scholarly journals A hierarchical approach to model decision making: a study in chemotactic behavior ofEscherichia coli

2019 ◽  
Author(s):  
Safar Vafadar ◽  
Kaveh Kavousi ◽  
Hadiseh Safdari ◽  
Ata Kalirad ◽  
Mehdi Sadeghi

AbstractReducing the complex behavior of living entities to its underlying physical and chemical processes is a formidable task in biology. Complex behaviors can be characterized as decision making: the ability to process the incoming information via an intracellular network and act upon this information to choose appropriate strategies. Motility is one such behavior that has been the focus many modeling efforts in the past. Our aim is to reduce the chemotactic behavior in E. coli to its molecular constituents in order to paint a comprehensive and end-to-end picture of this intricate behavior. We utilize a hierarchical approach, consisting of three layers, to achieve this goal: at the first level, chemical reactions involved in chemotaxis are simulated. In the second level, the chemical reactions give rise to the mechanical movement of six independent flagella. At the last layer, the two lower layers are combined to allow a digital bacterium to receive information from its environment and swim through it with verve. Our results are in concert with the experimental studies concerning the motility of E. coli cells. In addition, we show that our detailed model of chemotaxis is reducible to a non-homogeneous Markov process.

2018 ◽  
Author(s):  
Camilla Kao ◽  
Russell Furr

Conveying safety information to researchers is challenging. A list of rules and best practices often is not remembered thoroughly even by individuals who want to remember everything. Researchers in science thinking according to principles: mathematical, physical, and chemical laws; biological paradigms. They use frameworks and logic, rather than memorization, to achieve the bulk of their work. Can safety be taught to researchers in a manner that matches with how they are trained to think? Is there a principle more defined than "Think safety!" that can help researchers make good decisions in situations that are complex, new, and demanding?<div><br></div><div>Effective trainings in other professions can arise from the use of a mission statement that participants internalize as a mental framework or model for future decision-making. We propose that mission statements incorporating the concept of <b>reducing uncertainty</b> could provide such a framework for learning safety. This essay briefly explains the definition of <b>uncertainty</b> in the context of health and safety, discusses the need for an individual to <b>personalize</b> a mission statement in order to internalize it, and connects the idea of <b>greater control</b> over a situation with less uncertainty with respect to safety. The principle of reducing uncertainty might also help <b>non-researchers</b> think about safety. People from all walks of life should be able to understand that more control over their situations provides more protection for them, their colleagues, and the environment.</div>


Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 221
Author(s):  
Rafał Tytus Bray ◽  
Katarzyna Jankowska ◽  
Eliza Kulbat ◽  
Aneta Łuczkiewicz ◽  
Aleksandra Sokołowska

The paper presents the results of research on the use of ultrafiltration, using membranes of 200 and 400 kDa separation, for disinfection of municipal treated wastewater. The research was conducted on a fractional technical scale using real municipal treated wastewater from two large wastewater treatment plants treating most of the wastewater over the one-million polycentric Gdańsk agglomeration (1.2 million inhabitants). UF 200 kDa and UF 400 kDa processes enabled further improvement of the physical and chemical parameters of treated wastewater. Total phosphorus (to below 0.2 mg/L–UF 200 kDa, 0.13 mg/L–UF 400 kDa) and turbid substances (to below 0.2 mg/L, both membranes) were removed in the highest degree. COD was reduced efficiently (to below 25.6 mgO2/L–UF 200 kDa, 26.8 mgO2/L–UF 400 kDa), while total nitrogen was removed to a small extent (to 7.12 mg/L–UF 200 kDa and 5.7 mg/L–UF 400 kDa. Based on the reduction of indicator bacteria; fecal coliforms including E. coli (FC) and fecal enterococci (FE) it was found that the ultrafiltration is an effective method of disinfection. Not much indicator bacterial were observed in the permeate after processes (UF 200 kDa; FC—5 CFU/L; FE—1 CFU/L and UF 400 kDa; FC—70 CFU/L; FE—10 CFU/L. However, microscopic analysis of prokaryotic cells and virus particles showed their presence after the application of both membrane types; TCN 3.0 × 102 cells/mL–UF 200 kDa, 5.0 × 103 cells/mL–UF 400 kDa, VP 1.0 × 105/mL. The presence of potentially pathogenic, highly infectious virus particles means that ultrafiltration cannot be considered a sufficient disinfection method for treated wastewater diverted for reuse or discharged from high load wastewater treatment plants to recreational areas. For full microbiological safety it would be advisable to apply an additional disinfection method (e.g., ozonation).


2021 ◽  
pp. 001112872110077
Author(s):  
Lin Liu ◽  
R.R. Dunlea ◽  
Besiki Luka Kutateladze

The literature on sentencing has devoted ample consideration to how prosecutors and judges incorporate priorities such as retribution and public safety into their decision making, typically using legal and extralegal characteristics as analytic proxies. In contrast, the role of case processing efficiency in determining punishment outcomes has garnered little attention. Using recent data from a large Florida jurisdiction, we examine the influence of case screening and disposition timeliness on sentence outcomes in felony cases. We find that lengthier case processing time is highly and positively associated with punitive outcomes at sentencing. The more time prosecutors spend on a case post-filing, the more likely defendants are to receive custodial sentences and longer sentences. Case screening time, although not affecting the imposition of custodial sentences, is also positively associated with sentence length. These findings are discussed through the lens of instrumental and expressive functions of punishment.


