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Miniaturised piezoelectric devices are emerging energy harvesting sources that are appropriate for various implantable and wearable applications. However, these piezoelectric devices exhibit considerable internal resistance due to their internal impedance, which leads to self-start and low-energy conversion failures. This paper describes a dual-stage boost converter circuit by facilitating self-powering features and boosting the low voltage harvested by the piezoelectric devices into dc. The proposed circuit comprises conversion stages of ac-dc and dc-dc in Stages I and II, respectively. In addition, the proposed circuit does not require employing the auxiliary circuits to generate the train pulses by triggering the bidirectional switches to envelop the current being stored in Stage II and kick-start the self-powered circuit for piezoelectric energy harvesting systems. Theoretical assumptions and control strategies were tested and verified with ideal and impedance input sources. The proposed circuit could convert a low voltage of 3 Vac into 19 Vdc. The maximum attained output power by the proposed circuit was 3.61 mW. The outcome depicted that the proposed circuit boosted the low voltage and outperformed the existing literature circuits in terms of output voltage and power.

Combining both processing techniques of horizontal-to-vertical spectral ratio (HVSR) and surface-to-borehole spectral ratio (SBR), using the KiK-net and K-NET database in Japan, could be used in the present study to establish relationships of VS and resonant frequency ( $$f$$ ) versus depth to bedrock half-space ( $$h$$ ) based on the site-dependent variability. Remarkable correlations of the average $${V}_{s}$$ of layers overlying the bedrock half-space ( $$\overline{{V }_{S}}$$ ) versus $$h$$ are inversely resembling those of the $$f$$ versus $$h$$ . The maximum $$\overline{{V }_{S}}$$ values are 1262 m/s, 933 m/s, 842 m/s, and 568 m/s through site class of B, C, D, and E, respectively. These values of $$\overline{{V }_{S}}$$ are decreasing gradually resembling the $${V}_{s30}$$ through site class of B, C, D, and E according to (NEHRP, Report FEMA 368, NEHRP, Washington, 2000). The $$f$$ versus $$h$$ regressions at KiK-net sites yield gradual decrease in the correlation coefficients (i.e., a and b) through site class of B, C, D, and E, particularly the resulted a and b from SBR technique. K-NET sites yield significant lower correlation coefficients, which could be attributed to the K-NET shallow depths ( $$h$$ ) and their corresponding limited ranges of ( $$f$$ ). Although such relationships are site-specific and highly dependent on each region’s geologic conditions, fair comparisons based on site information and site-dependent variability between previous relationships of $$f$$ versus $$h$$ in the literature and the present study relationships are showing remarkable similarities. This indicates significant importance of introducing the seismic site classification as a crucial controlling factor in establishing the previous and the present $${V}_{s}$$ and $$f$$ versus $$h$$ nonlinear regression relationships.

The evaluation of groundwater presence by means of seismic wave velocities is of great concern for many hydrological related engineering applications. This work introduces a simple basic procedure to accurately and systematically identify groundwater levels using P‐wave and S‐wave velocities. This procedure is defined as a seismic reflectivity parameter and based on the seismic reflection coefficients of P‐wave and S‐wave at the unsaturated/saturated interfaces (i.e., groundwater level). The present procedure is applied to 1045 K‐NET sites in Japan. Observed velocity structures, accompanied by their bulk densities and detailed lithology, for the upper 20 m depth are obtained from the National Research Institute for Earth Science and Disaster Prevention, Japan. Calculations are carried out considering three distinct lithological conditions – gravel, sand and clay–silt sediments – in order to evaluate the ability of this approach (seismic reflectivity parameter) to detect the groundwater level and assess its practical limitations. The increase of the seismic reflectivity parameter value varies substantially with Poisson's ratio, resembling the relationship between VP/VS and Poisson's ratio in gravel, sand and clay–silt sediments. However, positive seismic reflectivity parameter values indicate groundwater presence, whereas negative seismic reflectivity parameter values indicate lithological variation. The seismic reflectivity parameter can also be used as a relative indicator for groundwater saturation levels. Fair comparisons are established between the seismic reflectivity parameter and the water seismic index technique. However, the seismic reflectivity parameter approach shows consistency with previous theoretical and experimental studies related to variations of VP and VS in saturated conditions, whereas the water seismic index shows inconsistency with these previous theoretical and experimental studies and an inability in determining saturation levels and detecting groundwater levels.

