee joint of Chinese, which is indispensible to the design of knee prosthesis used for compatriotic patients. Thirty-five items, including linear, radial and angular measurements, were taken from 105 cadaveric knees and knee X-ray films of 1,100 subjects. The method and calculation for proper correction of the X-ray image magnification and joint cartilage space was established. Correlation was found to exist between the X-ray correction coefficients and the body weight, which formed the basis for individualized correction of X-ray measurements. Statistical analysis revealed that most of the linear and radial measurements were highly related while the angular measurements were independent of others. Principal component analysis showed that the width of femoral condyle might be taken as the leading index in determining the dimension of the knee, and regression functions were established to supply the serial parameters for prosthetic design. Multivariate discriminate functions could aid the selection of knee prosthesis.

Quantitative pathological study of aggressiveness of giant cell tumor of bone.

Clinical behavior of giant cell tumor of bone (GCT) may vary remarkably from latent to very aggressive. Quantitative pathological methods were used to evaluate the aggressiveness of GCT. Fifteen cytometric parameters were measured and computed on routine sections of 40 GCTs which had been treated with curettage. The surgery factor (with or without additional procedures like bone cement packing or freezing after the curettage) was also taken into account and computed. Nineteen of the 40 GCTs were cured and 21 recurred. While no single one from the 15 parameters measured showed significant differences between the cured and recurrent groups according to the Mann-Whitney's U test or Student's t test, a 4-variable function was established with a stepwise discriminant analysis which could correctly identify 70.8% of the predicted cases as cured or recurrent (jackknife procedure). The function also suggested that in addition to the surgery factor, which no doubt had close relation with the prognosis, the most important risk factor in histological parameters was SA40, i.e. the percent of cells with nucleus larger than 40 square microns. Single cells extracted from paraffin-embedded blocks of 38 GCTs were analyzed by DNA-image cytometry. The 2c deviation index (2cDI) showed wide heterogeneity ranging from those consistent with benign tumors to those with apparent malignant ones, which may account for its diversity in clinical behaviour. Sixteen of the 38 cases had been treated with curettage, 8 of them were cured and followed up for at least 3 years and the remaining 8 recurred. The significant difference of 2cDI between the two groups suggested that these DNA parameters are useful in evaluating the aggressiveness of GCT for the selection of an adequate treatment. Quantitative approaches appeared to be more objective and more sensitive in evaluating the aggressiveness and predicting the prognosis of GCT than the subjective grading system used before.

Computer simulations of figure-ground discrimination in the visual system of the fly.

Figure-ground discrimination and pattern discrimination represent one of the most important problems in computer vision. Based on computational neuronal network model proposed by Reichardt et al. for figure-ground discrimination in the visual system of the fly, entire systematic computer simulations were carried out under nonstationary conditions. Results show that the model network and simulations have predictive power for behavioural experimental results. This paper proposes that motion perception and elementary pattern discrimination in human visual system may be mediated by some kind of figure-ground system with movement detectors as input layer.

[Cellular biological study of giant cell tumor of bone: a 10-year summary].

This article is a summary of the main research accomplishments on giant cell tumor of bone (GCT) carried out in this laboratory in the past ten years. The stromal cells (STC) in GCT have long been regarded as a single neoplastic element. By means of immunological method they are segregated into EA rosette-forming cells (RFC) and non-rosette-forming cells (NRFC). It is herein demonstrated that RFC are macrophages of the defensive mechanism, while NRFC bear the hallmarks of neoplastic cells. The views concerning the nature of the multinucleated giant cells (MGC) so far remains controversial. One of the authors, on the basis of the survival time in thin vitro culture, classifies them into short survival MGC (S-MGC) and long survival MGC (L-MGC). Immunological and cytochemical evidences indicate that S-MGC are similar to osteoblasts and foreign-body giant cells and express macrophage antigen. Moreover, macrophages in GCT can actually form MGC. L-MGC, however, present characteristics of neoplastic cells which are known to be able to form tumor giant cells. Thus the concept of GCT has been renovated. Evaluation of the aggressiveness of GCT is important and challenging, as the Jaffe grading system is no longer widely considered valid. In our laboratory this problem has been approached by cytomorphometry, nuclear DNA-cytometry and multifactor analysis techniques. Parameters which are conducive to predicting the prognosis of GCT are found, which would render help to clinical diagnosis and research of this semimalignant tumor.

[Flow cytometric analysis of DNA in giant cell tumor of bone].

