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Transition modeling in complex flow situations including adverse pressure gradient, streamline curvature, and massive flow separation represents one of the key challenges in computational fluid dynamics that greatly affects the flow characteristics in many thermal and fluid sciences applications. Here, we report a comparative study that helps investigate the capability of the curvature-sensitive kT−kL−ω−v2 transition model against the original kT−kL−ω algorithm in predicting the flow behavior surrounding a smooth circular cylinder subjected to Reynolds numbers in the range from 3.9×103 to 3.6×106. A C-program that fully accounts for the model's four transport equations is particularly developed and coupled with the transient solver of ansysfluent. The present simulation enables accurate prediction of the distributions of skin-friction and pressure coefficients along with careful specification of the corresponding drag coefficients and angles of separation and transition. The simulation reveals insignificant variations in the bulk flow behaviors using either model in both sub- and critical flow regimes while a remarkable improvement in the supercritical drag result is achieved using the curvature-sensitive model.

Purpose In upper brachial plexus injury (UBPI), restoring shoulder function is crucial. This study compares the transfer of long and lower medial heads of triceps branches to the axillary nerve to achieve proper restoration of function. Patients and methods A retrospective comparative study was conducted between two groups of patients with (UBPI). Group I patients (10) [mean age: 19 ± 10.6 years] were managed by transferring triceps long head branch to axillary nerve while group II patients (8) [mean age: 26 ± 9.6 years] were managed by triceps lower medial head branch transfer. The mean time from injury to surgery was 6 ± 1.3 and 5 ± 1.7 months respectively. All patients were followed up for a minimum of 12 months with the assessment of VAS, DASH score, active range of motion (AROM) and strength of shoulder abduction and external rotation; in addition to shoulder endurance and strengths of donors. Postoperative, three-monthly, electrodiagnostic assessments were performed. Results Postoperatively, the mean VAS and DASH scores; in addition to endurance time, showed significant enhancement in both groups. Patients in both groups have accomplished a mean abduction (AROM) of 98° ± 27.9 and 97° ± 11.9 respectively. The mean external rotation (AROM) was 48° ± 18.4 and 47° ± 9.2 respectively. Furthermore, group II patients had less triceps morbidity in addition to earlier and enhanced electrophysiological recovery. Conclusions Dual neurotization for shoulder function restoration in (UBPI) is capable of providing proper functional results with minimal donor morbidity. The triceps lower medial branch provides an excelling donor due to less triceps morbidity, extra length; yet, earlier and enhanced electrophysiological recovery.

Ternary oxides are considered promising electrode materials for light harvesting devices due to their optical and electronic properties that can be tuned by controlling their composition and doping ratio. Herein, a facile approach is demonstrated to fabricate ternary oxide perovskite nanofibers (NFs) and their investigation investigated as efficient electrode materials in dye-sensitized solar cells (DSSCs). The fabricated electrospun hexagonal perovskite-like (A3B8O21) nanofibers are made of several small single crystals that are connected together to several micrometers in length. Upon sintering to 650 ⁰C, highly porous perovskite nanofibers were obtained, which increased the dye adsorption capacity of the nanofibers and in turn resulted in higher photoconversion efficiency than the traditional nanotubes counterparts. The crystallinity, chemical, and thermal characteristics of the fabricated NFs were investigated using XRD, SEM, TEM, and TGA analyses. Moreover, Brunauer–Emmett–Teller (BET) measurements were used to evaluate the effect of annealing temperature on the pore size and the overall surface area of the NFs. The fabricated nanofibers were used to construct full solar cell devices, revealing enhancement in the overall performance as indicated via the photocurrent-voltage curves. This enhancement is mainly related to the higher adsorption rate of the dye on the nanofibers surface. Highly porous electrospun nanofibers are good platforms that should be useful for the future development of solar cell devices.

