Depression, anxiety and PTSD symptoms before and during the COVID-19 pandemic in the UK

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health is still being unravelled. It is important to identify which individuals are at greatest risk of worsening symptoms. This study aimed to examine changes in depression, anxiety and post-traumatic stress disorder (PTSD) symptoms using prospective and retrospective symptom change assessments, and to find and examine the effect of key risk factors.

METHOD

Online questionnaires were administered to 34 465 individuals (aged 16 years or above) in April/May 2020 in the UK, recruited from existing cohorts or via social media. Around one-third (n = 12 718) of included participants had prior diagnoses of depression or anxiety and had completed pre-pandemic mental health assessments (between September 2018 and February 2020), allowing prospective investigation of symptom change.

RESULTS

Prospective symptom analyses showed small decreases in depression (PHQ-9: -0.43 points) and anxiety [generalised anxiety disorder scale - 7 items (GAD)-7: -0.33 points] and increases in PTSD (PCL-6: 0.22 points). Conversely, retrospective symptom analyses demonstrated significant large increases (PHQ-9: 2.40; GAD-7 = 1.97), with 55% reported worsening mental health since the beginning of the pandemic on a global change rating. Across both prospective and retrospective measures of symptom change, worsening depression, anxiety and PTSD symptoms were associated with prior mental health diagnoses, female gender, young age and unemployed/student status.

CONCLUSIONS

We highlight the effect of prior mental health diagnoses on worsening mental health during the pandemic and confirm previously reported sociodemographic risk factors. Discrepancies between prospective and retrospective measures of changes in mental health may be related to recall bias-related underestimation of prior symptom severity.

Recurrent umbilical varix rupture with hemoperitoneum: a case report and review of literature

Background

Non-traumatic hemoperitoneum was a rare event with the risk of sudden death. Spontaneous rupture of hepatocellular carcinoma is the most intuitive diagnosis when hemoperitoneum occurs in cirrhotic patients who are not regularly followed up. However, other etiologies of hemoperitoneum, such as intra-abdominal varix rupture, should be kept in mind.

Case presentation

A 44-year-old man with alcoholic liver cirrhosis, Child–Pugh B was sent to our emergency department (ED) because of recurrent abdominal pain and hypovolemic shock. He had similar symptoms one month ago and was diagnosed as hepatocellular carcinoma (HCC) rupture with hemoperitoneum, therefore he underwent trans-arterial embolization (TAE). However, the follow-up magnetic resonance imaging (MRI) showed less possibility of hepatocellular carcinoma. Contrast enhanced abdominal computed tomography (CT) showed possible umbilical vein contrast agent extravasation. Exploratory laparotomy confirmed the diagnosis of rupture umbilical varix with hemoperitoneum.

Conclusion

Although umbilical varix rupture is a rare cause of hemoperitoneum, it should be kept in mind in cirrhotic patients with unexplained hemoperitoneum.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02167-3.

Surgical treatment of pelvic organ prolapse in women aged ≥75 years in Hong Kong: a multicentre retrospective study

INTRODUCTION

Pelvic organ prolapse (POP) is common among older women. With the increasing lifespan and emphasis on quality of life worldwide, older women increasingly prefer surgical treatment for POP. We reviewed the surgical treatment of POP in older women to characterise its safety, effectiveness, and the type most often selected.

METHODS

This multicentre, retrospective study was conducted at four hospitals between 2013 and 2018. Included patients were aged ≥75 years and had undergone POP surgery. We compared patient demographic characteristics, POP severity, and surgical outcomes between reconstructive and obliterative surgeries; these comparisons were also made among vaginal hysterectomy plus pelvic floor repair (VHPFR), transvaginal mesh surgery (TVM), vaginal hysterectomy (VH) plus colpocleisis, and colpocleisis alone.

