Thermal Screening Research Articles

Cost-effective FTIR and 1H NMR spectrometry used to screen valuable molecules extracted from selected West African trees by a sustainable biochar process

This study focused on wood extractives by a slow pyrolysis thermal extraction technique and screening of potentially valuable compounds from three African trees: Lophira lanceolata Tiegh. ex Keay., Dialium guineense Willd. and Afzelia africana Sm. The primary objective of the thermal treatment was biochar production but also liquids were collected and analyzed. Raw materials were cut into sizes of about 25 cm in length and then processed with slow pyrolysis from 20 °C up to 400 °C; the slow pyrolysis process included two stages, drying and pyrolysis. Five end-point temperatures were used in the range of 250 °C–400 °C. Raw distillates were collected at three temperatures (120 °C, 60 °C and 25 °C) and their composition screened by either cost-effective FTIR or benchtop 80 MHz 1H NMR methods. HR-NMR and 2D GC–MS were used to confirm some findings. Results from the drying stage indicated that all distillates contained mostly water >90%, acetic acid, methanol and some other compounds at very low levels. The percentages of acetic acid were 3.5% for L. lanceolate, 2.8% for D. guineensis and 3.8% for A. africana (% with respect to the identified peaks). Results from the pyrolysis stage revealed the presence of bioactive compounds such as ketones, methanol, hydrocarbons, acetic acid, esters, alkenes and phenolic compounds at higher quantities than in the drying stage. The quantity of phenols in certain runs and distillate fractions using NMR was 1%–20% for L. lanceolata, 7–17% for D. guineensis and 10%–17% for A. africana (% with respect to the composition of the identified peaks). The percentage of hydrocarbons was 1%–48% for L. lanceolata, 1%–34% for D. guineensis and 2%–33% for A. africana. The percentage of ketones was 7%–19% for L. lanceolate, 4%–27% for D. guineensis and 19%–22% for A. africana. In general, the results indicated the presence of potential valuable compounds at relatively high concentrations. By optimizing the slow pyrolysis process parameters, it is possible to collect distillates with high concentrations of valuable biomolecules.

Effectiveness of airport screening at detecting travellers infected with novel coronavirus (2019-nCoV).

We evaluated effectiveness of thermal passenger screening for 2019-nCoV infection at airport exit and entry to inform public health decision-making. In our baseline scenario, we estimated that 46% (95% confidence interval: 36 to 58) of infected travellers would not be detected, depending on incubation period, sensitivity of exit and entry screening, and proportion of asymptomatic cases. Airport screening is unlikely to detect a sufficient proportion of 2019-nCoV infected travellers to avoid entry of infected travellers.

Measurement of hazardous reactions under extreme conditions with a house-built high-performance adiabatic calorimeter

The continuous emergence of new materials and chemical processes has posed great challenge on the hazard assessment capacity, especially the capacity to mimic the reaction progress and to measure the heat released. Although a few thermal hazard screening tools are readily available, a flexible yet cost-effective adiabatic calorimeter that could be applied under extreme conditions is still missing. A house-built high-performance adiabatic calorimeter (HPAC) was developed to solve the problem. We validated the HPAC by comparing its performance with a commercially available Vent Sizing Package 2 in the measurement of H2O2 decomposition and Di-t-butyl peroxide decomposition. We then demonstrated the capability of the HPAC by successfully evaluating the thermal runaway and overpressure hazard of a residual oil hydrotreating reaction under high temperature and high pressure.