Transition modeling represents one of the key challenges in computational fluid dynamics. While numerical efforts were traditionally devoted to either improving Reynolds-averaged Navier–Stokes-based turbulence modeling or developing scale-resolving simulations, cautious attention has been recently given to field inversion and machine learning techniques. This paper discusses an updated development of field inversion model for transitional flows based on [Formula: see text] shear stress transport model using the continuous adjoint approach, instead of the typical discrete adjoint method. The original model is modified by multiplying the production term of the turbulent kinetic energy equation by a spatially varying discrepancy function [Formula: see text]. The adjoint equations and the relevant boundary conditions are specifically derived and integrated in OpenFOAM. The present model is validated using two zero pressure-gradient and four non-zero pressure-gradient from flow-over-flat-plate T3-series test cases. The gradient descent method is employed in the optimization process to minimize the discrepancy in the calculated shear stress. The inferred solution indicates a smooth transition to turbulence at the reported critical Reynolds numbers. The optimized model significantly improves the predictions of skin-friction coefficients, originally incorporated in the objective function. To demonstrate the usefulness of the present approach, the investigation is further extended to determine both velocity and shear Reynolds-stress profiles, which to our knowledge has not been reported before. Furthermore, a reduction in the percentage error from 50.2% to 7.3% is well observed in the predicted boundary layer thickness considering the laminar regime in the T3C5 test case.

Self-assembly is ubiquitous at all scales in nature. Most studies have focused on the self-assembly of micron-scale and nano-scale components. In this study, we explore the self-assembly of millimeter-scale magnetic particles in a bubble-column reactor to form 9 different structures. Two component systems (N–N and S–S particles) assemble faster than one-component systems (all particles have N–S poles) because they have more numerous bonding pathways. In addition, two-components add control to process initiation and evolution, and enable the formation of complex structures such as squares, tetrahedra and cubes. Self-assembly is collision-limited, thus, the formation time increases with the total number of bonds required to form the structure and the injected power. The dimensionless Mason number captures the interplay between hydrodynamic forces and magnetic interactions: self-assembly is most efficient at intermediate Mason numbers (the system is quasi-static at low Mason numbers with limited chances for particle interaction; on the other hand, hydrodynamic forces prevail over dipole–dipole interactions and hinder bonding at high Mason numbers). Two strategies to improve yield involve (1) the inclusion of pre-assembled nucleation templates to prevent the formation of incorrect initial structures that lead to kinetic traps, and (2) the presence of boundaries to geometrically filter unwanted configurations and to overcome kinetic traps through particle–wall collisions. Yield maximization involves system operation at an optimal Mason number, the inclusion of nucleation templates and the use of engineered boundaries (size and shape).

Background The aim of this retrospective study was to highlight the role of adding DWI to the conventional MRCP in differentiating benign and malignant obstructive biliary pathologies. MRCP is a non-invasive modality for investigating the morphological features of the pancreaticobiliary system. It can provide indirect evidence of a malignant lesion, such as irregularity of the inner border and abrupt stenosis, with shouldering of the edge suggesting cholangiocarcinoma, while a short segment with regular margin and symmetric narrowing suggests a benign cause. Although these findings are highly sensitive, they are not specific. DWI can complement morphological information obtained by conventional MRCP by providing additional functional information concerning the alteration of tissue cellularity due to pathological processes. Results The overall accuracy of the diagnosis, sensitivity, and specificity of the conventional MRCP in differentiation between the benign and malignant biliary structures was significantly increased by combing it with the DWI. Conclusions Adding DWI to conventional MRCP significantly improved the diagnostic accuracy regarding the characterization of differentiating benign and malignant biliary strictures.

Granular flow is common across different fields from energy resource recovery and mineral processing to grain transport and traffic flow. Migrating particles may jam and form arches that span constrictions and hinder particle flow. Most studies have investigated the migration and clogging of spherical particles, however, natural particles are rarely spherical, but exhibit eccentricity, angularity and roughness. New experiments explore the discharge of cubes, 2D crosses, 3D crosses and spheres under dry conditions and during particle-laden fluid flow. Variables include orifice-to-particle size ratio and solidity. Cubes and 3D crosses are the most prone to clogging because of their ability to interlock or the development of face-to-face contacts that can resist torque and enhance bridging. Spheres arriving to the orifice must be correctly positioned to create stable bridges, while flat 2D crosses orient their longest axes in the direction of flowlines across the orifice and favor flow. Intermittent clogging causes kinetic retardation in particle-laden flow even in the absence of inertial effects; the gradual increase in the local particle solidity above the constriction enhances particle interactions and the probability of clogging. The discharge volume before clogging is a Poisson process for small orifice-to-particle size ratio; however, the clogging probability becomes history-dependent for non-spherical particles at large orifice-to-particle size ratio and high solidities, i.e., when particle–particle interactions and interlocking gain significance.

