[A real-world study on the features of postpartum hepatitis flares in pregnant women with chronic HBV infection]

Objective: To analyze the clinical features of postpartum hepatitis flares in pregnant women with hepatitis B virus (HBV) infection. Methods: A retrospective study was conducted. Patients who met the enrollment criteria were included. Liver function and HBV virology tests were collected from pregnant women with chronic HBV infection at delivery, 6, 24, 36, and 48 weeks after delivery through the hospital information and test system. Additionally, antiviral therapy types and drug withdrawal times were collected. Statistical analysis was performed on all the resulting data. Results: A total of 533 pregnant women who met the inclusion criteria were included, with all patients aged (29.5±3.7) years old. A total of 408 cases received antiviral drugs during pregnancy to interrupt mother-to-child transmission. There was no significant difference in the levels of alanine aminotransferase (ALT, z = -1.981, P = 0.048), aspartate aminotransferase (AST, z = -3.956, P < 0.001), HBV load (z = -15.292, P < 0.001), and HBeAg (z = -4.77, P < 0.001) at delivery in patients who received medication and those who did not. All patients ALT, AST, total bilirubin, direct bilirubin, and albumin showed an upward trend within six weeks after delivery. A total of 231 cases developed hepatitis within 48 weeks after delivery. Among them, 173 cases first showed ALT abnormalities within six weeks postpartum. Conclusion: Hepatitis flare incidence peaked six weeks after delivery or six weeks after drug withdrawal in pregnant women with chronic HBV infection.

Triboelectric Nanosensor Integrated with Robotic Platform for Self-Powered Detection of Chemical Analytes

Rapid on-site detection of hazardous chemicals is imperative for remote security and environmental monitoring applications. However, the implementation of current sensing technologies in real environments is limited due to an external high-power requirement, poor selectivity and sensitivity. Recent progress in triboelectric nanosensors and nanogenerators presents tremendous opportunities to address these issues. Here, we report an innovative self-powered triboelectric nanosensor for detection of Hg²⁺ ions, a harmful chemical pollutant, in a rapid single step on-site detection mechanism. Based on the mechanism of solid-liquid contact electrification, tellurium nanowire (Te NW) arrays serving as a solid triboelectric material as well as the sensing probe underwent periodic contact and separation with the Hg²⁺ solution, leading to the in situ formation of mercury telluride nanowire (HgTe NWs) owing to the selective binding affinity of Te NWs toward Hg²⁺ ions. To realize the on-site sensing potential, Te NW arrays were mounted onto the robotic hands equipped with additional wireless transmission functionality for rapid detection of Hg²⁺ ions in resource-limited settings by employing a simple "touch and sense" mechanism. Such a demonstration of direct integration of self-powered sensors with robotics would lead to the development of low-cost, automated chemical sensing machinery for the on-field detection of harmful analytes.

[Research progress of polyetheretherketone and its composites in the field of dental implant]

Polyetheretherketone (PEEK) is a polymer material composed of aromatic rings connected by ether and ketone groups. It has advantages of excellent biocompatibility, stable chemical properties, and appropriate elasticity modulus. Since PEEK are increasingly used in dentistry in recent years, the properties, modification methods, and research advances of them in oral implantology were discussed in this review.

[Modified mattress inversion suturing with double barbed sutures used for totally laparoscopic esophagojejunostomy overlap anastomosis after radical total gastrectomy]

Objective: To explore the advantages and safety of a modified mattress inversion suturing using double barbed sutures compared with the traditional overlap method in totally laparoscopic esophagojejunostomy overlap anastomosis. Methods: A retrospective cohort study was conducted. The inclusion criteria were as follows: (1) patients were aged 18 - 80 years old; (2) adenocarcinoma was preoperatively confirmed by pathological analysis; (3) patients had undergone a complete laparoscopic radical total gastrectomy; (4) patients had undergone esophagojejunostomy using the overlap method; (5) patients received a grade of I-III on the American Society of Anesthesiologists physical status classification system; (6) patients' complete follow-up data had been collected. Patients with a history of other malignant tumors, multi-origin tumors, emergency surgery, non-R0 radical resection or distant metastasis were excluded. The clinical data of 89 gastric cancer patients who underwent total laparoscopic radical total gastrectomy in the Department of Gastrointestinal Surgery in the Sixth Affiliated Hospital of Sun Yat-sen University from January 2019 to December 2020 were collected. These patients were grouped according to the esophagojejunostomy method used. Of 89 patients, 32 received modified mattress inversion suturing with double barbed sutures to close the common opening of esophagojejunostomy (the modified anastomosis group), while 57 received traditional overlap anastomosis in which the common opening was closed by barbed suture (the traditional anastomosis group). The operation conditions (incision length, conversion to laparotomy, duration of esophagojejunostomy) and postoperative recovery (time to commencement of a liquid diet, duration of postoperative hospital stay, anastomotic leakage, anastomotic stenosis, and anastomotic bleeding) were compared between the two groups. Results: There was no significant difference in the baseline data of the two groups for any parameter (all P>0.05). All patients received complete laparoscopic radical gastrectomy without conversion to laparotomy. There were no significant differences in the length of the median incision, the proportion of food intake on the first day after surgery, or in the incidence of anastomotic complications such as anastomotic leakage, anastomotic stenosis, and anastomotic bleeding between the two groups (P>0.05). Compared with the traditional anastomosis group, patients in the modified anastomosis group had shorter anastomosis time [26 (19-62) minutes vs. 36 (20-50) minutes, Z=-2.546, P=0.011] and postoperative hospital stay [7 (6-12) days vs. 9 (7-42) days, Z=-4.202, P<0.001]. The differences were statistically significant (all P<0.05). In a subgroup analysis of tumor TNM stage III, Siewert type II and neoadjuvant chemotherapy patients, there was no significant difference in the incidence of anastomotic complications between the modified group and the traditional group. However, the postoperative hospital stay duration in the modified anastomosis group was less than in the traditional anastomosis group. The duration of anastomosis in Siewert type II patients was also shorter in the modified anastomosis group than in the traditional anastomosis group [26 (19-62) minutes vs. 38 (21-50) minutes, Z=-2.105, P=0.035], and the difference was statistically significant (all P<0.05). Conclusion: Complete laparoscopic esophagojejunostomy using modified mattress inversion suturing with double barbed sutures is a safe and feasible anastomosis method to close the common opening of esophagojejunostomy, with shorter operation time, faster postoperative recovery and shorter hospital stay than the traditional method.