In this study, the inversion modeling method variability of S-wave velocity structure results by inverting/forward-modeling waveforms and HVSR curves is investigated. For this purpose, eight KiK-net seismic stations using 636 foreshocks, mainshock of the 2011 Tohoku earthquake, and 4983 aftershocks obtained from KiK-net are used. The most reliable and representative inverted S-wave velocity structures are based on close fitting of the theoretical to the observed data of waveforms and HVSR curves. The inverted S-wave velocity structures derived from the total stress analyses are showing high degrees of similarity and consistency using both EW and NS components and evidenced by the isotropic HVSRs directionality related to the linear and nonlinear site effects. Conversely, stiffness variations due to nonlinearity, inferred from inverted S-wave velocity structures derived from the diffuse field assumption, significantly correspond with stiffness variations evaluated from the observed fundamental resonance frequencies. The corresponding percent of reduction and recovery reflect low variability in S-wave velocities that result from inversion modeling based on diffuse field assumption. Qualitatively, the presence of the stiffness degradation process due to linear and nonlinear site responses could be obviously detected using both inversion modeling methods based on total stress analyses and diffuse field assumption. Quantitatively, the precision of the nonlinearity evaluation is questionable due to significant uncertainties in the inverted S-wave velocity structures inferred from both inversion modeling methods. These uncertainties are strongly dependent on the theory of each inversion modeling method. The use of complementary methods with more prior information is suggested to resolve the nonuniqueness of the inverted S-wave velocities and hence overconfidence in the precision of the nonlinearity evaluation.

Background Abrupt bradycardia and hemodynamic instability during spinal anesthesia for cesarean section are not uncommon and are considered as one of the primary causes of intraoperative nausea and vomiting (IONV). We hypothesized that prophylactic use of hyoscine butyl-bromide (HBB) could improve hemodynamics and reduce IONV in parturients undergoing cesarean section. Methods A randomized, double-blind placebo-controlled trial was carried out in a tertiary university hospital, patients scheduled for elective cesarean section were equally randomized to receive either IV HBB 20 mg in 1 ml (Hyoscine group) or the same volume of 0.9% saline (Control group), one minute after spinal anesthesia. The primary endpoint was the incidence of intraoperative bradycardia (HR −1). Secondary endpoints included changes in mean arterial blood pressure (MAP), the incidence of Intraoperative and Postoperative nausea or vomiting (IONV & PONV), the fetal heart rate and, Apgar score. Results Of the 160 subjects randomized, 80 received HBB and 80 received placebo. There was a significant reduction in the incidence of the primary endpoint of intraoperative bradycardia (HR −1) in the Hyoscine group (0% vs 10%; OR = 0.05, 95% CI = [0.003, 0.93]; P = 0.004) compared with placebo. MAP showed an insignificant difference between groups over time. HBB significantly decreased incidences of IONV and PONV (p = 0.002 & 0.004) respectively. Conclusions In parturients undergoing cesarean section under spinal anesthesia, pretreatment with intravenous HBB was a safe measure for both the mother and the baby to reduce the risk of severe intraoperative bradycardia, but not hypotension. Furthermore, it was associated with less incidence of both IONV and PONV. Trial registration https://clinicaltrials.gov/ct2/show/NCT04069078

In this study, a complete model for a miniature excitation-powered piezoelectric generator (PG), analysis modes of operation and control of a full-bridge joule thief (FBRJT) circuit to identify the optimal points were investigated. The proposed model revealed the PG’s power dependency on mechanical excitation, acceleration, and frequency and defined the load behaviour for power optimisation. The proposed circuit, namely FBRJT, was integrated with the conventional full-bridge rectifier (FBR) in Stage 1 for AC-DC conversion and with the joule thief circuit in Stage 2 for DC-DC conversion. This integration acted as a boost converter without utilising the duty cycles and additional switching components. The electrical nature of the input of FBRJT with a simple structure, sensor-less control and auxiliary circuits showed a consistent agreement with the investigated testing scenarios using both ideal and impedance power sources. Additionally, the performance of the proposed circuit was also verified against the published results of power electronics circuits. The developed versatile circuit and control system can be utilised for many applications, such as mobile battery charging and energy harvesting.

