Liver and Muscle Contribute Differently to the Plasma Acylcarnitine Pool During Fasting and Exercise in Humans

BACKGROUND

Plasma acylcarnitine levels are elevated by physiological conditions such as fasting and exercise but also in states of insulin resistance and obesity.

AIM

To elucidate the contribution of liver and skeletal muscle to plasma acylcarnitines in the fasting state and during exercise in humans.

METHODS

In 2 independent studies, young healthy males were fasted overnight and performed an acute bout of exercise to investigate either acylcarnitines in skeletal muscle biopsies and arterial-to-venous plasma differences over the exercising and resting leg (n = 9) or the flux over the hepato-splanchnic bed (n = 10).

RESULTS

In the fasting state, a pronounced release of C2- and C3-carnitines from the hepato-splanchnic bed and an uptake of free carnitine by the legs were detected. Exercise further increased the release of C3-carnitine from the hepato-splanchnic bed and the uptake of free carnitine in the exercising leg. In plasma and in the exercising muscle, exercise induced an increase of most acylcarnitines followed by a rapid decline to preexercise values during recovery. In contrast, free carnitine was decreased in the exercising muscle and quickly restored thereafter. C8-, C10-, C10:1-, C12-, and C12:1-carnitines were released from the exercising leg and simultaneously; C6, C8, C10, C10:1, C14, and C16:1 were taken up by the hepato-splanchnic.

CONCLUSION

These data provide novel insight to the organo-specific release/uptake of acylcarnitines. The liver is a major contributor to systemic short chain acylcarnitines, whereas the muscle tissue releases mostly medium chain acylcarnitines during exercise, indicating that other tissues are contributing to the systemic increase in long chain acylcarnitines.

Comparison of clinicopathological features and prognosis of gastric cancer located in the lesser and greater curve

PURPOSE

Little is known about the features of gastric cancer located in the lesser and greater curve. This study aims to investigate the clinicopathological features and prognosis of gastric cancer located in the lesser and greater curve.

PATIENTS

From September 2008 to March 2015, 780 gastric cancer patients were enrolled in the present study. The associations between locations and features of patients were analyzed.

RESULTS

There were 571 male (73.2 %) and 209 female (26.8 %) patients. The median age was 56 years (ranged 21-86). There were 684 tumors located in the lesser curve (87.7 %) and 96 located in the greater curve (12.3 %). The incidence of melena was significantly lower in patients with tumors located in the lesser curve than that in the greater curve (8.5 vs 15.6 %, P = 0.024). The median size of tumors in the lesser curve was significantly larger than that in the greater curve (5.0 (0.3-15) vs 4.0 cm (0.5-15), P = 0.001). The remaining clinicopathological features were comparable between the two groups (all P > 0.05). Tumor location was not a risk factor for the prognosis of gastric cancer by univariate and multivariate analysis (both P > 0.05). The postoperative complications (all P > 0.05) and prognoses (P = 0.279) were comparable between tumors located in the lesser and greater curve.

CONCLUSIONS

The ratio of gastric cancer located in the lesser to greater curve was 7.1:1. Compared with tumors located in the greater curve, the incidence of melena was significantly lower and the tumor size was significantly larger in tumors located in the lesser curve. The prognoses were comparable between tumors located in the lesser and greater curve.

Decoupled polarization dynamics of incoherent waves and bimodal spectral incoherent solitons

We consider the propagation of strongly incoherent waves in optical fibers in the framework of the vector nonlinear Schrödinger equation (VNLSE) accounting for the Raman effect. On the basis of the wave turbulence theory, we derive a kinetic equation that greatly simplifies the VNLSE and provides deep physical insight into incoherent wave dynamics. When applied to the study of polarization effects, the theory unexpectedly reveals that the linear polarization components of the incoherent wave evolve independently from each other, even in the presence of weak fiber birefringence. When applied to light propagation in bimodal fibers, the theory reveals that the incoherent modal components can be strongly coupled. After a complex transient, the modal components self-organize into a vector spectral incoherent soliton: The two solitons self-trap and propagate with a common velocity in frequency space.

Autologous hematopoietic stem cell transplantation in patients with end-stage liver disease: a 5-year follow-up study of 48 patients

OBJECTIVE

To investigate the long-term therapeutic effect of autologous hematopoietic stem cell transplantation in patients with End-stage Liver Disease (ESLD).

PATIENTS AND METHODS

Forty-eight ESLD patients underwent autologous CD34+ stem cell transplantation were retrospectively reviewed. Changes in clinical and biochemical data, complications, and quality of life were monitored at 3, 6, 12, 36, and 60 months following the stem cell transplantation. Liver biopsies were obtained for histopathological analysis using Ishak system.

RESULTS

Marked improvement in clinical and biochemical data was observed during the long-term follow-up. Serum albumin was significantly increased (p<0.001), while total serum bilirubin, prothrombin time (PT), and international normalized ratio (INR) were all significantly decreased (p<0.001). Ishak inflammation and fibrosis scores were significantly decreased with the increased time (p<0.001). The number of patients with ascites, model of end-stage liver disease (MELD) score, Child-Pugh class, and indocyanine green (ICG) score were all markedly reduced with increased time. Meanwhile, the quality of life score of the patients was significantly increased (p<0.001). Six patients died during the 5-years follow-up, and complications occurred in 17 patients. The incidence of complications was significantly associated with mortality of the patients (p<0.05).

CONCLUSIONS

The study provided the evidence that autologous CD34+ stem cell transplantation could offer a long-term therapeutic benefit to patients with ESLD. The complications occurred during the process was significantly associated with survival of the patients. Future studies on a large cohort of patients are needed to confirm the long-term effect of stem cell therapy on ESLD.

Coexistence of intracranial aneurysm and hemangioblastoma: A case report and literature review

The association of intracranial aneurysm and hemangioblastoma is extremely rare. This report regards a patient affected by Von Hippel-Lindau syndrome with multiple hemangioblastoma and two intracranial aneurysms, of which one was on a hemangioblastoma feeder vessel and the other on an unrelated vessel. Review of the literature revealed 13 other previously reported cases. Possible mechanisms to explain the association are discussed.

