pH Quantification in Human Dermal Interstitial Fluid Using Ultra-Thin SOI Silicon Nanowire ISFETs and a High-Sensitivity Constant-Current Approach.

In this paper, we propose a novel approach to utilize silicon nanowires as high-sensitivity pH sensors. Our approach works based on fixing the current bias of silicon nanowires Ion Sensitive Field Effect Transistors (ISFETs) and monitor the resulting drain voltage as the sensing signal. By fine tuning the injected current levels, we can optimize the sensing conditions according to different sensor requirements. This method proves to be highly suitable for real-time and continuous measurements of biomarkers in human biofluids. To validate our approach, we conducted experiments, with real human sera samples to simulate the composition of human interstitial fluid (ISF), using both the conventional top-gate approach and the optimized constant current method. We successfully demonstrated pH sensing within the physiopathological range of 6.5 to 8, achieving an exceptional level of accuracy in this complex matrix. Specifically, we obtained a maximum error as low as 0.92% (equivalent to 0.07 pH unit) using the constant-current method at the optimal current levels (1.71% for top-gate). Moreover, by utilizing different pools of human sera with varying total protein content, we demonstrated that the protein content among patients does not impact the sensors' performance in pH sensing. Furthermore, we tested real-human ISF samples collected from volunteers. The obtained accuracy in this scenario was also outstanding, with an error as low as 0.015 pH unit using the constant-current method and 0.178 pH unit in traditional top-gate configuration.

Seismic microzonation of a region with complex surficial geology based on different site classification approaches.

A seismic microzonation study was conducted to refine the seismic hazard model for the city of Saguenay, Canada. The Quaternary geology underlying Saguenay shows complex glacial and post-glacial stratigraphy with a number of buried valleys filled with fluvioglacial and glaciomarine sediments. High impedance contrast between rock formations and surficial sediments is prone to seismic amplification. To evaluate their applicability, advantages and limitations in capturing the geological specificity of the study area, four site classification methods were applied: the current National Building Code of Canada (NBCC) and Eurocode 8, both mainly based on the average shear-wave velocity for the surficial sediments (V S,avg ) and for the top 30 m (V S,30 ); a method based on the fundamental site period (T 0 ); and a hybrid method based on the combination of V S,30 , T 0 and V S,avg . The study specifically aimed to evaluate the importance of the site classification parameters on the resulting microzonation maps. V S,30 is capable to present the geological and geotechnical site conditions, however, the results may be further improved by considering V s,avg in shallow and T 0 in thick layers of soil sediments as secondary parameters. The T 0 method gives also satisfactory results with T 0 showing a better correlation to V s,30 than to V s,avg . The versatile hybrid method may be challenging to apply in certain cases with its nine different site categories and parameters.

Geomechanical characterization of a heterogenous rock mass using geological and laboratory test results: a case study of the Niobec Mine, Quebec (Canada).

ABSTRACT: To conduct a successful geomechanical characterization of rock masses, an appropriate interpretation of lithological heterogeneity should be attained by considering both the geological and geomechanical data. In order to clarify the reliability and applicability of geological surveys for rock mechanics purposes, a geomechanical characterization study is conducted on the heterogeneous rock mass of Niobec Mine (Quebec, Canada), by considering the characteristics of its various identified lithological units. The results of previous field and laboratory test campaigns were used to quantify the variability associated to intact rock geomechanical parameters for the different present lithological units. The interpretation of geomechanical similarities between the lithological units resulted in determination of three main rock units (carbonatite, syenite, and carbonatite-syenite units). Geomechanical parameters of these rock units and their associated variabilities are utilized for stochastic estimation of geomechanical parameters of the heterogeneous rock mass using the Monte Carlo Simulation method. A comparison is also made between the results of probabilistic and deterministic analyses to highlight the presence of intrinsic variability associated with the heterogeneous rock mass properties. The results indicated that, for the case of Niobec Mine, the carbonatite-syenite rock unit could be considered as a valid representative of the entire rock mass geology since it offers an appropriate geomechanical approximation of all the present lithological units at the mine site, in terms of both the magnitude and dispersion of the strength and deformability parameters. ARTICLE HIGHLIGHTS: Evaluating the reliability and applicability of geological survey outcomes for rock mechanics purposes.A geomechanical characterization study is conducted on the heterogeneous rock mass by considering the various identified rock lithotypes.The geomechanical parameters of intact units and their associated variabilities are used to stochastically estimate the geomechanical parameters of the heterogeneous rock mass by employing the Monte Carlo Simulation.A comparison is also made between the results of probabilistic and deterministic geomechanical analyses.The results indicate that, in the case of Niobec Mine, the combined syenite-carbonatite rock unit could be considered as a valid representative of the entire rock mass.

Nanowire Tunnel FET with Simultaneously Reduced Subthermionic Subthreshold Swing and Off-Current due to Negative Capacitance and Voltage Pinning Effects.