Observed active fault zone related site amplification is calculated based on Fourier acceleration spectrum (FAS) at three different localities in Japan. The FASs are calculated using 26432 earthquakes recorded at 126 K-NET and KiK-net seismic stations, which are distributed on the fault zones, upthrown and downthrown sides. This observed amplification is strongly frequency-dependent because of the presence of the near-surface low-velocity flower fault structure and the deeper fault zone. Moreover, the amplification patterns at each study area are tectonic-specific patterns. Sources inside the active fault zones could produce amplification at high frequencies at stations on both fault zone and far away from the fault zone, because of the impact of the near-surface fault zone. Sources outside the active fault zones yield remarkable high amplification at low frequencies exhibiting a gradual increase through stations on hanging walls, fault zones, and footwalls. Interestingly, the peaks of the low-frequency amplification are corresponding to wavelengths that approximately equalize the width of the fault zone. The presence of fault zone low-velocity layers could be successfully detected by the diffuse field theory inversion.

It is commonly accepted that the horizontal-to-vertical spectral ratio (HVSR) technique enables the detection of the fundamental resonance frequency ($$f_{\text{HVSR}}$$) of a given site. The utility of this $$f_{\text{HVSR}}$$ is analyzed using the nonlinear regression relationships between $$f_{\text{HVSR}}$$ and bedrock depth ($$h$$). The derived relationships are mostly site-specific, so that the present paper consists of two main parts. The first is a literature review for the available empirical relationships between $$f_{\text{HVSR}}$$ and $$h$$. The aim of this part is to highlight the practical limitations of these established relationships and to make fair comparisons. The second is to generate new relationships, taking advantage of the very wide range of available lithological, geophysical, and geotechnical borehole drilling data of the 697 KiK-NET seismic stations in Japan. For this purpose, HVSR are calculated using 10,000 weak earthquakes or linear events recorded at KiK-NET stations to determine the $$f_{\text{HVSR}}$$ and correlate it with the corresponding $$h$$. The overlying layers/bedrock interface falling within sedimentary, igneous, or metamorphic layers significantly affect the derived frequency–depth relationships. In addition, these relationships are strongly reproduced by the $$V_{\text{p}} /V_{\text{s}}$$ ratio of the bedrock in the range of 1.6–2.2. Interestingly, it is found that $$f_{\text{HVSR}}$$ less than 1 Hz corresponding to $$h$$ more than 100 m leads the trend of the overall frequency–depth relationship.

Background Cerebral edema and increased intracranial pressure are of the major consequences of traumatic brain injury that affects the outcome. The aim of this study is to assess the efficacy of dexmedetomidine as an adjunct to conventional sedative therapy (propofol) compared to conventional sedative therapy alone in patients with traumatic brain injury, as regards its effects on hemodynamics and intracranial pressure. Methods This prospective randomized controlled clinical trial with 60 agitated and restless traumatic brain-injured patients was performed between May 2013 and May 2017. Patients who required mechanical ventilation, Glasgow coma scale (GCS)

In the present study, observed active fault zone related site amplification is calculated based on Fourier acceleration spectrum (FAS) at three different localities in Japan. For this purpose, the FASs are calculated using 26432 earthquakes recorded at 126 K-NET and KiK-net seismic stations, which are distributed on the fault zones and upthrown and downthrown sides. This observed amplification is strongly frequency-dependent because of the presence of the near-surface low-velocity flower fault structure and the deeper fault zone. Moreover, the amplification patterns at each study area are tectonic-specific patterns. Sources inside the active fault zones could produce amplification at high frequencies at stations on both fault zone and far away from the fault zone. This is because of the impact of the near-surface fault zone. Sources outside the active fault zones could not produce significant amplification at high frequencies, whereas remarkable high amplification at low frequencies exhibits a gradual increase through stations on hanging walls, fault zones, and footwalls. Remarkably, low-frequency amplification due to sources outside the active fault zones at stations on footwalls is much higher than those observed on hanging walls. Interestingly, the peaks of the low-frequency amplification are corresponding to wavelengths that approximately equalize the width of the fault zone. Diffuse field theory inversion using earthquake horizontal-to-vertical spectral ratio (EHVSR) could successfully detect the presence of fault zone low-velocity layers. However, analyzing the fault zone related site effects using HVSR is not effective because of the strong amplification related structural control of the active fault zones on the ground motions.

