[The identification of a novel reassortant H3N2 avian influenza virus based on nanopore sequencing technology and genetic characterization].

Objective: To identify a novel reassortant H3N2 avian influenza virus using nanopore sequencing technology and analyze its genetic characteristics. Methods: The positive samples of the H3N2 avian influenza virus, collected from the external environment in the farmers' market of Guangzhou, were cultured in chicken embryos. The whole genome was sequenced by targeted amplification and nanopore sequencing technology. The genetic characteristics were analyzed using bioinformatics software. Results: The phylogenetic trees showed that each gene fragment of the strain belonged to the Eurasian evolutionary branch, and the host source was of avian origin. The HA gene was closely related to the origin of the H3N6 virus. The NA gene was closely related to the H3N2 avian influenza virus from 2017 to 2020. The PB1 gene was closely related to the H5N6 avian influenza virus in Guangxi Zhuang Autonomous Region and Fujian Province from 2016 to 2022 and was not related to the PB1 gene of the H5N6 avian influenza epidemic strain in Guangzhou. The other internal gene fragments had complex sources with significant genetic diversity. Molecular characteristics indicated that the strain exhibited the molecular characteristics of a typical low pathogenic avian influenza virus and tended to bind to the receptors of avian origin. On important protein sites related to biological characteristics, this strain had mutations of PB2-L89V, PB1-L473V, NP-A184K, M1-N30D/T215A, and NS1-P42S/N205S. Conclusions: This study identified a novel reassortant H3N2 avian influenza virus by nanopore sequencing, with the PB1 gene derived from the H5N6 avian influenza virus. The virus had a low ability to spread across species, but further exploration was needed to determine whether its pathogenicity to the host was affected.

[Epidemiological characteristics of mpox epidemic in Guangzhou].

Objective: To understand the epidemiological characteristics of mpox epidemic in Guangzhou and provide scientific evidence for the prevention and control of the disease. Methods: Based on the mpox surveillance system in Guangzhou, suspected mpox cases with fever and rash were reported by local hospitals at all levels to centers for disease control and prevention in Guangzhou for sampling, investigation and diagnosis. Descriptive epidemiological analysis was conducted on the clinical characteristics and treatment of the mpox cases and positive detection rate reported in Guangzhou as of 24:00 on June 23. Whole genome sequencing of the virus isolates was performed using Illumina Miniseq high-throughput sequencing platform. Results: The first mpox case in Guangzhou was reported on June 10 in 2023. As of 24:00 on June 23, a total of 25 confirmed mpox cases were reported. All the mpox cases were men with a M(Q1,Q3) of 32 (26, 36) years, the majority of the cases were MSM (96.0%). The main clinical features were rash (100.0%, 25/25), lymphadenectasis (100.0%, 25/25) and fever (52.0%, 13/25). Rash usually occurred near the genitals (88.0%, 22/25). The close contacts, mainly family members (40.4%, 23/57), showed no similar symptoms, such as fever or rash. The positive rate of mpox virus in household environment samples was 30.5%. The analyses on 3 complete gene sequences of mpox virus indicated that the strains belonged to West African type Ⅱb clade, B.1.3 lineage. Conclusions: Hidden transmission of mpox virus had occurred in MSM in Guangzhou. However, the size of affected population is relatively limited, and the possibility of wide spread of the virus is low.

[Analysis on epidemiological characteristics of dengue fever and E gene evolution of dengue virus in Guangzhou, 2020].