RESULTS

In total, 343 patients were included; 84.3% and 15.7% underwent reconstructive and obliterative surgeries, respectively. Overall, 246 (71.7%), 43 (12.5%), 20 (5.8%), and 34 (9.9%) patients underwent VHPFR, TVM, VH plus colpocleisis, and colpocleisis alone, respectively. Patients who were older (81.9 vs 79.6 y; P=0.001), had vault prolapse (38.9% vs 3.5%; P<0.001), and had medical co-morbidities (37% vs 4.8%; P<0.001) chose obliterative surgery more frequently than reconstructive surgery. Obliterative surgeries had shorter operative time (73.5 min vs 107 min; P<0.001) and fewer surgical complications (9.3% vs 28.0%; P=0.003). Vaginal hysterectomy plus pelvic floor repair had the highest rate of surgical complications (most were minor), while colpocleisis alone had the lowest rate (30.1% vs 8.8%; P=0.01).

CONCLUSIONS

Pelvic organ prolapse surgeries were safe and effective for older women. Colpocleisis may be appropriate as primary surgery for fragile older women.

A Data Processing Pipeline for Prediction of Milling Machine Tool Condition from Raw Sensor Data

With recent advances in sensor and computing technology, it is now possible to use real-time machine learning techniques to monitor the state of manufacturing machines. However, making accurate predictions from raw sensor data is still a difficult challenge. In this work, a data processing pipeline is developed to predict the condition of a milling machine tool using raw sensor data. Acceleration and audio time series sensor data is aggregated into blocks that correspond to the individual cutting operations of the Computer Numerical Control (CNC) milling machine. Each block of data is preprocessed using well-known and computationally efficient signal processing techniques. A novel kernel function is proposed to approximate the covariance between preprocessed blocks of time series data. Several Gaussian process regression models are trained to predict tool condition, each with a different covariance kernel function. The model with the novel covariance function outperforms the models that use more common covariance functions. The trained models are expressed using the Predictive Model Markup Language (PMML), where possible, to demonstrate how the predictive model component of the pipeline can be represented in a standardized form. The tool condition model is shown to be accurate, especially when predicting the condition of lightly worn tools.

Untangling the Complexity of Liver Fluke Infection and Cholangiocarcinoma in NE Thailand Through Transdisciplinary Learning

This study demonstrates how a transdisciplinary learning approach provided new insights for explaining persistent Opisthorchis viverrini infection in northern Thailand, as well as elucidating problems of focusing solely on the parasite as a means of addressing high prevalence of cholangiocarcinoma. Researchers from diverse backgrounds collaborated to design an investigative homestay program for 72 Singaporean and Thai university students in five northeast Thai villages. The students explored how liver fluke infection and potential cholangiocarcinoma development are influenced by local landscape dynamics, aquatic ecology, livelihoods, food culture and health education. Qualitative fieldwork was guided daily by the researchers in a collaborative, co-learning process that led to viewing this health issue as a complex system, influenced by interlinked multidimensional factors. Our transdisciplinary experience has led us to believe that an incomplete understanding of these linkages may reduce the efficacy of interventions. Further, viewing liver fluke infection and cholangiocarcinoma as the same issue is inadvisable. Although O. viverrini infection is an established risk factor for the development of cholangiocarcinoma, multiple factors are known to influence the likelihood of acquiring either. Understanding the importance of the current livelihood transition, landscape modification and the resulting mismatch between local cultures and new socio-ecological settings on cholangiocarcinoma initiation and liver fluke transmission is of critical importance as it may help readjust our view of the respective role of O. viverrini and other socioeconomic risk factors in cholangiocarcinoma etiology and refine intervention strategies. As demonstrated in this study, transdisciplinary approaches have the potential to yield more nuanced perspectives to complex diseases than research that focuses on specific aspects of their epidemiology. They may therefore be valuable when designing effective solutions to context-sensitive diseases such as liver fluke infection and cholangiocarcinoma.

