Maximum Velocity Values Research Articles

Effects of Interfaces on Dynamics in Micro-Fluidic Devices: Slip-Boundaries’ Impact on Rotation Characteristics of Polar Liquid Film Motors**Supported by National Natural Science Foundation of China under Grant Nos. 11302118, 11275112, and Natural Science Foundation of Shandong Province under Grant No. ZR2013AQ015

A new approach for exploring effects of interfaces on polar liquids is presented. Their impact on the polar liquid film motor (PLFM) – a novel micro-fluidic device – is studied. We account for the interface’s impact by modeling slip boundary effects on the PLFM’s electro-hydro-dynamical rotations. Our analytical results show as increases (with denoting the slip length resulting from the interface’s impact on the film’s properties, k > -1 and R denoting the film’s radius): (a) PLFMs subsequently exhibit rotation characteristics under “negative-”, “no-”, “partial-” and “perfect-” slip boundary conditions; (b) The maximum value of the linear velocity of the steady rotating film increases linearly and its location approaches the film’s border; (c) The decay of the angular velocities’ dependency on the distance from the center of the film slows down, resulting in a macroscopic flow near the boundary. With our calculated rotation speed distributions consistent with the existing experimental ones, research aiming at fitting computed to measured distributions promises identifying the factors affecting , e.g., solid-fluid potential interactions and surface roughness. The consistency also is advantageous for optimizing PLFM’s applications as micro-washers, centrifuges, mixers in the lab-on-a-chip.

Organic zinc absorption by the intestine of broilers in vivo.

In Expt 1, a Zn-unsupplemented basal diet (control) and the basal diet supplemented with one of four different Zn sources, including ZnSO4, Zn-amino acid chelate with a weak chelation strength (Zn-AA W), Zn-protein chelate with a moderate chelation strength (Zn-Pro M) and Zn-protein chelate with a strong chelation strength (Zn-Pro S) were fed to broiler chickens from days 14 to 28. On day 28, Zn content in plasma from the hepatic portal vein increased (P0·05) and Zn-AA W(P<0·04) were higher than those for ZnSO4. These findings indicate that organic Zn absorption (especially Zn-Pro S) in intact living broilers was more effective than that of inorganic Zn; organic Zn absorption in the ligated duodenal segment was a saturable carrier-mediated process similar to that of ZnSO4. Moreover, except for MT, there might be other Zn transporters involved in Zn absorption that are affected by different Zn sources.

Characterization of Recombinant Fructose‐1,6‐Bisphosphatase (FBPase) Gene Mutations: Insights into Modulation of FBPase activity through Gene Mutation

Diabetes is a disease affecting how the body regulates glucose. Multiple factors contribute to Type II Diabetes resulting in hyperglycemia. Previous studies in patients with hypoglycemia identified two mutations in the coding region of the fructose‐1, 6‐bisphosphatase (FBPase) gene. Based on the mutations identified, the initial focus of our project was a full kinetic analysis of these mutations using the recombinant pig kidney FBPase enzyme. Results of this analysis showed an approximately 8‐fold decrease in the relative catalytic constant (Kcat) and catalytic efficiency (CE) compared to wild‐type enzyme (WTE). A separate mutation was done in the active site of the enzyme in order to investigate if the enzyme could be activated. Kinetic analysis of this mutation showed a 30‐fold increase in the relative Kcat and catalytic efficiency (CE). Other mutations in the adenosine monophosphate (AMP) binding‐site (K112A and Y113A) showed marked decrease in AMP inhibition (AMP is the enzyme's natural inhibitor). Kinetic analysis of the enzyme in the absence of AMP resulted in maximum velocity (Vmax) values for K112A and Y113A mutants that were similar to the wild‐type Vmax but which were elevated at higher concentrations of FBP substrate. This suggests that mutations of this type promote hyperglycemia by preventing AMP inhibition of the FBPase in vivo. Clinical implications for these results are discussed in relation to the project.