Combining both processing techniques of horizontal-to-vertical spectral ratio (HVSR) and surface-to-borehole spectral ratio (SBR), using the KiK-net and K-NET database in Japan, could be used in the present study to establish relationships of Vs, Vp, and resonant frequency (f) versus depth to bedrock half-space (h) based on the site-dependent variability in different lithologies. Remarkable correlations of the average Vs and Vp of layers overlying the bedrock half-space (i.e. Vs and Vp) versus h are inversely resembling the relationships of f versus h and their maxima of ≤ 1000 m/s and ≤ 3000 m/s, respectively. Moreover, their ranges are decreasing gradually through site class of B, C, D and E resembling the ranges of the Vs30 according to NEHRP Provision (2000). Underestimation in the correlation coefficients resulted from HVSR at K-NET sites due to shallow and limited ranges of h whenever compared with those resulted from HVSR and SBR at KiK-net sites. Rebuilding the f versus h based on site-dependent variability in different lithologies could strongly decrease scattering and deviations of data points. Although such relationships are site-specific and highly dependent on each region’s geologic conditions, fair comparisons based on site information and site-dependent variability of different bedrock lithologies between previous relationships of f versus h in the literature and the present study relationships are showing remarkable and reasonable similarities. This indicates significant importance of introducing the seismic site classification of different lithologies as a crucial controlling factor in establishing the previous and the present nonlinear regression relationships.

Background: Thyroidectomy is the surgical removal of a partial or complete thyroid gland in case of hyperthyroidism, thyroid cancer and goiter. The aims of this study: were to eveluate effect of designed nursing guidelines on minimizing postoperative complications for patients undergoing thyroidectomy through the following; 1) assess patients' knowledge and practice about thyroidectomy, 2) design nursing guidelines , 3) evaluate the effect of applying these guidelines on minimizing postoperative complications for patients undergoing thyroidectomy. Patients and method: This study was conducted in the general surgery department and outpatient surgery clinic at Assiut University Hospital. A convientent sample of 60 adult patients of both sexes, their ages ranged between 20 - 65 years old and were divided into two equal groups (study and control) thirty patients for each. Tools: Patient assessment sheet and thyroidectomy complications evaluation sheet. Results: there was statistically significant difference between the study and control groups regarding knowledge and practice scores, wound healing and other thyroidectomy complications. Conclusion: implementation of the designed nursing guidelines in the management of patients undergoing thyroidectomy had improved patients' outcomes: significantly increased level of knowledge and practice scores, and decreased overall postoperative complications rate. Recommendation Providing a written instruction booklet about perioperative care for thyroidectomy is of great importance for the patients.

Natural vibrations can be harnessed using piezoelectric transducers and converted into electrical energy to power small electronic devices such as sensors network for structural health monitoring. One promising wind energy harvester configuration is a piezoelectric cantilever beam with a bluff body attached at the free end. The strain-induced into the cantilever by the galloping motion, and therefore the power produced is dependent on the bluff body shape, wind speed and the incidence angle of the wind to the bluff body face. Thus far, most studies related to piezoelectric cantilever beam with transverse galloping bluff body were conducted in wind tunnels with laminar flow and graduated wind speed increase. There is no research conducted on natural and chaotic wind conditions. The effectiveness of the bluff body in varying wind conditions is not known. In this study, a self-tunable piezoelectric wind energy harvester was proposed by using a rotating base to account for the erratic nature of wind in the field. Three bluff body prisms (square, triangle and D-section), fitted to a piezoelectric cantilever with fixed and rotating bases, were sequentially studied under the natural wind condition. Results indicated that the rotating base configurations have a higher cut-in speed when compared with the motionless base but was able to produce higher output power, especially with the use of a square prism as the bluff body under typical urban windspeed (i.e. 3–6 m/s). This first-ever field study demonstrated the potential and advantage of employing the piezoelectric wind energy harvester with a rotating base under natural and erratic wind conditions.

