Rational strain design with minimal phenotype perturbation

Devising genetic interventions for desired cellular phenotypes remains challenging regarding time and resources. Kinetic models can accelerate this task by simulating metabolic responses to genetic perturbations. However, exhaustive design evaluations with kinetic models are computationally impractical, especially when targeting multiple enzymes. Here, we introduce a framework for efficiently scouting the design space while respecting cellular physiological requirements. The framework employs mixed-integer linear programming and nonlinear simulations with large-scale nonlinear kinetic models to devise genetic interventions while accounting for the network effects of these perturbations. Importantly, it ensures the engineered strain's robustness by maintaining its phenotype close to that of the reference strain. The framework, applied to improve the anthranilate production in E. coli, devises designs for experimental implementation, including eight previously experimentally validated targets. We expect this framework to play a crucial role in future design-build-test-learn cycles, significantly expediting the strain design compared to exhaustive design enumeration.

ADL-CDF: A Deep Learning Framework for COVID-19 Detection from CT Scans Towards an Automated Clinical Decision Support System

The emergence of deep learning has paved to solve many problems in the real world. COVID-19 pandemic, since the late 2019, has been affecting lives of people across the globe. Chest CT scan images are used to detect it and know its severity in patients. The problem with many existing solutions in COVID-19 detection using CT scan images is that inability to detect the infection when it is in initial stages. As the infection can exist on varied scales, there is need for more comprehensive approach that can ascertain the disease at all scales. Towards this end, we proposed a deep learning-based framework known as Automated Deep Learning-based COVID-19 Detection Framework (ADL-CDF). It does not need a human medical expert in diagnosis as it is capable of detecting automatically. The framework is assisted by two algorithms that involve image processing and deep learning. The first algorithm known as Region of Interest (ROI)-based Image Filtering (ROI-IF) which analyses given input CT scan images of a patient and discards the ones where ROI is missing. This algorithm minimizes time taken for processing besides reducing false positive rate. The second algorithm is known as Multi-Scale Feature Selection algorithm that fits into the deep learning framework's pipeline to leverage detection performance of the ADL-CDF. The proposed framework is evaluated against ResNet50V2 and Xception. Our empirical study revealed that our model outperforms the state of the art.

Paediatric dentists' knowledge of behavioural management principles in Tamil Nadu, India

AIM

Behaviour management is one of the essential skills of paediatric dentists. Appropriate use of behavioural principles helps the child in developing the skills and behaviours necessary to willingly undergo dental care, not hindered by undue anxiety or fear. However, very little is known about the knowledge of principles regarding behaviour management among paediatric dentists. Contingency management which is based on the principles of behaviour analysis is a widely accepted behavioural management technique and it includes reinforcement and punishment. The aim and objective of this study was to assess the knowledge of paediatric dentists regarding behavioural management principles related to contingency management.

MATERIALS AND METHODS

A cross- sectional survey was conducted among paediatric dental professionals and post-graduate students pursuing masters in paediatric dentistry across Tamil Nadu, India using Knowledge of Behavioural Principles as Applied to Children (KBPAC) questionnaire modified for the dental setting. The data were obtained, tabulated and statistically analysed using SPSS.

RESULTS

Responses were obtained from 130 participants, comprising 67 paediatric dental professionals and 63 post-graduate students. The overall average knowledge score was 40.72%. The mean knowledge level of paediatric dental professionals was (0.4378) versus (0.3597) among post-graduate students (p <0.05).

CONCLUSION

Knowledge of behavioural management principles related to contingency management among paediatric dentists in Tamil Nadu, India is low.