Quantitative differential diagnosis of breast tumors using shear wave velocity and different probe orientations ⁎

Abstract Objective The aim of this study was to evaluate the additional benefit of the difference of maximum and minimum shear wave velocity (SWV) values obtained at different probe orientations (D-value) for the differential diagnosis of breast tumors. Methods SWV (m/s) was measured in 123 breast tumors (92 benign, 31 malignant) in 76 female patients with the probe placed on the transverse, longitudinal, and 45° planes. The areas under the receiver operating characteristic (AUROC) curves were compared with respect to the maximum SWV, minimum SWV, D-value, maximum SWV combined with the D-value, and minimum SWV combined with the D-value. Results There was a significant difference among the values of the maximum SWV, minimum SWV, and D-value for the 3 planes (P &lt; 0.001). The AUROC curves for the maximum SWV, minimum SWV, and D-values of the 3 planes were 0.751 (P = 0.379), 0.486 (P = 0.863), and 0.603 (P = 0.204), respectively. The cutoff value for the maximum SWV for differentiating benign tumors from malignant tumors was 2.51 m/s (sensitivity 67%, specificity 50%). The cutoff value for the minimum SWV was 1.61 m/s (sensitivity 53%, specificity 50%). Adding the D-value increased the AUROC curve for the maximum SWV from 0.571 to 0.733 and the minimum SWV from 0.486 to 0.504 (P = 0.964), respectively. Conclusion SWV differs in different planes of breast tumors. The D-value can provide a reference for the differential diagnosis of breast tumors.

Numerical analysis on heat transfer of a complete anti-gravity loop-shaped heat pipe

Anti-gravity loop shaped heat pipe (AGLSHP) with continuous step-graded sintered wick is useful for enhancing the effective heat transfer in the anti-gravity direction. In this work, a complete steady state model has been presented to investigate in the thermal performance and hydraulic behavior of the AGLSHP. The governing equations for the heat and mass transfer are developed for the loop operation, with specific attention given to the evaporator region. By comparing the numerical simulation with the experimental data, the heat transfer mechanism is revealed. The liquid/vapor velocity and pressure distribution in the evaporator are discussed, and the temperature distribution along the transport line is also analyzed. The numerical results indicate that with the increase of the heat load, the maximum velocity and pressure value of the liquid and vapor increase as expected. The highest temperature position occurs at the outlet of evaporator surface. Providing the capillary pressure for the circulation of working fluid, the wick in the liquid line is paid more attention. Moreover, the longer condensation length is more effective in decreasing the temperature at the outlet of condenser and improving the heat transfer capacity of the AGSLHP.

Non-invasive assessment of liver fibrosis in patients with hepatitis C: Shear wave elastography and colour Doppler velocity profile technique versus liver biopsy

Background and study aimsDetermination of the presence and degree of liver fibrosis is essential for the prognosis and treatment of patients with chronic hepatitis C. Non-invasive methods of assessing fibrosis have been developed to reduce the need for biopsy. We determined the efficacy of shear wave elastography (SWE) and colour Doppler velocity as non-invasive methods for the assessment of liver fibrosis compared to liver biopsy among patients with chronic hepatitis C virus (HCV) infection. Patients and methodsIn total, 117 patients with chronic HCV infection and 50 healthy age- and sex-matched control subjects were included. For each patient and control, abdominal ultrasonography, Doppler ultrasonography of the right portal vein (PV), and SWE were performed, whereas liver biopsy was performed for patients. ResultsThe mean value of the right PV maximum velocity was lower in patients with different stages of fibrosis than in controls (p<0.001). The mean value of liver stiffness determined by SWE was significantly higher in patients with different stages of fibrosis than in controls. Cutoff values for liver stiffness determined by SWE for assessing fibrosis stages were F2⩾4.815, F3⩾6.335, and F4=7.540 with a sensitivity of 84.6%, 96.2%, and 100.0%; specificity of 88.5%, 93.8%, and 100.0%; positive predictive value (PPV) of 93.6%, 98.0%, and 100.0%; negative predictive value (NPV) of 74.2%, 88.2%, and 100.0%; and overall accuracy of 85.9%, 95.6%, and 100.0% [area under the ROC curve (AUC): 0.89, 0.96, and 1.0], respectively. Cutoff values for the right PV maximum velocity for assessing fibrosis stages were F2<23.4, F3<21, and F4<20 with a sensitivity of 65.0%, 57.4%, and 57.1%; specificity of 59.8%, 76.4%, and 75.5%; PPV of 33.8%, 58.3%, and 32.0%; NPV of 84.4%, 75.7%, and 89.7%; and overall accuracy of 61.1%, 69.5%, and 72.5% (AUC: 0.614, 0.696, and 0.625), respectively. ConclusionSWE is effective for the non-invasive assessment of liver fibrosis in patients with HCV infection. SWE provides a more accurate correlation with liver fibrosis stage than colour Doppler velocity profile for the assessment of liver fibrosis, especially in advanced stages (F3 and F4).