[Cone-beam CT analysis of the correlation between incisor root resorption rate and tooth movement index in adult patients with fixed orthodontics appliance]

Objective: To analyze the correlation between the root resorption rate and tooth movement of the maxillary and mandibular incisors before and after orthodontic treatment in adult patients using cone-beam CT (CBCT), and to explore the related factors that affect the apical root resorption. Methods: In this retrospective study, 23 adult patients with classⅠor class Ⅱ division 1 malocclusion [2 males and 21 females, mean age (23.4±6.3) years, treatment time (2.1±0.7) years] who received orthodontic treatment with fixed appliance in Department of Oral & Cranio-Maxillofacial Surgery, Shanghai Ninth People's Hospital from January 2017 to June 2021 were enrolled. Full-column CBCT examination was performed before and after treatment. A three-dimensional model was established to observe and record the volume of the maxillary and mandibular central and lateral incisors before and after treatment. The change of the incisal edge, the angle of rotation of the incisal edge, and the direction of the long axis of the tooth were also measured. The root resorption in each tooth before and after treatment was compared, and the root resorption rate was calculated. Pearson correlation analysis was performed on the root absorption rate before and after treatment with age, treatment time and tooth movement. Results: After treatment, the tooth volume of the maxillary and mandibular central and lateral incisors decreased significantly (P<0.01). The root absorption volumes were (20.2±6.0) mm3 and (11.2±4.7) mm3 in maxillary central and lateral incisors, and (14.7±4.6) mm3 and (14.8±5.0) mm3 in mandibular central and lateral incisors, respectively. The root absorption rates were (9.49±1.75)% and (9.13±3.24)% in maxillary central and lateral incisors, and (8.56±3.43)% and (9.13±3.24)%, in mandibular central and lateral incisors, respectively (F=0.56, P=0.640). The root resorption rate of maxillary central incisors had a weak positive correlation with the change of sagittal distance of incisal edge (r=0.36, P=0.015). The root resorption rate of mandibular central incisors had a moderate positive correlation with the vertical movement distance (r=0.48, P=0.001). The root resorption rate of mandibular lateral incisors was weakly positively correlated with the vertical movement of incisal edge and the treatment time (r=0.35, P=0.016; r=0.34, P=0.021), and was moderately positively correlated wit the change of sagittal movement of incisal edge (r=0.44, P=0.002). Conclusions: During orthodontic treatment, both maxillary and mandibular incisors had a certain degree of root resorption, which was related to sagittal and vertical movement of the incisors and the time of orthodontic treatment.

[Tracing investigation and analysis of a Clostridium botulinum food poisoning incident in Bayingolin Mongolian Autonomous Prefecture, Xinjiang]

To analyze a suspected case of Clostridium botulinum food poisoning in Bayingolin Mongolian Autonomous Prefecture, Xinjiang and to help validating the diagnosis and providing technical support for clinical treatment. The basic information and clinical manifestations of food poisoning cases were investigated by using the epidemiological method of food safety accidents. The botulinum toxin genes in the samples were detected by real-time PCR and inoculation of KM mouse. The enriched bacteria were further purified and validated. PFGE and cluster analysis were performed on five isolates. Clostridium botulinum type A was detected in two homemade fermented bean samples and stool lavage fluid samples of three patients from enriched samples by toxin test and real-time PCR, and were further validated after isolation of Clostridium botulinum. PFGE showed 100% homology among five isolates. Five isolates of bacteria isolated from the stool lavage fluid of three patients and two homemade fermented bean curd were identified as the same source through PFGE. The cause of this food poisoning cases is food pollution of Clostridium botulinum type A.

An analysis of the continuing professional development needs of radiographers and radiation therapists in Singapore

INTRODUCTION

Continuing Professional development (CPD) is deemed essential for the Radiographers (DR) and Radiation Therapists (RT) after Singapore commenced state registration. Diagnostic imaging and radiotherapy treatment services are constantly revolutionizing and those working in this field requires sufficient knowledge of the uptrends for training and development. The purpose of this survey is to identify the current training needs of the registered DR and RT in Singapore, and to understand their views about CPD activities.

METHODS

An online questionnaire was disseminated by the Singapore Society of Radiographers (SSR) to all registered DR and RT in Singapore, and all practicing in restructured and private hospitals were included. Data collection took place from January 2018 to April 2018.

RESULTS

102 responses were analysed, where 89 were DR and 13 were RT. CPD was provided in 72.5% (n = 74) of the participants' institutions, and 69.6% (n = 71) of participants were aware of CPD. Interestingly, participants were significantly more likely to be unaware of CPD when working in an institution which do not offer CPD. Training programme objective was the most important factor for selecting a programme. 93.1% (n = 95) preferred SSR to support them for CPD. There were a few constraints to CPD engagements identified such as financial factors, lack of time, and institution availability.

CONCLUSION

There was significant intrinsic motivation in a quality CPD activity. CPD activities should be current, accessible and relevant for the healthcare professionals to increase participation, which directly contributes to high standards of clinical care.

IMPLICATIONS FOR PRACTICE

Local healthcare institutions should be aware and address needs, gaps and aspirations of the local DR and RT community to ensure adequate preparation has been made upon initiation of mandatory CPD.

Determination of Strong-Phase Parameters in D→K_{S,L}^{0}π^{+}π^{-}

We report the most precise measurements to date of the strong-phase parameters between D^{0} and D[over ¯]^{0} decays to K_{S,L}^{0}π^{+}π^{-} using a sample of 2.93  fb^{-1} of e^{+}e^{-} annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. Our results provide the key inputs for a binned model-independent determination of the Cabibbo-Kobayashi-Maskawa angle γ/ϕ_{3} with B decays. Using our results, the decay model sensitivity to the γ/ϕ_{3} measurement is expected to be between 0.7° and 1.2°, approximately a factor of three smaller than that achievable with previous measurements, based on the studies of the simulated data. The improved precision of this work ensures that measurements of γ/ϕ_{3} will not be limited by knowledge of strong phases for the next decade. Furthermore, our results provide critical input for other flavor-physics investigations, including charm mixing, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.

Urban-rural disparity of preventive healthcare utilisation among children under the universal health insurance coverage in Taiwan: a national birth cohort analysis

OBJECTIVE

In the context of universal health insurance coverage, this study aimed to determine whether urban-rural inequality still exists in preventive health care (PHC) amongst children in Taiwan.

STUDY DESIGN

Prospective cohort study.

METHODS

A total of 184,117 mothers and their children born in 2009 were identified as the study cohort. The number of children born in urban, satellite and rural areas was 40,176, 57,565 and 86,805, respectively. All children were followed for 7 years, before which a total of seven times PHC were provided by Taiwan's National Health Insurance (NHI) programme. Ordinal logistic regression models were used to associate urbanisation level with the frequency of PHC utilisation. Stratified analyses were further performed in accordance with the children's birth weight and the mothers' birthplace.

RESULTS

Children from satellite areas had higher utilisation for the first four scheduled PHC visits. Children living in urban areas received more PHC for the fifth and sixth scheduled visits. Compared with those from rural areas, children in satellite areas exhibited a small but significant increase in odds in PHC utilisation, with a covariate-adjusted odds ratio (aOR) of 1.04 and 95% confidence interval (CI) of 1.02-1.06. By contrast, no significant difference was observed between rural and urban areas (aOR = 1.01). Further stratified analyses suggest more evident urban-rural difference in PHC utilisation amongst children with low birth weight and foreign-born mothers.

CONCLUSIONS

Given a universal health insurance coverage and embedded mechanisms in increasing the availability of healthcare resources in Taiwan, a slight urban-rural difference is observed in PHC utilisation amongst children. Hence, sociodemographic inequality in utilisation of PHC still exists. This issue should be addressed through policy intervention.

[Circadian clock and non-alcoholic fatty liver disease]

The circadian clock is a generator of self-sustaining physiological and behavioral rhythms, which can be guided by external environmental factors, so as to synchronize biological behaviors with external environmental changes. The modern lifestyles make the human body incapable of synchronization to the external time with the circadian rhythm, and thus form a social jet lag. Non-alcoholic fatty liver disease (NAFLD) is a disorder closely related to metabolic abnormalities. The circadian clock is closely related to metabolic abnormalities and NAFLD and changes among them may be involved with feeding mode and ingredients, sleeping time, and intestinal flora. Molecules associated with the circadian clock are expected to become potential drugs for the treatment of NAFLD. This article mainly reviews the latest research progress of circadian clock and NAFLD.