A growing family of MXenes, i.e., layered transition metal carbides and/or nitrides, has been becoming an important candidate of electrode material for new-concept energy storage devices due to their unique properties. This article timely and comprehensively reviewed state-of-the-art progress on electrochemical performance and mechanism of MXenes and their hybrids containing small molecules, polymers or oxides when utilized as crucial materials in energy storage devices, including ion batteries, supercapacitors, and ion capacitors as well as hydrogen storage. The relation between electrochemical performance and structure has been deeply explored in the aims of revealing the influence of logical combinations of chemical/physical properties, microstructure, steric configuration, and material compositions on the electrochemical performance of corresponding electrodes. The possible directions of development for MXene were also pointed out for further researches and potential applications.

Hexagonal single-crystal perovskite-like (A3B8O21) nanofibers were synthesized via the electrospinning technique. High-resolution transmission electron microscopy imaging showed that each single nanofiber is composed of several interconnected small crystals. The selected-area electron diffraction analysis reveals a single crystalline nature of the fabricated nanofibers. The fabricated nanofibers showed surface plasmon resonance characteristics. Theoretical and computational calculations using the Mie–Gans theory were performed to investigate the plasmonic and optical properties of the obtained nanofibers, which were also confirmed experimentally and compared to gold nanoparticles. The fabricated nanofibers were tested as novel substrate materials for surface-enhanced Raman spectroscopy, showing exceptional performance.

Although, the horizontal thermally stratified storage tanks (TSST) are nowadays the most popular, especially in the domestic solar water heaters, most of the literature is oriented towards the vertical tanks. Recently, a smart adaptive model for TSST was proposed, where the grid segments size and location changes automatically according the different variations in the tank. It showed good agreement with experimental work, however the model and its validation was presented for the vertical configuration only. In this work, the adaptive-grid model is extended to the horizontal cylindrical tank orientation while accounting for the changes in grid segments cross-section during moving in the vertical direction as to be aligned with the thermocline region; the proposed model is validated with experimental data available in the literature. The results show an excellent agreement with the literature and yield a significant reduction in the number of nodes needed for the modeling (∼32.7% reduction) when compared to other horizontal tank models while accounting for the changes tank geometry in the vertical direction.

Objective The aim of the study was to assess the usefulness of neuromuscular ultrasound in the diagnosis of idiopathic carpal tunnel syndrome (CTS) and to determine the relationships of ultrasonographic measurements with the clinical severity and the electrophysiological grading scale. Patients and methods One hundred CTS diseased hands and 100 nondiseased hands were assessed clinically and by nerve conduction studies. We measured ultrasonographic cross-sectional area (CSA) of the median nerve at various levels of the carpal canal (inlet and outlet), flattening ratio (FR), palmar bowing of the flexor retinaculum, wrist/forearm ratio, as well as median nerve mobility and power doppler signals. Data from patients and controls were compared to determine the diagnostic relations and the grade of severity. Results Measures of CSA of the median nerve at the inlet and at the outlet, palmer bowing and inlet/forearm ratio in the CTS group were significantly higher than the control group (P

Background Cubital tunnel syndrome (CuTS) is the second most common compressive neuropathy of the upper limb following carpal tunnel syndrome and is the most common site for entrapment for the ulnar nerve Objectives Our aim is to evaluate the role of ultrasonography (US) as a diagnostic tool for Cubital tunnel syndrome (CuTS) in comparison with nerve conduction study (NCS). Methods: twenty elbows with CuTS and twenty asymptomatic controls were assessed by NCS and underwent ultrasonography of elbows. Data from patients and controls were compared to determine the diagnostic relations in patients with CuTS and the grade of severity Results There was a high degree of correlation between NCS of the ulnar nerve, clinical parameters and variable US measurements. The CSA of the ulnar nerve was the most sensitive parameter and a cut-off point of 9.5 mm2 behind medial epicondyle was found to be 100% sensitive and 80% specific. The ulnar nerve ratios (UNR) had a diagnostic accuracy of 95% with 85% specificity. Conclusion Ultrasonographic measurements of the ulnar nerve CSA and UNR have a comparable diagnostic value as a non-invasive and an alternative modality for the evaluation of CuTS References [1] Simon N, Ralph J, Poncelet A, Engstrom J, Chin C, Kliot M. A comparison of ultrasonographic and electrophysiologic inchingin ulnar neuropathy at the elbow. Clin Neurophysiol. 2015;126(2):391-398. [2] Omejec G, Podnar S. Normative values for short-segment nerve conduction studies and ultrasonography of the ulnar nerve at the elbow. Muscle nerve. 2015;51(3):370-377. [3] Yoon J, Walker F, Cartwright M. Ultrasonographic swelling ratio in the diagnosis of ulnar neuropathy at the elbow. Muscle nerve. 2008;38(4):1231-1235. [4] Bayrak A, Bayrak I, Turker H, Elmali M, Nural M. Ultrasonography in patients with ulnar neuropathy at the elbow: Comparison of cross-sectional area and swelling ratio with electrophysiological severity. Muscle nerve. 2010;41(5):661-666. Disclosure of Interests None declared