Effects of sheng hua tang on uterine involution and ovarian activity in postpartum dairy cows

The effects of Sheng Hua Tang (SHT) on uterine involution and ovarian activity were investigated in postpartum dairy cows. SHT (70 g) was given to dairy cows (n = 10) to evaluate its effects for five days from the first postpartum day. Postpartum cows fed with a basal diet without SHT were used as the control group (n = 10). Ultrasounds and blood tests were recorded for four weeks from postpartum day seven with a 3-d interval. The results showed that the areas and diameters of endometria were significantly (p<0.01) reduced in the group that received SHT compared to the control group on the seventh postpartum day. The group that received SHT had an intrauterine fluid volume mean of 1.2±0.6 cm(3), which was significantly lower than that of the control group, 2.3±0.8 cm(3) (p<0.01) on the 13th postpartum day. In addition, the uterine tension score was a mean of 1.0±0.0 in the group that received SHT, which was also significantly lower than that of the control group, 1.5±0.5 (p<0.01) on the 19th postpartum day. Taken together, the Chinese herbal medicine remedy, SHT, promoted uterine involution and ovarian activity in postpartum dairy cows.

Cardiac transplantation and concomitant coronary artery bypass grafting: our experiences in 11 cases

INTRODUCTION

The shortage of donor hearts for transplantation could be alleviated by including the hearts of older donors. Previous literature revealed similar early and medium-term survival outcomes compared with those of younger donors. This study presents our experience with patients who underwent orthotopic heart transplantation and concomitant coronary artery bypass grafting at our institution.

METHODS

We present our experience with 11 patients with end-stage cardiomyopathy (8 men and 3 women) undergoing orthotopic heart transplantation and concomitant coronary artery bypass grafting from September 2002 to November 2011 at our institute.

RESULTS

All 11 donor organs would otherwise have been rejected, depriving potential recipients of organ transplantation. Two patients received concurrent 2-coronary-artery bypass, and the other 9 patients received concurrent single-coronary-artery bypass during orthotopic heart transplantation. All patients had an uneventful postoperative course, with follow-up completed 3 to 128 months after cardiac transplantation and concomitant coronary artery bypass grafting surgery.

CONCLUSIONS

Our experiences suggest that donor hearts requiring coronary artery bypass grafting, which form a small but significant donor subgroup, can be used effectively and safely when matched to the recipients' age and medical condition.

Combined heart transplantation and total replacement of thoracic aorta in Marfan's syndrome with recurrent aortic dissection: a case report

It is extremely rare for a patient to need simultaneous heart transplantation (HTx) and replacement of the thoracic aorta. A 23-year-old woman with Marfan's syndrome underwent Bentall's operation and replacement of the ascending aorta (AsA) due to a type A aortic dissection (AD) in August 2001. In March 2005, she began to experience dyspnea on exertion and was found to have a huge pseudoaneurysm at the aortic root, which had caused dehiscence of the aortic conduit. In July 2009, she suffered acute chest pain followed by hypotension and cold sweating. The computed tomography (CT) scan showed a recurrent dissection with a long intimal tear extending from the arch to the mid-portion of the descending thoracic aorta (DTA). Due to technical difficulties in the repair of the aortic root, she was placed on the HTx waiting list. The next day, she received a donor heart and underwent combined HTx and total replacement of the thoracic aorta. Explantation of the heart improved the exposure of the DTA. With the use of a vascular ring connector (Vasoring), the operation was successfully performed without need for a blood transfusion. The patient was still well at 2 years after the operation. Simultaneous replacement of the heart and the whole segment of the thoracic aorta is technically possible in Marfan patients who are complicated with aortic dissection.

Effect of temperature on optical and electronic properties of InGaP/InGaAIP multiple quantum wells

The optical and electronic properties in an InGaP/InGaAIP multiple quantum well (MQW) grown by using molecular-beam epitaxy utilizing the digital alloy technique were investigated through temperature-dependent photoluminescence (PL) measurements and numerical calculations. The high-resolution transmission electron microscopy images showed that the sample clearly displayed the InGaP wells and the InGaAIP barriers and separate confinement heterostructure layers. The PL measurements at various temperatures were performed to investigate the interband transitions of the InGaP/InGaAIP MQW. The electronic subband energies and the wavefunctions in the InGaP/InGaAIP MQW at several temperatures were determined by using a finite element method employing the standard 8-band k x p Lagrangian. The numerical results for optical interband transition energies from the ground state electron subband to the ground state heavy-hole subband of the InGaP/InGaAIP MQW at various temperatures were in reasonable agreement with the excitonic transition energies observed in the PL measurements.