Nanowire tunnel field-effect transistors (TFETs) have been proposed as the most advanced one-dimensional (1D) devices that break the thermionic 60 mV/decade of the subthreshold swing (SS) of metal oxide semiconductor field-effect transistors (MOSFETs) by using quantum mechanical band-to-band tunneling and excellent electrostatic control. Meanwhile, negative capacitance (NC) of ferroelectrics has been proposed as a promising performance booster of MOSFETs to bypass the aforementioned fundamental limit by exploiting the differential amplification of the gate voltage under certain conditions. We combine these two principles into a single structure, a negative capacitance heterostructure TFET, and experimentally demonstrate a double beneficial effect: (i) a super-steep SS value down to 10 mV/decade and an extended low slope region that is due to the NC effect and, (ii) a remarkable off-current reduction that is experimentally observed and explained for the first time by the effect of the ferroelectric dipoles, which set the surface potential in a slightly negative value and further blocks the source tunneling current in the off-state. State-of-the-art InAs/InGaAsSb/GaSb nanowire TFETs are employed as the baseline transistor and PZT and silicon-doped HfO2 as ferroelectric materials.

Negative Capacitance as Universal Digital and Analog Performance Booster for Complementary MOS Transistors.

Boltzmann electron energy distribution poses a fundamental limit to lowering the energy dissipation of conventional MOS devices, a minimum increase of the gate voltage, i.e. 60 mV, is required for a 10-fold increase in drain-to-source current at 300 K. Negative Capacitance (NC) in ferroelectric materials is proposed in order to address this physical limitation of CMOS technology. A polarization destabilization in ferroelectrics causes an effective negative permittivity, resulting in a differential voltage amplification and a reduced subthreshold swing when integrated into the gate stack of a transistor. The novelty and universality of this approach relate to the fact that the gate stack is not anymore a passive part of the transistor and contributes to signal amplification. In this paper, we experimentally validate NC as a universal performance booster: (i) for complementary MOSFETs, of both n- and p-type in an advanced CMOS technology node, and, (ii) for both digital and analog significant enhancements of key figures of merit for information processing (subthreshold swing, overdrive, and current efficiency factor). Accordingly, a sub-thermal swing down to 10 mV/decade together with an enhanced current efficiency factor up to 105 V-1 is obtained in both n- and p-type MOSFETs at room temperature by exploiting a PZT capacitor as the NC booster. As a result of the subthreshold swing reduction and overdrive improvement observed by NC, the required supply voltage to provide the same on-current is reduced by approximately 50%.

Physical Activity Stage of Change and Its Related Factors in Secondary School Students of Sarableh City: A Perspective from Iran.

BACKGROUND: Physical activity is highly beneficial to health. These benefits are so important and indispensable for adolescents. AIM: The aim of this study was to investigate the Physical activity stage of change and its related factors in the male secondary School students of Sarableh city. MATERIAL AND METHODS: In a cross-sectional study, 261 male secondary School students possessing the eligibility criteria were selected using the simple random sampling technique. After giving their informed consent, the students filled the stage of change questionnaire and the structures of the transtheoretical model in a self-reporting manner. Using SPSS.21, the data were analysed through One-way ANOVA and Pearson correlation test with a 0.05 level of significance. RESULTS: The mean age of the students was 16.16±0.89 years. According to the stage of change, 26.8 per cent (n = 70) were in preaction stages (precontemplation, contemplation, and preparation) and 73.2 per cent (n = 191) were in action and maintenance stages. The one-way ANOVA revealed that awareness is raising, self-reevaluation, counter conditioning and reinforcing management differed significantly across stages (P < 0.05). However, this difference is not significant for other cognitive and behavioural processes (P > 0.05). According to the findings, increase in the self-efficacy, pros and decrease in cons was found by students' progress in the Physical activity stage of change (P < 0.05). CONCLUSION: Self-efficacy and processes of change are warranted when designing Physical activity stage interventions in the adolescents.

Effect of hysteretic and non-hysteretic negative capacitance on tunnel FETs DC performance.

This work experimentally demonstrates that the negative capacitance effect can be used to significantly improve the key figures of merit of tunnel field effect transistor (FET) switches. In the proposed approach, a matching condition is fulfilled between a trained-polycrystalline PZT capacitor and the tunnel FET (TFET) gate capacitance fabricated on a strained silicon-nanowire technology. We report a non-hysteretic switch configuration by combining a homojunction TFET and a negative capacitance effect booster, suitable for logic applications, for which the on-current is increased by a factor of 100, the transconductance by 2 orders of magnitude, and the low swing region is extended. The operation of a hysteretic negative capacitance TFET, when the matching condition for the negative capacitance is fulfilled only in a limited region of operation, is also reported and discussed. In this late case, a limited improvement in the device performance is observed. Overall, the paper demonstrates the main beneficial effects of negative capacitance on TFETs are the overdrive and transconductance amplification, which exactly address the most limiting performances of current TFETs.