Objective: To assess the incidence of dengue fever and E gene evolution of dengue virus in Guangzhou in 2020 and understand the local epidemiological characteristics of dengue fever and spreading of dengue virus. Methods: The information of dengue fever cases in Guangzhou in 2020 was collected from Notifiable Infectious Disease System of Chinese Center for Disease Control and Prevention Information System. Serum samples from the cases were detected by real-time PCR. The E gene was sequenced and analyzed. Maximum likelihood phylogenetic trees were constructed using software MEGA 5.05. The statistical analysis was conducted using software SPSS 20.0. Results: A total of 33 dengue fever cases were reported in Guangzhou in 2020, including 31 (93.94%) imported cases and 2 (6.06%) local cases. Compared with the data during 2016 to 2019, the number of cases, overall incidence and local incidence all decreased with statistically significant differences (all P<0.05). The imported cases from Southeast Asia constituted 90.32% (28/31) of imported cases. The E gene sequences and the phylogenetic trees of imported and local cases demonstrated close relationship with the virus sequences from Southeast Asian, and they were less homologous with the sequences of dengue virus isolated in Guangzhou in previous years. Conclusions: The incidence of dengue in Guangzhou in 2020 was significantly affected by the imported cases, especially those from Southeast Asian countries. The study result demonstrated that dengue fever was not endemic in Guangzhou and it was caused by imported ones.

[Precise resection and defect repair of external nose malignant tumor].

Objective: To explore the methods for the accurate resection of malignant tumors of the external nose, and the accurate evaluation and repair of tissue defects. Methods: We collected 48 cases with nasal malignant tumors treated in 980 Hospital, Joint Support Force of the People's Liberation Army from January 2010 to June 2020, including 28 males and 20 females, aged 36-86 years. The pathological types of tumors included basal cell carcinomas (n=29), squamous cell carcinomas (n=11), trichilemmal carcinomas(n=6), denoid cystic carcinoma (n=1) and non-Hodgkin lymphoma (n=1). Tumor resection was mainly based on the traditional extended resection determined by the safety margin, and Mohs surgery was used to minimize the scope of resection, for the margin that significantly affected the repairing results, such as the lesion adjacent to the nasal alar margin, nasal columella or deep easy-penetrating margin. All cases obtained tumor resection and primary/secondary defect reconstruction. Results: According to the pathological type and tumor size, the safe resection margin was mainly 4-10 mm, and Mohs surgery was used in 24 cases. Limited-size defects in 38 cases were repaired with double-leaf flaps, kite flaps, nasal dorsum brow flaps, nasolabial flaps or free tissues. Among 10 cases with compound defects, 8 cases were repaired with frontal flaps, including 4 cases with single frontal flaps, 2 cases with additional titanium mesh stent reconstruction and 2 cases with over and out frontal flaps. During follow-up of 1 to 10 years, all the flaps survived without flap necrosis, and the postoperative nasal contour and ventilation were satisfactory. One patient had tumor recurrence 18 months after operation, 2 patients died of cardiovascular and cerebrovascular diseases, and other patients survived without tumors. Conclusions: Mohs surgery can basically meet the requirements for precise resection of external nasal malignant tumors. Individualized application of adjacent tissue flaps and various frontal flaps is a reasonable choice to achieve the satisfactory outcome of external nasal repair and to take into account the complexity of operation.

[Spatial autocorrelation of dengue cases and molecular biological characteristics of envelope gene of dengue virus in Guangzhou, 2019].

Objective: Analyze epidemiological situation of dengue fever,and survey impacts of four serotypes dengue viruses in Guangzhou, 2019. Methods: Information of patients was collected in Notifiable Infectious Disease Report System (NIDRS). Spatial autocorrelation of dengue cases was evaluated using ArcGIS version 10.2. Serum samples were tested by real-time PCR. Virus strains were isolated from positive sera. Then E gene was sequenced. Phylogenetic trees were including PhyMLsoftwarev 3.1. Results: A total of 1 655 dengue cases, consisted of 1 382 local cases and 273 imported cases, was confirmed in 2019. The incidence was 11.10 per 100 000 dengue cases were autocorrelated in Guangzhou. There were 18 high-high clusters. Most of the imported dengue cases were imported from Southeast Asian countries (86.08%,235/273) and African countries (2.56%,7/273). Of 749 serum samples detected by real-time PCR, the positive rate was 93.06% (697/749). Four hundred and sixty-four dengue virus strains had been isolated in 2019. Compared with data from the genotype tree of the former years, no genotype shift was discovered. Serotype 1 was still predominant. Serotype 2 was the significant strain in Baiyun district and Liwan district. Conclusions: Dengue fever was spreading all over Guangzhou in 2019. The suburban areas, which played a more critical role in causing the spread and outbreak of dengue fever, should be given more prominence. Inspection at ports should be enforced to prevent importing cases from African countries and Southeast Asian countries. The risk of serotype 2 cannot be overlooked. Four serotypes dengue viruses prevailed simultaneously in Guangzhou, which warns us to take precaution of severe dengue outbreaks.

