Electrostatic sprays of food-grade acids and plant extracts are more effective than conventional sprays in decontaminating Salmonella Typhimurium on spinach

About 40000 people fall victim to Salmonella infections every year in the United States. Recent occurrences of Salmonella contaminated spinach and its recalls have accelerated the need for efficient antimicrobials targeting these pathogens. Our study was aimed at evaluating the inhibitory properties of malic, tartaric, and lactic acids, and grape seed extract (GSE) alone and in combinations and their application methods against Salmonella Typhimurium-inoculated spinach using a response surface method. Fresh spinach leaves were washed, disinfected with sodium hypochlorite solution (0.04% v/v), rewashed with sterile deionized (DI) water, and inoculated with a 2nd-day culture of S. Typhimurium (7.0 log CFU/mL). Adhered S. Typhimurium population on day 0 were 7.5 log CFU/g. These were treated with individual and combinations of organic acids with GSE or DI water (control) adjusted to the same pH as that of the test solutions with both the modes of application and leaves were refrigerated at 4 °C. Malic acid (2%) in combination with GSE (3%) or lactic acid (3%) sprayed electrostatically showed reductions of 2.6 to 3.3 log CFU/g compared to lower log reductions (0.0 to 0.3 log CFU/g) by day 14 if sprayed conventionally. These findings indicate that malic acid in combination with GSE/lactic acid solutions applied by electrostatic spraying exhibited higher inhibition of pathogens than conventional spraying and can be used for commercial applications to enhance food safety.     

Continuous biogenic hydrogen production from dilute acid pretreated algal hydrolysate using hybrid immobilized mixed consortia

This study investigated the bioconversion of dilute acid (2% H₂SO₄) pretreated red algae (Gelidium amansii) hydrolysate into H₂ by anaerobic fermentation in a continuous stirred tank reactor under mesophilic conditions using hybrid immobilized cells as microbial catalyst. Two different hydraulic retention times (HRT) of 24 h and 16 h with a feed concentration of 15 g/L hexose equivalent have been investigated over 85 days of operation to evaluate H₂ production performance and stability of the continuous system. The highest hydrogen production rate (HPR) and hydrogen yield (HY) of 2.7 L/L/d and 1.3 mol/mol substrate hexose_added was achieved at 24 h HRT, while further operation at 16 h HRT led to a significant drop in the hydrogen production with a HPR and HY values of 1.8 L/L/d and 0.7 mol/mol substrate hexose_added, respectively. The bacterial community analysis characterized by 454 pyrosequencing revealed that the changes in HRT significantly influence the composition of the dominant microflora. At longer HRT (24 h), the phyla Firmicutes was abundant over 98%, whereas at shorter HRT (16 h), Proteobacteria being the dominant populations with 84%. These outcomes suggested that controlling appropriate HRT is prerequisite for efficient hydrogen production.     

Transport hindrances with electrodialytic recovery of citric acid from solution of strong electrolytes

Electrodialytic(ED) recovery of citric acid(CA) in the presence/absence of strong electrolytes(NaCl, CaCl_2 and FeCl_3) was separately analyzed under different process conditions. Recovery effectiveness was quantitatively estimated from current efficiency values. Efficiency attained optimum value with both flow rate and potential applied, while a monotonic rise was noted with temperature which got lowered beyond 0.1 mol·L~(-1) feed concentration. 40% drop in efficiency was recorded in the presence of strong electrolytes(NaCl, CaCl_2 and FeCl3) in feed relative to their presence in concentrate. Severe transport hindrance and efficiency loss were attributed to adsorption and allied physicochemical changes occurred with anion/cation exchange membranes(AEM/CEM) and these were confirmed through contact angle/Chronopotentiometry/AFM/EDX. Sluggish potential rise(Galvanostatic mode) in Chronopotentiometric analysis indicated diffusion limiting transport of organic acids influenced AEM resistance. XRD and EDX analysis indicated the presence of salt hydrates/ions(Ca~(2+)/Fe~(3+)) over CEM justifying the resistance buildup due to adsorption of multivalent metal ion(s) and salts.     