Effects of interchange ratio on sludge reduction and microbial community structures in an anaerobic/anoxic/oxic process with combined anaerobic side-stream reactor

Oxic-settling-anaerobic (OSA) process is effective in minimizing sludge production, by inserting an anaerobic side-stream reactor (ASSR) in the recycling bypass. Interchange ratio (IR), the quantity ratio of sludge entering the ASSR to the sludge in the main stream reactors, is one of the most important parameters for OSA process. In the present study, a laboratory-scale anaerobic/anoxic/oxic (A²/O) process combined with an ASSR (A²/O-ASSR) was operated for 366 days in parallel with a conventional A²/O process to investigate the effects of IR on sludge reduction. IR was assigned values of 5%, 8%, 10%, and 15%, and the A²/O-ASSR process achieved 14.0%, 16.0%, 24.1%, and 13.7% of sludge reduction, respectively. At the optimum IR of 10%, high through-put sequencing analysis showed that the microbes responsible for pollutant removal and ubiquitous in wastewater treatment remained predominant in the two systems, and slow-growing microbes related to hydrolysis, nitrogen and phosphorus removal increased in the A²/O-ASSR process, which probably played a key role in sludge reduction. 40.6-58.6% of sludge reduction was caused by sludge decay in the ASSR. The tiny amount of extracellular polymeric substance released in the A²/O-ASSR process was subthreshold to cause remarkable sludge reduction.

Measurement of the Cross Section for e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} and Observation of an Excited Ξ Baryon

Using a total of 11.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.009 and 4.6 GeV and collected with the BESIII detector at BEPCII, we measure fifteen exclusive cross sections and effective form factors for the process e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+} by means of a single baryon-tag method. After performing a fit to the dressed cross section of e^{+}e^{-}→Ξ^{-}Ξ[over ¯]^{+}, no significant ψ(4230) or ψ(4260) resonance is observed in the Ξ^{-}Ξ[over ¯]^{+} final states, and upper limits at the 90% confidence level on Γ_{ee}B for the processes ψ(4230)/ψ(4260)→Ξ^{-}Ξ[over ¯]^{+} are determined. In addition, an excited Ξ baryon at 1820  MeV/c^{2} is observed with a statistical significance of 6.2-6.5σ by including the systematic uncertainty, and the mass and width are measured to be M=(1825.5±4.7±4.7)  MeV/c^{2} and Γ=(17.0±15.0±7.9)  MeV, which confirms the existence of the J^{P}=3/2^{-} state Ξ(1820).

Observation of the Semileptonic D^{+} Decay into the K[over ¯]_{1}(1270)^{0} Axial-Vector Meson

By analyzing a 2.93  fb^{-1} data sample of e^{+}e^{-} collisions, recorded at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we report the first observation of the semileptonic D^{+} transition into the axial-vector meson D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e} with a statistical significance greater than 10σ. Its decay branching fraction is determined to be B[D^{+}→K[over ¯]_{1}(1270)^{0}e^{+}ν_{e}]=(2.30±0.26_{-0.21}^{+0.18}±0.25)×10^{-3}, where the first and second uncertainties are statistical and systematic, respectively, and the third originates from the input branching fraction of K[over ¯]_{1}(1270)^{0}→K^{-}π^{+}π^{0}.

Observation of the Leptonic Decay D^{+}→τ^{+}ν_{τ}

We report the first observation of D^{+}→τ^{+}ν_{τ} with a significance of 5.1σ. We measure B(D^{+}→τ^{+}ν_{τ})=(1.20±0.24_{stat}±0.12_{syst})×10^{-3}. Taking the world average B(D^{+}→μ^{+}ν_{μ})=(3.74±0.17)×10^{-4}, we obtain R_{τ/μ}=Γ(D^{+}→τ^{+}ν_{τ})/Γ(D^{+}→μ^{+}ν_{μ})=3.21±0.64_{stat}±0.43_{syst}., which is consistent with the standard model expectation of lepton flavor universality. Using external inputs, our results give values for the D^{+} decay constant f_{D^{+}} and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| that are consistent with, but less precise than, other determinations.

Complete Measurement of the Λ Electromagnetic Form Factors

The exclusive process e^{+}e^{-}→ΛΛ[over ¯], with Λ→pπ^{-} and Λ[over ¯]→p[over ¯]π^{+}, has been studied at sqrt[s]=2.396  GeV for measurement of the timelike Λ electric and magnetic form factors, G_{E} and G_{M}. A data sample, corresponding to an integrated luminosity of 66.9  pb^{-1}, was collected with the BESIII detector for this purpose. A multidimensional analysis with a complete decomposition of the spin structure of the reaction enables a determination of the modulus of the ratio R=|G_{E}/G_{M}| and, for the first time for any baryon, the relative phase ΔΦ=Φ_{E}-Φ_{M}. The resulting values are R=0.96±0.14(stat)±0.02(syst) and ΔΦ=37°±12°(stat)±6°(syst), respectively. These are obtained using the recently established and most precise value of the asymmetry parameter α_{Λ}=0.750±0.010 measured by BESIII. In addition, the cross section is measured with unprecedented precision to be σ=118.7±5.3(stat)±5.1(syst)  pb, which corresponds to an effective form factor of |G|=0.123±0.003(stat)±0.003(syst). The contribution from two-photon exchange is found to be negligible. Our result enables the first complete determination of baryon timelike electromagnetic form factors.

Study of e^{+}e^{-}→γωJ/ψ and Observation of X(3872)→ωJ/ψ

We study the e^{+}e^{-}→γωJ/ψ process using 11.6  fb^{-1} e^{+}e^{-} annihilation data taken at center-of-mass energies from sqrt[s]=4.008  GeV to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The X(3872) resonance is observed for the first time in the ωJ/ψ system with a significance of more than 5σ. The relative decay ratio of X(3872)→ωJ/ψ and π^{+}π^{-}J/ψ is measured to be R=1.6_{-0.3}^{+0.4}±0.2, where the first uncertainty is statistical and the second systematic (the same hereafter). The sqrt[s]-dependent cross section of e^{+}e^{-}→γX(3872) is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the Y(4200), with a mass of 4200.6_{-13.3}^{+7.9}±3.0  MeV/c^{2} and a width of 115_{-26}^{+38}±12  MeV. In addition, to describe the ωJ/ψ mass distribution above 3.9  GeV/c^{2}, we need at least one additional Breit-Wigner resonance, labeled as X(3915), in the fit. The mass and width of the X(3915) are determined. The resonant parameters of the X(3915) agree with those of the Y(3940) in B→KωJ/ψ and of the X(3915) in γγ→ωJ/ψ observed by the Belle and BABAR experiments within errors.

Observation of the Decay X(3872)→π^{0}χ_{c1}(1P)

Using a total of 9.0  fb^{-1} of e^{+}e^{-} collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e^{+}e^{-}→γX(3872) with X(3872)→π^{0}χ_{cJ} for J=0, 1, 2. We report the first observation of X(3872)→π^{0}χ_{c1}, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e^{+}e^{-}→γX(3872) with X(3872)→π^{+}π^{-}J/ψ, we find B(X(3872)→π^{0}χ_{c1})/B(X(3872)→π^{+}π^{-}J/ψ)=0.88_{-0.27}^{+0.33}±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π^{0}χ_{c0} and π^{0}χ_{c2} of 19 and 1.1, respectively.