On The Influence Of Titanium Alloy Composition And Layer Thickness On The Mechanical Properties Of A Polyimide Substrate

Metal-polymer bilayers and multilayers are being increasingly used in the microelectronics industry. In many cases, the reliability of the device or the package is determined by the mechanical behavior of these composite layers. Finite element analyses are being widely used to model these systems. An accurate experimental understanding of the mechanical behavior of these systems would further enhance the usefulness of such analyses. The present study focuses on the mechanical behavior of composite bilayers consisting of polyimide and sputtered Ti and Ti alloy thin films. Tensile tests and stretch-deformation tests have been performed on bilayers consisting of a polyimide substrate sputter-coated individually with a 50 nm and a 500 nm Ti layer, a 500 nm Ti-Cu layer, and a 500 nm Ti-Ni layer. Tensile moduli, stresses for 0.2%, 2% and 15% offset strains, and strains to failure have been obtained and compared. These values are discussed with reference to the known mechanical properties of the individual layers in the composite material.

The role of dispersed nocardioform filaments in activated sludge foaming

Activated sludge foaming caused by filamentous microorganisms is a major wastewater treatment plant operating problem. This paper presents the results of an investigation of the role of dispersed nocardioforms in activated sludge foaming. Dispersed nocardioforms had a greater propensity for foaming than floc-bound nocardioforms. The mode of effluent withdrawal from an aeration basin plays a major role in determining the relative proportion of dispersed and floc-bound nocardioforms in the activated sludge. Reactors with "trapping" features (sub-surface mixed liquor withdrawal) had significantly higher dispersed nocardioform populations than reactors with "non-trapping" features (surface mixed liquor withdrawal). High dispersed nocardioform filament concentrations were correlated with a high propensity for foaming. Cationic polymer and polyaluminum chloride reduced foaming by flocculating dispersed nocardioforms, thereby converting them to floc-bound nocardioforms. Low non-ionic surfactant concentrations changed the relative proportions of dispersed and floc-bound nocardioforms by deflocculating floc-bound filaments and converting them to the dispersed growth form. This could act as a trigger for initiating the rapid-onset nocardioform foaming events observed at activated sludge plants.

FTIR and FTRaman spectroscopic investigation of 2-bromo-4-methylaniline using ab initio HF and DFT calculations

The FTIR and FTRaman spectra of 2-bromo-4-methyl aniline (2-B-4-MA) molecule have been recorded using Brucker IFS 66V spectrometer in the range of 4000-100 cm(-1). The molecular geometry and vibrational frequencies in the ground state are calculated using the Hartree-Fock (HF) and B3LYP with 6-31+G*(d, p), 6-311+G*(d, p) and 6-311++G* (d, p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The isotropic HF and DFT analysis showed good agreement with experimental observations. Comparison of the fundamental vibrational frequencies with calculated results by HF and B3LYP methods indicates that B3LYP/6-311++G* (d, p) is superior to HF/6-31+G* for molecular vibrational problems. The complete data of this title compound provide the information for future development of substituted aniline. The influences of bromine atom, methyl group and amine group on the geometry of benzene and its normal modes of vibrations have also been discussed.

A balancing act: the consulting engineers' pragmatic view of process modelling

Modelling: what do we know, what do we want to know and why? The practical application of models to real projects is often circular because these questions weren't asked prior to making the decision to model the plant under study. Modelling wastewater treatment plants can provide insight into the inner workings of the process that might not be attainable any other way, but is that added process knowledge always needed or necessary and what criteria does one use to determine the level of effort required? These complex modelling decisions require education, communication, and improved understanding amongst both modellers and clients. This submission explores the use of models by consultants for consulting purposes and the balancing acts (time versus knowledge and cost versus benefit) that the consulting engineer must manage when embarking on any modelling project.

Human fibroblast growth factor 20 (FGF-20; CG53135-05): a novel cytoprotectant with radioprotective potential