[Outcomes of total deafness type of idiopathic suddendeafness in different ages]

Objective:This retrospective study was aimed to investigate the characteristics of hearing recovery in the complete deafness type of SSNHL(≥81 dBHL) in patients with different ages.Method:Clinical outcomes of 179 total deafness type of idiopathic sudden deafness were compared.Patients were divided into 5 groups according to age,they were,pediatric group(13 years or less),youthful group(14-44 years),middle-aged group(45-59 years),presenium group(60-74 years),senectitude group(75 years or higher).Patients were divided into 3 groups according to the initial degree of hearing loss: 81 dB group (81-89 dBHL),90 dB group(90- 99 dBHL),100 dB group(100 dBHL or higher).Routine comprehensive treatment including corticosteroids,the inner ear microcirculation improvement drugs,neurotrophic drugs,saturationoxygen and hyperbaric oxygen therapy,etc.was applied.Patients were treated in accordance with the age and body weight.Result:The percentage of youthful group(83/179,46.4%) was highest(P<0.05),middle-aged group(57/179,31.8%)followed(P<0.05),presenium group(26/179,14.5%)was lower(P<0.05),pediatric group(8/179,4.5%) and senectitude group(5/179,2.8%)were the lowest.No a complete recovery in either pediatric group or senectitude group.A complete recovery was rare in the other groups.Recovery rate of the different aged groups was similar(P>0.05).The percentage of 100 dB group(108/179,60.3%) was highest(P<0.05).The percentage of 81 dB group(39/179,21.8%)was similar to 90 dB group(32/179,17.9%)(P>0.05).Recovery rate was similar in 81 dB group(25/39,64.1%)and 90 dB group(18/32,56.2%)(P>0.05).Recovery rate of both 81 dB group and 90 dB group were greater than 100 dB group(24/108,22.2%)(P<0.05).The 100 dB group reduced the satisfactory recovery effects.There were no differences in the proportion of the patients with dizziness(95/179,53.1%)and without dizziness(84/179,46.9%)(P>0.05).Recovery rate of patients without dizziness(43/84,51.2%) was greater than with dizziness(24/95,25.3%)(P<0.05).The percentage of the patients without dizziness(31/39,79.5%)in 81 dB group was the highest(P<0.05),90 dB group(18/32,56.2%)followed(P<0.05).The percentage of the patients with dizziness in 100 dB group(73/108,67.6%)was highest(P<0.05).Recovery rate was similar in the patients without dizziness of 81 dB group(21/31,67.7%)and 90 dB group(11/18,61.1%)(P>0.05).Recovery rate of the above two groups was greater than that of 100 dB group(11/35,31.4%)(P<0.05).Conclusion:Recovery rate of the different aged groups was similar.The percentage of the patients with dizziness in 100 dB group was highest.Initial hearing threshold in excess of 100 dB reduced the satisfactory recovery in patients with total deafness type of SSNHL.Our results provided a good reference for other clinicians.

Shock wave generation triggered by a weak background in optical fibers

We experimentally report the observation of dispersive shock waves from a short pulse superimposed onto a small continuous wave background in optical fibers. We show that the background allows us to strongly enhance the extension and contrast of the oscillatory wave train inherent to the dispersive shock. More than seven periods of oscillations with high contrast are observed experimentally and confirmed with numerical simulations. The dynamics of the process are simply explained from spectro-temporal representations.

Recessive dystrophic epidermolysis bullosa caused by a de novo interstitial deletion spanning COL7A1 and a hemizygous splicing mutation in trans

BACKGROUND

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare heritable blistering skin condition caused by loss-of-function mutations in the COL7A1 gene. Incongruent gene transmission is occasionally reported in recessive diseases, and its underlying mechanism is often uniparental disomy (UPD).

AIM

To understand the genetic basis of incongruent gene transmission in a Chinese family with RDEB, in which a discrepancy of COL7A1 genotyping was encountered during our mutation analysis.

METHODS

We used a pCAS2 minigene-based in vitro splicing assay to confirm the pathogenicity of the splicing variant we identified in the proband. Next, a combination of genetic tools, including whole-genome SNP array analysis and multiplex ligation-dependent probe amplification copy number analysis, was used to unravel the cause of the discrepancy in the COL7A1 genotyping.

RESULTS

Sanger sequencing identified a novel, single-peak mutation, c.4980+5G>C, in COL7A1 in the proband, which was heterozygous in his father and wild type in his mother. In vitro splicing assay showed that c.4980+5G>C was pathogenic and led to skipping of COL7A1 exon 53. SNP array analysis and multiplex ligation-dependent probe amplification of the proband's DNA revealed a maternally derived, de novo, interstitial deletion on chromosome 3p21.31, which removed COL7A1 and 15 flanking genes, excluding the possibility of UPD.

CONCLUSION

Our findings favour an exceptionally rare event, namely a de novo COL7A1 microdeletion in concurrence with an inherited mutation in trans. This study should aid molecular diagnosis and genetic counselling of RDEB and possibly other recessive diseases in which genotyping discrepancy is encountered.

[Scalp surface skin grafts in reconstruction of external auditory meatus in congenital aural atresia]

OBJECTIVE

To investigate the clinical application of scalp skin grafts in reconstruction of external auditory meatus in congenital aural atresia.

METHODS

We conducted a retrospective study on 85 patients of congenital aural atresia, all of whom were unilateral, operated from March of 2008 to December of 2010 in ENT department of the Sun Yat-Sen Memorial Hospital. The patients enrolled in the study were between 6 to 37 years old (median age 12 years), 55 male and 30 female. Scalp surface graft in ipsilateral temporal region was harvested to cover the bony external auditory meatus.

RESULTS

All of these scalp split-thickness skin grafts survived without necrosis, no restenosis was found in these external auditory meatus. Neither scar nor alopecia was found in the skin-harvesting region, and hairs grew well. Granulations occurred in 27 cases in the first to sixth month posteroperatively, 20 cases recovered after local treatment. In the first year, 30 cases obtained hearing improvement more than 15 dB, 36 cases gained more than 25 dB and 19 cases gained more than 35 dB. Totally 8 patients were lost in the 4 to 5 years of follow-up, 70 cases (70/77, 90.9%) developed new external auditory meatus, 7 cases (7/77, 9.1%) suffered from stenosis in different degrees, but no atresia was found in these patients.

CONCLUSION

Scalp split-thickness skin grafts has significant clinical advantage in meatoplasty of congenital aural atresia.