Catechin stimulates osteogenesis by enhancing PP2A activity in human mesenchymal stem cells

SUMMARY

Using human mesenchymal stem cells, we identified catechin from a panel of herbal ingredients and Chinese traditional compounds with the strongest osteogenic effects. Catechin increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further clarified the signaling pathway that catechin mediated to stimulate osteogenesis.

INTRODUCTION

Human mesenchymal stem cells (hMSCs), useful as a species specific cell culture system for studying cell lineage differentiation, were examined as a tool to identify novel herbal ingredients and Chinese traditional compounds for enhancing osteogenesis.

METHODS

Immortalized and primary hMSCs were induced in osteogenic induction medium in the presence of a variety of herbal ingredients and Chinese traditional compounds and osteogenic differentiation was evaluated by histochemical assays and quantitative RT-PCR.

RESULTS

Using immortalized hMSCs, we first identified catechin, 18β-glycyrrhetinic acid, baishao, and danggui with osteogenic properties, which enhanced calcium deposition at the dose without significant cytotoxic effects. Primary hMSCs were then applied for confirming the osteogenic effects of catechin, which increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further found the extracellular signal-regulated kinase (ERK) pathway was downregulated upon stimulation with catechin. Catechin increased the level and activity of protein phosphatases 2A (PP2A) that dephosphorylates ERK kinase (MEK) and ERK. Further, PP2A inhibitor, okadaic acid, abolished the effect of catechin-mediated inactivation of ERK and stimulation of osteogenesis. The blocking effect of okadaic acid on osteogenesis was further reversed by PD98059, a specific inhibitor of MEK. Co-immunoprecipitation revealed the association of PP2A to both MEK and ERK.

CONCLUSIONS

These studies propose catechin enhanced osteogenesis by increasing the PP2A level that inhibits the MEK and ERK signaling in hMSCs. These results prove the concept of using hMSCs as a convenient tool for rapid and consistent screening of the osteogenic herbal ingredients and traditional Chinese compounds.

A transcriptome-based examination of blood group expression

Over the last two decades, red cell biologists witnessed a vast expansion of genetic-based information pertaining to blood group antigens and their carrier molecules. Genetic progress has led to a better comprehension of the associated antigens. To assist with studies concerning the integrated regulation and function of blood groups, transcript levels for each of the 36 associated genes were studied. Profiles using mRNA from directly sampled reticulocytes and cultured primary erythroblasts are summarized in this report. Transcriptome profiles suggest a highly regulated pattern of blood group gene expression during erythroid differentiation and ontogeny. Approximately one-third of the blood group carrier genes are transcribed in an erythroid-specific fashion. Low-level and indistinct expression was noted for most of the carbohydrate-associated genes. Methods are now being developed to further explore and manipulate expression of the blood group genes at all stages of human erythropoiesis.

Living-donor liver transplantation in patients with concurrent active tuberculosis at transplantation

SETTING

Although active tuberculosis (TB) is a contraindication for liver transplantation (LT), LT may be the only possible treatment option in patients with irreversible liver failure and concurrent TB.

OBJECTIVES

To assess the outcome of LT in patients with concurrent TB and liver failure.

METHODS

We retrospectively evaluated the clinical outcomes of nine LT recipients with concurrent TB in Korea, an intermediate TB burden country.

RESULTS

The primary causes of living-donor LT (LDLT) in nine patients were anti-tuberculosis drug-induced fulminant hepatic failure (n = 4) and end-stage liver disease (n = 5). The sites of active TB were the lungs (n = 5), lymph nodes (n = 3) and pleura (n = 1). After LDLT, most patients were treated with less hepatotoxic drugs, including fluoroquinolones, ethambutol and cycloserine; none was treated with pyrazinamide. One patient experienced acute rejection, probably attributable to an interaction between rifampicin and cyclosporine. All nine patients, including one taking rifabutin, successfully completed anti-tuberculosis treatment and have been followed up for a median of 926 days after LDLT, without relapse of TB.