[Study on the relationship between age-related hearing loss and cognitive impairment]

Objective: To investigate the correlation between age-related hearing loss and cognitive impairment. Methods: 201 elderly patients, who were admitted to the Department of Otorhinolaryngology of Peking University People's Hospital from March 1, 2017 to March 31, 2017, were evaluated with hearing screening and the Montreal Cognitive Assessment Scale. Among them, 101 were female and 100 were male, aged 60-90 years old. Taking the cognitive level as the dependent variable, and taking the age, sex, education, occupation, marital status, residence, and average hearing loss (average hearing threshold of 500, 1 000, 2 000, and 4 000 Hz), as well as the length of conscious hearing loss as the independent variables, the single factor analysis and multivariate linear regression analysis were used to screen the main factors affecting the cognitive level of the elderly. Results: Of the 201 elderly patients, 39 had normal hearing, 65 had mild hearing loss, 80 had moderate hearing loss, 16 had severe hearing loss, and 1 had profound hearing loss. The average degree of hearing loss was the influencing factor of cognitive impairment, and it mainly affected the directional force and abstract ability in the cognitive domains (P<0.05); The age, self-reported hearing loss, years of education, marital status, past ear diseases, and hypertension were relatively independent factors that affected the cognitive level(P<0.05). Conclusions: Age-related hearing loss is the risk factor for the cognitive impairment, especially for abstraction and orientation, in the elderly. The self-reported hearing loss is an independent risk factor for cognitive impairment.

Characterization of Shock-Sensitive Deposits from the Hydrolysis of Hexachlorodisilane

In this work, the shock sensitivity of hexachlorodisilane (HCDS) hydrolysis products was studied. The hydrolysis conditions included vapor and liquid HCDS hydrolysis in moist air. Shock sensitivity was determined by using a Fall hammer apparatus. Extensive infrared studies were done for the hydrolysis products. It was found that the Si-Si bond in HCDS during hydrolysis is preserved and can be cleaved by shock, leading to intramolecular oxidation of the neighboring silanol (Si-OH) groups to form a networked Si-O-Si structure and hydrogen gas. The limiting impact energy for shock sensitivity was also found proportional to the oxygen/silicon ratio in the deposit. Finally, recommendations are given for controlling the shock sensitivity of the hydrolyzed deposit.

[Analysis of nystagmus and medical history of 121 patients positive with positional test]

Objective: To observe the characteristics of positional nystagmus and clinical profile of patients with positive positional test, and to explore its possible pathogenesis.Method: One hundred and twenty-one patients with positive positional test in the vestibular function examination were enrolled in the Peking University International Hospital from January to June in 2017. According to the 2017 BPPV guidelines, patients with test positive positional nystagmus were divided into two groups: definite BPPV and the controversial syndrome. Analyses of gender, age and characteristics of nystagmus, with or without recurrent dizziness, headache, and motion sickness were undertaken between the two groups, as well as response to the repositioning maneuver. Result: Of the total 121 cases, 49 cases were diagnosed as definite BPPV, accounting for 40.5%, 72 cases as controversial syndrome, accounting for 59.5%. The proportion of women in the two group was 76.2% and 78.9%, respectively. The average age of definite BPPV and the controversial syndrome was 51.2±16.8 and 51.3±15.7, respectively.There were significant differences in nystagmus duration, spontaneous nystagmus and nystagmus after headshaking between the two groups by chi square test(P<0.01). The mean intensity of horizontal and vertical nystagmus in posterior semicircular canal BPPV was(10.2±7.4) °/s and(36.6±17.5) °/respectively. And the mean intensity of nystagmus in the strong and weak side in horizontal semicircular canal BPPV was(40.8±25.1) °/s and(20.7±11.1) °/respectively. The intensity of horizontal and vertical nystagmus of the controversial syndrome group was(7.2±7.7) °/s and(7.2±4.3) °/s respectively. The incidence of headache in the controversial syndrome group was significantly higher than that in the BPPV group, P=0.013. According to the guidelines, patients were evaluated one day after the initial treatment. The cure rate and effective rate of the definite BPPV group was 75%(36/48) and 87.5%(42/48),and was 0 and 30.4% in the controversial syndrome group respectively. Conclusion: The patients in controversial syndrome group have a preponderance of exhibiting positive nystagmus during positional test. Nystagmus were usually of low velocity and sustained. Most of these cases presented spontaneous nystagmus and headshaking induced nystagmus, as well as headache and lacunar infarctions in history, and the response to the repositioning maneuver were often poor. It may be related to vestibular migraine and central nervous system. The diagnosis of BPPV must be prudent.Both characteristics of nystagmus and medical history should be carefully analyzed to avoid overdiagnosis.

[Association and interaction of pre-pregnant body mass index and gestational weight gain of women on neonatal birthweight]

Objective: To investigate the association between maternal pre-pregnant body mass index and gestational weight gain, as well as their interaction on neonatal birthweight. Methods: We built a cohort in Anqing Municipal Hospital from January 2014 to March 2015, enrolling pregnant women who decided to give birth in this hospital. All women were asked to fill a questionnaire for basic information collection. Medical information of both pregnant women and their newborns were obtained through electronic medical record. Chi-square analysis, multinomial logistic regression, multiplicative and additive interaction methods were used to analyze the association between pre-pregnant body mass index and gestational weight gain as well as their interactions on birth weight of the neonates. Results: A total of 2 881 pregnant women were included in this study. Of the 2 881 newborns, 359 (12.46%) were small for gestational age (SGA) and 273 (9.48%) were large for gestational age (LGA). After adjusting the possible confounding factors, results from the multinomial logistic regression showed that pre-pregnancy underweight women were more possible to deliver SGA (aRR=1.33, 95%CI: 1.02-1.73). If the gestational weight gain was below the recommended criteria, the risk of SGA (aRR=1.64, 95%CI: 1.23-2.19) might increase. Pre-pregnancy overweight/obese could increase the risk of being LGA (aRR=1.86, 95%CI: 1.33-2.60). Maternal gestational weight gain above the recommendation level was associated with higher rates of LGA (aRR=2.03, 95%CI: 1.49-2.78). Results from the interaction analysis showed that there appeared no significant interaction between pre-pregnancy BMI and gestational weight on birthweight. Conclusion: Pre-pregnancy body mass index and gestational weight gain were independently associated with neonatal birthweight while pre-pregnancy BMI and gestational weight gain did not present interaction on birthweight.

