High Intensity Pulsed Light Emitting Diode (LED) Treatment for Simultaneous Salmonella Inactivation and Drying of Wheat Flour and Pet Food

According to the world health organization, almost 600 million people, or 1 in 10 people suffer from foodborne illnesses globally. Food industry uses several intervention methods to produce safe food products however, cases of food recalls and outbreaks due to microbial pathogens keep increasing every year. High intensity light pulses, emitted from Light Emitting Diode (LED) have the potential to reduce microbial pathogens and dry food products. The overall research objective of this thesis was to develop a LED reactor and determine the efficacy of high intensity light pulses with specific wavelengths to inactivate Salmonella and dry food products simultaneously, inside a newly built LED reactor. The first part of this research used light pulses with 275, 365, 395, and 455 nm wavelengths, emitted from LEDs to inactivate a 5 strains cocktail of Salmonella in wheat flour at 40%, 75% and 90% environmental relative humidity (RH) conditions. The 60 min treatment of the wheat flour using 275, 365, 395, and 455 nm light pulses at 25°C and 75% RH resulted in 1.07, 2.42, 3.67, and 2.64 log reductions in Salmonella, respectively. For the same energy dosage of 1199 J/cm2, treatments using 365, 395, and 455 nm light pulses resulted in 2.22, 2.48, and 1.61 log reductions in Salmonella in wheat flour, respectively. Environmental RH did not have significant influence (p ≥ 0.05) on Salmonella inactivation in wheat flour during LED treatments. Significant temperature increase resulted, decrease in water activity and drying of wheat flour during LED treatments with 275, 365, 395, and 455 nm light pulses. In the second part of this reserch, an LED reactor using 395 nm light pulses with a vibratory platform and mild hot air fluidization was developed to achieve simultaneous decontamination and drying of food products. Pet food pellets were inoculated with two strain cocktail of Salmonella and treated in three modes: 1. using LED treatment alone, 2. vibration + mild hot air (50 oC) fluidization, 3. inside LED reactor (LED treatment + vibrations + mild hot air (50 oC) fluidization). The highest average reduction of 2.26 log was observed after 30 min treatment of pet food pellets using the LED reactor. The water content of pet food pellets decreased from 0.27 to 0.06 kg water/kg dry solids, while the water activity decreased from 0.9 to 0.44 after 30 min treatment using mode 3, showing the fast drying efficacy of the LED reactor. Page and Weibull models were fit to describe the pet food drying kinetics while log-linear and Weibull models were used to fit the Salmonella inactivation kinetics. Significant lipid oxidation in pet food pellets was observed during LED treatment. The results suggest that the LED treatment is a promising method for achieving simultaneous Salmonella inactivation and drying of food products. An LED-based process can be developed in the future at the industrial level to achieve drying and decontamination of food products in a single processing step, with the integration of approaches to reduce product oxidation

Exploring Noncovalent Protease Inhibitors for the Treatment of Severe Acute Respiratory Syndrome and Severe Acute Respiratory Syndrome-Like Coronaviruses.

Over the last 20 years, both severe acute respiratory syndrome coronavirus-1 and severe acute respiratory syndrome coronavirus-2 have transmitted from animal hosts to humans causing zoonotic outbreaks of severe disease. Both viruses originate from a group of betacoronaviruses known as subgroup 2b. The emergence of two dangerous human pathogens from this group along with previous studies illustrating the potential of other subgroup 2b members to transmit to humans has underscored the need for antiviral development against them. Coronaviruses modify the host innate immune response in part through the reversal of ubiquitination and ISGylation with their papain-like protease (PLpro). To identify unique or overarching subgroup 2b structural features or enzymatic biases, the PLpro from a subgroup 2b bat coronavirus, BtSCoV-Rf1.2004, was biochemically and structurally evaluated. This evaluation revealed that PLpros from subgroup 2b coronaviruses have narrow substrate specificity for K48 polyubiquitin and ISG15 originating from certain species. The PLpro of BtSCoV-Rf1.2004 was used as a tool alongside PLpro of CoV-1 and CoV-2 to design 30 novel noncovalent drug-like pan subgroup 2b PLpro inhibitors that included determining the effects of using previously unexplored core linkers within these compounds. Two crystal structures of BtSCoV-Rf1.2004 PLpro bound to these inhibitors aided in compound design as well as shared structural features among subgroup 2b proteases. Screening of these three subgroup 2b PLpros against this novel set of inhibitors along with cytotoxicity studies provide new directions for pan-coronavirus subgroup 2b antiviral development of PLpro inhibitors

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

ALTERNATE WETTING AND DRYING TECHNIQUE AND ITS IMPACTS ON RICE PRODUCTION

The agriculture sector has been facing challenges due to climate change particularly increasing global water scarcity which threatens irrigated low land rice production. Alternate Wetting and drying (AWD) is a water management system where rice fields are not continuously submerged and the fields are allowed to dry intermittently during the rice-growing period. AWD technique is a necessity for modern farming of rice as it is profitable over the continuous flooding irrigation system which prevents the wastage of scarce and vital water resources, irrigation cost and protects the environment from degradation. It also protects human health from diseases like Malaria as there is an absence of continuous flooding for the mosquito to lay eggs. It helps to enhance food security by increasing the production, nutrient content, and minimizing the toxic elements in rice. However, if this technique is not done properly in the field from time to time, we can also get negative impacts. It varies according to soil condition, irrigation timing, environment, etc.</jats:p

EFFECTS OF CLIMATE CHANGE ON AGRICULTURE AND ITS MITIGATION THROUGH CLIMATE SMART AGRICULTURE PRACTICES IN NEPAL

Climate change has caused serious effect on agriculture production. The global population is increasing and to meet their demand for fuel, food, and fiber, Farmer should adopt sustainable agriculture practices which provides resilience to climate change and uplifts the farmers’ livelihood. Climate-smart agriculture practices are taken as eco-friendly practices that help to enhance production sustainably with minimum effect on resources and environments. These practices include No-tillage, reduced tillage, Intercropping, integrated pest management, Rainwater harvesting, use of information and communication technology, etc. As women are an integral part of agriculture production and are more vulnerable to climate change, the Gender-responsive approach needs to be addressed which helps to close the gender gap in agriculture. Nepal, as a vulnerable country in terms of climate change, is adopting different programs and policies at the national and local level to tackle climate change. Climate-smart villages(CSV) in Nepal are practicing different CSA practices at the farm level to secure foods and livelihoods.</jats:p