Common Cardiovascular Diseases in Women.

Cardiovascular disease is a leading cause of death for women in the United States. This article encompasses the epidemiology/etiology, clinical presentation, diagnostic assessment, management, and prognosis of some common cardiovascular disorders seen in women with a special focus on pregnancy.

Sulfonamide Derivatives as Novel Surfactant/Alkaline Flooding Processes for Improving Oil Recovery.

Over time, oil consumption has increased along with a continuous demand for petroleum products that require finding ways to increase hydrocarbon production more economically and effectively. So, enhanced oil recovery technologies are believed to be very promising and will serve as a key to meeting the future energy demand. This paper aims to introduce an innovative method to boost the EOR by using two novel types of surfactants synthesized from sulfonamide derivatives. Types I and II surfactants were analyzed using Fourier transform infrared spectroscopy, and their characterization was further performed using 1H NMR and 13C NMR spectroscopy. Additionally, the evaluation of these surfactants included interfacial tension measurements at concentrations up to 0.9 wt %. The combination of types I and II surfactants with alkaline (NaOH) was also investigated by the measurements of interfacial tension. A series of coreflood and sandpack tests under high-salinity conditions were carried out to assess the effects of a surfactant alone and alkaline-surfactant as a combination on improving oil recovery. The rock wettability was evaluated using relative permeability saturation curves, and the oil displacement efficiency was determined using fractional flow curves. The coreflood results demonstrated that alkaline-surfactant flooding with the chemical formula 0.2 wt % surfactant type II plus 0.5 wt % NaOH achieved a higher oil recovery of 74% OOIP compared to surfactant flooding with the chemical formula 0.5 wt % surfactant type II (64% OOIP) and waterflooding (saline solution with a 35,000 ppm salinity: 48% OOIP). Moreover, the experimental results showed that under both core and sandpack flood conditions, there was a noticeable reduction in oil-water interfacial tension, a change in rock wettability to more water-wet, and higher efficiency of oil displacement when alkaline was added to the surfactant. Based on current research, the alkaline-surfactant formulation is strongly recommended for chemical flooding because of its high efficacy and relatively low cost.

Development and Evaluation of a Mixed-Reality Tele-ultrasound System.

OBJECTIVE: The objective of this feasibility study was to develop and assess a tele-ultrasound system that would enable an expert sonographer (situated at the remote site) to provide real-time guidance to an operator (situated at the imaging site) using a mixed-reality environment. METHODS: An architecture along with the operational workflow of the system is designed and a prototype is developed that enables guidance in form of audiovisual cues. The visual cues comprise holograms (of the ultrasound images and ultrasound probe) and is rendered to the operator using a head-mounted display device. The position and orientation of the ultrasound probe's hologram are remotely controlled by the expert sonographer and guide the placement of a physical ultrasound probe at the imaging site. The developed prototype was evaluated for its performance on a network. In addition, a user study (with 12 participants) was conducted to assess the operator's ability to align the probe under different guidance modes. RESULTS: The network performance revealed the view of the imaging site and ultrasound images were transferred to the remote site in 233 ± 42 and 158 ± 38 ms, respectively. The expert sonographer was able to transfer, to the imaging site, data related to position and orientation of the ultrasound probe's hologram in 78 ± 13 ms. The user study indicated that the audiovisual cues are sufficient for an operator to position and orient a physical probe for accurate depiction of the targeted tissue (p < 0.001). The probe's placement translational and rotational errors were 1.4 ± 0.6 mm and 5.4 ± 2.2º. CONCLUSION: The work illustrates the feasibility of using a mixed-reality environment for effective communication between an expert sonographer (ultrasound physician) and an operator. Further studies are required to determine its applicability in a clinical setting during tele-ultrasound.

Tracheostomy insertion in COVID-19: insertion practice and factors leading to unplanned tube exchange.