Cloud computing is increasingly recognized as a new way to provide IT resources (e.g., on-demand, computing, storage, network...) in a transparent way, and effective. Because of the heterogeneity environment of the cloud computing, the scalability can be supported, which is considered a fundamental feature for big data application to achieve performance, efficiency, load balance, and energy consumption. One of the main challenges of the cloud computing is resource management to satisfy the customers' requirements (e.g., Cost, QoS of resources.. .) and resource utilization of the data center. On the other hand, the Scheduling of resources among customers' tasks is considered the main issue of resource management. Therefore, resource scheduling algorithms is a vital research area to improve the total execution time (i.e., makespan), cost, efficiency, and load balance in the case of virtual resources. In this paper, we present a synthesis of the existing algorithms concerning scheduling customers' tasks based on heuristics approach in the cloud environment. Accordingly, the significant issues that play a role in the selection of the scheduling algorithm are provided.

Objective: Perioperative fluid restriction in major abdominal surgeries carries a potential risk of organ dysfunction such as acute kidney injury. Profound fluid restriction should be applied cautiously. The aim of this study is to compare the accuracy of (serum creatnine, urine output and KDIGO compared to NGAL for detection of postoperative AKI after colorectal surgery.Methods: Restrictive fluid strategy was applied to all patients with 5 mL/kg/h of lactated ringer (LR) and was administered intraoperatively starting from the induction of general anesthesia till the end of surgery and patient extubation. Data collected included incidence of AKI with three screening tools in addition to intra and postoperative complications.Results: None of the above tested AKI based criteria has satisfactory both sensitivity and specificity. The sensitivity of urine output for detection of AKI was 72.7 [39.0-94.0] while its specificity was 79.8 [69.9-87.6], for creatinine above 0.3 mg/dl; the sensitivity was 63.6 [30.8-89.1] and specificity was 98.9 [93.9-99.9], and for KDIGO the sensitivity was 81.8 % [95% CI 48.2-97.7] and specificity was 74.2% [95% CI 63.8-82.9].Conclusion: Despite use CVP for detection of hypovolemia, there is still high incidence of AKI. Creatinine based criteria, urine based criteria or combination of both are inaccurate when volume restriction is applied.

The use of intrathecal morphine may result in serious side effects in parturients undergoing cesarean delivery. Nalbuphine, is a mu receptor antagonist and a ĸappa receptor agonist. Combinations of opioid agonist and agonist antagonist can decrease the incidence of opioid related side effects. We aimed to investigate the effect of adding nalbuphine, to intrathecal morphine on postoperative nausea and vomiting and pruritus after a cesarean delivery.Eighty parturient undergoing elective cesarean delivery under spinal anesthesia were randomized into two similar groups. Group 1: received 10 mg of 0.5% hyperbaric bupivacaine with 0.2 mg morphine. Group 2: received as a group 1 plus 0.5 mg nalbuphine, with total volume 2.5 mL in both groups. Measurements: Data on the severity of nausea and vomiting were collected using a numerical rating scale and visual analogue scale was used to quantify pruritus. Onset and duration of sensory blockade, Visual Analog Scale for pain, the first time to ask for rescue analgesia and total rescue analgesic consumption were recorded.Nausea and vomiting and pruritus severity scores and number of patients developed nausea and vomiting and pruritus were significantly lower (P0.001) in group 2. Onset and duration of sensory block, time to first request for rescue analgesia, Visual Analog Scale for pain and paracetamol consumption showed no statistically differences between both groups (P0.05).We concluded that the addition of nalbuphine to intrathecal bupivacaine plus morphine significantly reduced the incidence and severity of postoperative nausea and vomiting and pruritus without affecting analgesic potency.

The main problem associated with using composite sandwich panels with foam core is their ability to withstand shear load. The aim of the present work is to extend the knowledge of mechanical properties both on constituent components and on the whole sandwich structures, focusing on the effects induced by inserting semi-circular shear keys between the skin and the foam core. The sandwich panel under investigation is composed of glass fibre reinforced polymer (GFRP) skin with polyvinylchloride (PVC) and polyurethane (PU) foam core, while the shear keys are made of chopped strand (CS) glass fibre impregnated with epoxy resin. The material properties of the skin, keys and foam core materials were investigated through a series of quasi-static tests. The mechanical properties of each component were used as input data in order to implement the finite element (FE) analysis using ABAQUS software. Parametric investigation using the FE analysis to select the most suitable pitch (space between shear keys along the panel) of the shear keys taking into consideration the materials and geometrical nonlinearities as well as the complex interaction between all the mating surfaces was performed. Five different pitches have been investigated namely 15, 25, 35, 45 and 55 mm. The results showed that the model with 45 mm pitch represents the most sustainable model among the others. The FE results were verified with the measured ones extracted from the out-of-plane shear test.

