A novel stress monitoring method through stress-induced respiratory alterations: non-contact measurement of respiratory V(T)/T(I) alterations induced by stressful sound using a 10 GHz microwave radar

We have developed a non-contact stress monitoring system which measures respiratory V(T)/T(I) (tidal volume/inspiration time) alterations using a 10 GHz microwave radar. The measurable distance of the system is 50 cm, which is 10 times longer than our previously developed stress monitoring system which measures heart rate variability using a 24-GHz microwave-radar. The study was conducted with eight subjects (23 ± 1 years old) to evaluate the efficacy of the system. An audio stimulus at 95 dB sound pressure level was presented to the subjects following a silent period of 120 seconds. During the silent period, V(T)/T(I) averaged 826 ± 384 ml s(-1), while it increased significantly (p < 0.05) with an average of 1227 ± 704?ml s(-1) during audio stimulus low frequency component (LF)/high frequency component (HF), which reflects sympatho-vagal valance, showed a peak during audio stimuli. This paper aims to study the efficacy of the non-contact stress monitoring system for its future applications in many fields including health and safety.

Percutaneous vertebroplasty for pain management in spinal metastasis with epidural involvement

Percutaneous vertebroplasty (PVP) has been widely used for the treatment of painful malignant lesions of the spine. Spinal metastasis with epidural involvement, with or without symptoms of neurologic compression, is regarded by some authors as a contraindication or relative contraindication to the procedure. To evaluate safety and effectiveness of PVP in pain management of spinal metastasis with epidural involvement, we retrospectively analyzed PVP in 32 patients with metastatic disease, who presented with at least one vertebral lesion with destruction of the posterior vertebral body wall or epidural extension of tumor. Among these patients, nine had signs of spinal cord or cauda equina compression. Procedural safety was evaluated by any post-procedure adverse events. The PVP analgesic efficacy was evaluated by follow-up neurological examination. Pain intensity was scored on a visual analog scale scored from 0 (no pain) to 10 (maximum pain intensity). The effective pain relief was defined as at least 50% improvement in pain score as compared with pre- procedure baseline. Follow-up assessments were performed at 1 day; 1 week; 1, 3, and 6 months after the procedure. Fifty-three vertebrae in 32 patients were treated in this group. Analgesic efficacy in survival patients was rated at 97% (31/32) at 1day and 1 week, 86.7% (26/30) at 1 month, 82.3% (24/29) at 3 months, and 76.9% (20/26) at 6 months after procedure. Leakage of PMMA was detected in 64% (33/53) treated vertebrae. No systemic complications were observed in all treated patients.

Morphology development and size control of poly(trimethylene terephthalate) nanofibers prepared from poly(trimethylene terephthalate)/cellulose acetate butyrate in situ fibrillar composites

Formation of nano-fibrillar composite structures provides an effective method for preparing thermoplastic nanofibers. By mixing two immiscible thermoplastic polymers in a twin screw extruder, poly(trimethylene terephthalate) (PTT) formed nano-fibrillar morphology in cellulose acetate butyrate (CAB) matrix, and then PTT nanofibers were obtained from PTT/CAB in situ fibrillar composites after removing the matrix phase of CAB. Blend ratio, shear rate, and draw ratio were three important parameters in the extrusion process, which could affect the shape and size of nanofibers. By varying the process conditions, average diameter of PTT nanofibers could be controlled in the range of 80-400 nm. Besides this, the mechanism of nano-fibrillar formation in PTT/CAB blends was also studied by collecting samples at different stages in the extruder. The morphology developmental trends of PTT dispersed phase with different blend ratios were nearly the same. From initial to metaphase and later phase development, the PTT dispersed component undergo the formation of sheets, holes, and network structures, then the size reduction and formation of nanofibers.

Optimal systolic and diastolic reconstruction windows for coronary CT angiography using 320-detector rows dynamic volume CT

AIM

To investigate the optimal pattern of systolic and diastolic reconstruction windows for coronary computed tomography (CT) angiography using 320-detector rows dynamic volume CT (DVCT).

MATERIAL AND METHODS

A prospective analysis was performed on the data from 77 patients who were admitted between December 2008 and July 2009 for DVCT. The images were reconstructed in 10% steps throughout the 10-100% of R-R interval. Data sets for the three major coronary arteries [right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LCX)] were evaluated by two independent readers. The quality of the images from each examined artery was graded from 1 (no motion artefacts) to 4 (severe motion artefacts over the entire vessel). The optimal systolic and diastolic reconstruction windows and the relationship between image quality and heart rate (HR) were analysed. The HR at which the optimal reconstruction window shifted from diastole to systole was predicted.

RESULTS

The average HR during imaging was 69.5±12.8 beats/min (range 46-102beats/min). HR was positively correlated with the proportion of systole (r=0.78, p<0.001). As HR increased, the optimal reconstruction windows shifted to later phases in both systole and diastole. Image quality for optimal systolic and diastolic reconstructions both deteriorated significantly with higher HRs (r=0.38, p<0.001; r=0.82, p<0.001). However, image quality in systolic reconstructions did not deteriorate as much as in diastolic reconstructions. The cut-off HRs at which optimal reconstruction intervals turned from diastole to systole was 90.8beats/min.

CONCLUSIONS

In patients with a low HR, the optimal coronary reconstruction window is in mid-late diastole. As the HR increases, systolic reconstruction often yields superior image quality compared with diastolic reconstruction.