[Molecular-related epidemic characteristics of influenza A (H3N2) viruses in Guangzhou, 2019].

Objective: To isolate the influenza A (H3N2) viruses from different sources in Guangzhou in 2019 and analyze these viruses' evolution and variation characteristics. Methods: The hemagglutinin (HA) and neuraminidase (NA) genes of H3N2 isolates from outpatient monitoring, influenza outbreaks, and inpatient severe cases in Guangzhou in 2019 were sequenced. Bioinformatics software analyzed the variations and evolution characteristics of HA and NA genes. Results: The epidemic peaks of influenza A (H3N2) viruses were made up of period Ⅰ (from January to August) and period Ⅱ (from November to December). The positive rate of influenza A (H3N2) in males was 13.46% (703/5 221), which was higher than that in females (11.50%, 510/4 435) (χ2=8.43,P=0.00). The group's positive rate of 10-20 years old was the highest (25.18%,665/2 641). The isolates from different sources were highly homologous and closely related to 3C.2a.1 branches, which could be further divided into three small groups of Group 1-3. Gene recombination was observed between different branches. The mutations of HA antigen sites gradually appeared from Group 1 to Group 3, leading to new antigen drift. Variations of HA antigenic sites mainly occurred in the region of A and B. The mutations of receptor binding sites of Group 1 and Group 3 viruses occurred in the anterior and posterior walls. There were two glycosylation sites lacked on region A of HA antigen observed in the isolates of Group 2-3. Conclusions: Genetic variations of H3N2 influenza viruses in Guangzhou included gene mutations and gene recombination. Under the pressure of the vaccine, the evolution of viruses was rapid. Therefore, the monitoring of molecular-related epidemic characteristics of the H3N2 influenza virus was necessary.

[Free rectus abdominis myocutaneous flap for the reconstruction of major and complex defects in the craniofacial regions after ablation of advanced sinonasal carcinomas].

Objective: To explore the method and plausibility of using free rectus abdominis flap (FRAF) to reconstruct the major and complex defects in the craniofacial regions after ablation of advanced sinonasal carcinoma. Methods: From 2007 to 2018 at No. 980 Hospital of Joint Logistic Supportive Force of People's Liberation Army of China, 13 patients with advanced carcinoma of nasal cavity and paranasal sinuses, including 11 males and 2 females, aged from 33 to 67 years, were treated with FRAF to repair the invasion of skull base, face and orbit. Based on adequate and meticulous preoperative evaluations on patients and tumors, complete resection of tumor bulks was performed. According to the sites, characters and extents of the defects, FRAF was introduced in different ways into reconstruction of major and complex defects in the craniofacial regions after resection of advanced sinonasal carcinomas, restoring the structure and contour of the craniofacial region. Results: Complete resection of tumors was achieved in all cases. For repairing the major and complex defects resulted from tumor ablation, FRAF graft was conducted in 13 patients with advanced sinonasal carcinomas. The recipient vessels were facial artery and vein in 9 cases, superficial temporal artery and vein in 4 cases. Vascular bridging with the external jugular vein was carried out in 2 cases who underwent submandibular neck dissections, in which facial artery and vein were used as recipient vessels. Free fibular flap was used along with FRAF in a case undergone bilateral maxillectomy. Pedicled galea capitis and periosteal flap were applied simultaneously in 3 cases with dura defects at the skullbase resulted from tumor resection. All flaps used in 13 cases survived uneventfully without major complications, with successful repair of defects, reconstruction of structures and restoration of contour of craniofacial regions. Conclusion: With adequate evaluation of resectability of tumors as well as nature and extent of defects after tumor removal, FRAF transplantation is an ideal method and strategy of choice for reconstructing the major and complex defects in craniofacial regions resulted from tumor ablation of advanced sinonasal carcinomas.