[The investigation rate and influence factors of tinnitus with chronic suppurative otitis media]

Objective:To investigate the incidence of tinnitus and its influencing factors in patients with chronic suppurative otitis media, and to provide clinical data for the study of the pathogenesis of tinnitus.Method:The clinical data of 77 patients with chronic suppurative otitis media who underwent modified radical mastoidectomy and tympanoplasty were investigated. When tinnitus and otitis media happened in the same side,then the tinnitus is judged to be otitis media related. Patients were further divided into otitis media related tinnitus and the no tinnitus groups. The differences of tinnitus severity, sleep disturbance, migraine (migraine features), snoring and gastroesophageal reflux were compared between the two groups in tinnitus occurrence and classification.Result:The incidence of otitis media related tinnitus was 55.8%(43/77). Most of the tinnitus happened(33/43) later than the occurrence of otitis media for several years or even decades. There were 43 cases of tinnitus associated with otitis media, and 31 cases without tinnitus. Between the groups, significant differences were observed in migraine features, and the P value is 0.011, while no significant differences were noticed in the severity of hearing loss and sleep disorders, snoring, gastroesophageal reflux. Ranking of otitis media related tinnitus was positively related to the degree of hearing loss, especially the bone conduction threshold. With Spearman rank correlation test,P values of mean value(250Hz,500Hz,1kHz,2kHz,4kHz), middle frequency (1kHz, 2kHz)and high frequency (4kHz) of bone conduction threshold were 0.010,0.019 and 0.003, and the correlation coefficients were 0.391,0.356 and 0.443, respectively.Conclusion:The occurrence of tinnitus in patients with otitis media may not be consistent with the time of otitis media, and theoretically later than the occurrence of otitis media is more reasonable. Whether tinnitus occurs in patients with otitis media is not related to sleep disorders, the degree of air conduction and bone conduction hearing loss, but is related to migraine features. The severity of tinnitus associated with otitis media is associated with bone conduction hearing loss.

[Relevant factors of tinnitus in the elderly: an analysis of 150 volunteers]

Objective:To evaluate and characterize tinnitus in elderly volunteers，try to find out the relevant factors that can affect the incidence of tinnitus.Method:The study included 150 elderly volunteers. All volunteers had taken the otology examination and pure tone audiometry. They were interviewed by the investigators who were trained together, using the same questionnaire. The characteristics of tinnitus and the relationship between all relevant factors and tinnitus were analyzed.Result:Average age was 71.4 years. There are now 77 patients with tinnitus(51.3%), of which 31 cases have sustained tinnitus for more than 3 months, accounting for 40.3% of existing tinnitus volunteers. There was negative correlation between tinnitus and age. There was positive correlation between tinnitus and hearing loss. Tinnitus and headache had no correlation(P>0.05).Conclusion:After reach a certain age(70 years old), the incidence of tinnitus decreased. Hearing loss might be the most dangerous factor.If the hearing loss was more serious, the incidence of the tinnitus became higher. Tinnitus in the elderly may be the result of a combination of factors.

[Retroperitoneal laparoscopic debridement therapy for infected severe acute pancreatitis]

Objective: To investigate the feasibility and availability of retroperitoneal laparoscopic debridement therapy for patients with infected severe acute pancreatitis. Methods: Clinical data of 6 patients with severe acute pancreatitis who underwent retroperitoneal laparoscopic necrotic tissue debridement therapy in the Severe Acute Pancreatitis Center of Sir Run Run Hospital between August 2014 and October 2015 was retrospectively analyzed. The laparoscopic instruments and sponge forceps were used to remove necrotic tissue under retroperitoneal space, and double-cavity drainage tube was left for continuous washing. The perioperative indicators were collected and analyzed. Results: Two of six patients underwent two surgeries, and the others underwent one surgery, with an average operation time of (220.0±58.3) minutes and a mean hospital stay time of 62.6 days (35-117 days). One patient underwent re-operation after 33 days because of intraperitoneal hemorrhage, and another patient suffered pancreatic pseudocyst after the surgery, but no one died in hospital. Conclusion: Retroperitoneal laparoscopic debridement therapy is an additional choice for patients with infected severe acute pancreatitis, especially for those who had limited necrosis under retroperitoneal space. Furthermore, the therapy is in line with the concept of minimally invasive surgery and enhanced recovery after surgery.

[Initial study of transthoracic echocardiography guided three-dimensional printing on the application of assessment of structural heart disease]

Objective: To investigate the feasibility and diagnostic value of preoperative transthoracic echocardiography guided three dimensional printing model (TTE Guided 3DPM) on the assessment of structural heart disease (SHD). Methods: From February 2016 to October 2016, 44 patients underwent cardiac surgery in Tianjin Chest Hospital, forty-four patients were assessed preoperatively using TTE Guided 3DPM, including 25 males and 19 females, aged 3-75 years, with an average of (44±22) years. compared to conventional three dimensional transthoracic echocardiography (3D-TTE), and took direct intraoperative findings as "Golden Standard" simultaneously. There are twelve patients with SHD, including four cases with mitral prolapse, two cases with partial endocardial cushion defect, two cases with secondary atrial septal defect, two cases with rheumatic mitral stenosis, one case with tetralogy of Fallot, one case with ventricular septal defect (VSD), thirty-two patients without SHD were designed as negative control. Results: The sensitivity and specificity of TTE Guided 3DPM were greater than or equal to 3D-TTE, P value of McNemar test of 3D-TTE was greater than 0.05, the difference was not statistically significant, kappa=0.745, P<0.01, indicated that the results of 3DTTE and the gold standard were generally consistent.P value of McNemar test of TTE Guided 3DPM was greater than 0.05, the difference was not statistically significant, kappa=0.955, P<0.01, indicated that the results of TTE Guided 3DPM and gold standards were consistent. Compared with 3D-TTE and TTE Guided 3DPM, P value was greater than 0.05, the difference was not statistically significant, kappa=0.879, P<0.01, indicated that the results of 3D-TTE and TTE Guided 3DPM were consistent. TTE Guided 3DPM displayed the three-dimensional structure of SHD cardiac lesions clearly, which were consistent with intraoperative findings. Conclusion: TTE Guided 3DPM provides essential information for the preoperative evaluation and decision of SHD.

Pterostilbene as treatment for severe acute pancreatitis

Acute pancreatitis (AP) has a fast onset and progression, which lead to an unfavorable prognosis. Therefore, the development of novel drugs for its treatment is critical. As a homologous derivative of resveratrol, pterostilbene exerts a variety of effects including anti-inflammatory, antioxidant, and antitumor effects. This study investigated the potential of pterostilbene for treatment of severe AP (SAP) and related mechanisms. Effects of pterostilbene were evaluated in a Wistar rat model of AP. Serum levels of amylase (AMY), creatinine (Cr), and alanine aminotransferase (ALT) were quantified. Furthermore, serum levels of tumor necrosis factor (TNF)-a and interleukin (IL)-1b were quantified using enzyme-linked immunosorbent assay. Nuclear factor (NF)-kB expression in pancreatic tissues was quantified by real-time PCR and western blotting. The production of reactive oxygen species (ROS) was determined using a spectrometer, while superoxide dismutase (SOD) activity was assayed. In the AP rat model, the expression of inflammatory markers TNF-a and IL-1b, expression of NF-kB, and serum indices (AMY, Cr, and ALT) increased compared to the corresponding levels in the control group (P < 0.05). Pterostilbene reduced serum levels of TNF-a and IL-1b; decreased NF-kB gene expression, serum indices, and ROS generation; and increased SOD activity in a dose-dependent manner. In conclusion, pterostilbene can alleviate SAP-induced tissue damage by decreasing the inflammatory response and by promoting antioxidation leading to the protection of pancreatic tissues.