Condition for the negative capacitance effect in metal-ferroelectric-insulator-semiconductor devices.

In this paper, we report a detailed study of the negative capacitance field effect transistor (NCFET). We present the condition for the stabilization of the negative capacitance to achieve the voltage amplification across the active layer. The theory is based on Landau's theory of ferroelectrics combined with the surface potential model in all regimes of operation. We demonstrate the validity of the presented theory on experimental NCFETs using a gate stack made of P(VDF-TrFE) and SiO2. The proposed analytical modeling shows good agreement with experimental data.

A single-cell correlative nanoelectromechanosensing approach to detect cancerous transformation: monitoring the function of F-actin microfilaments in the modulation of the ion channel activity.

Cancerous transformation may be dependent on correlation between electrical disruptions in the cell membrane and mechanical disruptions of cytoskeleton structures. Silicon nanotube (SiNT)-based electrical probes, as ultra-accurate signal recorders with subcellular resolution, may create many opportunities for fundamental biological research and biomedical applications. Here, we used this technology to electrically monitor cellular mechanosensing. The SiNT probe was combined with an electrically activated glass micropipette aspiration system to achieve a new cancer diagnostic technique that is based on real-time correlation between mechanical and electrical behaviour of single cells. Our studies demonstrated marked changes in the electrical response following increases in the mechanical aspiration force in healthy cells. In contrast, such responses were extremely weak for malignant cells. Confocal microscopy results showed the impact of actin microfilament remodelling on the reduction of the electrical response for aspirated cancer cells due to the significant role of actin in modulating the ion channel activity in the cell membrane.

Comparison of therapeutic effect of low-dose low-molecular-weight heparin (enoxaparin) vs. oral prednisone in treatment of patients with lichen planus; A clinical trial.

BACKGROUND: The aim of this study was to evaluate and compare the therapeutic efficacy of subcutaneous enoxaparin versus oral prednisone (as a standard treatment) in patients with disseminated lichen planus. MATERIALS AND METHODS: In this parallel randomized clinical trial study, overall 48 patients completed the study. 25 patients were treated with subcutaneous enoxaparin 5 mg weekly and 23 patients with 0.5 mg/kg prednisone orally daily until complete remission or a maximum of 8 weeks. The results of itching severity, extent of active lesions and drug side effects were compared. In remission, patients were followed for 6 months for recurrent lesions. RESULTS: In enoxaparin group, 8 patients (32%) had complete remission and 10 patients (40%) had partial improvement. In the oral prednisone group, 16 patients (69.6%) had complete remission and 6 patients (26.1%) had partial improvement (P = 0.005). Average size of active lesions in both groups decreased significantly after treatment, but analysis of covariance showed that the mean lesion size after treatment in the oral prednisone group was significantly lower than the enoxaparin group (P = 0.005). The relapse rate from improved patients in the enoxaparin group was 6 (33%) and in oral prednisone group was 9 (40.9%, P = 0.083). In the enoxaparin group no serious complications was seen. But 22% in the oral prednisone group show side effect, the most common complications were dyspepsia. CONCLUSION: Low dose enoxaparin on lichen Planus have therapeutic effect and is important for the least side effects but not as much as oral prednisone. But it could be accepted as an alternative treatment.

Effect of coriander seed (Coriandrum sativum L.) ethanol extract on insulin release from pancreatic beta cells in streptozotocin-induced diabetic rats.

Coriander (Coriandrum sativum L.) is grown as a spice crop all over the world. The seeds have been used to treat indigestion, diabetes, rheumatism and pain in the joints. In the present study, an ethanol extract of the seeds was investigated for effects on insulin release from the pancreatic beta cells in streptozotocin-induced diabetic rats. Blood samples were drawn from the retro-orbital sinus before and 1.5, 3 and 5 h after administration of the seed extract. Serum glucose levels were determined by the glucose oxidase method. To determine the insulin releasing activity, after extract treatment the animals were anaesthetized by diethyl ether, the pancreas was excised, fixed in 10% formaldehyde and embedded in paraffin for sectioning. Pancreatic sections of 5 microm were processed for examination of insulin-releasing activity using an immunocytochemistry kit. The results showed that administration of the ethanol extract (200 and 250 mg/kg, i.p.) exhibited a significant reduction in serum glucose. Administration of streptozotocin decreased the number of beta cells with insulin secretory activity in comparison with intact rats, but treatment with the coriander seed extract (200 mg/kg) increased significantly the activity of the beta cells in comparison with the diabetic control rats. The extract decreased serum glucose in streptozotocin-induced diabetic rats and increased insulin release from the beta cells of the pancreas.