Inherent predominance of high chiral angle metallic carbon nanotubes in continuous fibers grown from a molten catalyst

We present evidence that high temperature CVD growth of SWNTs under conditions of continuous spinning of macroscopic fibers leads to an inherent predominance of high chiral angle CNTs, peaking at the armchair end. Raman, UV-vis-NIR absorption, and photoluminescence spectroscopy measurements show the prevalence of metallic SWNTs. The complete chiral angle distribution is obtained by electron diffraction of over 390 CNTs. It is biased towards high chiral angles and peaks at the armchair end (30°), in good agreement with the established atomistic models for SWNT growth from a liquid catalyst. Based on the Fe-C-S constituent binary and ternary phase diagrams, thermodynamic calculations of phase compositions from fast cooling and experimental evidence of a post-synthesis catalyst, the proposed thermodynamic path of the catalyst is to form a solid FCC Fe core and a liquid Fe-S shell. S in the outer liquid shell first stabilizes the edge of the nascent CNT, but once a graphitic wall forms it is rejected due to the high interfacial energy of the Fe-C-S alloy.

Low nanomolar concentrations of Cucurbitacin-I induces G2/M phase arrest and apoptosis by perturbing redox homeostasis in gastric cancer cells in vitro and in vivo

Cucurbitacin-I (Cu-I, also known as Elatericin B or JSI-124) is developed to inhibit constitutive and abnormal activation of STAT3 in many cancers, demonstrating a potent anticancer activity by targeting disruption of STAT3 function. Here, we for the first time systematically studied the underlying molecular mechanisms of Cu-I-induced gastric cancer cell death both in vitro and in vivo. In our study, we show that Cu-I markedly inhibits gastric cancer cell growth by inducing G2/M phase cell cycle arrest and apoptosis at low nanomolar concentrations via a STAT3-independent mechanism. Notably, Cu-I significantly decreases intracellular GSH/GSSG ratio by inhibiting NRF2 pathway to break cellular redox homeostasis, and subsequently induces the expression of GADD45α in a p53-independent manner, and activates JNK/p38 MAPK signaling. Interestingly, Cu-I-induced GADD45α and JNK/p38 MAPK signaling form a positive feedback loop and can be reciprocally regulated by each other. Therefore, the present study provides new insights into the mechanisms of antitumor effects of Cu-I, supporting Cu-I as an attractive therapeutic drug in gastric cancer by modulating the redox balance.

Intermedin/adrenomedullin 2 polypeptide promotes adipose tissue browning and reduces high-fat diet-induced obesity and insulin resistance in mice

OBJECTIVES

There is an urgent need to develop interventions and policies to mitigate the health effects of obesity by targeting its metabolic mediators. Adrenomedullin 2 (AM2)/intermedin (IMD) is a secreted peptide that has an important role in protecting the cardiovascular system. However, the role of AM2 in type 2 diabetes is unknown.

METHODS

Wild-type (WT) and aP2/AM2 transgenic (aAM2-tg) mice were fed a high-fat diet (HFD) for 8 weeks, and WT mice were treated with AM2 through mini-osmotic pumps. Indirect calorimetry, ambulatory activity and food intake, hyperinsulinemic-euglycemic clamp test, glucose and insulin tolerance tests were used for assessing insulin resistance. Rat primary adipocytes and pre-adipocyte-derived adipocytes were used for in vitro experiments. Real-time PCR and western blot were used for analyses of gene expression and protein level.

RESULTS

AM2 and receptor activity-modifying proteins expressions were significantly decreased in the adipose tissue of obese mice. AM2 treatment significantly reduced blood glucose, fasting serum insulin and free fatty acid levels, improved glucose tolerance and insulin sensitivity, and increased the glucose infusion rate during a hyperinsulinemic-euglycemic clamp test, indicating ameliorated HFD-induced insulin resistance. These effects were consistently observed in aAM2-tg mice under HFD conditions, whereas the aAM2-tg mice showed less weight gain and improved glucose tolerance and insulin sensitivity. More importantly, the aAM2-tg mice had increased oxygen consumption and CO2 production, reflecting more energy expenditure. These effects may be due to increased AMP-activated protein kinase phosphorylation and reduced peroxisome proliferator-activated receptor gamma co-activator 1α (PGC1α) acetylation, which result in interactions between PGC1α and PR domain containing 16 and then promote uncoupling protein 1 (UCP1) expression in adipocytes.

CONCLUSIONS

These results indicate that endogenous AM2 might be involved in energy metabolism in adipocytes through the upregulation of UCP1 expression.

Sputum bacteriology in steady-state bronchiectasis in Guangzhou, China

BACKGROUND

The impact of potentially pathogenic micro-organisms (PPMs) on Chinese patients with steady-state bronchiectasis is unknown.

METHODS

Peripheral blood and sputum were sampled to determine inflammatory markers and sputum bacterial density. Spirometry and diffusing capacity were measured. Quality of life was assessed using the St George's Respiratory Questionnaire.

RESULTS

Of 144 patients with steady-state bronchiectasis, Pseudomonas aeruginosa was isolated in 44 cases (30.6%). Compared with other PPMs, P. aeruginosa had a more pronounced influence on airway inflammation and spirometry, but not on systemic inflammation or quality of life. The impact of PPMs other than P. aeruginosa on clinical indices was similar. Bacterial density was not correlated with most clinical parameters. Factors associated with PPM isolation included bronchiectasis symptoms for ⩾ 10 years (OR 2.13) and ⩾ 4 bronchiectatic lobes (OR 2.82). Having ⩾ 4 exacerbations within 2 years (OR 2.18) and cystic bronchiectasis (OR 2.23) was associated with the colonisation of PPMs, i.e., isolating an identical PPM on at least two occasions within 1 year.

CONCLUSION

In patients with steady-state bronchiectasis in Guangzhou, P. aeruginosa is the most common organism causing heightened airway inflammation and poor lung function. PPM isolation or colonisation should be suspected in case of longer duration of symptoms, multilobar bronchiectasis, frequent exacerbation and cystic bronchiectasis.

Prevalence and Determinants of Metabolic Syndrome-identified by Three Criteria among Men in Rural China: A Population-based Cross-sectional Study Conducted during 2007-2008

OBJECTIVE

The aim of this study was to estimate MS prevalence according to three criteria and its risk factors among men in rural China.

DESIGN

Cross-sectional study.

SETTING

The Nantong Metabolic Syndrome Study (NMSS) was conducted during 2007-2008 in Nantong, China.

PARTICIPANTS

6997 male participants aged 18-74 years.

MEASUREMENTS

In person interviews, blood glucose and lipid measurements were accomplished.