The photocatalytic conversion of CO2 into chemical fuels is an attractive route for recycling this greenhouse gas. However, the large scale application of such approach is limited by the low selectivity and activity of the currently used photocatalysts. Using first principles calculations, we report on the selection of optimum oxynitride perovskites as photocatalysts for photoelectrochemical CO2 reduction. The results revealed six perovskites that perfectly straddle the carbon dioxide redox potential; namely, BaTaO2N, SrTaO2N, CaTaO2N, LaTiO2N, BaNbO2N, and SrNbO2N. The electronic structure and the effective mass of the selected candidates are discussed in details, the partial and total density of states illustrated the orbital hybridization and the contribution of each element in the valence and conduction band minima. The effect of cation size in the ABO2N perovskites on the band gap is investigated and discussed. The optical properties of the selected perovskites are calculated to account for their photoactivity. Moreover, the effect of W doping on improving the selectivity of perovskites toward specific hydrocarbon product (methane) is discussed in details. This study reveals the promising optical and structural properties of oxynitride perovskite candidates for CO2 photoreduction. NPRP Grant no. NPRP 6-351-1-072 from the Qatar National Research Fund (a member of Qatar Foundation).

We demonstrate, for the first time, the synthesis of highly ordered niobium oxynitride microcones as an attractive class of materials for visible-light-driven water splitting. As revealed by the ultraviolet photoelectron spectroscopy (UPS), photoelectrochemical and transient photocurrent measurements, the microcones showed enhanced performance (~1000% compared to mesoporous niobium oxide) as photoanodes for water splitting with remarkable stability and visible light activity.

Background:Plantar fasciitis is the most common cause of hind foot pain. Treatment is aimed at pain reduction and maintaining or improving function. Several types of injected materials are used including corticosteroids, hyaluronic acid and Platelet-rich plasma.Objectives:The aim of this study was to evaluate the efficacy of hyaluronic acid injection in comparison to corticosteroid injection for the treatment of degenerative plantar fasciitis.Methods:This study included forty patients with degenerative plantar fasciitis diagnosed according to clinical examination and ultrasound findings. They were divided into two groups. Group one included twenty patients who were injected with Methylprednisolone (MP). Group two included another twenty patients who were injected with hyaluronic acid (HA). Clinical assessment was done including morning heel pain, localized heel tenderness, patient assessment of heel pain using the numerical rating scale (NRS), Functional assessment using the Manchester-Oxford foot questionnaire (MOXFQ) and musculoskeletal ultrasound assessment including planter fascia thickness, echogenicity, power Doppler signals, erosions and calcification.Patients were injected and a follow up was done at two and six weeks for each group.Results:The two groups MP &HA showed no significant baseline differences in clinical and sonographic variables, while they both significantly improved from baseline after two &six weeks injection (POver all, MP group had significant improvement clinically and sonographically than HA group after two weeks (PConclusion:Our study supports the use of a single injection of hyaluronic acid as therapy for plantar fasciitis in preference to methylprednisolone acetate injections, while MP offers short term improvement (after two weeks). HA injection offers better therapeutic advantages in the intermediate-term follow up (after six weeks). Moreover, it has a longer duration of action and enables better tissue healing and can therefore be used as an effective alternative treatment for plantar fasciitis.Disclosure of Interests: :None declared