Toxicity and kinetic studies of H+, K+-ATPase sensitivity to cyfluthrin and fenpropathrin in Egyptian field populations of Spodoptera littoralis

Toxicity of two pyrethroids (cyfluthrin and fenpropathrin) against cotton leafworm, Spodoptera littoralis, larvae werecollected from heavily sprayed fields in different areas in Dakahlia and El-Beheira Governorate. H+, K+-ATPase (protonpump)activity was measured in laboratory (lab.) strain and compared with enzyme activities for other collected strains. Thesensitivity of H+, K+-ATPase activity was measured by I50 values. The I50 values of cyfluthrin were 0.24; 0.46; 0.54; 0.65, and0.68 μM for lab; Abo-Hommos; Shobrakheet; Aga, and El-Senbellaween strains respectively, while I50 values offenpropathrin were 0.44; 0.58; 0.66; 0.84, and 0.87 μM for lab and four field strains respectively. Also, proton-pump enzymekinetic parameters, Km (Michaelis-Menten kinetics, constant) and Vmax (maximum velocity) values and the inhibitionconstant (Ki) were determined. The obtained data proved that cyfluthrin and fenpropathrin compounds were competitiveinhibitors of proton-pump activity. Results indicated that, the pyrethroid have shown potentiality against larvae of S.littoralis, so, these pyrethroids may be effect of a novel mechanism of action for inhibition of proton-pump activity, theserecommended for S. littoralis larvae control. It could be concluded that the use of pyrethroid, may avoid increasing ofresistance by effect of new mode of action where they disrupt the development of target pest, Therefor proton-pump may playan important role the mode of action of these pesticides in future.

Monitoring of the vibration induced on the Arno masonry embankment wall by the conservation works after the May 25, 2016 riverbank landslide

BackgroundThe concepts of disaster risk reduction and disaster risk management involve the development, improvement, and application of policies, strategies, and practices to minimize disaster risks throughout society. Nowadays, preserving architectural heritage and ancient monuments from disasters is an important issue in the cultural life of modern societies. The “health” of a building/structure may be evaluate by its deterioration or damage level: monitor the aging and promptly detect relevant damages, play a central role, and structure dynamic characterization and microtremor analysis are considered powerful techniques in this field. A wide bibliography about structures/buildings seismic dynamic characterization is counterpoised to a missing one about their seismic response during conservation/safety works. This paper focus on the seismic response and monitoring of a historical masonry embankment wall during the conservation works carried out after a riverbank landslide that seriously damaged it.ResultsThe H/V results of the acquired traces show that main resonance frequency of the masonry embankment wall is between 4 Hz and 15 Hz, in agreement with the frequency range of roughly 10-meters-high, squat and monolithic structure. The whole monitoring period can be divided into three intervals corresponding to three different kind of workings: i) piling work; ii) parapet breakdown, excavation, embankment arrangement and foot wall consolidation; iii) backfill and restoring of the original condition, ordinary construction activities. The maximum peak component particle velocity substantial increase during the second period. All the stations have a higher energy content in the 10-20 Hz frequency range, but the spectra analysis clearly shows that the NS component, perpendicular to the wall, is the most stressed one. Moreover, despite the considerable distance from the August 24 Central Italy earthquake epicentre, the earthquake waveform is clearly recognizable at each station. In fact, the energy is focused around 2 Hz and the signals show directivity neither for the spectrum nor for the H/V.ConclusionThis work may contribute to characterize the vibrations induced by piling work at close range, and help to define the maximum acceptable vibration pattern for such structures, since literature is missing of such case studies. The maximum peak component particle velocity values clearly showed the work advancement. This paper also shows how the H/V technique is a valuable method to estimate the resonant frequency not only of buildings, but also of a squat and monolithic structure like the Lungarno Torrigiani masonry embankment wall.