The aim was to evaluate the radioprotective properties of recombinant human fibroblast growth factor 20 (FGF-20; CG53135-05) in vitro and in vivo and to examine its effects on known cellular pathways of radioprotection. Relative transcript levels of the cyclooxygenase 2 (COX2), Mn-super oxide dismutase (SOD), CuZn-SOD, extracellular (EC)-SOD, nuclear respiratory factor 2 (Nrf2), glutathione peroxidase 1 (GPX1) and intestinal trefoil factor 3 (ITF3) genes, which are involved in radiation response pathways, were assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) in NIH/3T3, IEC18, CCD-18Co, CCD-1070sk and human umbilical vein endothelial cells (HUVEC) cells exposed to FGF-20. Activation of the radioprotective signal transduction pathways initiating with the serine/threonine Akt kinase and the extracellular regulated kinase (ERK) were analysed. Levels of intracellular hydrogen peroxide and cytosolic redox potential were also measured in irradiated and unirradiated cells in the presence or absence of FGF-20. The effects of FGF-20 on cell survival in vitro following ionizing radiation were evaluated using clonogenic assays. To test the potential activity of FGF-20 as a radioprotectant in vivo, mice were administered a single dose of FGF-20 (4 mg kg(-1), intraperitoneally (i.p.) 1 day before lethal total-body irradiation and evaluated for survival. In vitro exposure to FGF-20 increased expression of the Nrf2 transcription factor and oxygen radical scavenging enzymes such as MnSOD, activated signal transduction pathways (ERK and Akt) and resulted in increased survival of irradiated cells in vitro. FGF-20 treatment also resulted in a concomitant reduction in intracellular levels of injurious reactive oxygen species (ROS) following acute ionizing irradiation. Finally, prophylactic administration of FGF-20 to mice before potentially lethal, whole-body X-irradiation led to significant increases in overall survival. FGF-20 reduced the lethal effects of acute ionizing radiation exposure in cells by up-regulating important signalling and free radical scavenging pathways. Survival-sparing effects of FGF-20 prophylaxis in acutely irradiated mice presumably are elicited by comparable mechanisms. These results indicate that FGF-20, has significant radioprotective attributes with potential applications in clinical and non-clinical exposure settings.

Effect of thermal treatment on carbon-doped silicon oxide low dielectric constant materials

Carbon-doped silicon oxide (SiOCH) low dielectric constant (low-k) material is a good candidate for advanced interconnect technology. Good thermal stability of the dielectric is required due to the many thermal processes involved during IC fabrication. The thermal stability of tetramethylcyclotetrasiloxane (TMCTS) based plasma-enhanced chemical vapor deposition (PECVD) carbon doped low-k material with annealing temperature from 400 to 800 degrees C in N2 was studied. The thermal stability temperature of TMCTS based carbon doped low-k material is 600 degrees C. Above 600 degrees C annealing, the thermal energy can break Si-CH3, Si-C, Si-H, and C-H bonds leading to outgasing, which results in film composition change, weight loss, and thickness shrinkage. Film composition changes, especially carbon loss and oxygen incorporation, can degrade its reliability extremely. Carbon is desorbed in the form of CH4, CO, and other hydrocarbon.

A simplified method for the determination of blood lactic acid levels in occupational health practice

Blood lactate assays are now widely used as measures of oxygen debt, especially in the areas of assessment of anaerobic power; assessment of fatigue; VO2(max) end-point determination, and rationalisation of work-rest cycles. A need exists for a method which will meet the following criteria: simplicity--single, small samples; rapidity, and feasibility with easily available instrument and chemicals. In order to develop such a method, the standard Barker and Summerson method was modified so as to use 0.02 ml of blood sample, and the following tests were carried out on 25 subjects at rest, and various levels of work: paired comparisons on analysis by macro and micro methods on the same sample of blood; paired comparisons on venous and capillary (fingertip) samples. In both cases, the paired values showed high correlation (0.99) and highly significant differences of means (P = 0.01 and 0.001, respectively). The regression equations obtained were also highly significant (P = 0.001). The combined equation was Y = 0.9655 X -0.4366; samples taken 2,4,5,6 and 10 mins after work showed that peak occurred in the 4th min sampling (2 vs 4 and 4 vs 6 min means significantly different at P = 0.05, and analysis of variance significant at (P = 0.001). It may be concluded that drawing, fingertip sample 4 mins after the end of work, analysing by the micro method, and using the regression equation will give the true peak blood lactate level, and satisfy the systems criteria defined.