Prognosis of colorectal carcinoma depends on many factors, such as age and sex of patient; location; multiplicity; local extent and size of tumor, bowel obstruction, or perforation; as well as tumor microscopic type and grade; vascular and perineural invasion; and nodal and distant metastasis. The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes strongly implicated in tumor invasion and metastasis, hence in tumor prognosis. The purpose of this study was to assess the role of MMP-2 and MMP-9 expression in colorectal tumorigenesis, invasion, and metastasis, hence their prognostic values.Immunohistochemical analysis of MMP-2 and MMP-9 in colorectal cancer cells, an immunohistochemical score based on the intensity of immunoreactivity and proportion of immunoreactive cells that established for each MMP, and correlation of this expression with the established prognostic factors.MMP-2 was expressed in 81.8% (strong expression in 40%) of cases, and MMP-9 was expressed in 72% (strong expression in 35%) of cases.MMP-2 and MMP-9 are widely expressed in colorectal carcinoma, suggesting significant diagnostic and prognostic values in these tumors. Increased levels of MMP-2 and MMP-9 protein expression in colorectal carcinoma tissues as compared to normal tissues suggest their association with colorectal tumor invasion and metastasis and that they could be targets for intervention and therapy in colorectal carcinoma.

Gallstones are more common in patients with liver cirrhosis than in healthy individuals. Higher morbidity and mortality were reported in cirrhotic patients with either laparoscopic or open cholecystectomy. The aim of this study was to compare laparoscopic and open cholecystectomy in cirrhotic patients with symptomatic cholelithiasis in a prospective, randomized manner.Thirty patients with symptomatic cholelithiasis associated with Child-Pugh class A or B liver cirrhosis were prospectively and randomly grouped equally to either laparoscopic or open cholecystectomy. The two groups were compared regarding operative time, morbidity, mortality, postoperative liver function, and hospital stay.The two groups were comparable regarding demographic data, preoperative and postoperative Child-Pugh scoring, mean operative time (57.3 minutes for laparoscopic and 48.5 for open), and complications (33.3% for each). Hospital stay was shorter for the laparoscopic group. One conversion (6.7%) to open surgery was reported. No periopertive mortality occurred in either group.For Child-Pugh class A and B cirrhotics, laparoscopic cholecystectomy is comparable to the open approach regarding operative time, morbidity, mortality, and effect on liver function, but with shorter hospital stay. Considering the other well-documented advantages of the laparoscopic approach, namely, less pain, earlier mobilization and feeding, and better cosmoses, laparoscopic cholecystectomy would be the first choice in cirrhotic patients.

In the present study, a set of three strong motions accompanied by 21 before and after mainshock motions from liquefied soil at the Kushiro Port vertical array site have been obtained.S-wave velocity variation is estimated using a new proposed nonlinear GA inversion technique. This inversion technique is reproductive in assessment forS-wave velocities due to its direct link with the simulation FEM program and matching technique between the observed and simulated waveforms. Layers (6 ∼ 23 m depth) have been found to be responsible for liquefaction at the Kushiro Port site. Stiffness degradation due to liquefaction could be predicted by applying the inversion technique on the horizontal components of the mainshocks at different time-windows and then multiplying the weighting functions by the nonlinear simulated ground motions. These weighting functions were applied to delete the misfit time window of the nonlinear simulated ground motions when these were compared to the observed records. Finally, stacking was applied for the weighted nonlinear simulated ground motions. A strong degree of liquefaction is concluded during the Kushiro-Oki (1993) and the Hokkaido Toho-Oki (1994) earthquakes, whereas a low degree of liquefaction was detected to have occurred during the Tokachi-Oki (2003) earthquake due to high increase of rigidity following a trend that resembles a consolidation curve.