RESULTS

The prevalence of MS was 12.86%, 8.55% and 15.28% according to IDF, ATPIII and ATPIII-modified criteria, respectively. The IDF and ATP III-modified criteria agreed only moderately with ATP III criteria (κ= 0.56 and 0.68), whereas ATP III-modified and the IDF criteria agreed perfectly (κ= 0.90). Vigorous occupational physical activity was associated with a low prevalence of MS with Odds ratio (OR) of 0.58 (95% confidence interval (CI): 0.45-0.74). Beer drinkers (alcohol ≤ 6.2 g/day) and rice wine drinkers (alcohol ≤ 9.0 g/day) had about 34% and 33% low risks of developing MS respectively, compared with non-drinkers. OR of MS was 1.95 (95% CI: 1.39-2.73) in men who had familial history of at least two diseases, including hypertension and diabetes, compared with men without familial history of those diseases.

CONCLUSIONS

Our data suggested that MS is highly prevalent among men in rural China. Family history of diabetes and hypertension is a risk factor in MS development. Physical activity, rice wine and beer consumption are associated with a significantly lower risk.

Colossal dielectric performance of pure barium titanate ceramics consolidated by spark plasma sintering

The pure BaTiO₃ nanoceramics have a high permittivity up to 6 × 10⁴ and a low dielectric loss. The polaron dipoles configured by oxygen vacancies and Ti³⁺ cations within grains could contribute to the colossal dielectric permittivity of the ceramics.

Performance Evaluation of a Nanofluid-Based Direct Absorption Solar Collector with Parabolic Trough Concentrator

Application of solar collectors for hot water supply, space heating, and cooling plays a significant role in reducing building energy consumption. For conventional solar collectors, solar radiation is absorbed by spectral selective coating on the collectors’ tube/plate wall. The poor durability of the coating can lead to an increased manufacturing cost and unreliability for a solar collector operated at a higher temperature. Therefore, a novel nanofluid-based direct absorption solar collector (NDASC) employing uncoated collector tubes has been proposed, and its operating characteristics for medium-temperature solar collection were theoretically and experimentally studied in this paper. CuO/oil nanofluid was prepared and used as working fluid of the NDASC. The heat-transfer mechanism of the NDASC with parabolic trough concentrator was theoretically evaluated and compared with a conventional indirect absorption solar collector (IASC). The theoretical analysis results suggested that the fluid’s temperature distribution in the NDASC was much more uniform than that in the IASC, and an enhanced collection efficiency could be achieved for the NDASC operated within a preferred working temperature range. To demonstrate the feasibility of the proposed NDASC, experimental performances of an NDASC and an IASC with the same parabolic trough concentrator were furthermore evaluated and comparatively discussed.

Sleep duration and timing in relation to osteoporosis in an elderly Chinese population: a cross-sectional analysis in the Dongfeng-Tongji cohort study

This population-based cross-sectional study in an older Chinese population shows a link between sleep duration, sleep timing, and osteoporosis risk, suggesting that sleep may have a role in osteoporosis development. These findings may help to identify contributing mechanisms and provide new opportunities for sleep-focused interventions to prevent osteoporosis.

INTRODUCTION

Accumulated evidence suggests that sleep pattern disruption may lead to alterations in physiology, potentially triggering the development of osteoporosis. The present study sought to examine whether sleep duration or sleep timing is associated with osteoporosis.

METHODS

A total of 31,769 participants (aged 45-86 years) were recruited from the Dongfeng-Tongji cohort study. All participants completed questionnaires and medical examinations and provided blood samples. The presence of osteoporosis was determined using calcaneal quantitative ultrasonography. Logistic regression models were used to evaluate the association of sleep duration and timing with osteoporosis, after adjusting for potential confounders.

RESULTS

The prevalence of osteoporosis was 14.2 % in men and 23.9 % in women. After controlling for potential confounders, the adjusted odds ratio (OR) [95 % confidence interval (CI)] for osteoporosis comparing sleep duration of 9 h or longer with the reference (7-8 h) was 1.40 (1.22-1.62) in men and 1.20 (1.07-1.33) in women. Men with early sleep timing (going to sleep before 21:00 h) were more likely to have osteoporosis (OR, 1.43; 95 % CI, 1.16-1.78) than those with normal sleep timing (going to sleep between 21:00 and 23:00 h). In the interaction analysis, participants with long sleep duration and early sleep timing had the highest risk of osteoporosis both in men (OR, 1.79; 95 % CI, 1.48-2.16) and women (OR, 1.41; 95 % CI, 1.19-1.66).

CONCLUSIONS

Long sleep duration (≥9 h) and early sleep timing were independently and interactively associated with an increased risk of osteoporosis in this older Chinese population.

Validation of the Mandarin Chinese version of the Leicester Cough Questionnaire in bronchiectasis

BACKGROUND

The Leicester Cough Questionnaire (LCQ) has been validated for assessing cough-specific health status in bronchiectasis. We translated the LCQ into Mandarin Chinese and investigated its validity, reliability and responsiveness.

METHODS

The LCQ was translated into Mandarin Chinese using the forward-backward translation procedure. A total of 144 out-patients completed the Mandarin Chinese version of the LCQ (LCQ-MC), the Hospital Anxiety and Depression Scale (HADS) and the St George's Respiratory Questionnaire. Reassessments were performed during exacerbations and at 6 months. Concurrent validation, internal consistency, repeatability and responsiveness were determined.

RESULTS

Minor cultural adaptations were made to the wording of LCQ-MC. No other difficulties were found during the translation process, with all items easily adapted to acceptable Mandarin Chinese. The questionnaire was not changed in terms of content layout and the order of the questions. In cognitive debriefing interviews, participants reported that the questionnaire was acceptable, relevant, comprehensive and easy to complete. The LCQ-MC showed good concurrent validity, internal consistency and test-retest reliability. Responsiveness was shown by significant changes in LCQ-MC scores between steady state, the first exacerbation and following 2-week antibiotic treatment (both interval changes, P < 0.01) CONCLUSION: The LCQ-MC is a valid, reliable and responsive instrument for determining cough-specific health status in Chinese bronchiectasis patients.