[Epidemiological and genetic characteristics of H5 subtype avian influenza virus in Guangzhou, 2014-2019].

Objective: To analyze the characteristics of spread and genetic evolution of H5 subtype avian influenza virus in Guangzhou from 2014 to 2019. Methods: H5 subtype virus was detected by fluorescence quantitative RT-PCR from the environmental samples in Guangzhou poultry markets. The genes of HA and NA of 48 isolates randomly selected were sequenced, including 46 isolates from environmental samples and 2 isolates from cases. The characteristics of molecular variation and genetic evolution were analyzed by using bioinformatics software. Results: A total of 1 094 strains of H5 subtype avian influenza virus were isolated from 52 284 samples (2.09%). All the strains belonged to Clade 2.3.4.4.C. NA gene belonged to H6N6 of Eurasian lineage. The cleavage sites of all the strains showed the characteristics of highly pathogenicity. Receptor binding sites were avian-derived receptors. However, mutations of S123P, S133A and T156A occurred, which implied that these strains could tend to bind to human receptors. There was an additional glycosylation site at 140 in strains isolated after 2017. The variation of antigen loci mainly occurred in B and E regions. Conclusions: H5 subtype avian influenza virus spread in Guangzhou from 2014 to 2019 with annual increased proportion of positive rate, and the sequencing results indicated that it belonged to Clade 2.3.4.4.C of H5N6 highly pathogenic virus, and genetic evolution and mutation continued, especially the common mutations which could enhance the binding capacity to human receptors. It is necessary to strengthen the surveillance.

Dynamics of Polarons in Organic Conjugated Polymers with Side Radicals.

Based on the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model, and using the molecular dynamics method, we discuss the dynamics of electron and hole polarons propagating along a polymer chain, as a function of the distance between side radicals and the magnitude of the transfer integrals between the main chain and the side radicals. We first discuss the average velocities of electron and hole polarons as a function of the distance between side radicals. It is found that the average velocities of the electron polarons remain almost unchanged, while the average velocities of hole polarons decrease significantly when the radical distance is comparable to the polaron width. Second, we have found that the average velocities of electron polarons decrease with increasing transfer integral, but the average velocities of hole polarons increase. These results may provide a theoretical basis for understanding carriers transport properties in polymers chain with side radicals.

Classifying Cognitive Profiles Using Machine Learning with Privileged Information in Mild Cognitive Impairment.

Early diagnosis of dementia is critical for assessing disease progression and potential treatment. State-or-the-art machine learning techniques have been increasingly employed to take on this diagnostic task. In this study, we employed Generalized Matrix Learning Vector Quantization (GMLVQ) classifiers to discriminate patients with Mild Cognitive Impairment (MCI) from healthy controls based on their cognitive skills. Further, we adopted a "Learning with privileged information" approach to combine cognitive and fMRI data for the classification task. The resulting classifier operates solely on the cognitive data while it incorporates the fMRI data as privileged information (PI) during training. This novel classifier is of practical use as the collection of brain imaging data is not always possible with patients and older participants. MCI patients and healthy age-matched controls were trained to extract structure from temporal sequences. We ask whether machine learning classifiers can be used to discriminate patients from controls and whether differences between these groups relate to individual cognitive profiles. To this end, we tested participants in four cognitive tasks: working memory, cognitive inhibition, divided attention, and selective attention. We also collected fMRI data before and after training on a probabilistic sequence learning task and extracted fMRI responses and connectivity as features for machine learning classifiers. Our results show that the PI guided GMLVQ classifiers outperform the baseline classifier that only used the cognitive data. In addition, we found that for the baseline classifier, divided attention is the only relevant cognitive feature. When PI was incorporated, divided attention remained the most relevant feature while cognitive inhibition became also relevant for the task. Interestingly, this analysis for the fMRI GMLVQ classifier suggests that (1) when overall fMRI signal is used as inputs to the classifier, the post-training session is most relevant; and (2) when the graph feature reflecting underlying spatiotemporal fMRI pattern is used, the pre-training session is most relevant. Taken together these results suggest that brain connectivity before training and overall fMRI signal after training are both diagnostic of cognitive skills in MCI.