Background: Tracheostomy insertion in patients with coronavirus disease 2019 (COVID-19) presents unique challenges. Patients frequently have high ventilatory requirements, and as an aerosol generating procedure, tracheostomy insertion creates the potential for staff transmission. Problems with tracheostomies contribute to morbidity and mortality, and tracheostomy changes may increase risks of staff transmission. We sought to quantify the incidence of clinically necessitated tracheostomy changes, establish the indications for change and investigate the incidence of staff transmission. Methods: We conducted a single institution, retrospective, observational cohort study of all intensive care unit (ICU) patients with COVID-19 who had a tracheostomy between March 2020 and April 2021. The institution is a large tertiary referral centre in Ireland. Results: Forty-three patients had a tracheostomy during the study period. All were a Shiley™ Flexible Adult Taperguard or Shiley™ XLT Tracheostomy. 14 patients (33%) required a tracheostomy change, with the majority (57%) involving a change from a standard size to an extended length tracheostomy. Persistent leak was the most common indication for change (71.6%). Other indications included patient-ventilator dyssynchrony, persistent cough and accidental decannulation. No staff transmission of COVID-19 occurred during this study. Conclusions: The incidence of tracheostomy change was 33%, highlighting the importance of selecting the right tracheostomy for each patient. We discuss how key characteristics of tracheostomies such as type, size, length and inner diameter may impact flow, resistance and work of breathing, leading to unplanned tracheostomy change. No staff transmission occurred arising from tracheostomy insertion, adding to increasing evidence that tracheostomy insertion in COVID-19 appears safe with adherence to guidelines describing the correct use of personal protective equipment.

A Recurrent Pleomorphic Xanthoastrocytoma in the Cerebellum in a Young Adult: A Case Report and Review of the Literature.

Pleomorphic xanthoastrocytoma (PXA) is a rare glioma. It accounts for less than 1% of all astrocytomas. About 98% of PXAs originate supratentorially with the temporal lobe being the most common location. Cases of infratentorial PXAs are rarely reported in the medical literature. The tumor presents with a wide variation of symptoms based on the neuroanatomy involved with the location and size of the tumor, with seizures being the most reported symptom. The diagnosis depends on histological and clinical features along with radiologic features. We searched the keywords "Pleomorphic xanthastrocytoma, PXA, cerebellum, infratentorium, astrocytoma, gliomas" in the PubMed database; from 1979 to the current date, 28 cases were found in the medical literature featuring PXA in the infratentorium. We present the 29th case in the literature and the first in Syria. Our patient had a lesion in the right cerebellum and presented with a history of intermittent headache for 5 months followed by progressive gait disturbances and blurry vision and was misdiagnosed at the time of presentation with a high-grade glioma which is a common confusion because of the histological and clinical similarities. The patient underwent a suboccipital craniotomy, and adjuvant therapy with a combination of radiotherapy and chemotherapy with temozolomide was initiated at first. Then, the patient presented with a relapse of symptoms and went through another surgery where frozen sections suggested the diagnosis of PXA; further histopathological and immunohistochemical studies confirmed the diagnosis. Alongside highlighting the diagnostic challenge of this rare tumor, we did a brief review of the literature.

Evaluation of user-interfaces for controlling movements of virtual minimally invasive surgical instruments.

BACKGROUND: Recent tele-mentoring technologies for minimally invasive surgery (MIS) augments the operative field with movements of virtual surgical instruments as visual cues. The objective of this work is to assess different user-interfaces that effectively transfer mentor's hand gestures to the movements of virtual surgical instruments. METHODS: A user study was conducted to assess three different user-interface devices (Oculus-Rift, SpaceMouse, Touch Haptic device) under various scenarios. The devices were integrated with a MIS tele-mentoring framework for control of both manual and robotic virtual surgical instruments. RESULTS: The user study revealed that Oculus Rift is preferred during robotic scenarios, whereas the touch haptic device is more suitable during manual scenarios for tele-mentoring. CONCLUSION: A user-interface device in the form of a stylus controlled by fingers for pointing in 3D space is more suitable for manual MIS, whereas a user-interface that can be moved and oriented easily in 3D space by wrist motion is more suitable for robotic MIS.