Experimental and numerical study of the impact of the collector roof inclination on the performance of a solar chimney power plant

The solar chimney power plant (SCPP) is a promising solution to produce electrical power from solar energy. The optimization of the solar setup geometry is required to enhance its performance. In this paper, a numerical study is presented to evaluate the performance of the solar chimney power plants while varying the collector roof angle. The considered system is defined by the collector height equal to h=50mm, the chimney diameter equal to d=160mm, the collector diameter equal to D=2750mm and the chimney height equal to H=3000mm. Four collector roof angles, equal to β=−1.5°, β=−1°, β=0° and β=1°, were investigated. For each collector roof angle, the distribution of the magnitude velocity, the air temperature, the pressure, the incident radiation and the turbulence characteristics were presented and discussed. The efficient choice of the optimal geometry is based on the calculation of the maximum value of the air velocity within the SCPP. Results indicate that a negative collector-roof positively increases the air velocity. The obtained results present an interesting data which can provide the thermal characteristics of the air flow for the designers and the engineers to improve the overall efficiency of the solar setup.

Enzymatic degradation and metabolic product of tylosin residue using enzyme extracted from Burkholderia vietnamiensis strain

The aims of this study were to extract a tylosin‐degrading enzyme from Burkholderia vietnamiensis and to investigate the enzymatic degradation of tylosin and metabolic product formed. The results showed that the enzyme was extracted and purified to homogeneity with 23.5‐fold purification and a specific activity equal to 247.1 U mg−1 protein. This enzyme with a concentration of 1000 U mL−1 could degrade 100% of 200 mg L−1 tylosin after 180 min of incubation at 35°C. The toxicity of metabolites was lower than that of parent compound. The degradation kinetics followed an empirical model of the natural logarithm of concentration versus the natural logarithm of time, and the calculated half‐lives were about 3.54–3.91 min when the initial concentrations of tylosin ranged from 200 to 600 mg L−1. The enzymatic reaction of tylosin degradation could be well described using Michaelis‐Menten equation, and values of Michaelis constant and maximum velocity were 326.91 µmol L−1 and 16.08 µmol L−1 min−1, respectively. High‐performance liquid chromatography and mass spectrum indicated that tylosin was degraded into two metabolites. The pathway of enzymatic degradation might be that tylosin A was firstly transformed to tylosin B, and then the hydrolysis of lactone bond and the reduction of aldehyde group occurred. These results may provide the basis for biotreatment and removal of tylosin residue in solid and liquid wastes. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 879–886, 2017

Numerical simulation of the formation and the dripping of droplet in the Electroslag Remelting process

Based on the magnetohydrodynamic module of the commercial computational fluid dynamics software FLUENT, a 3-D mathematical model was developed to describe the multi-field coupling phenomenon in the electroslag remelting process. The model predicted value is in good agreement with the experimental measurements. The simulation results show that, during the melt dripping process, the resistance of the electroslag remelting system is decreasing while the current density and velocity, as well as the temperature are increasing gradually. The maximum value of current density, electromagnetic force, and velocity appears when the melt droplet detaches and the quality of large droplets fall into the slag-metal interface. The maximum value of the current density is increased by almost one order of magnitude. The maximum value of the electromagnetic force and velocity increased by 2.5 and 4.7 times, respectively. The maximum value of Joule heating and temperature appears when the droplets fall into the slag-metal interface. The maximum value of the Joule heating and temperature increased for about 174.7% and 26.8%, respectively, when compared with the moment of the melt droplet formation.