Lithium metal-sulfur (Li-S) batteries are attracting broad interest because of their high capacity. However, the batteries experience the polysulfide shuttle effect in cathode and dendrite growth in the Li metal anode. Herein, a bifunctional and tunable mesoporous carbon sphere (MCS) that simultaneously boosts the performance of the sulfur cathode and the Li anode is designed. The MCS homogenizes the flux of Li ions and inhibits the growth of Li dendrites due to its honeycomb structure with high surface area and abundance of nitrogen sites. The Li@MCS cell exhibits a small overpotential of 29 mV and long cycling performance of 350 h under the current density of 1 mA cm-2 . Upon covering one layer of amorphous carbon on the MCS (CMCS), an individual carbon cage is able to encapsulate sulfur inside and reduce the polysulfide shuttle, which improves the cycling stability of the Li-S battery. As a result, the S@CMCS has a maximum capacity of 411 mAh g-1 for 200 cycles at a current density of 3350 mA g-1 . Based on the excellent performance, the full Li-S cell assembled with Li@MCS anode and S@CMCS cathode shows much higher capacity than a cell assembled with Li@Cu anode and S@CMCS cathode.

Metallic phase 2D molybdenum disulfide (MoS

We report on the first principles calculation of the electronic, structural and optical properties of BaTaO2N, using density functional theory (DFT) and finite difference time domain (FDTD) methods. Band structure calculations were performed to calculate the direct and indirect bandgaps of the material. Density of states and Mulliken charge analysis as well as the electronic contour maps were established to determine the type of bonding and hybridization between the various electronic states. The dielectric constant, reflectivity, absorption, optical conductivity and energy-loss function were also calculated. Moreover, FDTD was used to investigate the optical properties of a larger and more reliable structure of BaTaO2N powder in good agreement with the reported experimental parameters. The calculated electronic, structural and optical properties showed the potential of BaTaO2N for solar energy conversion and optoelectronic applications.

A novel design of D-shaped photonic crystal fiber polarization splitter based on surface plasmon resonance is presented. The polarization splitter involves a gold nanowire and depositing of a gold film along with side-polishing of PCF. The numerical results show an ultracompact device length as short as 84 μm with extinction ratios of −21.5 dB and −41 dB and insertion losses of −0.57 dB and −0.3 dB for the x- and y-polarized modes, respectively, at wavelength of 1.55 μm.

Metallic phase 2D molybdenum disulfide (MoS2 ) is an emerging class of materials with remarkably higher electrical conductivity and catalytic activities. The goal of this study is to review the atomic structures and electrochemistry of metallic MoS2 , which is essential for a wide range of existing and new enabling technologies. The scope of this paper ranges from the atomic structure, band structure, electrical and optical properties to fabrication methods, and major emerging applications in electrochemical energy storage and energy conversion. This paper also thoroughly covers the atomic structure-properties-application relationships of metallic MoS2 . Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistry, and performance of metallic MoS2 is advancing actual applications of this material. This new level of understanding also enables a myriad of new and exciting applications, which motivated this review. There are excellent reviews already on the traditional semiconducting MoS2 , and this review, for the first time, focuses on the uniqueness of conducting metallic MoS2 for energy applications and offers brand new materials for clean energy application.

Lithium (Li) metal anodes have attracted much interest recently for high-energy battery applications. However, low coulombic efficiency, infinite volume change, and severe dendrite formation limit their reliable implementation over a wide range. Here, an outstanding stability for a Li metal anode is revealed by designing a highly porous and hollow Li foam. This unique structure is capable of tackling many Li metal problems simultaneously: first, it assures uniform electrolyte distribution over the inner and outer electrode's surface; second, it reduces the local current density by providing a larger electroactive surface area; third, it can accommodate volume expansion and dissipate heat efficiently. Moreover, the structure shows superior stability compared to fully Li covered foam with low porosity, and bulky Li foil electrode counterparts. This Li foam exhibits small overpotential (≈25 mV at 4 mA cm-2 ) and high cycling stability for 160 cycles at 4 mA cm-2 . Furthermore, when assembled, the porous Li metal as the anode with LiFePO4 as the cathode for a full cell, the battery has a high-rate performance of 138 mAh g-1 at 0.2 C. The beneficial structure of the Li hollow foam is further studied through density functional theory simulations, which confirms that the porous structure has better charge mobility and more uniform Li deposition.

