High photosensitivity few-layered MoSe2 back-gated field-effect phototransistors

In this paper, we report on the fabrication and optoelectronic properties of high sensitive phototransistors based on few-layered MoSe2 back-gated field-effect transistors, with a mobility of 19.7 cm² V⁻¹ s⁻¹ at room temperature. We obtained an ultrahigh photoresponsivity of 97.1 AW⁻¹ and an external quantum efficiency (EQE) of 22 666% using 532 nm laser excitation at room temperature. The photoresponsivity was improved near the threshold gate voltage; however, the selection of the silicon dioxide as a gate oxide represents a limiting factor in the ultimate performance. Thanks to their high photoresponsivity and external quantum efficiency, the few-layered MoSe2-based devices are promising for photoelectronic applications.

Gate dependent Raman spectroscopy of graphene on hexagonal boron nitride

Raman spectroscopy, a fast and nondestructive imaging method, can be used to monitor the doping level in graphene devices. We fabricated chemical vapor deposition (CVD) grown graphene on atomically flat hexagonal boron nitride (hBN) flakes and SiO2 substrates. We compared their Raman response as a function of charge carrier density using an ion gel as a top gate. The G peak position, the 2D peak position, the 2D peak width and the ratio of the 2D peak area to the G peak area show a dependence on carrier density that differs for hBN compared to SiO2. Histograms of two-dimensional mapping are used to compare the fluctuations in the Raman peak properties between the two substrates. The hBN substrate has been found to produce fewer fluctuations at the same charge density owing to its atomically flat surface and reduced charged impurities.

Spinal 5-HT3 receptors facilitate behavioural hypersensitivity induced by elevated calcium channel alpha-2-delta-1 protein

BACKGROUND

Peripheral nerve injury induces up-regulation of the calcium channel alpha-2-delta-1 proteins in the dorsal root ganglia and dorsal spinal cord that correlates with neuropathic pain development. Similar behavioural hypersensitivity was also observed in injury-free transgenic (TG) mice over-expressing the alpha-2-delta-1 proteins in neuronal tissues. To investigate pathways regulating alpha-2-delta-1 protein-mediated behavioural hypersensitivity, we examined whether spinal serotonergic 5-HT3 receptors are involved similarly in the modulation of behavioural hypersensitivity induced by either peripheral nerve injury in a nerve injury model or neuronal alpha-2-delta-1 over-expression in the TG model.

METHODS

The effects of blocking behavioural hypersensitivity in these two models by intrathecal or systemic injections of 5-HT3 receptor antagonist, ondansetron, were compared.

RESULTS

Our data indicated that the TG mice displayed similar behavioural hypersensitivities to non-painful mechanical stimulation (tactile allodynia) and painful thermal stimulation (thermal hyperalgesia) as that observed in the nerve injury model. Interestingly, tactile allodynia and thermal hyperalgesia in both models can be blocked similarly by intrathecal, but not systemic, injection of ondansetron.

CONCLUSIONS

Our data suggest that spinal 5-HT3 receptors are likely to play a role in alpha-2-delta-1-mediated behavioural hypersensitivities through a descending serotonergic facilitation.

Prognostic value of cardiac troponins in elderly patients with hip fracture--a systematic review

Cardiac troponins can be elevated in cardiac ischemic conditions or other diseases such as pulmonary embolism or renal failure, where they may predict outcome. We hypothesized that cardiac troponins offer useful prognostic information regarding morbidity and mortality in elderly hip fracture patients undergoing surgical therapy. A literature review was conducted using PubMed and CINAHL plus with full text (EBSCOhost). Articles with original data relating troponins to prognosis in elderly hip fracture patients were reviewed. Studies with patients not undergoing surgery or undergoing elective or nonhip fracture surgery were excluded. Six papers met inclusion criteria. Troponin elevation was seen in 26.7-39% of patients, while myocardial infarction, cardiac complications, and cardiac death occurred in ≤35% troponin-positive patients in four of six studies. Several noncardiac factors were associated with elevated troponin including higher American Society of Anaesthesiologists score, current smoking, reduced mobility/activity level, lower hemoglobin, and living in residential care. Patients with elevated troponin had longer lengths of stay, increased risk for discharge to long-term care facilities, and higher mortality. Increased age, male sex, and higher American Society of Anaesthesiologists score were also associated with mortality. Elevated troponin can be used as a marker of increased morbidity/mortality in elderly hip fracture patients undergoing surgery, as hypothesized, even in the absence of cardiac complications. Perioperative troponin evaluation may be useful for risk stratification, but further studies are needed to clarify risks and benefits of such testing.

Telomere length in patients with systemic lupus erythematosus and its associations with carotid plaque

OBJECTIVE

To evaluate telomere length (TL) between patients with SLE and healthy controls and to test if TL is associated with carotid plaque.

METHODS

A pilot study of 154 patients with SLE and 152 controls was performed from the SOLVABLE (Study of Lupus Vascular and Bone Long-Term Endpoints) cohort. Demographic and cardiovascular disease (CVD) factors were collected at baseline. The presence or absence of plaque was evaluated by B-mode US. Genomic DNA was isolated from whole peripheral blood. TL was quantified using real-time quantitative PCR.