Internal gravity waves excited by a pulsating perturbation source

Abstract The problem of an internal gravity wave field from a pulsating point source of perturbations in the flow of a stratified medium of finite depth with horizontal velocity of the source V less than the maximum value of the group velocity of the internal gravity waves c is considered, unlike to the previously considered case V > c. Constructed asymptotic solutions make it possible to describe the amplitude-phase characteristics of individual modes comprising the full field of internal gravity waves. The excited waves consist of waves of two types: ring-like waves and wedge-shaped waves. Features of the mode structure of the excited fields are considered as functions of the parameters of the stratified medium and the characteristics of the perturbation source.

Study of the kinematic variables of unilateral and habitual mastication of healthy individuals.

To describe and compare the temporal-spatial kinematic variables of mandibular movement during deliberate unilateral and habitual mastication in healthy young-adult individuals. The study sample was composed of eight male healthy volunteers aged 19 to 24 years. The kinematic data were obtained using a motion analysis system - Qualisys Track Manager (QTM) ProReflex MCU. Recordings were performed during deliberate unilateral mastication (UM) and habitual mastication (HM) of firm-consistency gummy candy. The following variables were analyzed: (1) masticatory sequence: duration, number of masticatory cycles, and chewing rate; (2) masticatory cycle: duration, vertical and medial-lateral mandibular range of motion in relation to the skull, and maximum velocity during the opening and closing phases. Data of the variables were compared during UM and HM by the paired t test, and the effect sizes ('d' Cohen) were calculated. Regarding the variables of the masticatory sequence, smaller chewing rate was observed for UM compared with that for HM (1.19±0.21Hz and 1.29±0.16Hz, respectively, p=0.004, d=0.53). Smaller values of maximum velocity during the opening (MU=67.4 mm/s and MH=80.02, p=0.053, d=0.80) and closing (MU=71.77±9.35mm/s and MH=3.51±7mm/s, p=0.014, d=0.79) phases of the masticatory cycle were observed in deliberate unilateral mastication compared with those in habitual mastication. Kinematic variables associated with the sequence and cycle of mastication are influenced by the chewing pattern adopted - deliberate unilateral or habitual.

Organophosphorus pesticides stress deranged kinetic values of a few midgut carbohydrases of naiad of Trithemis aurora (burm.) (Odonata: Libellulidae)

The 40 Hrs. treatment of last instar naiad of Trithemis aurora (Burm.) in Chlorphyriphos and Quinalphos pesticides concentrations (LC50 = 5.12 ×10-7 ppm and 7.6 × 10-8 ppm) has shown significant variations in the enzyme kinetic parameters and arrested the enzymatic activity in the midgut tissue of last instar naiad of T. aurora causing deleterious effect on various carbohydrases at standard temp. and pH value. The midgut amylase ( μ and β amylase) showed the change in the velocity of enzymatic reaction under LC50 conc. of chlorpyriphos. The data of initial velocity and substrate concentration were processed to achieve their reciprocal values. These values were plotted and a characteristic Lineweaver Burke straight line was observed from the graph and values of maximum reaction velocity (Vmax) and Michaelis Menten constants (km) were assessed. The present organophosphorus pesticide showed an inhibitory impact on midgut amylase reaction velocity. The double reciprocal plot of initial velocity and substrate concentration after exposing the enzyme under LC50 conc. of chlorphyriphos resulted in varied Vmax and Km. values. These carbohydrase on treatment with LC50 conc. of chlorphyriphos showed an inhibitory change in the reaction velocity. The 1/V and 1/S values were plotted to achieve a characteristic Lineweaver – Burke pattern of Vmax and km values obtained as 5.0 × 10-2 [M] and 2.0 under LC50 chlorphyriphos stress for α amylase. The km and Vmax values were obtained from 0.625 × 10-3 [M] to 1.25 × 10-2 [M] for various other midgut carbohydrases with Vmax value obtained from 0.28 to 5.0 under chlorpyriphos stress. The Quinalphos inhibited the enzymatic efficiencies of various carbohydrases severely and changed Km and Vmax values were found under the pesticidal stress and found as potent uncompetitive inhibitor for enzymes as values compared to the controlled enzymatic reactions by deranging the kinetic values. The Km values determined as on 1/V and 1/S basis found deranged from 1.66 × 10-3 [M] to 10 × 10-2 [M]. The Vmax values were found in a range of 0.41 to 3.3 under LC50 Quinalphos stress for midgut hydrolases. The analysis of enzymec kinetic values revealed the great inhibitory and deranged activities of various carbohydrases under both the pesticide constrain. The present toxicants were found to change the enzymatic velocity negatively. The LC50 concentrations of these toxicants were sufficient to inhibit the activity of present hydrolases as α and β amylase, α glucosidase, α galactosidase, β galactosidase, β frictosidase and α trehalase obtaining a meaningful Lineweaver – Burke line of plotted reciprocals of data of reaction velocity and substrate concentration.