Per-arnt-sim (PAS) domain-containing protein kinase is downregulated in human islets in type 2 diabetes and regulates glucagon secretion

AIMS/HYPOTHESIS

We assessed whether per-arnt-sim (PAS) domain-containing protein kinase (PASK) is involved in the regulation of glucagon secretion.

METHODS

mRNA levels were measured in islets by quantitative PCR and in pancreatic beta cells obtained by laser capture microdissection. Glucose tolerance, plasma hormone levels and islet hormone secretion were analysed in C57BL/6 Pask homozygote knockout mice (Pask-/-) and control littermates. Alpha-TC1-9 cells, human islets or cultured E13.5 rat pancreatic epithelia were transduced with anti-Pask or control small interfering RNAs, or with adenoviruses encoding enhanced green fluorescent protein or PASK.

RESULTS

PASK expression was significantly lower in islets from human type 2 diabetic than control participants. PASK mRNA was present in alpha and beta cells from mouse islets. In Pask-/- mice, fasted blood glucose and plasma glucagon levels were 25 ± 5% and 50 ± 8% (mean ± SE) higher, respectively, than in control mice. At inhibitory glucose concentrations (10 mmol/l), islets from Pask-/- mice secreted 2.04 ± 0.2-fold (p < 0.01) more glucagon and 2.63 ± 0.3-fold (p < 0.01) less insulin than wild-type islets. Glucose failed to inhibit glucagon secretion from PASK-depleted alpha-TC1-9 cells, whereas PASK overexpression inhibited glucagon secretion from these cells and human islets. Extracellular insulin (20 nmol/l) inhibited glucagon secretion from control and PASK-deficient alpha-TC1-9 cells. PASK-depleted alpha-TC1-9 cells and pancreatic embryonic explants displayed increased expression of the preproglucagon (Gcg) and AMP-activated protein kinase (AMPK)-alpha2 (Prkaa2) genes, implying a possible role for AMPK-alpha2 downstream of PASK in the control of glucagon gene expression and release.

CONCLUSIONS/INTERPRETATION

PASK is involved in the regulation of glucagon secretion by glucose and may be a useful target for the treatment of type 2 diabetes.

Clinical Significance of CDH13 Promoter Methylation in Serum Samples from Patients with Bladder Transitional Cell Carcinoma

H-cadherin (CDH13; also known as T-cadherin), which functions as a tumour suppressor, is frequently silenced by promoter methylation in human cancers including bladder transitional cell carcinoma (TCC). This study investigated the clinical significance of methylation of the CDH13 gene promoter in serum from patients with bladder TCC. Methylation status of CDH13 in serum samples from 127 patients with primary bladder TCC and 41 healthy volunteers (controls) was examined by methylation-specific polymerase chain reaction. CDH13 methylation was found in 39 patients with bladder TCC (30.7%) but in no controls. CDH13 methylation was significantly associated with advanced tumour stage, high-grade tumour, large tumour size, tumour recurrence and poor prognosis. The results suggested that CDH13 methylation in serum may be a potential predictive biomarker for malignancy in bladder TCC, and an independent pre-therapeutic predictor of outcome. Demonstration of CDH13 methylation in serum may facilitate in the prediction of which patients require more aggressive additional post-operative systemic therapy.

Enhancing the removal of arsenic, boron and heavy metals in subsurface flow constructed wetlands using different supporting media

The presence of arsenic and heavy metals in drinking water sources poses a serious health risk due to chronic toxicological effects. Constructed wetlands have the potential to remove arsenic and heavy metals, but little is known about pollutant removal efficiency and reliability of wetlands for this task. This lab-scale study investigated the use of vertical subsurface flow constructed wetlands for removing arsenic, boron, copper, zinc, iron and manganese from synthetic wastewater. Gravel, limestone, zeolite and cocopeat were employed as wetland media. Conventional gravel media only showed limited capability in removing arsenic, iron, copper and zinc; and it showed virtually no capability in removing manganese and boron. In contrast, alternative wetland media: cocopeat, zeolite and limestone, demonstrated significant efficiencies--in terms of percentage removal and mass rate per m3 of wetland volume--for removing arsenic, iron, manganese, copper and zinc; their ability to remove boron, in terms of mass removal rate, was also higher than that of the gravel media. The overall results demonstrated the potential of using vertical flow wetlands to remove arsenic and metals from contaminated water, having cocopeat, zeolite or limestone as supporting media.

Design of a Si-based lattice-matched room-temperature GeSn/GeSiSn multi-quantum-well mid-infrared laser diode

This paper presents modeling and simulation of a silicon-based group IV semiconductor injection laser diode in which the active region has a multiple quantum well structure formed with Ge(0.9)Sn(0.1) quantum wells separated by Ge(0.75)Si(0.1)Sn(0.15) barriers. These alloy compositions were chosen to satisfy three conditions simultaneously: a direct band gap for Ge(0.9)Sn(0.1), type-I band alignment between Ge(0.9)Sn(0.1) and Ge(0.75)Si(0.1)Sn(0.15,) and a lattice match between wells and barriers. This match ensures that the entire structure can be grown strain free upon a relaxed Ge(0.75)Si(0.1)Sn(0.15) buffer on a silicon substrate - a CMOS compatible process. Detailed analysis is performed for the type I band offsets, carrier lifetime, optical confinement, and modal gain. The carrier lifetime is found to be dominated by the spontaneous radiative process rather than the Auger process. The modal gain has a rather sensitive dependence on the number of quantum wells in the active region. The proposed laser is predicted to operate at 2.3 μm in the mid infrared at room temperature.