CONCLUSION

When properly managed, the prognosis of LDLT recipients with concurrently active TB at transplantation is very favourable. The current protocol, which considers active TB an absolute contraindication for LT, should be modified or relaxed, particularly for patients with LDLT.

Endoscopic ultrasonography-guided fine-needle aspiration in the management of mediastinal diseases: local experience of a novel investigation

OBJECTIVE

To study the efficacy and safety of endoscopic ultrasonography-guided fine-needle aspiration in the management of mediastinal diseases in Hong Kong.

DESIGN

Retrospective review of prospectively collected data.

SETTING

University teaching hospital, Hong Kong.

PATIENTS

A total of 125 consecutive patients with various mediastinal and pulmonary lesions that underwent trans-oesophageal endoscopic ultrasonography-guided fine-needle aspiration from July 1998 to June 2007.

MAIN OUTCOME MEASURES

The diagnostic accuracy and safety of the procedure and its influence in patient management.

RESULTS

Malignancy was confirmed in 62 (50%) of the patients and excluded in 42 (34%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of endoscopic ultrasonography-guided fine-needle aspiration in diagnosing mediastinal malignancies were 75% (95% confidence interval, 64-83%), 100% (90-100%), 100% (93-100%), 67% (54-78%), and 83%, respectively. Eighty-six (69%) of the patients had their initial plan of invasive investigations changed. Only one (0.8%) patient developed a septic complication in a mediastinal cyst after puncturing, and was treated surgically.

CONCLUSIONS

Trans-oesophageal endoscopic ultrasonography-guided fine-needle aspiration is a minimally invasive, effective, and safe method of diagnosing malignant mediastinal disease. It may reduce the need for other invasive investigations.

Light-extraction enhancement of red AlGaInP light-emitting diodes with antireflective subwavelength structures

We demonstrate the enhancement of light extraction in 633 nm AlGaInP light-emitting diodes (LEDs) with antireflective subwavelength structures (SWS). From the contour plots by the rigorous coupled wave analysis method, it is found that the reduction of the internal reflection strongly depends on the period of SWS. The Ag nanoparticles formed by thermal dewetting were used as an etch mask for dry etch process to fabricate antireflective SWS on the LED surface. The tapered pillars on the GaP were fabricated, on average, with distances below 200 nm, satisfying the required antireflection condition at the emission wavelength. The improvement in light output power by approximately 26.4% was achieved for the fabricated AlGaInP LEDs with SWS compared to the conventional LEDs due to a strongly reduced Fresnel internal reflection at the GaP/air interface. The improved directionality in the far-field pattern was also obtained due to the directional light extraction enhancement.

High-speed characteristics of vertical cavity surface emitting lasers and resonant-cavity-enhanced photodetectors based on intracavity-contacted structure

We fabricated vertical cavity surface emitting lasers (VCSELs) and resonant-cavity-enhanced photodetectors (RCE-PDs) with GaAs/AlGaAs distributed Bragg reflectors (DBRs), operating at lambda approximately 980 nm, based on an intracavity-contacted structure. The top-DBR mesa diameter of the VCSELs was optimized to 18 microm in terms of slope efficiency, differential series resistance, and 3 dB bandwidth. For VCSELs with an oxide aperture of 4.5 microm and a top-DBR mesa diameter of 18 microm, the threshold current was about 1.2 mA, exhibiting maximum output power of approximately 3.49 mW (at 20 degrees C) with good uniformity. The effect of the overetching in the outermost layer of RCE-PDs on the device performance was also investigated. For RCE-PDs based on the VCSEL structure, a peak responsivity of 0.44 A/W (at lambda approximately 979.7 nm) with a spectral width of approximately 3 nm and a dark current of 68 pA under a bias voltage of -5 V at 20 degrees C was obtained. The maximum 3 dB bandwidths of approximately 11.5 GHz with a modulation current efficiency factor of 5.6 GHz/mA(1/2) at -7 mA and 9 GHz at -7 V were achieved for VCSELs and RCE-PDs, respectively.

