Physics-informed machine learning: case studies for weather and climate modelling.

Machine learning (ML) provides novel and powerful ways of accurately and efficiently recognizing complex patterns, emulating nonlinear dynamics, and predicting the spatio-temporal evolution of weather and climate processes. Off-the-shelf ML models, however, do not necessarily obey the fundamental governing laws of physical systems, nor do they generalize well to scenarios on which they have not been trained. We survey systematic approaches to incorporating physics and domain knowledge into ML models and distill these approaches into broad categories. Through 10 case studies, we show how these approaches have been used successfully for emulating, downscaling, and forecasting weather and climate processes. The accomplishments of these studies include greater physical consistency, reduced training time, improved data efficiency, and better generalization. Finally, we synthesize the lessons learned and identify scientific, diagnostic, computational, and resource challenges for developing truly robust and reliable physics-informed ML models for weather and climate processes. This article is part of the theme issue 'Machine learning for weather and climate modelling'.

Silver coated bioactive glass particles for wound healing applications.

Bioactive glass particles (0.42SiO(2)-0.15CaO-0.23Na(2)O-0.20ZnO) of varying size (<90 µm and 425-850 µm) were synthesized and coated with silver (Ag) to produce Ag coated particles (PAg). These were compared against the uncoated analogous particles (Pcon.). Surface area analysis determined that Ag coating of the glass particles resulted in increased the surface area from 2.90 to 9.12 m(2)/g (90 µm) and 1.09-7.71 m(2)/g (425-850 µm). Scanning electron microscopy determined that the Ag coating remained at the surface and there was little diffusion through the bulk. Antibacterial (Escherichia coli--13 mm and Staphylococcus epidermidis--12 mm) and antifungal testing (Candida albicans--7.7 mm) determined that small Ag-coated glass particles exhibited the largest inhibition zones compared to uncoated particles. pH analysis determined an overall higher pH consider in the smaller particles, where after 24 h the large uncoated and Ag coated particles were 8.27 and 8.74 respectively, while the smaller uncoated and Ag coated particles attained pH values of 9.63 and 9.35 respectively.

Antimicrobial Effects of Different Synbiotic Compounds against Pathogenic Bacteria Isolated from Beef, Mutton, and Chicken.

Today, there has been a growing interest in synbiotic usage in the food industry to solve the problems related to food contaminations. The present study aimed to evaluate the antibacterial effects of nine symbiotic compounds on bacteria isolated from different meat types. Pathogenic bacteria were isolated from 60 different meat samples. Then, the antibacterial effects of nine synbiotic components were assessed against isolated bacteria using well diffusion and radial streak methods. In addition, minimum inhibitory and minimum bactericidal concentrations of each synbiotic formulation were determined. The highest antibacterial activity against Listeria monocytogenes and Staphylococcus aureus was for synbiotic compounds consisting of Streptococcus salivarius, raffinose, inulin, and trehalose, respectively. Furthermore, the highest antibacterial efficacies against Escherichia coli and Salmonella were for synbiotic formulations consisting of Bacillus cereus and inulin, raffinose, and trehalose, respectively. In conclusion, synbiotic formulations containing S. salivarius and B. cereus may be an alternative approach to preventing food-borne pathogens.

Ultrastrong and Flexible Hybrid Hydrogels based on Solution Self-Assembly of Chitin Nanofibers in Gelatin Methacryloyl (GelMA).

We demonstrate ultrastrong and flexible hydrogels by self-assembling chitin nanofiber in the presence of gelatin methacryloyl. We tune the mechanical properties of the hydrogel with chitin nanofiber content and show proof-of-concept applications in engineering vascular tissue.

The effect of cyclosporine A and trifluoperazine on amylase secretion from rat parotid glands in vitro.

In the present study the effects of trifluoperazine (TFP) and/or cyclosporine A (CsA) on the amylase secretion of rat parotid gland lobules were investigated. Cyclosporine A, in doses of 10(-6), 3 x 10(-6) and 10(-5) M, caused a dose-dependent reduction in amylase secretion. Trifluoperazine, a well-established calmodulin antagonist, also significantly reduced amylase secretion by the gland, confirming that the secretion is calmodulin dependent. Concurrent administration of CsA and TFP showed a marked positive interaction in reducing the secretion of amylase. Thus, the hypothesis that CsA may have Ca2+/calmodulin antagonistic properties is supported by the present study.

Cadmium chloride exhibits a profound toxic effect on bacterial microflora of the mice gastrointestinal tract.

Cadmium (Cd²(+)), a naturally occurring heavy metal, is an important environmental pollutant and a potent toxicant to bacteria. The gastrointestinal (GI) tract microflora has a marked capacity to cope with the increased load of ingested metals. However, heavy metals may have harmful effects on GIT microflora. Under the conditions of experimental exposure to cadmium, changes in the population of intestinal microflora in healthy mice were examined. Five experimental groups received 23 to 50 mg kg⁻¹ cadmium in drinking water and control group was given water free from cadmium for 45 days. Intestinal contents and biopsy samples were aseptically collected and bacterial counts were performed. The microflora of the intestine in control group was represented by bacteria of the genera Bacillus cereus, Lactobacillus spp., Clostridium spp., Escherichia coli, Klebsiella spp., Pseudomonas spp., Enterococcus spp. and Proteus spp. As the result of dysbiosis induced by the introduction of cadmium, a sharp decrease in the population of all microbial species in the intestine was observed. The deleterious effect of cadmium appeared to be less in the large intestine and rectum than that of small intestine, suggesting a site-specific influence of cadmium. The gram-negative bacteria tested were less sensitive to cadmium compared to the gram-positive bacteria because of their possible different ability to uptake the metal ions.

Tunable diode-laser measurement of carbon monoxide concentration and temperature in a laminar methane-air diffusion flame.

The application of tunable diode lasers for in situ diagnostics in laminar hydrocarbon diffusion flames is demonstrated. By the use of both direct-absorption and wavelength-modulation (second-derivative) techniques, carbon monoxide concentrations and the local flame temperature are determined for a laminar methane-air diffusion flame supported on a Wolfhard-Parker slot burner. In both cases the results are found to be in excellent agreement with prior measurements of these quantities using bothrobe and optical techniques.