A case study focused on modeling the dispersion of Yperite (Sulfur Mustard) and arsenical chemical agents CLARK I and II in sediment from munitions disposed at the Paardenmarkt site, Belgium, is discussed. Based on conceptual models, simulations were run for the dispersion of Yperite and CLARK I and II in marine sediments, generating concentration data for temporal and geographical scales in the event of a leakage from an idealized munition. Based on the simulation, leakage of Yperite from a munition into the surrounding marine sediment will give toxic effects only up to a few centimeters from the munition casing. Utilizing a munition with an estimated 44 g of arsenic for the CLARK I and II simulations, the arsenical degradents at the level of Estimated No Effects Concentration or higher gives a volume of sediments in the shape of a sphere with a radius of 0.5 m in a time period of 10 years; increasing threefold in volume over a period of 100 years.

We studied gall bladder contractility in 61 children with beta-thalassaemia who were asymptomatic for gall bladder disease and 51 sex- and age-matched controls in Cairo, Egypt, using real-time ultrasonography. Multiple gall bladder stones were present in 18.0% of thalassaemia patients and sludge in 6.6%. There were statistically significant differences between thalassaemia patients and controls in gall bladder fasting volume, residual volume, emptying time and contraction index. There was significant positive correlation between fasting and residual volumes and age, weight and height, and between fasting volume and body mass index and serum ferritin level. Contraction index was negatively correlated with serum total bilirubin. Impaired gall bladder motility was evident in patients with beta- thalassaemia and it may be related to disease duration, serum ferritin and total serum bilirubin level.

313 references were reviewed to obtain data relevant to the fate, transport, and environmental impacts of chemical agents in marine environments. The review covers the chemical agents phosgene, cyanogen chloride, hydrogen cyanide, sulfur mustard, Lewisite nitrogen mustard \201HN1\202, Tabun, Sarin, and VX. Parameters covered in the review are boiling point, melting point, density, vapor pressure, solubility, Henry?s Law constant, partition coefficients, dissociation constants, and hydrolysis rate constants and products. Recent ecotoxicity data are also discussed. Data gaps for these parameters and agents are identified and prioritized. In addition to the specific data gaps, the authors have identified several general issues that extend beyond single compounds or types of data. Given the available data and what they suggest will be the dominant fate and transport mechanisms, there are no data gaps that leave one unable to conduct a reasonable assessment for any agent. The primary source of uncertainty in the evaluation of the fate, transport, and environmental impacts of these agents remains the rate at which they are released into the environment. The data gaps identified in this work appear to cause a significantly smaller level of uncertainty.

This paper reports the toxicity and environmental impact of neutralents produced from the hydrolysis of binary chemical agent precursor chemicals DF (methylphosphonic difluoride) and QL (2-[bis(1-methylethyl)amino]ethyl ethyl methylphosphonite). Following a literature review of the neutralent mixtures and constituents, basic toxicity tests were conducted to fill data gaps, including acute oral and dermal median lethal dose assays, the Ames mutagenicity test, and ecotoxicity tests. For methylphosphonic acid (MPA), a major constituent of DF neutralent, the acute oral LD50 in the Sprague-Dawley rat was measured at 1888 mg/kg, and the Ames test using typical tester strains of Salmonella typhimurium and Escherichia coli was negative. The 48-h LC50 values for pH-adjusted DF neutralent with Daphnia magna and Cyprinodon variegatus were >2500 mg/L and 1593 mg/L, respectively. The acute oral LD50 values in the rat for QL neutralent constituents methylphosphinic acid (MP) and 2-diisopropylaminoethanol (KB) were both determined to be 940 mg/kg, and the Ames test was negative for both. Good Laboratory Practice (GLP)-compliant ecotoxicity tests for MP and KB gave 48-h D. magna EC50 values of 6.8 mg/L and 83 mg/L, respectively. GLP-compliant 96-h C. variegatus assays on MP and KB gave LC50 values of 73 and 252 mg/L, respectively, and NOEC values of 22 and 108 mg/L. QL neutralent LD50 values for acute oral and dermal toxicity tests were both > 5000 mg/kg, and the 48-h LD50 values for D. magna and C. variegatus were 249 and 2500 mg/L, respectively. Using these data, the overall toxicity of the neutralents was assessed.