Identification of mutations in U2HR in two Chinese families with Marie Unna hereditary hypotrichosis

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal dominant genodermatosis characterized by coarse, wiry, twisted hair developing during early childhood, with subsequent progressive hair loss. Recently, mutations in U2HR, an inhibitory upstream open reading frame in the 5' untranslated region of the human hairless gene (HR), were identified as the underlying cause of MUHH. We investigated two unrelated Chinese multigenerational families with MUHH. By sequencing U2HR in the two families, we identified two previously reported mutations, c.1A >T (p.Met1?) and c.104A>G (p*35Wext1263*). Both these mutations cosegregated with the disease phenotype in the two families.

Impact of adherence to GOLD guidelines on 6-minute walk distance, MRC dyspnea scale score, lung function decline, quality of life, and quality-adjusted life years in a Shanghai suburb

We performed a 1-year cluster-randomized field trial to assess the effect of standardized management of chronic obstructive pulmonary disease (COPD) on lung function and quality of life (QOL) measures in patients in China. We used the Global Initiative for Chronic Obstructive Lung Disease (GOLD) treatment guidelines and assessed indexes including pulmonary function, QOL, quality-adjusted life years (QALY), Medical Research Council (MRC) dyspnea scale, 6-min walk distance (6-MWD), number of emergency visits, and frequency of hospitalization. Of a total of 711 patients with chronic cough and asthma, 132 were diagnosed as having COPD and 102 participated in this study [intervention group (N = 47); control group (N = 55)]. We found that adherence to GOLD guidelines had a perceivable impact on 6-MWD, MRC dyspnea scale score, and QOL. The average QALY increased by 1.42/person/year in the intervention group, but declined by 0.95/person/year in the control group. We conclude that standardized management improves disease severity, QOL, and QALY in COPD patients when treatment protocols adhere to GOLD guidelines.

Nomogram for Predicting Time to Death After Withdrawal of Life-Sustaining Treatment in Patients With Devastating Neurological Injury

Reliable prediction of time of death after withdrawal of life-sustaining treatment in patients with devastating neurological injury is crucial to successful donation after cardiac death. Herein, we conducted a study of 419 neurocritical patients who underwent life support withdrawal at four neurosurgical centers in China. Based on a retrospective cohort, we used multivariate Cox regression analysis to identify prognostic factors for patient death, which were then integrated into a nomogram. The model was calibrated and validated using data from an external retrospective cohort and a prospective cohort. We identified 10 variables that were incorporated into a nomogram. The C-indexes for predicting the 60-min death probability in the training, external validation and prospective validation cohorts were 0.96 (0.93-0.98), 0.94 (0.91-0.97), and 0.99 (0.97-1.00), respectively. The calibration plots after WLST showed an optimal agreement between the prediction of time to death by the nomogram and the actual observation for all cohorts. Then we identified 22, 26 and 37 as cut-points for risk stratification into four groups. Kaplan-Meier curves indicated distinct prognoses between patients in the different risk groups (p < 0.001). In conclusion, we have developed and validated a nomogram to accurately identify potential cardiac death donors in neurocritical patients in a Chinese population.

Inflammatory Responses, Spirometry, and Quality of Life in Subjects With Bronchiectasis Exacerbations

BACKGROUND

Bronchiectasis exacerbations are critical events characterized by worsened symptoms and signs (ie, cough frequency, sputum volume, malaise).

OBJECTIVES

Our goal was to examine variations in airway and systemic inflammation, spirometry, and quality of life during steady state, bronchiectasis exacerbations, and convalescence (1 week following a 2-week antibiotic treatment) to determine whether potentially pathogenic microorganisms, including Pseudomonas aeruginosa, were associated with poorer conditions during bronchiectasis exacerbations.

METHODS

Peripheral blood and sputum were sampled to detect inflammatory mediators and bacterial densities. Spirometry and quality of life (St George Respiratory Questionnaire [SGRQ]) were assessed during the 3 stages.

RESULTS

Forty-eight subjects with bronchiectasis (43.2 ± 14.2 y of age) were analyzed. No notable differences in species and density of potentially pathogenic microorganisms were found during bronchiectasis exacerbations. Except for CXCL8 and tumor necrosis factor alpha (TNF-α), serum inflammation was heightened during bronchiectasis exacerbations and recovered during convalescence. Even though sputum TNF-α was markedly higher during bronchiectasis exacerbations and remained heightened during convalescence, the variations in miscellaneous sputum markers were unremarkable. Bronchiectasis exacerbations were associated with notably higher SGRQ symptom and total scores, which recovered during convalescence. FVC, FEV1, and maximum mid-expiratory flow worsened during bronchiectasis exacerbations (median change from baseline of -2.2%, -0.8%, and -1.3%) and recovered during convalescence (median change from baseline of 0.6%, 0.7%, and -0.7%). Compared with no bacterial isolation, potentially pathogenic microorganism or P. aeruginosa isolation at baseline did not result in poorer clinical condition during bronchiectasis exacerbations.

CONCLUSIONS

Bronchiectasis exacerbations are characterized by heightened inflammatory responses and poorer quality of life and spirometry, but not by increased bacterial density, which applies for subjects with and without potentially pathogenic microorganism isolation when clinically stable. (ClinicalTrials.gov registration NCT01761214.).

Assessment by three-dimensional power Doppler ultrasound of cerebral blood flow perfusion in fetuses with congenital heart disease

OBJECTIVES

To use three-dimensional (3D) power Doppler ultrasound to investigate cerebral blood flow perfusion in fetuses with congenital heart disease (CHD).

METHODS

The vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the total intracranial volume and the main arterial territories (middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA)) were evaluated prospectively and compared in 112 fetuses with CHD and 112 normal fetuses using 3D power Doppler. Correlations between the 3D power Doppler indices and neurodevelopment scores at 12 months of age were assessed in a subset of the CHD group, and values were compared with those of controls.

RESULTS

Compared with the controls, the VI, FI and VFI of the total intracranial volume and the three main arteries were significantly higher in fetuses with hypoplastic left heart syndrome and left-sided obstructive lesions (P < 0.001), and the 3D power Doppler values in the ACA territory were significantly higher in fetuses with transposition of the great arteries (P < 0.01). The largest proportional increase in the blood flow perfusion indices in the fetuses with CHD relative to controls was observed in the ACA territory (P < 0.05). Among 41 cases with CHD that underwent testing, the mean Psychomotor Development Index (PDI) and Mental Development Index (MDI) scores were significantly lower than in 94 of the controls that were tested (P < 0.001). Among these CHD cases, total intracranial FI was positively correlated with PDI (r = 0.342, P = 0.029) and MDI (r = 0.339, P = 0.030), and ACA-VI and ACA-VFI were positively correlated with PDI (r = 0.377 and 0.389, P = 0.015 and 0.012, respectively) but were not correlated with MDI (r = 0.243 and 0.203, P = 0.126 and 0.204, respectively).