Reduction of High-Titer Cold Agglutinins by Plasmapheresis to Resolve Serological Problem in a Patient

Background: Cold agglutinins are auto-antibodies that can be a nuisance in cross matching and in blood grouping. Here we report an unusual case of a high titer and wide amplitude cold agglutinin reduced by plasmapheresis. Methods and Materials: A 56-year-old man with severe anemia requested a transfusion of red blood cells. However, there was a problem in blood for blood grouping. The discrepancy of blood typing was subsequently resolved using group O absorbed plasma along with repetition of forward grouping with warm-washed red blood cells. The presence of high-thermal-amplitude and a high-titer anti-I cold agglutinin were detected in further serologic investigation. It revealed reactivity against autologous and adult O red blood cells at 37°C by the thermal amplitude screening test, and demonstrated a very high titer of 65,536 against adult O cells by titration studies at 4°C. The patient received two plasma exchange sessions of 1.5 plasma volumes each. There was a significant reduction of the titer of cold agglutinins and of the thermal amplitude by plasmapheresis as well (p < 0.01). Results: After successful cross-matching with post plasma exchanges, four units of red blood cells were infused to the patient without any hemolysis symptoms or signs. Conclusions: We now reported a patient with abnormally ascended titer of cold agglutinins and wide-thermal-amplitude, but we also successfully performed ABO typing and cross matching after 2 plasma exchange sessions of 1.5 plasma volumes each.

Responding to COVID-19 pandemic: Why a strong health system is required.

Responding to COVID-19 pandemic: Why a strong health system is required.

COVID-19 Pandemic preparedness and response by India: Did lockdown serve its purpose? a Commentary.

COVID-19, the novel Coronavirus, which originated in Wuhan, China, had spread rapidly across the globe in the short period of the year. Since it was a new disease, there was no medical intervention available at the outset of the pandemic. Hence, the only mode of prevention was various non-pharmacological interventions, of various levels, at various levels, that could have saved any country from the wrath of this baleful virus. Prevention and preparedness have been the critical factors in the appropriate management at the country level. Indian government acted pro-actively in the implementation of preventive strategies right from the unfolding of the events at the far south end of the country. The government of India started thermal screening at a few of the airports on the 17th of January, which is way before the first case was reported. The passengers who had travelled back into the country ever since were placed under strict surveillance, and evacuees were to be kept in quarantine for the following 14 days. At the same time, early identification of positive cases and contact tracing aptly supported by active surveillance in a few states have played a vital role in containment. As a lesson learned from other countries, the Indian government started measures like social distancing before a significant number of cases emerged in the country. On the 16th of March, govt ordered the closure of all schools in the country. GoI had shown their immaculate understanding of the benefits of non-pharmacological interventions, with the dual purpose of delaying the peak of cases and buying some time for further strengthening of the healthcare system and procurement of PPE; India started the process of lockdown on the 24th of March. At the beginning of April month, GoI had announced significant investments of Rs.15000 crores for ‘India COVID-19 Emergency Response and Health System Preparedness Package’. All the above-mentioned measures had contributed to serving the prime purpose of early, emphatic containment of SARS-CoV-2 in a country like India, inhabited by 1.3 billion people. Although the surge of cases in India seems to be high, looking just at the numbers, when we infer the same result in comparison to the no of cases would have been there without the lockdown, no action at policymakers would have overwhelmed the health services severely. Hence, the lockdown in India had served the purpose for which it was imposed, thereby had prevented major humanitarian losses on account of COVID-19.

Skin temperature maps as a measure of carotid artery stenosis

In this study, the effect of carotid artery stenosis on the neck skin temperature maps was investigated. With the presence of stenosis, alterations in the carotid artery hemodynamics bring about changes in the heat transfer to the surrounding tissue. This is expected to be captured in the resulting temperature map over the external neck skin surface; possibly it correlates to the presence of stenosis. A total of twenty carotid artery samples, from ten patients with both sides normal (0% stenosis), stenosis (>50%) on one side, and stenosis (>50%) on both sides, were studied. Duplex Ultrasound and infrared (IR) thermography examinations were performed. A computational study, on an ideal 3-dimensional (3D) carotid artery and jugular vein model encapsulated with a solid neck tissue phantom resembling the human neck, was carried out. Incorporating the patient-specific geometrical (depth of artery and stenosis) and flow (peak systolic and end diastolic inlet velocity) boundary conditions, conjugate bio-heat transfer was studied using a finite volume numerical scheme. Simulation results and in-vivo thermal maps show that the average temperature on the external neck skin surface is significantly higher for normal patients (32.82 ± 0.53 °C versus 32.00 ± 0.37 °C, p < 0.001). Furthermore, the thermal region of interests (TROIs) were extracted from the in-vivo thermal images, which both qualitatively and quantitatively distinguish the normal and diseased cases. This study suggests the potential of thermal feature-based screening of patients with carotid artery stenosis.