On numerical investigation of local Nusselt distribution between flat surface and impinging air jet from straight circular nozzle and power law correlations generation

The computational study of heat transfer characteristics over a flat surface under the impingement of an air jet is the most advanced scheme in the research field of convective heat transfer technology. This research aims to construct the semiempirical relations for predicting the magnitude of local Nusselt number (Nu) against the various impinging and target surface parameters. The impinging parameter includes Reynolds number (Re) and nozzle‐target spacing (Z/d), while the target surface parameter represents the Prandtl number (Pr) and nondimensional geometric thickness (t/d) of the target surface. The graphical representation of Nu versus r/d for different Pr and t/d justifies the saturation in the Nusselt profile beyond a critical value. The critical limit of Pr × t/d, reported in this study, rounds to 0.012. Hence, two sets of empirical relations for Pr × t/d < 0.012 and Pr × t/d > 0.012 must be defined. The semiempirical relations for Pr × t/d > 0.012 is only a function of impinging parameters, since the variation in Pr and t/d does not affect the Nu profile beyond this range. This work takes an initiative in reporting the semiempirical power law relations, which represent the local Nu magnitude within the range of Pr × t/d < 0.012. The reported empirical relations are the functions of Pr, t/d, Z/d, Re, and r/d.     

Is Barrett's esophagus characterized by more pronounced acid reflux than severe esophagitis?

OBJECTIVE: Barrett's esophagus is related to gastroesophageal reflux disease (GERD). However, only a small fraction of patients with GERD develop Barrett's esophagus. We evaluated whether gastroesophageal acid reflux is more pronounced in Barrett's patients than in patients with moderate or severe endoscopic esophagitis. METHODS: Retrospective evaluation of results of esophageal manometry and 24 hour ambulatory pH monitoring performed between 1990 and 1996 at the Leiden University Medical Center in those patients who also underwent endoscopy < or = 3 months before pH-metry. Included were 51 patients with Barrett's esophagus, 30 patients with severe esophagitis, 45 patients with moderate esophagitis, and 24 healthy control subjects. RESULTS: Patients with Barrett's esophagus had significantly increased acid reflux time (p < 0.01-0.05) compared to patients with moderate, but not compared to patients with severe esophagitis. Distal esophageal body motility and LES pressure were significantly (p < 0.01-0.05) reduced in patients with Barrett's esophagus compared to patients with moderate esophagitis but not compared to those with severe esophagitis. CONCLUSION: Although acid reflux is increased in patients with Barrett's esophagus and esophageal motility is impaired, other factors apart from acid exposure and motility contribute to the development of Barrett's esophagus.     

Hands‐On CFD Educational Interface for Engineering Courses and Laboratories

This study describes the development, implementation, and evaluation of an effective curriculum for students to learn computational fluid dynamics (CFD) in introductory and intermediate undergraduate and introductory graduate level courses/laboratories. The curriculum is designed for use at different universities with different courses/laboratories, learning objectives, applications, conditions, and exercise notes. The common objective is to teach students from novice to expert users who are well prepared for engineering practice. The study describes a CFD Educational Interface for hands‐on student experience, which mirrors actual engineering practice. The Educational Interface teaches CFD methodology and procedures through a step‐by‐step interactive implementation automating the CFD process. A hierarchical system of predefined active options facilitates use at introductory and intermediate levels, encouraging self‐learning, and eases transition to using industrial CFD codes. An independent evaluation documents successful learning outcomes and confirms the effectiveness of the interface for students in introductory and intermediate fluid mechanics courses.     