De novo assembly and characterization of the root transcriptome and development of simple sequence repeat markers in Paphiopedilum concolor

Paphiopedilum orchids (Orchidaceae) have attracted much attention from botanists and horticulturists because of their peculiar leaves and beautiful flowers. Furthermore, the dry roots of Paphiopedilum plants have well-known medicinal uses. However, it is unknown how sensitive and plastic the root genes are to environmental changes or how these environmental changes regulate the biosynthesis of active ingredients. In this study, we chose Paphiopedilum concolor for root sequencing, as it is widely used as a parent in breeding experiments. A total of 3.77 Gb of sequence data were generated by Illumina paired-end sequencing. De novo assemblies yielded 72,952 contigs, 67,434 scaffolds, 64,304 unigenes with average lengths of 937, 1022, and 1047 bp, respectively. Based on Basic Local Alignment Search Tool with known protein sequences, 40,815 (63.5%) unigenes were annotated with an E-value cutoff of 1.0E-5. Among the unigenes, 24,605 were classified in the Gene Ontology database, 17,361 were assigned to Cluster of Orthologous Groups, and 14,170 were annotated in Kyoto Encyclopedia of Genes and Genomes. Among these annotations, over 1195 unigenes related to secondary metabolic pathways, as well as 609 unigenes involved in plant hormone synthesis and signal transduction, were identified. In addition, 5322 potential simple sequence repeats (SSRs) were identified, and 4989 primer pairs for 3975 sequences containing SSRs were obtained. This study provides valuable insights into the mechanisms of genes that regulate root growth and development and provides a comprehensive resource for genes related to secondary metabolism in roots and for marker-assisted studies in Paphiopedilum.

Neuropsychological functions among adolescents with persistent, subsyndromal and remitted attention deficit hyperactivity disorder

BACKGROUND

Previous studies have reported mixed results on neuropsychological deficits in attention deficit hyperactivity disorder (ADHD) and only a few studies have focused on adolescents. There is also a debate about whether the executive function (EF) impairments in ADHD are primary deficits or have some contribution from the underlying non-EF processes. The aim of this study was to investigate the impairments in EF and neuropsychological function with relatively low executive demand (low-EF) in adolescents with childhood diagnosis of ADHD as a function of current ADHD status.

METHOD

Psychiatric diagnostic interviews and computerized neuropsychological tests classified into EF and low-EF tasks were completed by 435 adolescents with a childhood diagnosis of ADHD (300 adolescents classified as persistent ADHD, 109 as subsyndromal ADHD and 26 as remitted ADHD based on the current diagnosis) and 263 typically developing (TD) adolescents.

RESULTS

There were significant EF (spatial working memory, spatial planning and verbal working memory) and low-EF (signal detectability, spatial span and visual recognition memory) impairments in persistent and subsyndromal ADHD. The impairments in EF were independent of low-EF despite significant moderate correlations between any two of these tasks. Adolescents with remitted ADHD showed no deficit in either EF or low-EF.

CONCLUSIONS

This study suggests that adolescents with persistent and subsyndromal ADHD have EF and low-EF impairments that might contribute to ADHD independently.

Genetic polymorphisms of the DNA repair gene MPG may be associated with susceptibility to rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease and can lead to deformities and severe disabilities, due to irreversible damage of tendons, joints, and bones. A previous study indicated that a DNA repair system was involved in the development of RA. In this study, we investigated the association of four N-methylpurine-DNA glycosylase (MPG) gene polymorphisms (rs3176364, rs710079, rs2858056, and rs2541632) with susceptibility to RA in 384 Taiwanese individuals (192 RA patients and 192 control subjects). Our data show a statistically significant difference in genotype frequency distributions at rs710079 and rs2858056 SNPs between RA patients and control groups (P = 0.040 and 0.029, respectively). Our data also indicated that individuals with the GG genotype at rs2858056 SNP may have a higher risk of developing RA. In addition, compared with the haplotype frequencies between case and control groups, individuals with the GCGC haplotype appeared to be at a greater risk of RA progression (P = 0.003, OR = 1.75; 95&percnt; CI = 1.20-1.55). Our results suggest that rs710079 and rs2858056 polymorphisms and the GCGC haplotype in the MPG gene are associated with the risk of RA progression, and thus may be used as molecular markers of RA if they are confirmed by further research.

Pharmacokinetics of ketamine in plasma and milk of mature Holstein cows

The purpose of this study was to evaluate the pharmacokinetics of ketamine in mature Holstein cows following administration of a single intravenous (i.v.) dose. Plasma and milk concentrations were determined using a high-performance liquid chromatography assay. Pharmacokinetic parameters were estimated using a noncompartmental method. Following i.v. administration, plasma T(max) was 0.083 h and plasma C(max) was 18,135 ± 22,720 ng/mL. Plasma AUC was 4484 ± 1,398 ng·h/mL. Plasma t(½β) was 1.80 ± 0.50 h and mean residence time was 0.794 ± 0.318 h with total body clearance of 1.29 ± 0.70 L/h/kg. The mean plasma steady-state volume of distribution was calculated as 0.990 ± 0.530 L/kg and volume of distribution based on area was calculated as 3.23 ± 1.51 L/kg. The last measurable time for ketamine detection in plasma was 8.0 h with a mean concentration of 24.9 ± 11.8 ng/mL. Milk T(max) was detected at 0.67 ± 0.26 h with C(max) of 2495 ± 904 ng/mL. Milk AUC till the last time was 6593 ± 2617 ng·h/mL with mean AUC milk to AUC plasma ratio of 1.99 ± 2.15. The last measurable time that ketamine was detected in milk was 44 ± 10.0 h with a mean concentration of 16.0 ± 9.0 ng/mL.

Modelling the growth of Japanese eel Anguilla japonica in the lower reach of the Kao-Ping River, southern Taiwan: an information theory approach

Information theory was applied to select the best model fitting total length (L(T))-at-age data and calculate the averaged model for Japanese eel Anguilla japonica compiled from published literature and the differences in growth between sexes were examined. Five candidate growth models were the von Bertalanffy, generalized von Bertalanffy, Gompertz, logistic and power models. The von Bertalanffy growth model with sex-specific coefficients was best supported by the data and nearly overlapped the averaged growth model based on Akaike weights, indicating a similar fit to the data. The Gompertz, generalized von Bertalanffy and power growth models were also substantially supported by the data. The L(T) at age of A. japonica were larger in females than in males according to the averaged growth mode, suggesting a sexual dimorphism in growth. Model inferences based on information theory, which deal with uncertainty in model selection and robust parameter estimates, are recommended for modelling the growth of A. japonica.

Baculovirus-derived hemagglutinin vaccine protects chickens from lethal homologous virus H5N1 challenge

Since outbreaks of highly pathogenic avian influenza (HPAI) in both human and poultry from 2003, it is critical to have effective vaccines. A cDNA fragment coding the entire hemagglutinin (HA) gene derived from an H5N1 strain (A/duck/China/E319-2/03) was cloned and expressed using the baculovirus system. Two weeks after receiving two doses of recombinant HA (rHA) vaccines, chickens develop high antibody response for hemagglutination inhibition (HI) at titer 7.2 log(2). Challenge studies revealed that vaccinated chickens with HI titers greater than 3 log(2) could have immunoprotection against the same HPAI H5N1 strain virus challenge through intranasal route. Additionally, HI titer of 5 log(2) determined whether the live viruses could not be detected from oropharyngeal, cloacal discharge or in tissues. This result suggests that the rHA expressed from baculovirus system could be a candidate for the development of a safe and efficient subunit vaccine for HPAI (H5N1).