A CMOS neuroelectronic interface based on two-dimensional transistor arrays with monolithically-integrated circuitry

The ability to monitor and to elicit neural activity with a high spatiotemporal resolution has grown essential for studying the functionality of neuronal networks. Although a variety of microelectrode arrays (MEAs) has been proposed, very few MEAs are integrated with signal-processing circuitry. As a result, the maximum number of electrodes is limited by routing complexity, and the signal-to-noise ratio is degraded by parasitics and noise interference. This paper presents a single-chip neuroelectronic interface integrating oxide-semiconductor field-effect transistors (OSFETs) with signal-processing circuitry. After the chip was fabricated with the standard complementary-metal-oxide-semiconductor (CMOS) process, polygates of specific transistors were etched at die-level to form OSFETs, while metal layers were retained to connect the OSFETs into two-dimensional arrays. The complete removal of polygates was confirmed by high-resolution image scanners, and the reliability of OSFETs was examined by measuring their electrical characteristics. Through a gate oxide of only 7nm thick, each OSFET can record and stimulate neural activity extracellularly by capacitive coupling. The capability of the full chip in neural recording and stimulation was further experimented using the well-characterised escape circuit of the crayfish. Experimental results indicate that the OSFET-based neuroelectronic interface can be used to study neuronal networks as faithfully as conventional electrophysiological tools. Moreover, the proposed simple, die-level fabrication process of the OSFETs underpins the development of various field-effect biosensors on a large scale with on-chip circuitry.

Endoscopic submucosal dissection used for treating early neoplasia of the foregut using a combination of knives

BACKGROUND

Endoscopic submucosal dissection (ESD) has emerged as a novel technique for achieving en bloc resection for early esophageal or gastric carcinoma limited to the mucosa. The authors report their experience with a combination of various devices to treat early neoplasia of the foregut using the ESD technique.

METHODS

In this prospective case series, ESD was performed for early esophageal or gastric carcinoma limited to the mucosa. These lesions were staged by endoscopic ultrasonography before resection. Magnifying endoscopy and chromoendoscopy were used to locate the tumor and define the margin. The resection was accomplished with submucosal dissection using the insulated tip knife, the hook knife, and the triangular tip knife. The resected specimen was examined systematically for the lateral and deep margins.

RESULTS

From January 2004 to March 2006, ESD was performed to manage 30 cases of early gastric or esophageal carcinoma. For 29 of these patients, R0 resection was successfully achieved. The mean operating time was 84.6 min. One patient experienced reactionary hemorrhage 12 h after resection, which was controlled endoscopically. There was no perforation. Most of the circumferential mucosal incisions were performed using the insulated tip knife (76.6%), whereas submucosal dissection was accomplished with a combination of various knives. One of the specimens showed involvement of the lateral margin, whereas another patient had two areas of new early gastric cancer 6 months after the initial procedure. These patients received salvage laparoscopically assisted gastrectomy.

CONCLUSIONS

Endoscopic submucosal dissection to manage early neoplasia of the foregut can be achieved safely and effectively with a combination of knives.

A novel gene, Pi40(t), linked to the DNA markers derived from NBS-LRR motifs confers broad spectrum of blast resistance in rice