[Analyses of clinicopathologic factors affecting neck control after postoperative radiation as adjuvant treatment for lymph node metastasis in head and neck squamous cell carcinoma].

OBJECTIVE: To investigate the clinicopathologic factors associated with neck control and distant metastasis in patients with neck metastases in head and neck squamous cell carcinoma (HNSCC) after postoperative radiation as adjuvant treatment. METHODS: Clinicopathologic data of 208 pathologic N+ (pN+ ) patients with HNSCC initially treated with neck dissection and postoperative radiation in Bethune International Peace Hospital of China from January 2004 to December 2009 were reviewed. The clinicopathologic factors, includeding age, sex, primary tumor site, pathologic T and N stage, tumor growth pattern, histological grade, tumor resection margin, size and number of positive lymph node, number of levels with positive lymph node, and extracapsular nodal spread (ECS), were evaluated for their association with neck control and distant metastasis in patients with HNSCC after postoperative radiation. Univariate χ(2) test and multiple stepwise logistic regression model were used for the analysis. RESULTS: Overall 5-year neck control rate after postoperative radiotherapy was 72.6% (151/208), with 84.0% (63/75) for SND, 72.9% (78/107) for MRND, and 38.5% (10/26) for RND, respectively. Univariate analysis showed that neck control after postoperative radiation was related with following factors: primary tumor site, pathologic N stage, size of positive node, number of levels with positive node, number of positive node, and ECS. Pathologic N stage and number of levels with positive lymph node were associated with distant metastasis. Multivariate analysis indicated that ECS was the most significant risk factor for neck metastasis after surgery and postoperative radiotherapy and the number of levels with positive node was the most significant risk factor for distant metastasis. CONCLUSIONS: ECS is the most important pathologic factor in planning postoperative adjuvant treatment for pN+ patients with HNSCC, therefore ECS should be evaluated routinely after neck dissection. The value of postoperative radiotherapy in controlling the ECS-related recurrence after surgery is limited. Postoperative concurrent chemoradiotherapy and targeted therapy can be considered in HNSCC patients with ECS.

[Dynamic maternal measles antibody level in infants: a longitudinal study].

OBJECTIVE: To understand the dynamic maternal measles antibody level in infants in Guangzhou. METHOD: Women who delivered babies in a maternal and child health care hospital in Guangzhou and their infants who were never affected by measles were included in our study. All the serum samples collected from mothers and infants were tested by using enzyme linked immunosorbent assay(ELISA)for the quantitative measurement of measles IgG antibodies. A longitudinal sero-epidemiological study was conducted to investigate the duration of the presence of measles maternal antibodies in infants based on the measurement at different time points(0, 3, 5, 7 month). RESULT: A total of 689 mothers and their 691 infants(two pairs of twins)were included in the study. The concentration and the sero-positivity rate of measles antibody in mothers was 513.8 mIU/ml and 81.6% respectively. The concentration and the sero-positivity rate of measles antibody in infants was 732.8 mIU/ml and 87.3%, respectively. The measles antibody levels of newborns were positively associated with those of mothers(r=0.917 5, P<0.001), which declined rapidly at 3 months after birth and mostly turned to be negative at 7 months after birth. Measles antibody turned be negative at 3 months after birth in low, middle level groups, but remained to be positive in high level group at 5 months after birth. CONCLUSION: The maternal measles antibody could rarely protect infants at age of 8 months even though mother had been vaccinated or acquired natural immunity. It is suggested to adjust the time of the first dose measles vaccination in infants and increase the measles antibody level of child bearing aged women to reduce the incidence of measles in infants.

[Treatment of isolated sphenoid sinus disease by trans-basal lamella approach to sphenoid sinus].

