Inductively coupled transmission of neuro-active signals: analysis of optimal parameters

Fifteen parameters that play a role in the optimal transmission of therapeutic signals by inductively coupled implantable neurostimulator have been investigated. For this purpose, at first, a model of the system was constructed from which the system transfer function was obtained. Then, the relationship between the transfer gain and each parameter was evaluated using mathematical equations and a specifically built computer program. This study showed that the gain could be increased selecting small values for some parameters (the number of active coil windings, first radii of inner and outer paths of the core, heights of the core base and windings, position under the skin, internal resistances of the active and passive coils, tissue impedance between the contacts of electrode), and high values for the others (the number of passive coil windings, second radii of inner and outer paths of the core, frequency of the signal, relative magnetic permeability of the core). Critical saturation values were another considerable point. The nearest commercially available standard values should be preferred in practical applications.     

Comparison of subclinical left and right ventricular systolic dysfunction in non-dipper and dipper hypertensives: impact of isovolumic acceleration

Objectives: To evaluate subclinical left ventricular and right ventricular systolic impairment in dipper and non-dipper hypertensives by using isovolumic acceleration.

Methods: About 45 normotensive healthy volunteers (20 men, mean age 43?±?9 years), 45 dipper (27 men, mean age 45?±?9 years) and 45 non-dipper (25 men, 47?±?7 years) hypertensives were enrolled. Isovolumic acceleration was measured by dividing the peak myocardial isovolumic contraction velocity by isovolumic acceleration time.

Results: Non-dippers indicated lower left ventricular (2.2?±?0.4?m/s² versus 2.8?±?1.0?m/s², p?2 versus 3.5?±?1.0?m/s², p?=?0.012) compared with dippers. Left ventricular mass index (p?=?0.001), interventricular septal thickness (p?=?0.002) and myocardial performance index (p?p?=?0.002), mass index (p?=?0.001) and right ventricular myocardial performance index (p?Conclusion: The present study demonstrates that non-dipper hypertensives have increased left and right ventricular subclinical systolic dysfunction compared with dippers. Isovolumic acceleration is the only echocardiographic parameter in predicting this subtle impairment.     

Targeted vessel reconstruction in non‐contrast‐enhanced steady‐state free precession angiography

Image quality in non‐contrast‐enhanced (NCE) angiograms is often limited by scan time constraints. An effective solution is to undersample angiographic acquisitions and to recover vessel images with penalized reconstructions. However, conventional methods leverage penalty terms with uniform spatial weighting, which typically yield insufficient suppression of aliasing interference and suboptimal blood/background contrast. Here we propose a two‐stage strategy where a tractographic segmentation is employed to auto‐extract vasculature maps from undersampled data. These maps are then used to incur spatially adaptive sparsity penalties on vascular and background regions. In vivo steady‐state free precession angiograms were acquired in the hand, lower leg and foot. Compared with regular non‐adaptive compressed sensing (CS) reconstructions (CS_low), the proposed strategy improves blood/background contrast by 71.3 ± 28.9% in the hand (mean ± s.d. across acceleration factors 1–8), 30.6 ± 11.3% in the lower leg and 28.1 ± 7.0% in the foot (signed‐rank test, P < 0.05 at each acceleration). The proposed targeted reconstruction can relax trade‐offs between image contrast, resolution and scan efficiency without compromising vessel depiction. Copyright © 2016 John Wiley & Sons, Ltd.     

Does moxifloxacin alter oxidant status in the cornea? An experimental study

Objective: In this experimental study, we investigated the possible effects of intracameral moxifloxacin on oxidative stress parameters and endothelial cell morphology in corneal tissue.

Methods: In total, 30 rats were randomly assigned to three groups of 10 rats: the sham group (Group 1, n?=?10); the control group (Group 2), where balanced salt solution (BSS) was administered at a dose of 0.01?cc (n?=?10); and the treatment group (Group 3), where moxifloxacin was administered at a dose of 0.05?mg/0.01?cc (n?=?10). Total antioxidant status (TAS) and total oxidant status (TOS) in corneal tissue and blood samples were measured and the oxidative stress index (OSI) was calculated. Also, corneal tissue histopathology was evaluated with caspase-3 and caspase-8 staining. Apoptotic activity was also evaluated.

Results: In blood samples, TAS, TOS, and OSI levels were not statistically significantly different (all p?>?0.05). Compared with the sham and control groups, TOS and OSI levels in cornea tissue were significantly different in the moxifloxacin group (all p?p?>?0.05). Compared with the sham and control groups, apoptotic activity was higher in the moxifloxacin group, in both immunohistochemical staining for caspase-3 and caspase-8.

Conclusions: Intracameral moxifloxacin injection seems to be safe systemically, but it may have toxic effects on corneal tissues, as suggested by oxidative stress parameters and a histopathological evaluation.     