Analysis of ERCC2/XPD functional polymorphisms in systemic lupus erythematosus

Sunlight/ultraviolet (UV) irradiation has been recognized as an important risk factor for developing systemic lupus erythematosus (SLE). However, the interpretation of genetic variations involved in UV-light sensitivity is largely unknown. Recent studies indicated that two genetic variations of ERCC2/XPD gene (rs1799793 in exon 10 and rs13181 in exon 23) have been found to exert negative influences on nucleotide excision repair system. To analyse the possible contribution of the ERCC2/XPD functional single nucleotide polymorphisms in genetic susceptibility to SLE, the rs13181 and rs1799793 SNPs in ERCC2/XPD were genotyped by polymerase chain reaction followed by restriction fragment length polymorphism analysis. Association was studied by case-control analyses using samples from 172 SLE patients and 160 healthy controls. Haplotype analysis was performed to detect the association with genetic predisposition to SLE and the clinical features. Although these two functional genetic variations are linked to several immune dysfunction-induced diseases, no statistically significant differences in allele or genotype frequencies were observed between SLE patients and controls. Haplotype analysis showed that none of ERCC2/XPD haplotypes was associated with the incidence of SLE disease, nor the preference of clinical features. In conclusion, the ERCC2/XPD functional polymorphisms analysed in this study showed no association in genetic susceptibility to SLE.

The Separative Bioreactor: A Continuous Separation Process for the Simultaneous Production and Direct Capture of Organic Acids

The replacement of petrochemicals with biobased chemicals requires efficient bioprocesses, biocatalysis, and product recovery. Biocatalysis (e.g., enzyme conversion and fermentation) offers an attractive alternative to chemical processing because biocatalysis utilize renewable feedstocks under benign reaction conditions. One class of chemical products that could be produced in large volumes by biocatalysis is organic acids. However, biocatalytic reactions to produce organic acids typically result in only dilute concentrations of the product because of product inhibition and acidification that drives the reaction pH outside of the optimal range for the biocatalyst. Buffering or neutralization results in formation of the acid salt rather than the acid, which requires further processing to recover the free acid product. To address these barriers to biocatalytic organic acid production, we developed the "separative bioreactor" based on resin wafer electrodeionization, which is an electro-deionization platform that uses resin wafers fabricated from ion exchange resins. The separative bioreactor simultaneously separates the organic acid from the biocatalyst as it is produced, thus it avoids product inhibition enhancing reaction rates. In addition, the separative bioreactor recovers the product in its acid form to avoid neutralization. The instantaneous separation of acid upon formation in the separative bioreactor is one of the first truly one-step systems for producing organic acids. The separative bioreactor was demonstrated with two systems. In the first demonstration, the enzyme glucose fructose oxidoreductase (GFOR) was immobilized in the reactor and later regenerated in situ. GFOR produced gluconic acid (in its acid form) continuously for 7 days with production rates up to 1000 mg/L/hr at >99% product recovery and GFOR reactivity >30mg gluconic acid/mg GFOR/hour. In the second demonstration, the E. coli strain CSM1 produced lactic acid for up to 24 hours with a productivity of >200 mg/L/hr and almost 100% product recovery.

Characterization of an H5N1 avian influenza virus from Taiwan

In 2003, an avian influenza (AI) virus of H5N1 subtype (A/Duck/China/E319-2/03; Dk/CHN/E319-2/03) was isolated from a smuggled duck in Kinmen Island of Taiwan. Phylogenetic analysis and pairwise comparison of nucleotide and amino acid sequences revealed that the virus displayed high similarity to the H5N1 viruses circulating in Asia during 2004 and 2005. The hemagglutinin (HA) protein of the virus contained multiple basic amino acid residues (-RERRRKR-) adjacent to the cleavage site between the HA1 and HA2 domains, showing the highly pathogenic (HP) characteristics. The HP phenotype was confirmed by experimental infection of chickens, which led up to 100% mortality within 24-72h postinfection. The virus replicated equally well in the majority of organs of the infected chickens with titers ranging from 10(7.5) to 10(4.7) 50% embryo lethal dose (ELD50) per gram of tissue. In a mouse model the virus exhibits low pathogenic characteristics with a lethal infection observed only after applying high inoculating dose (>or=10(7.6) ELD50) of the virus. The infectious virus particles were recovered only from the pulmonary system including trachea and lungs. Our study suggests that ducks infected with H5N1 AIV of HPAI pathotype showing no disease signs can carry the virus silently and that bird smuggling represent a serious risk for H5N1 HPAI transmission.

Photocatalysis of 2,2',3,4,4',5'-hexachlorobiphenyl and its intermediates using various catalytical preparing methods

Four etching solutions used on support materials and two coating methods of TiO(2) were conducted to investigate the effects of catalytical preparing methods on the photocatalysis of 2,2',3,4,4',5'-hexachlorobiphenyl (PCB congener 138). The results of XRD analyses confirmed that various etching solutions used on support substrates did not influence the characteristics of titanium(IV) oxide. The XRD patterns of crystallization for the catalysts before and after purification remained unchanged. Hydrofluoric acid used as an etching solution for the support substrates provided the best adhesion stability for the catalysts that demonstrated the highest photocatalytic efficiency for congener 138. Xenon and ultraviolet lamps were used to compare the irradiation effect on photocatalysis. The shortest half-lives of congener 138 were 7.4 and 12.2 h using xenon and UV reactors, respectively. Lower chlorinated biphenyls (lower congener numbers) were identified through the continuous dechlorination of congener 138. PCB congeners 99, 87, 66, 49, 28, 17, 9, and 7 were detected as a result of dechlorination from higher chlorinated congeners to lower chlorinated congeners along with the extension of exposure times. The concentrations of chloride ion were increased with increasing exposure time through dechlorination, while the concentrations of organic chlorine of congener 138 were decreased. Meta-dechlorination was the most commonly found mechanism for the photocatalysis of PCB 138. The activation energy of the photocatalysis of congener 138 was 70.8 kJ mol(-1).

The effects of early postnatal dexamethasone therapy on pulmonary outcome in premature infants with respiratory distress syndrome: a two-year follow-up study

AIM

To evaluate the pulmonary outcome at corrected age of 2 y on preterm infants who participated in a double-blind trial of early postnatal dexamethasone therapy (< 12 h after birth) for the prevention of chronic lung disease.

METHODS

Clinical respiratory status, blood gases, acid-base balance and pulmonary function were evaluated at corrected age of 2 y in 116 preterm infants (59 infants in the control group; 57 in the dexamethasone-treated group). In the dexamethasone-treated group, dexamethasone was administered intravenously every 12 h in tapering doses: 0.25 mg/kg on days 1 through 7, 0.12 mg/kg on days 8 through 14, 0.05 mg/kg on days 15 through 21, and 0.02 mg/kg on days 21 through 28.

RESULTS

The clinical and laboratory characteristics in the perinatal period were comparable between the groups. At the time of follow-up (mean +/- SD corrected age was 25.1 +/- 4.8 mo for the control group and 24.6 +/- 5.1 mo for the dexamethasone-treated group), there was a slightly lower mean body weight and body length, and a lower psychomotor developmental index in the dexamethasone-treated group than in the control group (10.9 +/- 2.1 vs 11.5 +/- 1.9 kg, 84.4 +/- 6.1 vs 85.9 +/- 5.8 cm, and 82 +/- 24 vs 89 +/- 26, respectively); however, these differences were not statistically significant. There were no significant differences between the control and dexamethasone-treated groups in clinical respiratory status, blood gases, acid-base balance or in lung mechanics (V(T): 9.5 +/- 2.0 vs 9.4 +/- 1.9 ml/kg; V(min): 0.23 +/- 0.04 vs 0.23 +/- 0.03 l/min/kg; C(RS): 13.1 +/- 3.9 vs 12.6 +/- 3.6 ml/kPa/kg; R(RS): 1.56 +/- 0.64 vs 1.62 +/- 0.58 kPa/l/s, respectively).