Background/Scope: Mechanical drilling, the gold standard to reach oil and gas reservoirs, is associated with drilling risks and increased time and costs. Laser drilling has emerged as a potential new drilling tool. However, studies about its practical applications are limited. This study investigates the feasibility and performance of laser technology in drilling oil wells. Methods: Core samples from the three lithologies were irradiated with Nd:YAG laser at different power intensities and exposure times while holding other parameters constant. Some core samples were saturated with brine to investigate the effect of fluid saturation. We developed a novel laser drilling system that enables users to input the lithology of encountered formations and output the power intensity needed to be drawn from the electric source to maintain the constant ROP. Results: The Nd:YAG laser beam fully penetrated the cores in all the study trials conducted in shale. In limestone, the laser beam fully penetrated the cores in 5/13 trials and partially penetrated them in 7 trials. The experiments could not be performed in sandstone due to rough surfaces and high porosity. The ROP values ranged between 58 and 66 ft/hr (mean 62.4 ±5.3 ft/hr) in shale and between 221.7 and 460.6 ft/hr (mean 328.5±71.5 ft/hr ft/hr) in limestone. The specific energy values ranged between 650 and 5433 KJ/cm3 (mean 2885.1±1525.8 KJ/cm3) for the limestone samples. A statistically significant inverse correlation was observed between laser energy and ROP (r=-0.952, P Added value: The study provides further evidence that laser drilling technology is a promising new technology for oil well drilling. The current study utilized high specific power laser which has not been previously used and developed a novel computer based constant ROP laser system. The rock removal mechanism should be shifted away from melting to spallation to achieve an efficient laser drilling mechanism through the optimization of the laser specific power and decreasing the specific energy during rock removal. Laser beam reflection, sample thickness and fluid saturation were identified as potential factors that influence the efficiency and performance of the laser drilling operation.

To evaluate dento-skeletal effects of the Pendulum Hygienic Distalizer (P.H.D), utilized on expansion of the maxillary arch and distalizing of maxillary first molars.Ten patients were selected from the outpatient clinic of Department of Orthodontics, Faculty of Dentistry, Mansoura University having: (1) Skeletal Class I with moderate maxillary crowding; (2) Angle Class II molars relation; (3) Constricted maxillary arch (posterior crossbite); (4) Ages ranged from 11 to 14 years with an average age of 12 years and 2 months. The changes that, brought by the appliance were evaluated from the lateral cephalometric, postero-anterior radiographs and study cast model taken before and after appliance application by means of a paired t-test.Significant amounts of maxillary expansion, molar distalization, molar distal tipping and anchorage loss were observed. The amount of maxillary expansion was 4.35 ± 072 mm. The mean maxillary first molar distal movement was 2.27 ± 0.52 mm with a distal tipping of 1.71 ± 0.74 degrees in 3.19 ± 0.53 months. The rate ofdistal movement was 0.70 mm per month. Reciprocal mesial movement of the first premolars was 1.73 ± 0.92 mm with a mesial tipping of 2.60 ± 1.02 degrees. Maxillary incisors moved 1.80 ± 0.85 mm and tipped 2.02 ± 1.43 degrees mesially.It was concluded that the Pendulum Hygienic Distalizer works well with the treatment philosophy of Class II malocclusion with posterior cross-bite by expansion the maxillary arch and distalizing of maxillary molars.

We present molecular mechanics (MM) calculations as models of activated complexes for the β-lactam forming [2+2] cycloaddition between imino ester 4 and the zwitterionic intermediates derived from ketenes and various chiral nucleophilic catalysts. Our method employs the use of Monte Carlo conformational searches utilizing the MMFF force field contained within the Macromodel program. These models accurately predict the sense of stereochemical induction observed experimentally. Also, the predicted energetic differences for minima leading to (R) or (S)-derived ketene facial selectivity correlate in a general sense with the magnitude of the enantioselectivity. This work establishes that our approach represents a viable method for the design of new nucleophilic catalysts a priori using MM calculations.

We report practical methodology for the catalytic, asymmetric synthesis of beta-lactams resulting from the development of a catalyzed reaction of ketenes (or their derived zwitterionic enolates) and imines. The products of these asymmetric reactions can serve as precursors to a number of enzyme inhibitors and drug candidates as well as valuable synthetic intermediates. We present a detailed study of the mechanism of the beta-lactam forming reaction with proton sponge as the stoichiometric base, including kinetics and isotopic labeling studies. Stereochemical models based on molecular mechanics (MM) calculations are also presented to account for the observed stereoregular sense of induction in our reactions and to provide a guidepost for the design of other catalyst systems.