The DNA content of 44 giant cell tumors (GCTs) was determined by flow cytometry and simultaneous analysis of cell surface antigens and cellular DNA was performed in two of these GCTs. Two grade III GCTs, one with lung metastases, were all aneuploid. Out of 42 grades I and II GCTs, 16 were aneuploid, statistically, there was no difference in proliferative activity and rate of aneuploidy between grade I and grade II GCTs, but significant difference between primary and local recurrent GCTs existed. After 5 passages in culture the proliferative rate of cells in 13 GCTs increased significantly, the rate of cells bearing GCT associated antigen stepped up and in 2 GCTs tested specially. All these findings demonstrate: (1) the morphological difference of these tumors was not remarkable (2) DNA determinations as an adjunct to conventional histopathologic assessment may provide objective clinically relevant information for prognosis, (3) tumor and non-tumor cells co-exist in GCTs and only tumor cells could survive in long-term culture in vitro.

[p53 antioncogene abnormal in osteosarcoma].

Immunohistochemical evaluation of 24 osteosarcoma using an anti-p53 protein monoclonal antibody (Moab p53-12) showed strong positive reaction in the nuclei of tumor cells in 14 osteosarcoma (58.3%). Many studies have proved that this overexpression of p53 protein in tumor cells is associated with mutation of the p53 gene. Contrast study with DNA flow cytometry made on osteosarcoma showed that most of the p53 strongly positive tumors have higher DNA Index value than negative or slightly positive ones, though no statistically difference existed between two groups. Southern blot hybridization of p53 gene was also made in osteosarcomas. 5 of 20 cases (20%) had the structural changes of p53 gene. 3 of them were part or whole deletion of the gene. 2 of them had the extra-band, indicating the rearrangement of the gene.

Implication of transcriptional repression in compound C-induced apoptosis in cancer cells.

Compound C, a well-known inhibitor of AMP-activated protein kinase (AMPK), has been reported to induce apoptosis in some types of cells. However, the underlying mechanisms remain largely unclear. Using a DNA microarray analysis, we found that the expression of many genes was downregulated upon treatment with compound C. Importantly, compound C caused transcriptional repression with the induction of p53, a well-known marker of transcriptional stress response, in several cancer cell lines. Compound C did not induce the phosphorylation of p53 but dramatically increased the protein level of p53 similar to some other transcriptional inhibitors, including 5,6-dichloro-1-ß-D-ribobenzimidazole (DRB). Consistent with previous reports, we found that compound C initiated apoptotic death of cancer cells in an AMPK-independent manner. Similar to DRB and actinomycin D (ActD), two classic transcription inhibitors, compound C not only resulted in the loss of Bcl-2 and Bcl-xl protein but also induced the phosphorylation of eukaryotic initiation factor-alpha (eIF2α) on Ser51. Hence, the phosphorylation of eIF2α might be a novel marker of transcriptional inhibition. It is noteworthy that compound C-mediated apoptosis of cancer cells is correlated with decreased expression of Bcl-2 and Bcl-xl and the phosphorylation of eIF2α on Ser51. Remarkably, compound C exhibits potent anticancer activities in vivo. Taken together, our data suggest that compound C may be an attractive candidate for anticancer drug development.

Functional outcomes following surgical treatment of bilateral mandibular condylar fractures.

Debate continues regarding unilateral or bilateral treatment for mandibular condylar fractures. This retrospective study evaluates the functional outcomes of bilateral condylar process fractures after surgical intervention. From May 1994 to December 2004, 51 adult patients with bilateral mandibular condylar process fractures were studied. There were 33 cases of bilateral condylar fractures (type I); 12 cases of condylar-subcondylar fractures (type II); and six cases of bilateral subcondylar fractures (type III). All patients underwent open reduction and internal fixation. Four patients had chin deviation, six had malocclusion, three had poor chewing function and eight had limited mouth opening. Type I patients had a significantly higher incidence of limited mouth opening (P=0.039) and associated maxillary fractures (n=12) and psychiatric disease (n=6) which yielded significantly poor functional outcomes. Complications included transient facial paresis (n=4), fracture and loosening of postoperative plates (n=3) and surgical wound infections (n=2). Open reduction with rigid fixation for bilateral condylar fractures provided satisfactory functional outcomes in this study. Concomitant maxillary fractures and underlying psychiatric problems are poor outcome factors. Aggressive rehabilitation in the first 9 months is important for early functional recovery.