Use of a Molecular Switch Probe to Activate or Inhibit GIRK1 Heteromers In Silico Reveals a Novel Gating Mechanism

G protein-gated inwardly rectifying K⁺ (GIRK) channels form highly active heterotetramers in the body, such as in neurons (GIRK1/GIRK2 or GIRK1/2) and heart (GIRK1/GIRK4 or GIRK1/4). Based on three-dimensional atomic resolution structures for GIRK2 homotetramers, we built heterotetrameric GIRK1/2 and GIRK1/4 models in a lipid bilayer environment. By employing a urea-based activator ML297 and its molecular switch, the inhibitor GAT1587, we captured channel gating transitions and K⁺ ion permeation in sub-microsecond molecular dynamics (MD) simulations. This allowed us to monitor the dynamics of the two channel gates (one transmembrane and one cytosolic) as well as their control by the required phosphatidylinositol bis 4-5-phosphate (PIP₂). By comparing differences in the two trajectories, we identify three hydrophobic residues in the transmembrane domain 1 (TM1) of GIRK1, namely, F87, Y91, and W95, which form a hydrophobic wire induced by ML297 and de-induced by GAT1587 to orchestrate channel gating. This includes bending of the TM2 and alignment of a dipole of two acidic GIRK1 residues (E141 and D173) in the permeation pathway to facilitate K⁺ ion conduction. Moreover, the TM movements drive the movement of the Slide Helix relative to TM1 to adjust interactions of the CD-loop that controls the gating of the cytosolic gate. The simulations reveal that a key basic residue that coordinates PIP₂ to stabilize the pre-open and open states of the transmembrane gate flips in the inhibited state to form a direct salt-bridge interaction with the cytosolic gate and destabilize its open state.     

Large-scale synthesis of centrifugally spun tantalum oxynitride fiber electrocatalysts for hydrogen evolution reaction

Tantalum oxynitride (TaO_xN_1−x) fibers were synthesized and evaluated for their electrocatalytic hydrogen activity using an in-house developed centrifugal spinning setup. By tailoring the composition of the spinning solution and optimizing collector distance and rotation speed of the spinneret, bead-free TaO_xN_1−x fibers with a diameter of 800 nm were obtained. The fibers were structurally characterized through phase and elemental analysis, confirming the formation of monoclinic TaO_xN_1−x with clear splitting of the X-ray photoelectron spectroscopy peaks indicating Ta was in +5 oxidation state. The resulting oxynitride fibers exhibited superior electrocatalytic performance with low overpotentials (250 mV) to generate 10 mA/cm² compared to Ta₂O₅ oxide fibers. Interestingly, the enhanced activity of oxynitride fibers was observed to be suppressed in basic medium due to the high oxophilicity of tantalum ions and a negative Gibbs adsorption-free energy, leading to poisoning of the active sites. This work demonstrates a facile pathway for the fabrication of high-performance electrocatalysts, based on TaO_xN_1−x fibers, from a cost-effective and energy-efficient centrifugal spinning technique.     

Algorithm selection for SMT

International Journal on Software Tools for Technology Transfer - This paper presents MachSMT, an algorithm selection tool for Satisfiability Modulo Theories (SMT) solvers. MachSMT supports the...     

Inhibiting Erastin-Induced Ferroptotic Cell Death by Purine-Based Chelators

Ferroptosis is a cell death event caused by increased lipid peroxidation leading to iron-dependent oxidative stress and is associated with a wide variety of diseases. In recent years, ferroptosis inhibition has emerged as a novel strategy to target different pathologies. Here, we report the synthesis of two purine derivatives, 1 and 2 , for iron chelation strategy and evaluate their potency to inhibit erastin-induced ferroptosis. Both compounds showed efficient iron chelation in solution as well as in cellular environment. The crystal structure of the purine derivatives with iron demonstrated a 2 : 1 (ligand to metal center) stoichiometry for iron and purine derivative complexation. The synthesized compounds also decrease the reactive oxygen species concentration in cell cultures. Compound 2 showed better potency towards the prevention of ferroptotic cell death as compared to commercially available iron chelator in the erastin-induced ferroptosis cell culture model. Such purine analogues are potential functional scaffolds for the development of target molecules for ferroptosis inhibition.