Structural Basis for Allosteric Ligand Recognition in the Human CC Chemokine Receptor 7.

SummaryThe CC chemokine receptor 7 (CCR7) balances immunity and tolerance by homeostatic trafficking of immune cells. In cancer, CCR7-mediated trafficking leads to lymph node metastasis, suggesting the receptor as a promising therapeutic target. Here, we present the crystal structure of human CCR7 fused to the protein Sialidase NanA by using data up to 2.1 Å resolution. The structure shows the ligand Cmp2105 bound to an intracellular allosteric binding pocket. A sulfonamide group, characteristic for various chemokine receptor ligands, binds to a patch of conserved residues in the Gi protein binding region between transmembrane helix 7 and helix 8. We demonstrate how structural data can be used in combination with a compound repository and automated thermal stability screening to identify and modulate allosteric chemokine receptor antagonists. We detect both novel (CS-1 and CS-2) and clinically relevant (CXCR1-CXCR2 phase-II antagonist Navarixin) CCR7 modulators with implications for multi-target strategies against cancer.

Redox- and Ligand Binding-Dependent Conformational Ensembles in the Human Apoptosis-Inducing Factor Regulate Its Pro-Life and Cell Death Functions.

Aims: The human apoptosis-inducing factor (hAIF) supports OXPHOS biogenesis and programmed cell death, with missense mutations producing neurodegenerative phenotypes. hAIF senses the redox environment of cellular compartments, stabilizing a charge transfer complex (CTC) dimer that modulates the protein interaction network. In this context, we aimed to evaluate the subcellular pH, CTC formation, and pathogenic mutations effects on hAIF stability, and a thermal denaturation high-throughput screening (HTS) assay to discover AIF binders. Results: Apoptotic hAIFΔ1-101 is not stable at intermembrane mitochondrial space (IMS) pH, but the 77-101 residues confer stability to the mitochondrial isoform. hAIF and its CTC populate different conformational ensembles with redox switch to the CTC producing a less stable and compact protein. The pathogenic G308E, ΔR201, and E493V mutations modulate hAIF stability; particularly, ΔR201 causes a population shift to a less stable conformation that remodels active site structure and dynamics. We have identified new molecules that modulate the hAIF reduced nicotinamide adenine dinucleotide (NADH)/oxidized nicotinamide adenine dinucleotide (NAD+) association/dissociation equilibrium and regulate its catalytic efficiency. Innovation: Biophysical methods allow evaluating the regulation of hAIF functional ensembles and to develop an HTS assay to discover small molecules that might modulate hAIF stability and activities. Conclusions: The mitochondrial soluble 54-77 portion stabilizes hAIF at the IMS pH. NADH-redox-linked conformation changes course with strong NAD+ binding and protein dimerization, but they produce a negative impact in overall hAIF stability. Loss of functionality in the R201 deletion is due to distortion of the active site architecture. We report molecules that may serve as leads in the development of hAIF bioactive compounds.

Novel Hepatitis B Virus Capsid-Targeting Antiviral That Aggregates Core Particles and Inhibits Nuclear Entry of Viral Cores.