CONCLUSIONS

Cerebral blood flow perfusion was increased relative to controls in most fetuses with CHD and was associated with neurodevelopment scores at 12 months. Prenatal 3D power Doppler ultrasound might help to identify cases of brain vasodilatation earlier and inform parental counseling.

MiR-26b modulates insulin sensitivity in adipocytes by interrupting the PTEN/PI3K/AKT pathway

BACKGROUND

MicroRNAs (miRNAs) have emerged as epigenetic regulators of metabolism and energy homeostasis. There is a growing body of evidence pointing to miRNAs that have important regulatory roles in insulin sensitivity.

OBJECTIVE

The aim of this work was to explore the expression and mechanism of action of miR-26b in obesity-related insulin resistance (IR) in adipocytes.

METHODS

Quantitative real-time PCR was performed to determine miR-26b expression in obese rodent models, human obesity subjects and insulin-resistant adipocytes. We analysed the roles of miR-26b overexpression and inhibition on glucose uptake in adipocytes. Western blotting was used to detect the levels of protein molecules involved in the phosphoinositide-3-kinase (PI3K) pathway. Bioinformatics and the Dual Luciferase Assay were used to identify the target gene of miR-26b. We assessed the regulatory roles of miR-26b on the phosphatase and tensin homologue (PTEN)/PI3K/AKT pathway and the relationship between miR-26b and the metabolism of human obese subjects.

RESULTS

Levels of miR-26b are reduced in visceral adipose tissue (VAT) in obese rodent models, human obesity and insulin-resistant adipocytes. MiR-26b promotes insulin-stimulated glucose uptake and increases insulin-stimulated glucose transporter type 4 translocation to the plasma membrane in human mature adipocytes. MiR-26b modulates insulin-stimulated AKT activation via inhibition of its target gene, PTEN, and significantly increases insulin sensitivity via the PTEN/PI3K/AKT pathway. The expression level of miR-26b negatively correlates with increasing body mass index and homeostasis model assessment for IR in human obese subjects.

CONCLUSION

Decreased miR-26b expression in VAT may be involved in obesity-related IR by interrupting the PTEN/PI3K/AKT pathway.

Epidemiology of chronic rhinosinusitis: results from a cross-sectional survey in seven Chinese cities

BACKGROUND

Chronic sinusitis (CRS) is a common otorhinolaryngologic disease that is frequently encountered in everyday practice, but there is a lack of precise data regarding the prevalence of CRS in developing countries. We performed a national investigation in China to determine the prevalence and associated factors of CRS.

METHODS

We conducted a cross-sectional investigation in 2012. A stratified four-stage sampling method was used to select participants randomly from seven cities in mainland China. All participants were interviewed face-to-face via a standardized questionnaire. Unconditional logistic regression analyses were conducted to examine the association between smoking and sinusitis after adjusting for socio-demographic factors.

RESULTS

This study included a total of 10 636 respondents from seven cities. The overall prevalence of CRS was 8.0% and ranged from 4.8% to 9.7% in seven centres. Chronic sinusitis affected approximately 107 million people in mainland China. Chronic sinusitis was particularly prevalent among people with specific medical conditions, including allergic rhinitis, asthma, chronic obstructive pulmonary disease and gout. The prevalence was slightly higher among males (8.79%) than females (7.28%) (P = 0.004), and the prevalence varied by age group, ethnicity and marital status and education (P < 0.05), but not by household per capita income or living space (P > 0.05). Both second-hand tobacco smoke and active smoking were independent risk factors for CRS (P = 0.001).

CONCLUSIONS

Chronic sinusitis is an important public health problem in China. Our study provides important information for the assessment of the economic burden of CRS and the development and promotion of public health policies associated with CRS particularly in developing countries.

Genome-wide copy number profiling using high-density SNP array in chickens

Phenotypic diversity is a direct consequence resulting mainly from the impact of underlying genetic variation, and recent studies have shown that copy number variation (CNV) is emerging as an important contributor to both phenotypic variability and disease susceptibility. Herein, we performed a genome-wide CNV scan in 96 chickens from 12 diversified breeds, benefiting from the high-density Affymetrix 600 K SNP arrays. We identified a total of 231 autosomal CNV regions (CNVRs) encompassing 5.41 Mb of the chicken genome and corresponding to 0.59% of the autosomal sequence. The length of these CNVRs ranged from 2.6 to 586.2 kb with an average of 23.4 kb, including 130 gain, 93 loss and eight both gain and loss events. These CNVRs, especially deletions, had lower GC content and were located particularly in gene deserts. In particular, 102 CNVRs harbored 128 chicken genes, most of which were enriched in immune responses. We obtained 221 autosomal CNVRs after converting probe coordinates to Galgal3, and comparative analysis with previous studies illustrated that 153 of these CNVRs were regarded as novel events. Furthermore, qPCR assays were designed for 11 novel CNVRs, and eight (72.73%) were validated successfully. In this study, we demonstrated that the high-density 600 K SNP array can capture CNVs with higher efficiency and accuracy and highlighted the necessity of integrating multiple technologies and algorithms. Our findings provide a pioneering exploration of chicken CNVs based on a high-density SNP array, which contributes to a more comprehensive understanding of genetic variation in the chicken genome and is beneficial to unearthing potential CNVs underlying important traits of chickens.

Factors associated with menopausal symptoms among middle-aged registered nurses in Beijing

OBJECTIVE

To determine factors related to menopause symptoms among middle-aged registered nurses in Beijing.

METHODS

Self-administered questionnaires that included closed-ended questions on many factors possibly related to menopausal symptoms were distributed to 2100 registered nurses aged 40-55 at 20 hospitals in Beijing, China.

RESULTS

Menopausal status was most associated with menopausal symptoms (p < 0.01), including hot flashes and sweating, paresthesiae, insomnia, arthralgia/myalgia, palpitations, skin formication and an unsatisfactory sexual life. The odds ratios (ORs) were highest for hot flashes and sweating. Upsetting events in the past year and being pessimistic were significantly inversely correlated with almost all the symptoms analyzed. Hot flashes and sweating (p < 0.01), paresthesiae (p < 0.01), unsatisfactory sexual life (p < 0.01), irritability (p < 0.05), depression or suspicion (p < 0.05) and dizziness (p < 0.05) were negatively correlated with the frequency of sexual activity.