Preliminary design and evaluation of a remote tele-mentoring system for minimally invasive surgery.

BACKGROUND: Tele-mentoring during surgery facilitates the transfer of surgical knowledge from a mentor (specialist surgeon) to a mentee (operating surgeon). The aim of this work is to develop a tele-mentoring system tailored for minimally invasive surgery (MIS) where the mentor can remotely demonstrate to the mentee the required motion of the surgical instruments. METHODS: A remote tele-mentoring system is implemented that generates visual cues in the form of virtual surgical instrument motion overlaid onto the live view of the operative field. The technical performance of the system is evaluated in a simulated environment, where the operating room and the central location of the mentor were physically located in different countries and connected over the internet. In addition, a user study was performed to assess the system as a mentoring tool. RESULTS: On average, it took 260 ms to send a view of the operative field of 1920 × 1080 resolution from the operating room to the central location of the mentor and an average of 132 ms to receive the motion of virtual surgical instruments from the central location to the operating room. The user study showed that it is feasible for the mentor to demonstrate and for the mentee to understand and replicate the motion of surgical instruments. CONCLUSION: The work demonstrates the feasibility of transferring information over the internet from a mentor to a mentee in the form of virtual surgical instruments. Their motion is overlaid onto the live view of the operative field enabling real-time interactions between both the surgeons.

Towards development of a tele-mentoring framework for minimally invasive surgeries.

BACKGROUND: Tele-mentoring facilitates the transfer of surgical knowledge. The objective of this work is to develop a tele-mentoring framework that enables a specialist surgeon to mentor an operating surgeon by transferring information in a form of surgical instruments' motion required during a minimally invasive surgery. METHOD: A tele-mentoring framework is developed to transfer video stream of the surgical field, poses of the scope and port placement from the operating room to a remote location. From the remote location, the motion of virtual surgical instruments augmented onto the surgical field is sent to the operating room. RESULTS: The proposed framework is suitable to be integrated with laparoscopic as well as robotic surgeries. It takes on average 1.56 s to send information from the operating room to the remote location and 0.089 s for vice versa over a local area network. CONCLUSIONS: The work demonstrates a tele-mentoring framework that enables a specialist surgeon to mentor an operating surgeon during a minimally invasive surgery.

Optic nerve sheath diameter by ultrasound is a good screening tool for high intracranial pressure in traumatic brain injury.

OBJECTIVES: This study aimed to determine the role of ONSD measurement by US for diagnosis of high ICP in TBI patients. METHODS: ONSD measurement by US was performed in adult TBI patients within 1 h of planned CT brain, while CT signs of high ICP were determined. Invasive ICP measurement was performed simultaneously in patients who had intraventricular device in situ. High ICP was determined as ICP > 22 mmHg. RESULTS: A total of 48 patients were enrolled. Twenty-eight patients had positive CT criteria for high ICP, while 20 patients were negative. The mean value of ONSD was 0.63 ± 0.06 cm in positive group compared with 0.55 ± 0.07 cm in negative one with significant difference (p < 0.001). A total of 22 patients had intraventricular device. Thirteen patients had high ICP, while 9 patients had normal ICP. The mean value of ONSD was 0.66 ± 0.05 cm in high ICP group compared with 0.58 ± 0.08 cm in normal one with significant difference (p = 0.004). ONSD with cut-off value > 0.61 cm predicted high ICP with sensitivity of 84.62% and specificity of 66.67% with significant AUC of 0.85 (p = 0.006). CONCLUSION: ONSD measurement by ultrasound is a good screening tool for high ICP in traumatic brain injury patients.