CONCLUSION

There was no apparent adverse respiratory outcome associated with early postnatal dexamethasone therapy.

Translocation of unstable heterochromatin as the mechanism of sister chromatid exchange formation: a proposed hypothesis

The phenomenon of sister chromatid exchange has remained an enigma in that the actual mechanism for its formation has never been elucidated. It has long been suspected that the process involves some form of breakage and rejoining of DNA, but that hypothesis has never been proved. Recent work in this laboratory using cells from a premature aging disorder (Werner's syndrome) has promulgated the hypothesis that heterochromatin may not be an integral structure of chromosomes, but rather serves as a surface feature or covering. Furthermore, heterochromatin in Werner's syndrome chromosomes was found to be unstable and easily sloughed-off the chromosome surface. In this investigation evidence is presented which shows that incorporation of bromodeoxyuridine into DNA causes instability in the purported heterochromatin covering, resulting in translocation of segments of heterochromatin from the unifilarly-substituted chromatid to the bifilarly-substituted sister chromatid. Such translocation may represent the long-elusive mechanism of sister chromatid exchange formation.

A limit on spin-charge separation in high-Tc superconductors from the absence of a vortex-memory effect

There is a long-standing debate about whether spin-charge separation is the root cause of the peculiar normal-state properties and high superconducting transition temperatures of the high-Tc materials. In the proposed state of matter, the elementary excitations are not electron-like, as in conventional metals, but rather the electron 'fractionalizes' to give excitations that are chargeless spin-1/2 fermions (spinons) and charge +e bosons (chargons). Although spin-charge separation has been well established in one dimension, the theoretical situation for two dimensions is controversial and experimental evidence for it in the high-Tc materials is indirect. A model with sharp experimental tests for a particular type of separation in two dimensions has recently been proposed. Here we report the results of those experimental tests, placing a conservative upper limit of 190 K on the energy of the proposed topological defects known as visons. There is still debate about the extent to which this experiment can settle the issue of spin-charge separation in the high-Tc copper oxides, because some forms of the separation are able to avoid the need for visons. But at least one class of theories that all predict a vortex-memory effect now are unlikely models for the copper oxides.

A linear cyclic oximate-bridged tetracopper(II) complex

The crystal structure of the title complex, tetrakis[mu-6-amino-3-methyl-4-azahex-3-en-2-one oximato(1-)-kappa4N,N',N":O]tetracopper(II) tetraperchlorate 0.6-hydrate, [Cu4(C6H12N3O)4](ClO4)4*0.6H2O, shows the cation to be an oximate-bridged tetramer composed of four 6-amino-3-methyl-4-azahex-3-en-2-one oxime ligands and four copper(II) ions and to have crystallographically imposed 4 symmetry. Each Cu(II) atom is four-coordinated by the three N atoms of one oxime ligand and by the O atom of another oxime ligand in a distorted square-planar geometry.

Limits on spin-charge separation from h/2e fluxoids in very underdoped YBa2Cu3O(6+x)

Magnetic flux in superconductors is usually quantized in units of h/2e. Here we report scanning SQUID and scanning Hall probe studies of single fluxoids in high purity YBa2Cu3O6.35 crystals (T(c) less, similar 13 K), extending flux quantization studies to a region of the cuprate phase diagram where the superfluid density is sufficiently low that novel behavior has been predicted. Some scenarios in which superconductivity results from spin-charge separation predict h/e fluxoids in materials with low superfluid density. Our observations of only h/2e fluxoids set limits on these theories.

Electrically-assisted transdermal delivery of buprenorphine

The objective of this study was to explore the electrically assisted transdermal delivery of buprenorphine. Oral delivery of buprenorphine, a synthetic opiate analgesic, is less efficient due to low absorption and large first-pass metabolism. While transdermal delivery of buprenorphine is expected to avoid the first-pass effect and thereby be more bioavailable, use of electrical enhancement techniques (iontophoresis and/or electroporation) could provide better programmability. Another use of buprenorphine is for opiate addiction therapy. However, a patch type device is subject to potential abuse as it could be removed by the addict. This abuse can be prevented if drug particles are embedded in the skin. The feasibility of doing so was investigated by electro-incorporation. Buprenorphine HCl (1 mg/ml) in citrate buffer (pH 4.0) was delivered in vitro across human epidermis via iontophoresis using a current density of 0.5 mA/cm(2) and silver-silver chloride electrodes. Electroporation pulses were also applied in some experiments. For electro-incorporation, drug microspheres or particles were driven into full thickness human skin by electroporation. It was observed that the passive transdermal flux of buprenorphine HCl was significantly enhanced by iontophoresis under anodic polarity. The effectiveness of electro-incorporation seemed inconclusive, with pressure also playing a potential role. Delivery was observed with electro-incorporation, but the results were statistically not different from the corresponding controls.

Rapid intravenous administration of amino acids prevents biliary sludge induced by total parenteral nutrition in humans

The aim of this study was to evaluate whether daily rapid intravenous administration of amino acids (IVAA) prevented the formation of biliary sludge in humans receiving long-term total parenteral nutrition (TPN). Thirty adult patients receiving TPN for more than 28 consecutive days were studied. They were randomized to receive either saline solution (placebo) intravenously (15 patients) or 6.9% branched chain amino acid (BCAA)-enriched amino acid (15 synthetic amino acids; Freamine HBC) solution given by administration rapid intravenous (15 patients). The groups were similar with respect to age, sex, diagnosis, liver function test results, amylase levels, TPN time, and time of study. All patients underwent weekly ultrasound studies. Volume and emptying studies of the gallbladder in response to the study drug were performed after 1 week. As a result, none of the patients receiving rapid IVAA had sludge, whereas 11 of the 15 patients receiving placebo had sludge (P < 0.01). Results of emptying studies showed significant contraction of the gallbladder in those in the rapid IVAA group, but not in the placebo group. Consequently, the data suggest that rapid IVAA given daily prevents TPN-induced stasis and sludge in the gallbladder. We conclude that rapid IVAA should be used as routine prophylaxis against biliary sludge and formation of gallstones in patients receiving long-term TPN.

Effect of organizational and environmental factors on service differentiation strategy of integrated healthcare networks

During the past decade, the missions/goals of medical providers of healthcare services in the United States have shifted--from emphasizing individual, independent illness treatments to focusing on the continuum of care, population-based wellness, and providing the appropriate care in the most efficient way. Integrated healthcare networks (IHNs)--or integrated healthcare delivery systems--have been focusing heavily on their level of various partnership integration (i.e. service differentiation strategy) in order to offer a full continuum of care. The aim of this study, using the individual IHN as the unit of analysis, was to identify organizational and environmental factors that influence IHN administrators to focus on their service differentiation of market lines, including the establishment of third-party payers' contracts, the affiliation of managed-care organizations, and the alliances of various nonhospital medical providers, to provide a continuum of care. The study findings show that tax status of an IHN, its age, and market competition affect its service differentiation strategy in the provision of a full continuum of care.