CONCLUSION

Many factors may influence symptoms of the menopause. We found that menopausal status was most strongly associated with most menopausal symptoms, especially hot flashes and sweating. Psychosocial factors also played an important role. A higher frequency of sexual activity negatively correlated with most menopausal symptoms.

Enhanced angiogenesis promoted by human umbilical mesenchymal stem cell transplantation in stroked mouse is Notch1 signaling associated

Cellular therapy has provided hope for restoring neurological function post stroke through promoting endogenous neurogenesis, angiogenesis and synaptogenesis. The current study was based on the observation that transplantation of human umbilical cord mesenchymal stem cells (hUCMSCs) promoted the neurological function improvement in stroked mice and meanwhile enhanced angiogenesis in the stroked hemisphere. Grafted hUCMSCs secreted human vascular endothelial growth factor A (VEGF-A). Notch1 signaling was activated after stroke and also in the grafted hUCMSCs. To address the potential mechanism that might mediate such pro-angiogenic effect, we established a hUCMSC-neuron co-culture system. Neurons were subjected to oxygen glucose deprivation (OGD) injury before co-culturing to mimic the in vivo cell transplantation. Consistent with the in vivo data, co-culture medium claimed from hUCMSC-OGD neuron co-culture system significantly promoted the capillary-like tube formation of brain-derived endothelial cells. Moreover, coincident with our in vivo data, Notch 1 signaling activation was detected in hUCMSCs after co-cultured with OGD neurons as demonstrated by the up-regulation of key Notch1 signaling components Notch1 and Notch1 intercellular domain (NICD). In addition, OGD-neuron co-culture also increased the VEGF-A production by hUCMSCs. To verify whether Notch1 activation was involved in the pro-angiogenic effect, γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) was added into the co-culture medium before co-culture. It turned out that DAPT significantly prevented the Notch1 activation in hUCMSCs after co-culture with OGD neurons. More importantly, the pro-angiogenic effect of hUCMSCs was remarkably abolished by DAPT addition as demonstrated by inhibited capillary-like tube formation and less VEGF-A production. Regarding how Notch1 signaling was linked with VEGF-A secretion, we provided some clue that Notch1 effector Hes1 mRNA expression was significantly up-regulated by OGD-neuron co-culturing and down-regulated after additional treatment of DAPT. In summary, our data provided evidence that the VEGF-A secretion from hUCMSCs after being triggered by OGD neurons is Notch1 signaling associated. This might be a possible mechanism that contributes to the angiogenic effect of hUCMSC transplantation in stroked brain.

Down-regulation of miR-205 promotes stemness of hepatocellular carcinoma cells by targeting PLCβ1 and increasing CD24 expression

Hepatocellular carcinoma (HCC) is a particularly lethal form of cancer. Overall survival evenafter liver surgery is unsatisfactory due to high metastatic capacity and recurrence rates. Cancer stem cells (CSCs) were recently proposed to elucidate the molecular mechanism of HCC metastasis and recurrence. In our study, we found that down-regulation of miR-205 promoted stem cell inhibition of HCC.Expression of miR-205 and PLCβ1 was investigated by qRT-PCR. MiR-205 and PLCΒ1 expression were associated with disease free survival(DFS) by log-rank test. Computational predicting software was used to predict potential targets of miR-205. MiR-205 and PLCΒ1 were transfected into cells to analyze the stem cell inhibition. MiR-205 was significantly down-regulated and PLCβ1 dramatically up-regulated in tumors compared with matched tissues (P<0.0001). High miR-205 and low PLCβ1 expression was found to be associated with better DFS. PLCβ1 was one of the potential targets of miR-205 and the dual luciferase report system demonstrated that PLCβ1 was a direct target of miR-205 in cells. When miR-205 and PLCβ1 were transfected into cells, we found that the number of spheres increased and the CD24+ subpopulation of HCC cells dramatically increased.Down-regulation of miR-205 promotes stem cell inhibition of HCC by targeting PLCβ1 and increasing CD24 expression.

Wnt3a promotes human umbilical cord mesenchymal stem cells to differentiate into epidermal-like cells

OBJECTIVE

Mesenchymal stem cells are a population of pluripotent cells that can differentiate into epidermal-like cells under certain conditions. Wnt3a can promote the proliferation and differentiation of stem cells. However, the role of Wnt3a in the differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) into epidermal-like cells is unknown.

MATERIALS AND METHODS

Third-generation hUCMSCs were cultured in normal medium, epidermal stem cell-conditioned medium, and conditioned medium with added Wnt3a. After culturing for 5 days, the expression of cytokeratin 19 (CK19), an antigen specific for epidermal-like cells, was assessed by immunofluorescence and flow cytometry. The expression of CK19 mRNA was confirmed by reverse transcription-polymerase chain reaction(RT-PCR), and β-catenin expression was detected by western blot.

RESULTS

hUCMSCs differentiated into epidermal-like cells when cultured in conditioned medium as shown by positive immunofluorescence staining for CK19. Flow cytometry showed that the number of cells positive for CK19 in the epidermal stem cell-conditioned medium group was significantly higher than that of control group, but lower than that of the Wnt3a-conditioned group (p < 0.05). RT-PCR showed that the expression level of CK19 mRNA in the conditioned medium group was significantly lower than that of the Wnt3a group (p < 0.01). Westernblots showed that the expression of β-catenin in the conditioned medium group was significantly lower than that of the Wnt3a group (p < 0.01).

CONCLUSIONS

These results suggest that Wnt3a can effectively promote the differentiation of hUCMSCs into epidermal-like cells.

Group 4 metal complexes bearing the aminoborane motif: origin of tandem ring-opening metathesis/vinyl-insertion polymerization

The origin of tandem ring-opening metathesis/vinyl-insertion polymerization using tailored group 4 metal complexes is outlined.

Effects of platelet infusion, anticoagulant and other risk factors on the rehaemorrhagia after surgery of hypertensive cerebral hemorrhage

OBJECTIVE

Our objective is to explore the effect of platelet infusion, anticoagulant and other risk factors on the rehaemorrhagia after surgery of hypertensive cerebral hemorrhage (HCH), and to provide a reference for the prevention and treatment of rehaemorrhagia in patients with HCH.