Role of electroencephalogram in diagnosis of attention deficit hyper activity disorder

Introduction: Attention deficit hyper activity disorder (ADHD), is the most prevalent neurodevelopmental disorder of childhood, which is characterized by the presence of inattention, hyperactivity, and/or impulsivity, EEG is the substrate of brain activity underlying cognition and behavior.Objective: To detect the abnormalities in the electroencephalogram (EEG) in patients with ADHD also to find the relation between attention deficit hyperactivity disorder symptom severity and results of EEG. Method: sixty patients of ADHD and 60 age and sex matched control were evaluated with EEG to detect abnormal waves. Results: Patients with ADHD show abnormal EEG results in the form of background slowing in3 patients (5%) and epileptiform discharge in 19 patients (32%) frontal slowing in 13 patients(22%) normal EEG in 25 patients (42%).Conclusion: There is increased low frequency activity and decreased high frequency activity in children with ADHD, this may aid as an indicator in the diagnosis of ADHD

Collective thermal transport in pure and alloy semiconductors.

Conventional models for predicting thermal conductivity of alloys usually assume a pure kinetic regime as alloy scattering dominates normal processes. However, some discrepancies between these models and experiments at very small alloy concentrations have been reported. In this work, we use the full first principles kinetic collective model (KCM) to calculate the thermal conductivity of Si1-xGex and InxGa1-xAs alloys. The calculated thermal conductivities match well with the experimental data for all alloy concentrations. The model shows that the collective contribution must be taken into account at very low impurity concentrations. For higher concentrations, the collective contribution is suppressed, but normal collisions have the effect of significantly reducing the kinetic contribution. The study thus shows the importance of the proper inclusion of normal processes even for alloys for accurate modeling of thermal transport. Furthermore, the phonon spectral distribution of the thermal conductivity is studied in the framework of KCM, providing insights to interpret the superdiffusive regime introduced in the truncated Lévy flight framework.

Evidence of Universal Temperature Scaling in Self-Heated Percolating Networks.

During routine operation, electrically percolating nanocomposites are subjected to high voltages, leading to spatially heterogeneous current distribution. The heterogeneity implies localized self-heating that may (self-consistently) reroute the percolation pathways and even irreversibly damage the material. In the absence of experiments that can spatially resolve the current distribution and a nonlinear percolation model suitable to interpret them, one relies on empirical rules and safety factors to engineer these materials. In this paper, we use ultrahigh resolution thermo-reflectance imaging, coupled with a new imaging processing technique, to map the spatial distribution ΔT(x, y; I) and histogram f(ΔT) of temperature rise due to self-heating in two types of 2D networks (percolating and copercolating). Remarkably, we find that the self-heating can be described by a simple two-parameter Weibull distribution, even under voltages high enough to reconfigure the percolation pathways. Given the generality of the phenomenological argument supporting the distribution, other percolating networks are likely to show similar stress distribution in response to sufficiently large stimuli. Furthermore, the spatial evolution of the self-heating of network was investigated by analyzing the spatial distribution and spatial correlation, respectively. An estimation of degree of hotspot clustering reveals a mechanism analogous to crystallization physics. The results should encourage nonlinear generalization of percolation models necessary for predictive engineering of nanocomposite materials.

Fractal Lévy Heat Transport in Nanoparticle Embedded Semiconductor Alloys.

Materials with embedded nanoparticles are of considerable interest for thermoelectric applications. Here, we experimentally characterize the effect of nanoparticles on the recently discovered Lévy phonon transport in semiconductor alloys. The fractal space dimension α ≈ 1.55 of quasiballistic (superdiffusive) heat conduction in (ErAs)x:InGaAlAs is virtually independent of the Er content 0.001 < x < 0.1 but instead controlled by alloy scattering of the host matrix. The increased nanoparticle concentration does reduce the diffusive recovery length by an order of magnitude. The bulk conductivity drops by 3-fold, in close agreement with a Callaway model. Our results may provide helpful hints toward engineering superdiffusive heat transport similar to what has been achieved with light in Lévy glasses.