Evaluation of an Extended Autocorrelation Phase Estimator for Ultrasonic Velocity Profiles Using Nondestructive Testing Systems.

In this paper the extended autocorrelation velocity estimator is evaluated and compared using a nondestructive ultrasonic device. For this purpose, three velocity estimators are evaluated and compared. The autocorrelation method (ACM) is the most used and well established in current ultrasonic velocity profiler technology, however, the technique suffers with phase aliasing (also known as the Nyquist limit) at higher velocities. The cross-correlation method (CCM) is also well known and does not suffer with phase aliasing as it relies on time shift measurements between emissions. The problem of this method is the large computational burden due to several required mathematical operations. Recently, an extended autocorrelation method (EAM) which combines both ACM and CCM was developed. The technique is not well known within the fluid engineering community, but it can measure velocities beyond the Nyquist limit without the ACM phase aliasing issues and with a lower computational cost than CCM. In this work, all three velocity estimation methods are used to measure a uniform flow of the liquid inside a controlled rotating cylinder. The root-mean-square deviation variation coefficient (CVRMSD) of the velocity estimate and the reference cylinder velocity was used to evaluate the three different methods. Results show that EAM correctly measures velocities below the Nyquist limit with less than 2% CVRMSD. Velocities beyond the Nyquist limit are only measured well by EAM and CCM, with the advantage of the former of being computationally 15 times faster. Furthermore, the maximum value of measurable velocity is also investigated considering the number of times the velocity surpasses the Nyquist limit. The combination of number of pulses and number of samples, which highly affects the results, are also studied in this work. Velocities up to six times the Nyquist limit could be measurable with CCM and EAM using a set of parameters as suggested in this work. The results validate the use of the NDT tool to measure velocities even beyond Nyquist limit by using EAM.

Visualization of CSF Flow with Time-resolved 3D MR Velocity Mapping in Aqueductal Stenosis Before and After Endoscopic Third Ventriculostomy : AFeasibility Study.

The aim of this study was to evaluate timed-resolved three-dimensional (3D) magnetic resonance (MR) velocity mapping as amethod for investigation of cerebrospinal fluid (CSF) flow changes in patients with aqueductal stenosis (AS) treated by endoscopic third ventriculostomy (ETV). The MR velocity mapping was performed in 12AS patients before and after ETV and in 10 healthy volunteers by using a3-Tesla MR system. Time-resolved 3D MR velocity mapping data were acquired with astandard 3D phase contrast (PC) sequence with cardiac triggering. Values of mean (vmean) and maximum (vpeak) velocity were measured at several ventricular structures using dedicated software. Of the patients 11 showed asatisfactory clinical improvement after ETV, whereas one patient needed subsequent shunt implantation. All AS patients showed significant hypomotile CSF flow dynamics in the third ventricle when compared to healthy subjects before surgery (p< 0.05). In contrast, CSF flow velocity was increased within the Foramen of Monro in AS patients. After ETV, all AS patients showed adecrease of CSF flow dynamics within the third ventricle. Mean and peak CSF flow velocities through the ventriculostomy were 1.72± 0.59cm/s (vmean) and 3.53± 0.79cm/s (vpeak), respectively after ETV. The patient who needed shunt implantation after ETV had the lowest flow velocities through the ventriculostomy. This study demonstrates that timed-resolved 3D MR velocity mapping is auseful imaging investigation for diagnostics and follow-up in patients with AS. This new technique provides an insight into the physiological CSF flow changes related with AS and its treatment.