Pulmonary Arterial Hemodynamic Assessment by a Novel Index in Systemic Sclerosis Patients: Pulmonary Pulse Transit Time

Objectives

Systemic sclerosis (SSc) is a chronic, inflammatory, and autoimmune connective tissue disease that is associated with vascular lesions, and fibrosis of the skin and visceral organs. Cardiac complications may occur as a secondary effect of SSc as a result of pulmonary arterial hypertension and interstitial lung disease. The objective of this study was to assess whether the pulmonary pulse transit time (pPTT) could serve as a diagnostic marker for pulmonary arterial alterations in patients with SSc, prior to development of pulmonary hypertension.

Methods

Twenty-five SSc patients as a study group and 25 age- and sex-matched healthy volunteers for the control group were recruited to the study. Right ventricle function parameters, such as tricuspid annular plane systolic excursion (TAPSE), estimated pulmonary artery systolic pressure (ePASP), right ventricular dimensions, right ventricle fractional area changes, and myocardial perfusion index (MPI) were measured and calculated. Pulmonary pulse transit time was defined as the time interval between the R-wave peak in the ECG and the corresponding peak late systolic pulmonary vein flow velocity.

Results

Right ventricle myocardial performance index (RVMPI) and eSPAP were significantly higher in the SSc group than the controls (p?=?0.032, p?=?0.012, respectively). Pulmonary pulse transit time and TAPSE was shorter in the patients with SSc (p?=?0.006, p?=?0.015, respectively). In correlation analysis, pPTT was inversely correlated with RVMPI (r?=???0.435, p?=?0.003), eSPAP (r?=???0.434, p?=?0.003), and disease duration (r?=???0.595, p?=?0.003). Conversely, it positively correlated with TAPSE (r?=?0.345, p?=?0.022).

Conclusion

pPTT was found to be shorter in SSc patients. pPTT might serve as a surrogate marker of pulmonary hemodynamics in patients with SSc, even prior to the development of pulmonary hypertension.

     

Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures

Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H₂O₂. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H₂O₂ concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold–silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H₂O₂ concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HF : H₂O₂ concentrations of 4.7 M : 0.68 M and room temperature with an etching rate of ≈0.7 μm min⁻¹, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures.

Specially designed X-ray zone plates with high aspect-ratios have been fabricated via metal-assisted chemical etching, by controlling the reaction kinetics.     

Sonographic assessment of subacromial bursa distension during arm abduction: establishing a threshold value in the diagnosis of subacromial impingement syndrome

Purpose

In this study, we aimed to establish a quantitative threshold value in the diagnosis of subacromial impingement syndrome by measuring the thickness of the subacromial bursa during abduction and adduction.

Materials and methods

Forty-five patients with subacromial impingement syndrome and 54 healthy individuals underwent dynamic shoulder ultrasonography. The subacromial bursa, between the supraspinatus tendon margin and peribursal adipose tissue, was measured between the acromion and humeral head at its widest part. The subacromial impingement ratio was calculated by dividing the subacromial bursa thickness during abduction to the subacromial bursa thickness during adduction. Shapiro–Wilk test was used in the assessment of normal distribution of parameters.

Results

The mean subacromial bursa thickness in the abduction position was 1.8 ± 1.1 mm in the study group and 0.9 ± 0.3 mm in the control group. The mean subacromial bursa thickness in the adduction position was 0.9 ± 0.5 mm in the study group and 0.8 ± 0.3 mm in the control group. The subacromial impingement ratio showed a statistically significant difference between groups (p < 0.0001), and the ratio being 2.0 ± 0.5 in the study group and 1.2 ± 0.1 in the control group. For measurements performed in the abduction position, the best cut-off value was calculated as 1.3 mm, and sensitivity and specificity were 70.6 and 85.2%, respectively. The best cut-off value was 1.4 for the subacromial impingement ratio, and sensitivity and specificity were 88.2 and 96.3%, respectively.

Conclusion

Subacromial impingement ratio is a very practical and reliable method in subacromial impingement syndrome diagnosis.

     

A novel mutation of sgk-1 gene in central serous chorioretinopathy

AIM

To investigate the association of serum glucocorticoid kinase gene-1 (SGK-1) DNA variants with chronic central serous chorioretinopathy (CSC).

METHODS

We enrolled 32 eyes of 32 patients who were diagnosed with chronic CSC and composed 32 normal eyes as a control group. Peripheral blood was used for DNA extraction and polymerase chain reaction (PCR) amplification. SGK1 gene was sequenced by using BigDye^® Terminator v3.1 cycle sequencing KIT (Applied Biosystems, Foster City, CA, USA). The SGK1 gene and its variants were investigated in CSC patient group and control group.

RESULTS

We identified a new polymorphism M32V in two person in the patient group (Minor allele frequency (MAF)=0.009) on the region of 1-60 amino acids. The rs1057293 was located in the encoder region of the SGK 1 gene but not associated with CSC (P=0.68). An intrinsic rs1743966 is also not associated (P=0.28).

CONCLUSIONS

The new polymorphism M32V is located on the region of 1-60 amino acids which is necessary for localization to the mitochondria in CSC patient. This mutation is probably important for the energy metabolism and plays an important role in the cellular response to hyperosmotic stress and other stress stimuli. Both rs1057293 and rs1743966 are not associated with CSC.