RESULTS

SLE women had a short TL compared with healthy controls (4.57 vs 5.44 kb, P = 0.03). SLE women showed shorter TL than controls across all age groups: <35 years (4.38 vs 6.37 kb), 35-44 years (4.52 vs 5.30 kb), 45-54 years (4.77 vs 5.68 kb) and ≥55 years (4.60 vs 4.71 kb). Among patients with SLE and carotid plaque there was a trend towards shorter TL at a younger age and it was significantly lower in the 35- to 44-year age group when compared with controls (P = 0.025). Multiple logistic regression analysis indicated a risk of carotid plaque with older age [odds ratio (OR) 1.09; 95% CI 1.06, 1.12] but not with TL (OR 1.05; 95% CI 0.97, 1.13).

CONCLUSION

SLE women had significantly shorter TL than controls. SLE women trended towards shorter TL at a younger age. When carotid plaque was identified, the younger SLE women had shorter TL. Only older age but not shorter TL was independently associated with carotid plaque. Additional studies are needed to confirm if TL is a novel biomarker for cardiovascular disease in SLE.

The safety and efficacy of antitumour necrosis factor-alpha therapy for inflammatory bowel disease in patients post liver transplantation: a case series

BACKGROUND

The role of antitumour necrosis factor-alpha (anti-TNF) therapy for inflammatory bowel disease (IBD) among liver transplant recipients is largely unknown given the rarity of this population and the paucity of literature on the subject.

AIM

To investigate the safety and efficacy of anti-TNF therapy for refractory IBD in the post liver transplant population.

METHODS

The liver transplant database at London Health Sciences Centre was searched to identify adult patients with IBD treated with anti-TNF therapy post transplantation.

RESULTS

Six patients (five men, one woman) were identified, aged 28-65. All patients had cadaveric orthotopic liver transplants. Four patients required transplantation due to primary sclerosing cholangitis, one due to autoimmune hepatitis, and one due to biliary atresia. Five patients suffered from Crohn's disease and the remaining patient from indeterminate colitis. All patients were treated with infliximab 5 mg/kg every 8 weeks after undergoing induction at weeks 0, 2 and 6, with the exception of one patient. The duration of infliximab therapy ranged from 8 weeks to 4 years. Four patients treated with infliximab experienced sustained improvement of their IBD symptoms post transplantation, as documented by Harvey-Bradshaw Index scores demonstrating clinical remission. Of the remaining two patients, neither had sustained improvement of their IBD with infliximab or subsequent adalimumab. One patient was diagnosed with systemic lupus erythematosus and another with colorectal adenocarcinoma following anti-TNF therapy. Otherwise, no side effects were attributed to anti-TNF therapy.

CONCLUSIONS

Based on this case series, anti-TNF therapy appears to be safe and effective for treating refractory IBD in patients post liver transplantation. These patients respond to anti-TNF therapy similar to those who have not been previously transplanted.

Abstract 189: Hypercholesterolemia Blunts Gender Differences in Vascular Endothelin-1 Activity in Middle-Aged Adults

Background: Compared with age-matched women, healthy middle-aged men have a higher vascular activity of the vasoconstrictor and proatherosclerotic peptide endothelin-1(ET-1). Hypercholesterolemia is a major atherosclerotic risk factor and is associated with increased ET-1 activity. Whether high cholesterol levels abrogate gender differences in vascular ET-1 activity has not been studied. This investigation has been conducted to test the hypothesis that hypercholesterolemia blunts the gender difference in ET-1 activity present in middle-aged men and women.

Methods: Forearm blood flow (FBF) responses were measured by strain-gauge plethysmography during the intra-arterial infusion of the selective ET A receptor blocker BQ-123 in 19 women and 21 men with hypercholesterolemia (total cholesterol >240 mg/dL).

Results: Baseline characteristics were similar between women and men (see table). BQ-123 administration resulted in a significant progressive vasodilator response in both the female and male group (p < 0.001 for both). When these responses were compared between the two gender groups, no significant differences were observed (p=NS).

Conclusions: Hypercholesterolemia increases the vascular activity of ET-1 in middle-aged women and men. The lack of difference in ET-1 activity between women and men suggests that hypercholesterolemia eliminates the gender differences in ET-1 vascular activity, potentially offsetting the advantage in cardiovascular risk of middle-aged women compared with middle-aged men.

Pulmonary artery sarcoma mimicking a pulmonary embolism

Sarcomas involving the lung are a rare occurrence, often a result of metastatic disease from primary malignancies involving the skin, liver, breast or heart. Primary pulmonary artery sarcomas are rarer still, with limited cases reported world-wide and consequently data regarding treatment modalities are sparse and largely experimental. These tumors are often mistaken for a pulmonary embolism and seemingly supported by radiological findings. Patients will often present without symptom resolution despite therapeutic anticoagulation. The following case illustrates how a soft tissue sarcoma of the pulmonary artery can mimic a pulmonary embolism, thus, resulting in both a diagnostic and therapeutic dilemma. A positron emission tomography scan was an invaluable tool in this case, showing increased radiotracer uptake and placing neoplasm at the top of the differential diagnosis. This ultimately led to a biopsy that was vimentin positive, cytokeratin negative and CD117 negative, thus consistent with soft tissue sarcoma.