Regulated Lignin Structural Units and Soil Organic Carbon Content by Cowpea Peroxidase

&lt;p class="Standard"&gt;Peroxidases participate in lignin biosynthesis, but there is no biochemical resolution between the structural units of lignin and soil organic carbon (SOC) contents. Black-eyed beans are staple high-protein foods for millions of at-risk populations in every continent. Its cultivation in semiarid zones could be leveraged to maximize SOC sequestration. Cowpea was treated with stoichiometric mixes of mineral nutrients. Peroxidase was electrophoretically purified from leaves, and assayed for o-dianisidine (guaiacyl units) and pyrogallol (p-hydroxyphenyl units) substrate specificities. Lignin, and SOC compositions were determined by gravimetry. Sulfate-treated cowpea produced the highest lignin (318.88 kg·ha&lt;sup&gt;-1&lt;/sup&gt;) because the o-dianisidine maximum velocity (V&lt;sub&gt;max&lt;/sub&gt;) value (0.36 µM·min&lt;sup&gt;-1&lt;/sup&gt;·mg&lt;sup&gt;-1&lt;/sup&gt;) was higher than that for the pyrogallol (0.08 µM·min&lt;sup&gt;-1&lt;/sup&gt;·mg&lt;sup&gt;-1&lt;/sup&gt;), but the SOC (64.75 kg·ha&lt;sup&gt;-1&lt;/sup&gt;) was low due to the guaiacyl being higher than p-hydroxyphenyl units. Peroxidase V&lt;sub&gt;max&lt;/sub&gt; value was low (0.12 µM·min&lt;sup&gt;-1&lt;/sup&gt;·mg&lt;sup&gt;-1&lt;/sup&gt;) for both substrates in the control cowpea, and accordingly lignin (268.44 kg·ha&lt;sup&gt;-1&lt;/sup&gt;) and SOC (42.33 kg·ha&lt;sup&gt;-1&lt;/sup&gt;) compositions were very low. The pyrogallol V&lt;sub&gt;max&lt;/sub&gt; value (0.5 µM·min&lt;sup&gt;-1&lt;/sup&gt;·mg&lt;sup&gt;-1&lt;/sup&gt;) was lower than the o-dianisidine value (1.0 µM·min&lt;sup&gt;-1&lt;/sup&gt;·mg&lt;sup&gt;-1&lt;/sup&gt;) for KK-treated cowpea, and accordingly the lignin contents (227.4 kg·ha&lt;sup&gt;-1&lt;/sup&gt;) possessed variable compositions of guaiacyl and p-hydroxyphenyl units, leading to very high SOC composition (214.56 kg·ha&lt;sup&gt;-1&lt;/sup&gt;). The high SOC sequestration technology involving fertilization with stoichiometric mixes of mineral nutrients could enable limited resource farmers who cultivate cowpeas as cover crop in the Sahel to improve SOM while producing their staple crop.&lt;/p&gt;

MOLECULAR CHARACTERIZATION OF TWO ACETYLCHOLINESTERASE GENES FROM THE RICE LEAFFOLDER, Cnaphalocrocis medinalis (LEPIDOPTERA: PYRALIDAE).

In this study, two full-length cDNA sequences (Cmace1 and Cmace2) encoding putative acetylcholinesterases (AChEs) were cloned and characterized from the rice leaffolder, Cnaphalocrocis medinalis, an important lepidopteran rice pest in Asia. Cmace1 encodes a CmAChE1 consisting of 689 amino acid residues, while Cmace2 encodes a 639 amino acids CmAChE2. The two CmAChEs both have N-terminal signal peptides and conserved motifs including the catalytic triad, choline-binding sites, oxianion hole, acyl pocket, peripheral anionic subsite, and the characteristic FGESAG motif and conserved 14 aromatic amino acids. Phylogenetic analysis showed that Cmace1 and Cmace2 are clustered into distinct clusters that are completely diverged from each other. Reverse-transcription quantitative PCR analysis revealed that Cmace1 and Cmace2 were predominately expressed in the larval brain and at the fifth-instar larvae stage, and the transcription levels of Cmace1 were significantly higher than those of Cmace2 in all the tested samples. Recombinant CmAChE1 and CmAChE2 were heterologously expressed in baculovirus system. Using acetylthiocholine iodide (ATChI) as substrate, the Michaelis constant (Km ) values of rCmAChE1 and rCmAChE2 were 39.81 ± 6.49 and 68.29 ± 6.72 μmol/l, respectively; and the maximum velocity (Vmax ) values of the two rCmAChEs were 0.60 ± 0.02 and 0.31 ± 0.06 μmol/min/mg protein, respectively. Inhibition assay indicated that rCmAChE1 was more sensitive to the organophosphate insecticides chlorpyrifos and triazophos than rCmAChE2. This study is the first report of molecular cloning and biochemical characterization of two acetylcholinesterase genes/enzymes in C. medinalis.