Objective:The aim of this study is to investigate the safety and practicability of the trans-horizontal basal lamella sphenoidotomy approach in the treatment of the isolated sphenoid sinus disease.Method:Sphenoidotomy and posterior-ethmoidotomy by endoscopic trans-horizontal basal lamella approach were performed in 64 patients who were diagnosed with isolated sphenoid sinus.The horizontal course of the basal lamella is perforated and opened,and the superior meatus is entered.Then sphenoidotomy and posterior-ethmoidotomy were performed by the landmark superior turbinate.Result:All patients were successfully operated without serious complications.After 1 year follow-up,no recurrence were found in 30 cases of fungal sphenoid sinusitis patients,12 cases of chronic sphenoidal sinusitis patients,13 cases of sphenoid sinus cyst patients,6 cases of sphenoid sinus polyps patients,and 3 cases of sphenoid sinus inverted papilloma patients.The ostium of sphenoid sinus maintained well without atresia.Conclusion:Trans-horizontal basal lamella approach to sphenoid sinus is safe and effective in the treatment of isolated lesion,and the opening of sphenoid sinus and posterior-ethmoid sinus were enlarged better by this technique.

Prospective Evaluation of Rapid Antigen Tests for Diagnosis of Respiratory Viral Pathogens.

Acute respiratory infection is a frequently transmitted illness of concern to doctors and patients. Considering its airborne transmission, early diagnosis of such disease is particularly important. This study explored respiratory viral infections with influenza virus, parainfluenza virus, respiratory syncytial virus, human metapneumovirus, human bocavirus, coronavirus, and other early diagnostic substances as confirmed by literature resources. This study also used the corresponding monoclonal antibodies that were produced with the use of hybridoma technology, which were fixed on the chip after purification, for further serum detection. Using this method, a new technique to simultaneously detect 6 kinds of febrile respiratory viruses in a protein chip was developed. The accuracy rate of this method can be >99.65%. This product is inexpensive and capable of high-precision and high-throughput screening, which are prominent advantages.

Isothermal cross-priming amplification implementation study.

UNLABELLED: Cross-priming amplification (CPA) was evaluated for the early detection of norovirus (NV), rotavirus A (RV-A), enteric adenovirus (EAdV) and astrovirus (AstV). The analytical sensitivity of the CPA assay was 10(3) copies ml(-1) for NV, RV-A and AstV detection and 10(4) copies ml(-1) for EAdV detection. For each of the four pathogens, the positive detection rate by CPA was similar to real-time PCR methods and higher than the rate observed in an ELISA. The detection coincidence rates of CPA and RT-PCR for NV, RV-A, EAdV and AstV were 98, 99, 99 and 100%, respectively. All CPA assays were negative in 89 healthy control samples. These results demonstrate the high analytical sensitivity and specificity of the CPA assay. CPA assays are relatively straightforward to perform, and such assays represent a potential detection method for locations in which resources are limited. SIGNIFICANCE AND IMPACT OF THE STUDY: Over one billion people suffer from diarrhoeal diseases every year. This leads to significant morbidity and mortality, particularly the children under five. Rapid and specific detection of the pathogens that cause diarrhoeal diseases would be advantageous, enabling rapid treatment and management of the spread of pathogens. Here, a fast, cross-contamination-proof and user-friendly nucleic acid isothermal amplification method called cross-priming amplification (CPA) was used to test four pathogens with high analytical sensitivity and specificity. The results indicate that CPA has great potential for improving medical diagnostics, particularly in resource-limited areas.

Survivability and molecular variation in Vibrio cholerae from epidemic sites in China.