An estimated 240 million are chronically infected with hepatitis B virus (HBV), which can lead to liver disease, cirrhosis, and hepatocellular carcinoma. Currently, HBV treatment options include only nucleoside reverse transcriptase inhibitors and the immunomodulatory agent interferon alpha, and these treatments are generally not curative. New treatments with novel mechanisms of action, therefore, are highly desired for HBV therapy. The viral core protein (Cp) has gained attention as a possible therapeutic target because of its vital roles in the HBV life cycle. Several classes of capsid assembly effectors (CAEs) have been described in detail, and these compounds all increase capsid assembly rate but inhibit HBV replication by different mechanisms. In this study, we have developed a thermal shift-based screening method for CAE discovery and characterization, filling a much-needed gap in high-throughput screening methods for capsid-targeting molecules. Using this approach followed by cell-based screening, we identified the compound HF9C6 as a CAE with low micromolar potency against HBV replication. HF9C6 caused large multicapsid aggregates when capsids were assembled in vitro and analyzed by transmission electron microscopy. Interestingly, when HBV-expressing cells were treated with HF9C6, Cp was excluded from cell nuclei, suggesting that this compound may inhibit nuclear entry of Cp and capsids. Furthermore, mutational scanning of Cp suggested that HF9C6 binds the known CAE binding pocket, indicating that key Cp-compound interactions within this pocket have a role in determining the CAE mechanism of action.

Emodin-nicotinamide (1:2) cocrystal identified by thermal screening to improve emodin solubility

Emodin (EM), an anthraquinone obtained from natural products, is known for many pharmacological activities. However, further evaluation and interpretation of toxicity or pharmacological activity of emodin are limited due to its poor aqueous solubility. We aimed to identify an emodin cocrystal with improved pharmaceutical properties. Among various compounds screened by thermal analysis, nicotinamide (NCT) was identified as a potential cocrystal coformer, based on the presence of an exothermal peak in DSC profiles of the physical mixture of EM and NCT. Crystallization of EM-NCT cocrystal (EM-NCT) using slow or rapid solvent evaporation method yielded a novel cocrystal at 1:2 ratio. Single crystal structure analysis revealed EM dimers and NCT tetramers connected alternatively via H-bonds to make one-dimensional chains which are joined by inter-chain H-bonds between NCT to form two-dimensional layers. The EM molecules are planar with intramolecular H-bonds between O atoms. Compared with EM, the EM-NCT cocrystal showed improved aqueous solubility, dissolution rate, and stability. Hence, EM-NCT cocrystal is proposed as a more suitable solid form for further development as pharmaceutical products.

Re-running the QCD shear viscosity

The remarkably small shear viscosity to entropy density ratio of the quark–gluon plasma (QGP) is a key insight from heavy-ion experiments. Nonetheless, the basic understanding of this ‘observable’ still seems to be rudimentary, with existing perturbative QCD estimates suggesting —a view that we scrutinise here. In order to extrapolate the available perturbative approach to phenomenologically relevant temperatures, we consider carefully controllable higher order corrections: we adapt the leading order effective kinetic scheme (instead of the catchy next-to-leading log formula ), by using cross sections with a running coupling. This effect should be pertinent (for a QGP) and we argue for a choice of scale-dependence that makes it consistent with thermal screening. We conclude that does not indicate genuine non-perturbative effects, it may rather be understood within resummation-improved perturbative QCD, with some uncertainties from deploying kinetic theory near to its limit.

Fabrication of Gradient Nanopattern by Thermal Nanoimprinting Technique and Screening of the Response of Human Endothelial Colony-forming Cells.

Nanotopography can be found in various extracellular matrices (ECMs) around the body and is known to have important regulatory actions upon cellular reactions. However, it is difficult to determine the relation between the size of a nanostructure and the responses of cells owing to the lack of proper screening tools. Here, we show the development of reproducible and cost-effective gradient nanopattern plates for the manipulation of cellular responses. Using anodic aluminum oxide (AAO) as a master mold, gradient nanopattern plates with nanopillars of increasing diameter ranges [120-200 nm (GP 120/200), 200-280 nm (GP 200/280), and 280-360 nm (GP 280/360)] were fabricated by a thermal imprinting technique. These gradient nanopattern plates were designed to mimic the various sizes of nanotopography in the ECM and were used to screen the responses of human endothelial colony-forming cells (hECFCs). In this protocol, we describe the step-by-step procedure of fabricating gradient nanopattern plates for cell engineering, techniques of cultivating hECFCs from human peripheral blood, and culturing hECFCs on nanopattern plates.