Rice blast disease caused by Magnaporthe grisea is a continuous threat to stable rice production worldwide. In a modernized agricultural system, the development of varieties with broad-spectrum and durable resistance to blast disease is essential for increased rice production and sustainability. In this study, a new gene is identified in the introgression line IR65482-4-136-2-2 that has inherited the resistance gene from an EE genome wild Oryza species, O. australiensis (Acc. 100882). Genetic and molecular analysis localized a major resistance gene, Pi40(t), on the short arm of chromosome 6, where four blast resistance genes (Piz, Piz-5, Piz-t, and Pi9) were also identified, flanked by the markers S2539 and RM3330. Through e-Landing, 14 BAC/PAC clones within the 1.81-Mb equivalent virtual contig were identified on Rice Pseudomolecule3. Highly stringent primer sets designed for 6 NBS-LRR motifs located within PAC clone P0649C11 facilitated high-resolution mapping of the new resistance gene, Pi40(t). Following association analysis and detailed haplotyping approaches, a DNA marker, 9871.T7E2b, was identified to be linked to the Pi40(t) gene at the 70 Kb chromosomal region, and differentiated the Pi40(t) gene from the LTH monogenic differential lines possessing genes Piz, Piz-5, Piz-t, and Pi-9. Pi40(t) was validated using the most virulent isolates of Korea as well as the Philippines, suggesting a broad spectrum for the resistance gene. Marker-assisted selection (MAS) and pathotyping of BC progenies having two japonica cultivar genetic backgrounds further supported the potential of the resistance gene in rice breeding. Our study based on new gene identification strategies provides insight into novel genetic resources for blast resistance as well as future studies on cloning and functional analysis of a blast resistance gene useful for rice improvement.

Photodissociation of 1,3,5-Triazine: An Ab Initio and RRKM Study

The ab initio/Rice-Ramsperger-Kassel-Marcus (RRKM) approach has been applied to investigate the photodissociation mechanism of 1,3,5-triazine at different wavelengths of the absorbed photon. Reaction pathways leading to various decomposition products have been mapped out at the G3(MP2,CC)//B3LYP level, and then the RRKM and microcanonical variational transition state theories have been applied to compute rate constants for individual reaction steps. Relative product yields (branching ratios) for the dissociation products have been calculated using the steady-state approach. The results show that, after being excited by 275, 248, or 193 nm photons, the triazine molecule isomerizes to an opened-ring structure on the first singlet excited-state potential energy surface (PES), which is followed by relaxation into the ground electronic state via internal conversion. On the contrary, excitation by 285 and 295 nm photons cannot initiate the ring-opening reaction on the excited-state PES, and the molecule relaxes into the energized ring isomer in the ground electronic state. The dissociation reaction starting from the ring isomer is calculated to have branching ratios of various reaction channels significantly different from those for the reaction initiating from the opened-ring structure. The existence of two distinct mechanisms of 1,3,5-triazine photodissociation can explain the inconsistency in the translational energy distributions of HCN moieties at different wavelengths observed experimentally.

Familial aggregation of metabolic syndrome among the Chinese: report from the Chin-Shan community family study

Genetic study on metabolic syndrome is a great challenge, due to its complex traits and the pleiotropic manifestation of atherosclerosis. Familial aggregation and recurrence risk ratio can provide the insight of possible genetic mechanism. The Chin-Shan community family study was based on adolescent probands and their relatives (1356 subjects) who were recruited from one junior high school in the community. Structured questionnaires and biochemical measures were obtained in standard procedures. Definition of metabolic syndrome was followed using the criteria defined by the third adult treatment panel, with a modification of the criteria for adolescent and Asian population. Grandmothers had the highest frequencies (70%) in metabolic syndrome and various atherosclerotic risks. Three factors were found and thus explained 68% of the overall variance. Estimated heritability was the highest in LDL and cholesterol factor (0.36 and 0.40), then blood pressure/obesity factor (0.27), and insulin resistance/dyslipidemia (0.27). Recurrence risk ratio among siblings was 2.95 (95% confidence interval [CI]: 1.39-6.26). The adjusted odds ratio (OR) of proband's metabolic syndrome status was 1.99 (95% CI: 1.08-3.66). The adjusted odds ratios for the three factors for predicting metabolic syndrome were all significant, with highest risk in blood pressure/obesity factor (OR: 1.27, CI: 1.22-1.33), then insulin resistance/dyslipidemia (OR: 1.29, CI: 1.16-1.23). This study demonstrated clearly familial aggregation and recurrence risk ratio of metabolic syndrome and components among the general ethnic Chinese population in Taiwan.