The survival behaviour of Vibrio cholerae in cholera epidemics, together with its attributes of virulence-associated genes and molecular fingerprints, are significant for managing cholera epidemics. Here, we selected five strains representative of V. cholerae O1 and O139 involved in cholera events, examined their survival capacity in large volumes of water sampled from epidemic sites of a 2005 cholera outbreak, and determined virulence-associated genes and molecular subtype changes of the surviving isolates recovered. The five strains exhibited different survival capacities varying from 17 to 38 days. The virulence-associated genes of the surviving isolates remained unchanged, while their pulsotypes underwent slight variation. In particular, one waterway-isolated strain maintained virulence-associated genes and evolved to share the same pulsotype as patient strains, highlighting its role in the cholera outbreak. The strong survival capacity and molecular attributes of V. cholerae might account for its persistence in environmental waters and the long duration of the cholera outbreak, allowing effective control measures.

Transmission of avian influenza A(H7N9) virus from father to child: a report of limited person-to-person transmission, Guangzhou, China, January 2014.

We investigated a possible person-to-person transmission within a family cluster of two confirmed influenza A(H7N9) patients in Guangzhou, China. The index case, a man in his late twenties, worked in a wet market that was confirmed to be contaminated by the influenza A(H7N9) virus. He developed a consistent fever and severe pneumonia after 4 January 2014. In contrast, the second case, his five-year-old child, who only developed a mild disease 10 days after disease onset of the index case, did not have any contact with poultry and birds but had unprotected and very close contact with the index case. The sequences of the haemagglutinin (HA) genes of the virus stains isolated from the two cases were 100% identical. These findings strongly suggest that the second case might have acquired the infection via transmission of the virus from the sick father. Fortunately, all 40 close contacts, including the other four family members who also had unprotected and very close contact with the cases, did not acquire influenza A(H7N9) virus infection, indicating that the person-to-person transmissibility of the virus remained limited. Our finding underlines the importance of carefully, thoroughly and punctually following-up close contacts of influenza A(H7N9) cases to allow detection of any secondary cases, as these may constitute an early warning signal of the virus's increasing ability to transmit from person-to-person.

Hand-foot-and-mouth disease and weather factors in Guangzhou, southern China.

Hand-foot-and-mouth disease (HFMD) is becoming one of the common airborne and contact transmission diseases in Guangzhou, southern China, leading public health authorities to be concerned about its increased incidence. In this study, we aimed to examine the effect of weather patterns on the incidence of HFMD in the subtropical city of Guangzhou for the period 2009-2012, and assist public health prevention and control measures. A negative binomial multivariable regression was used to identify the relationship between meteorological variables and HFMD. During the study period, a total of 166,770 HFMD-confirmed cases were reported, of which 11 died, yielding a fatality rate of 0·66/10,000. Annual incidence rates from 2009 to 2012 were 132·44, 311·40, 402·76, and 468·59/100,000 respectively. Each 1°C rise in temperature corresponded to an increase of 9·38% (95% CI 8·17-10·51) in the weekly number of HFMD cases, while a 1 hPa rise in atmospheric pressure corresponded to a decrease in the number of cases by 6·80% (95% CI -6·99 to -6·65), having an opposite effect. Similarly, a 1% rise in relative humidity corresponded to an increase of 0·67% or 0·51%, a 1 m/h rise in wind velocity corresponded to an increase of 4·01% or 2·65%, and a 1 day addition in the number of windy days corresponded to an increase of 24·73% or 25·87%, in the weekly number of HFMD cases, depending on the variables considered in the model. Our findings revealed that the epidemic status of HFMD in Guangzhou is characterized by high morbidity but low fatality. Weather factors had a significant influence on occurrence and transmission of HFMD.

Electroluminescence enhancement in polymer light-emitting diodes through inelastic scattering of oppositely charged bipolarons.

Combining the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model and the extended Hubbard model (EHM), the scattering and combination of oppositely charged bipolarons in conjugated polymers are investigated using a nonadiabatic evolution method. On the basis of this physical picture, bipolarons can scatter into a singlet biexcitonic state, in which two electrons and two holes are trapped together by a lattice distortion. This biexcitonic state can emit one photon to an exciton state, which can subsequently decay to the ground state. The results indicate that the scattering and combination of oppositely charged bipolarons may provide guidance for improving the internal quantum efficiency for electroluminescence to as high as 75% in polymer light-emitting diodes.