A CFD analysis of slag properties, electrode shape and immersion depth effects on electric submerged arc furnace heating in ferronickel processing

A 2D, steady-state computational fluid dynamics (CFD) analysis of an industrial electric arc furnace (EAF) is presented. The analysis accounts for the electrode shape and immersion depth, as well as for the dependence of Joule heating on the properties of the slag. The equations for the electric potential, momentum and heat transfer were solved across four distinct regions (i.e. air, slag, ferronickel and firebricks) and the final profile of the slag/metal interface was calculated as a function of the operating parameters of the furnace. The results indicate that the amount of Joule heat produced by the Söderberg electrodes increased with increasing applied voltage and electrical conductivity of the slag; the Joule heat peaked for a value of slag electrical conductivity equal to 3S/m. A highly conductive slag along with a greater electrode immersion depth was found to facilitate the melting process. The maximum slag velocity values computed were of the order of 0.8m/s in the vicinity of the electrode tips.

Experimental and CFD flow studies in an intracranial aneurysm model with Newtonian and non-Newtonian fluids

According to the clinical data, flow conditions play a major role in the genesis of intracranial aneurysms. The disorder of the flow structure is the cause of damage of the inner layer of the vessel wall, which leads to the development of cerebral aneurysms. Knowledge of the alteration of the flow field in the aneurysm region is important for treatment. The aim is to study quantitatively the flow structure in an patient-specific aneurysm model of the internal carotid artery using both experimental and computational fluid dynamics (CFD) methods with Newtonian and non-Newtonian fluids. A patient-specific geometry of aneurysm of the internal carotid artery was used. Patient data was segmented and smoothed to obtain geometrical model. An elastic true-to-scale silicone model was created with stereolithography. For initial investigation of the blood flow, the flow was visualized by adding particles into the silicone model. The precise flow velocity measurements were done using 1D Laser Doppler Anemometer with a spatial resolution of 50 μ m and a temporal resolution of 1 ms. The local velocity measurements were done at a distance of 4 mm to each other. A fluid with non-Newtonian properties was used in the experiment. The CFD simulations for unsteady-state problem were done using constructed hexahedral mesh for Newtonian and non-Newtonian fluids. Using 1D laser Doppler Anemometer the minimum velocity magnitude at the end of systole -0.01 m/s was obtained in the aneurysm dome while the maximum velocity 1 m/s was at the center of the outlet segment. On central cross section of the aneurysm the maximum velocity value is only 20% of the average inlet velocity. The average velocity on the cross-section is only 11% of the inlet axial velocity. Using the CFD simulation the wall shear stresses for Newtonian and non-Newtonian fluid at the end of systolic phase (t= 0.25 s) were computed. The wall shear stress varies from 3.52 mPa (minimum value) to 10.21 Pa (maximum value) for the Newtonian fluid. For the non-Newtonian fluid the wall shear stress minimum is 2.94 mPa; the maximum is 9.14 Pa. The lowest value of the wall shear stress for both fluids was obtained at the dome of the aneurysm while the highest wall shear stress was at the beginning of the outlet segment. The vortex in the aneurysm region is unstable during the cardiac cycle. The clockwise rotation of the streamlines at the inlet segment for Newtonian and non-Newtonian fluid is shown. The results of the present study are in agreement with the hemodynamics theory of aneurysm genesis. Low value of wall shear stress is observed at the aneurysm dome which can cause a rupture of an aneurysm.