We report a new method for the catalytic, asymmetric synthesis of beta-substituted aspartic acid derivatives in which the nucleophilic catalyst serves up to four discrete roles in a one-pot procedure: catalytic dehydrohalogenation of acid chlorides to form ketenes; catalytic dehydrohalogenation of alpha-chloroamines to form the corresponding imines; catalyzed [2 + 2]-cycloaddition to produce intermediate acyl beta-lactams; and finally, nucleophilic ring opening to afford optically enriched beta-substituted aspartic acids in high enantioselectivity and diastereoselectivity.

The dielectric properties of some cadmium and mercury amino alcohol complexes were studied within the temperature range of 100?300 K at the frequencies of 100, 300 and 1000 kHz. The polarization mechanisms are suggested and the dependence of both ? and tg ? on both temperature and frequency are analyzed. The analysis of the data reveals semi-conducting features based mainly on the hopping mechanism.

We present a comprehensive roadmap for the precise control of the dimensions and optical properties of anodically fabricated zirconia nanotubes. The effects of anodization time, applied voltage, solvent composition, as well as fluoride and water content are investigated. The length of the resulting nanotubes showed a strong dependence on the concentration and mobility of F - ions, whilst O2- ion content was found to play a key role in controlling the nanotube wall thickness. A new insight into the formation of Zirconia nanotubes is introduced and discussed based on the Point Defect Model (PDM). Also, the energy consumption in the fabrication process of the nanostructured electrodes is modelled based on the involved thermodynamics and kinetic aspects. The effect of the dimensions of the nanotubes on the optical characteristics of the arrays was studied using Finite Difference Time Domain (FDTD). The results show a decrease in transmittance with increasing length and wall thickness, and decreasing pore size of the nanotubes. The reported results provide deep insight into the structure-property relationships of ZrO2 nanotubes, which will be of great help in large-scale industrial applications. NPRP Grant no. NPRP 6-569-1-112 from the Qatar National Research Fund (a member of Qatar Foundation). Scopus

Anodically fabricated tantalum oxide (Ta2O5) nanorod array carpets are converted into the corresponding tantalum oxynitride (TaON) through nitridation in an ammonia atmosphere. The measured optical bandgap energy of TaON is ∼2.3 eV, which is also confirmed via the density functional theory calculations. When used to photoelectrochemically split water (AM 1.5G illumination, 1 M KOH, and 0.6 V applied DC bias), the multilayer nanorod films show visible-light incident photon conversion efficiencies (IPCE) as high as 7.5%. The enhanced photochemical activity is discussed in terms of the ordered one-dimensional morphology as well as the electron effective mass in TaON and Ta2O5.

We report a catalytic asymmetric reaction process that involves the use of solid-phase reagents and catalysts that constitute the packing of a series of "reaction columns". This process was applied to the catalytic asymmetric synthesis of beta-lactams, to yield pure products with excellent enantio- and diastereoselectivity. We have identified several advantages to conducting chemical reactions on sequential columns, including ease of catalyst and reagent recovery and simplified purification steps that preclude the need for chromatography.

Electron paramagnetic resonance spectra of cobalt and copper complexes of ethanolamines is studied at −110 and 25°C. The g values are determined. The magnetic susceptibilities of the cobalt, nickel and copper complexes are measured in the 4.2 − 293°K temperature range. The Curie - Weiss constant, θ, values proved that M-M Interactions appeared In the cobalt and copper complexes and didn't appear in the nickel complexes.

[reaction: see text] We describe methodology for the in situ generation of reactive monosubstituted ketenes from acid chlorides through a shuttle deprotonation process using NaH as an inexpensive stoichiometric base and a crown ether cocatalyst. We have successfully applied this new procedure to the catalytic, asymmetric synthesis of beta-lactams and alpha-haloesters.

[reaction: see text] We have developed an efficient methodology for the generation of ketenes by employing a catalytic shuttle base and potassium carbonate as a stoichiometric base. We have applied this technology to the catalytic, asymmetric alpha-bromination of acid chlorides.