PATIENTS AND METHODS

The patients with HCH admitted during April, 2007-June, 2012 in our hospital were selected. The general data such as age and gender, disease course, past pathogenic characters, past and present medical history such as treatment, personal history, family history and son on, were collected. The data were analyzed by t test, ANOVA, Chi-squared test and logistic regression analysis.

RESULTS

The application of aspirin and platelets has significant effect on rehaemorrhagia after surgery of HCH: 72 patients received aspirin, of which 14 cases had rehaemorrhagia while 197 patients did not receive aspirin, of which 20 cases had rehaemorrhagia. The difference between these two groups was statistically significant (p < 0.05). 186 patients received platelet infusions, of which 18 cases had rehaemorrhagia whereas among other 83 patients not receiving platelet infusions, 16 cases had rehaemorrhagia. Statistical analysis showed a significant difference between these two groups (p < 0.05). In the univariate logistic regression analysis of related data in patients with rehaemorrhagia after surgery of HCH, diastolic or systolic blood pressure at admission, the time from onset to surgery, coagulation disorder, surgical method, hematoma volume, cerebral hemia, effect of hematoma clearance and GCS at admission were the potential risk factors for rehaemorrhagia after surgery of HCH (p < 0.05). In the multivariate logistic regression analysis of related data in the same patients, diastolic blood pressure at admission (> 120 mmHg), systolic blood pressure at admission (> 200 mmHg), the time from onset to surgery and coagulation disorder were screened out (p < 0.05) to be associated with rehaemorrhagia.

CONCLUSIONS

Aspirin increased the risk of rehaemorrhagia after surgery of HCH. On the contrary, infusion of platelets decreased the risk of rehaemorrhagia and improved the prognosis of patients. High diastolic and/or high systolic blood pressure at admission, ultra-early surgery after onset of HCH and coagulation disorder were related with rehaemorrhagia after operation of HCH. Our results indicate that rehaemorrhagia rate can be decreased by controlling related risk factors.

A comparison study on mental health status between suicide survivors and survivors of accidental deaths in rural China

Suicide has become a major public health problem worldwide. For every suicide there are six suicide survivors, a term referring to family members or friends of a person who has died by suicide. Within the literature there has been ongoing debate regarding the bereavement process and if it differs in survivors of suicide as opposed to survivors of those who have died from accidental death. There are scarcely any published reports on comparison between these two groups of survivors in China. In this study, we aimed to explore the difference of mental health status between suicide survivors and survivors of accidental deaths in China. We used a cross-sectional study design to collect data of survivors. Consecutive sampling was used and 92 suicide survivors and 64 survivors of accidental deaths were interviewed. The Symptom Checklist-90-Revised was used to assess the survivors' mental health status. After controlling for demographic variables and time interval between death and interview, no significant differences were found on mental health status between these two groups of survivors. Several explanations might account for the lack of differences. Further studies employing qualitative measures and suicide-specific instruments are needed to explore the bereavement of Chinese suicide survivors.

Diagnosis of lymph node micrometastasis at the pN₀ stage of lung adenocarcinoma using a combination of markers

This study aimed to detect micrometastatic tumor cells in the lymph nodes of patients with pN0 lung adenocarcinoma using a combination of thyroid transcription factor-1 (TTF-1) expression and cytokeratin 7 (CK7) expression and to investigate the association of lymph node micrometastasis with the clinicopathological characteristics of patients with lung adenocarcinoma. A total of 54 patients with pN0 lung adenocarcinoma and whose primary tumors were positive for both TTF-1 and CK7 expression were included in this study. In total, 893 lymph nodes were obtained from these 54 patients and were analyzed for micrometastasis by immunohistochemical staining with anti-CK7 and anti-TTF-1 antibodies. CK7- and TTF-1-positive cells were found in the lymph nodes of 9 (16.7%) of 54 patients, and 21 (2.4%) of 893 lymph nodes exhibited positivity for these factors. No cells positive for both CK7 and TTF-1 were detected in the 5 lymph nodes obtained from patients with benign lung tumors. Lymph node micrometastasis was found to be associated with the differentiation grade and primary tumor position (P < 0.05). The detection of lymph node micrometastasis by a combination of CK7 and TTF-1 immunohistochemical staining provides a more accurate assessment of tumor staging for pN0 lung adenocarcinoma.

Chromosome 12p13 variants predict recurrence of ischaemic stroke in a Chinese population

BACKGROUND AND PURPOSE

A recent genome-wide association study identified two genetic variants (rs12425791 and rs11833579) on chromosome 12p13 that confer risk of ischaemic stroke. The purpose of this study was to examine whether these two polymorphisms are associated with stroke onset and prognosis in a Chinese population.

METHODS

rs12425791 and rs11833579 were genotyped using the improved multiple ligase detection reaction in 913 patients with ischaemic stroke. Analyses of genotype association with onset and prognosis outcomes were evaluated by the Kaplan-Meier method, the log-rank test and Cox proportional hazards models.

RESULTS

rs12425791 and rs11833579 were not associated with age of stroke onset (P = 0.786 and 0.340, respectively). However, these two polymorphisms were significantly associated with risk of stroke recurrence, especially for the large-artery atherosclerosis (LAA) subtype, in recessive models [hazard ratio (HR) 2.52; 95% confidence interval (CI) 1.04-6.12 for rs12425791; HR 2.13; 95% CI 1.03-4.40 for rs11833579]. The combined genotype of these two single-nucleotide polymorphisms showed a locus-dosage effect on recurrence of LAA subtype and was an independent prognostic factor for LAA subtype in the final multivariate Cox regression model.

CONCLUSIONS

These findings indicated that rs12425791 and rs11833579 on chromosome 12p13 may be useful biomarkers for predicting the prognosis of patients with the LAA subtype of ischaemic stroke.

THz quantum cascade lasers operating on the radiative modes of a 2D photonic crystal

Photonic-crystal lasers operating on Γ-point band-edge states of a photonic structure naturally exploit the so-called "nonradiative" modes. As the surface output coupling efficiency of these modes is low, they have relatively high Q factors, which favor lasing. We propose a new 2D photonic-crystal design that is capable of reversing this mode competition and achieving lasing on the radiative modes instead. Previously, this has only been shown in 1D structures, where the central idea is to introduce anisotropy into the system, both at unit-cell and resonator scales. By applying this concept to 2D photonic-crystal patterned terahertz frequency quantum cascade lasers, surface-emitting devices with diffraction-limited beams are demonstrated, with 17 mW peak output power.