Fabrication of Gradient Nanopattern by Thermal Nanoimprinting Technique and Screening of the Response of Human Endothelial Colony-forming Cells

Fabrication of Gradient Nanopattern by Thermal Nanoimprinting Technique and Screening of the Response of Human Endothelial Colony-forming Cells

Thermal behaviour of Peracetic Acid for the epoxydation of vegetable oils in the presence of catalyst

Abstract Peroxyacids are commonly used in chemical processing, synthesis and bleaching. Recently, they have been demonstrated to be very versatile for the epoxidation of unsaturated oil, aiming at the synthesis of polyepoxides (plasticizer, resins and adhesives). These processes are characterized by high yields and selectivity. However, due to their hazard and instability, the peroxy reactants are often obtained from the corresponding organic acid in situ by combination with Hydrogen Peroxide, in the presence of a mineral (Sulphuric or Phosphoric) acid as catalyst. The aim of this study is to analyse the thermal stability of the catalytic system used for vegetable oil peroxidation with the purpose of operating under safety conditions and then identify the safety parameters necessary to prevent the runaway reaction. This paper presents the study of the decomposition of peroxyacetic acid in aqueous phase by using a Thermal Screening Unit. Also, the effect of the presence of the acid catalysts was analysed.

Self-consistent gyrokinetic modeling of neoclassical and turbulent impurity transport

Trace impurity transport is studied with the flux-driven gyrokinetic GYSELA code (Grandgirard et al 2016 Comput. Phys. Commun. 207 35). A reduced and linearized multi-species collision operator has been recently implemented, so that both neoclassical and turbulent transport channels can be treated self-consistently on an equal footing. In the Pfirsch–Schlüter regime that is probably relevant for tungsten, the standard expression for the neoclassical impurity flux is shown to be recovered from gyrokinetics with the employed collision operator. Purely neoclassical simulations of deuterium plasma with trace impurities of helium, carbon and tungsten lead to impurity diffusion coefficients, inward pinch velocities due to density peaking, and thermo-diffusion terms which quantitatively agree with neoclassical predictions and NEO simulations (Belli et al 2012 Plasma Phys. Control. Fusion 54 015015). The thermal screening factor appears to be less than predicted analytically in the Pfirsch–Schlüter regime, which can be detrimental to fusion performance. Finally, self-consistent nonlinear simulations have revealed that the tungsten impurity flux is not the sum of turbulent and neoclassical fluxes computed separately, as is usually assumed. The synergy partly results from the turbulence-driven in–out poloidal asymmetry of tungsten density. This result suggests the need for self-consistent simulations of impurity transport, i.e. including both turbulence and neoclassical physics, in view of quantitative predictions for ITER.

Thermal modelling and screening method for skin pathologies using active thermography

This paper presents a novel screening approach of human skin pathologies using Active IR Thermography. The inputs of the proposed algorithm are the values of the physical parameters of the skin. Parameters are estimated based on dynamic thermographic measurements of human skin and the developed thermal model of the tissue. The calculations were based on the inverse thermal modelling. Classification was done using Support Vector Machine, Linear Discriminant Analysis and k-Nearest Neighbours classifiers. As an example, one presented the results of screening for psoriasis.

Sacral Skin Temperature Assessed by Thermal Imaging: Role of Patient Vascular Attributes.