Enhanced thermoelectric properties in bulk nanowire heterostructure-based nanocomposites through minority carrier blocking.

To design superior thermoelectric materials the minority carrier blocking effect in which the unwanted bipolar transport is prevented by the interfacial energy barriers in the heterogeneous nanostructures has been theoretically proposed recently. The theory predicts an enhanced power factor and a reduced bipolar thermal conductivity for materials with a relatively low doping level, which could lead to an improvement in the thermoelectric figure of merit (ZT). Here we show the first experimental demonstration of the minority carrier blocking in lead telluride-silver telluride (PbTe-Ag2Te) nanowire heterostructure-based nanocomposites. The nanocomposites are made by sintering PbTe-Ag2Te nanowire heterostructures produced in a highly scalable solution-phase synthesis. Compared with Ag2Te nanowire-based nanocomposite produced in similar method, the PbTe-Ag2Te nanocomposite containing ∼5 atomic % PbTe exhibits enhanced Seebeck coefficient, reduced thermal conductivity, and ∼40% improved ZT, which can be well explained by the theoretical modeling based on the Boltzmann transport equations when energy barriers for both electrons and holes at the heterostructure interfaces are considered in the calculations. For this p-type PbTe-Ag2Te nanocomposite, the barriers for electrons, that is, minority carriers, are primarily responsible for the ZT enhancement. By extending this approach to other nanostructured systems, it represents a key step toward low-cost solution-processable nanomaterials without heavy doping level for high-performance thermoelectric energy harvesting.

Cytotoxic activity and phytochemical analysis of Arum palaestinum Boiss

Objective:To evaluate the in vitro cytotoxic activity of the fractionated extract as well as isolated compounds of Arum palaestinum Boiss. (A. palaestinum) (black calla lily), and to identify the volatile components which may be responsible for the potential antitumor activity. Methods: A. palaestinum was collected from its natural habitats and subjected to phytochemical analysis for separation of pure compounds. In vitro cytotoxic activity was investigated against four human carcinoma cell lines Hep2, HeLa, HepG2 and MCF7 for the fractionated extract and isolated compounds. While, the diethyl ether fraction was subjected to GC–MS analysis as it exhibited the most potent cytotoxic effect to evaluate the active constituents responsible for the cytotoxic activities. Results:Four flavonoid compounds were isolated (luteolin, chrysoeriol, isoorientin, isovitexin) from the diethyl ether and ethyl acetate. The extracts and the pure isolated compounds showed a significant high antiproliferative activity against all investigated cell lines. The GC–MS analysis revealed the separation and identification of 15 compounds representing 95.01%of the extract and belonging to different groups of chemical compounds. Conclusions:The present study is considered to be the first report on the cytotoxic activities carried out on different selected fractions and pure compounds of A. palaestinum to provide evidences for its strong antitumor activities. In addition, chrysoeriol and isovitexin compounds were isolated for the first time from the studied taxa.

Composition modulation of Ag2Te nanowires for tunable electrical and thermal properties.

In this article, we demonstrated that composition modulation of Ag2Te nanowires can be achieved during the self-templated transformation of Te nanowires into Ag2Te nanowires during solution phase synthesis, which provides a mean to tune the carrier density of the Ag2Te nanowires. Both nearly stoichiometric and Ag-rich nanowires have been synthesized, which give rise to p-type and n-type Ag2Te nanocomposites after hot press, respectively. The electrical and thermal properties of the two kinds of samples have been measured. Theoretical modeling based on the near-equilibrium Boltzmann transport equations has been used to understand the experimental results. We found that ZT of the heavily doped n-type sample reaches 0.55 at 400 K, which is the highest ZT value reported for Ag2Te at the same temperature mainly due to the reduced thermal conductivity by the nanostructures. Theoretical analysis on the carrier transport shows that the power factor is also very well optimized in the doped Ag2Te sample considering the reduced carrier mobility by the nanostructures.