The purpose of this study was to test the hypothesis that temperature differentials measured by thermal imaging of sacral versus a remote skin area in critically ill patients differentiate those with significant vascular disease and risk for pressure injury of the sacral area. Prospective cohort study. The sample comprised 100 patients (58 men, 42 women) with mean ± SD ages of 70.4 ± 14.4 and 74.0 ± 14.5 years, respectively, who were admitted to a cardiovascular intermediate care unit or a neurosurgical intensive care unit in the southeastern region of the United States. A commercially available thermal imaging system was used to obtain simultaneous standard photographic and infrared thermal images (11 × 14 inches) that included the patient's buttocks and a remote skin area after the patient was off-loaded for about 4 minutes. Images were processed to determine temperature differences between the sacral region (deemed to have an elevated risk for pressure injury) and a remote region of the skin located at least 10-cm proximal to the sacrum, with an average sacrum-to-remote distance of 17.9 ± 3.0 cm that was deemed to be at minimal risk. Prior measurements of healthy subjects showed that sacral skin was on average 0.75°C less than the remote skin site (ΔT =-0.75°C). For the present analysis, a threshold ΔTTH of twice that amount (ΔT =-1.5°C) or more was considered to put a patient at greater than normal risk based on the hypothesis that low sacral temperatures were associated with lowered blood perfusion issues of various clinical conditions. The vascular status of patients who equaled or exceeded this threshold was compared to the other patients. Thirty-two patients exceeded ΔTTH, with an average ΔT of -1.92°C ± 0.62°C. In 6 patients, ΔT was greater than +1.5°C, with average of +1.98°C ± 0.49°C. The remaining 63 patients had an average ΔT of 0.13°C ± 0.58°C. Chi-square analysis of the proportions of patients exceeding or not exceeding thresholds in relation to their known vascular disease status revealed no significant difference between these subgroups. Although infrared thermal screening may provide visually impressive and potentially useful images in some cases, the use of temperature differentials to detect patients at particularly high risk for pressure injury owing to local blood flow is not supported by results of this study.

Efficient one-pot three-component method for the synthesis of highly fluorescent coumarin-containing 3,5-disubstituted-2,6-dicyanoaniline derivatives under microwave irradiation

ABSTRACTA simple and concise approach to the synthesis of coumarin-containing highly fluorescent asymmetric/symmetric 3,5-diaryl/heteroaryl-2,6-dicyanoaniline derivatives are reported. The compounds were synthesized through base catalyzed three-component one-pot synthesis reaction of 2-(1-(7-(diethylamino)-2-oxo-2H-chromen-3-yl)ethylidene)malononitrile, aliphatic, aromatic/heteroaromatic aldehydes, and malononitrile in solvent-free reaction medium, catalyzed by piperidine under microwave irradiation method. The reaction gave the novel, highly fluorescent coumarin-containing 3,5-disubstituted-2,6-dicyanoaniline derivatives in good yields at 300 W, 80 °C in 2 min. This method provides several advantages; such as shorter reaction time, environmental friendliness, simple workup procedure, lower energy consumption and, generally, good yields with high purity. In addition, the synthesized compounds are fluorescently active dyes even in day light, except for compounds including nitro substituent, and show maximum absorption wavelengths (λabs.max) in the visible region in DMSO at room temperature. Thermal properties of all the synthesized compounds were also evaluated with thermal gravimetric analysis for usability as optic dye. Optical and thermal screening studies of the compounds showed that the dyes have excellent photophysical and thermal stability properties.

Effect of anisotropic thermal transport on the resistive plasma response to resonant magnetic perturbation field

Plasma response to the resonant magnetic perturbation (RMP) field is numerically investigated by an extended toroidal fluid model, which includes anisotropic thermal transport physics parallel and perpendicular to the total magnetic field. The thermal transport is found to be effective in eliminating the toroidal average curvature induced plasma screening (the so called Glasser-Green-Johnson, GGJ screening) in a slow toroidal flow regime, whilst having minor effect on modifying the conventional plasma screening regimes at faster flow. This physics effect of interaction between thermal transport and GGJ screening is attributed to the modification of the radial structure of the shielding current, which resulted from the plasma response to the applied field. The modification of the plasma response (shielding current, response field, plasma displacement, and the perturbed velocity) also has direct consequence on the toroidal torques produced by RMP. Modelling results show that thermal transport reduces the resonant electromagnetic torque as well as the torque associated with the Reynolds stress, but enhances the neoclassical toroidal viscous torque at slow plasma flow.