2021 ◽  
Vol 2 (1) ◽  
pp. 168-186
Author(s):  
Bahareh Vafakish ◽  
Lee D. Wilson

The nanoreactor concept and its application as a modality to carry out chemical reactions in confined and compartmentalized structures continues to receive increasing attention. Micelle-based nanoreactors derived from various classes of surfactant demonstrate outstanding potential for chemical synthesis. Polysaccharide (glycan-based) surfactants are an emerging class of biodegradable, non-toxic, and sustainable alternatives over conventional surfactant systems. The unique structure of glycan-based surfactants and their micellar structures provide a nanoenvironment that differs from that of the bulk solution, and supported by chemical reactions with uniquely different reaction rates and mechanisms. In this review, the aggregation of glycan-based surfactants to afford micelles and their utility for the synthesis of selected classes of reactions by the nanoreactor technique is discussed. Glycan-based surfactants are ecofriendly and promising surfactants over conventional synthetic analogues. This contribution aims to highlight recent developments in the field of glycan-based surfactants that are relevant to nanoreactors, along with future opportunities for research. In turn, coverage of research for glycan-based surfactants in nanoreactor assemblies with tailored volume and functionality is anticipated to motivate advanced research for the synthesis of diverse chemical species.


2018 ◽  
Vol 62 (10) ◽  
Author(s):  
Shehara M. Mendis ◽  
Shawn Vasoo ◽  
Brian D. Johnston ◽  
Stephen B. Porter ◽  
Scott A. Cunningham ◽  
...  

ABSTRACT Escherichia coli bacteremia is caused mainly by sequence type complex 131 (STc131) and two clades within its fluoroquinolone-resistance-associated H30 subclone, H30R1 and H30Rx. We examined clinical and molecular correlates of E. coli bacteremia in two geographically distinct centers. We retrospectively studied 251 unique E. coli bloodstream isolates from 246 patients (48 from the Mayo Clinic, Rochester, MN [MN], and 198 from Tan Tock Seng Hospital, Singapore [SG]), from October 2013 through March 2014. Isolates underwent PCR for phylogroup, STc, blaCTX-M type, and virulence gene profiles, and medical records were reviewed. Although STc131 accounted for 25 to 27% of all E. coli bacteremia isolates at each site, its extended-spectrum-β-lactamase (ESBL)-associated H30Rx clade was more prominent in SG than in MN (15% versus 4%; P = 0.04). In SG only, patients with STc131 (versus other E. coli STc isolates) were more likely to receive inactive initial antibiotics (odds ratio, 2.8; P = 0.005); this was true specifically for patients with H30Rx (odds ratio, 7.0; P = 0.005). H30Rx comprised 16% of community-onset bacteremia episodes in SG but none in MN. In SG, virulence scores were higher for H30Rx than for H30R1, non-H30 STc131, and non-STc131 isolates (P < 0.02 for all comparisons). At neither site did mortality differ by clonal status. The ESBL-associated H30Rx clade was more prevalent and more often of community onset in SG, where it predicted inactive empirical treatment. The clonal distribution varies geographically and has potentially important clinical implications. Rapid susceptibility testing and clonal diagnostics for H30/H30Rx might facilitate earlier prescribing of active therapy.


2018 ◽  
Vol 35 (1) ◽  
pp. 39-50
Author(s):  
Helen Sisson ◽  
Yvonne Wilkinson

The human papillomavirus (HPV) vaccine is a key intervention in the prevention of HPV infection and associated cancers. This review emphasizes the importance of understanding what influences decision-making about this vaccine. Guided by the work of Whittemore and Knafl, and Pluye and Hong, we identified 25 studies, from which four prominent themes emerged: fear and risk, pain, parental involvement, and involvement of others. Fear of cervical cancer was a strong motivation to receive the vaccine, and the extent of parental involvement also had an impact on decision-making. Recommendations to receive the vaccine by health-care providers were also an important influence. School nurses are fundamental to the promotion and delivery of the HPV vaccine and should stress the significant role that it plays in the prevention of cancer. Additionally, school nurses should ensure that discussions about HPV infection and vaccine include parents where appropriate and should distinctly recommend vaccination to those eligible.


2021 ◽  
Vol 266 ◽  
pp. 03005
Author(s):  
D. N. Shabanov ◽  
E. Trambitsky ◽  
E. Borovkova

This article describes the structural studies of a cement conglomerate, its evolution from the moment of formation to the loss of operational properties. Physical and chemical phenomena and interactions of various elements of cement stone are considered. The study of its rheology includes creating a virtual model and monitoring the formation of the structure of cement pastes by acoustic emission (AE). The results of combined experimental studies to determine the residual life of cement stone samples using AE and tensometry methods are presented. The authors created a complex for monitoring the stress-strain state of artificial conglomerates, which includes both internal and acoustic sensors.


Author(s):  
M.Yu. KOSTENKO ◽  
G. RYMBALOVICH ◽  
I.N. GORYACHKINA ◽  
R.V. BEZNOSYUK ◽  
G.A. BORISOV

Целью исследований явилась оценкавлияния обработки горячим туманом биологического препарата Азотовит и гуминовых продуктовГумат калия, Экоростсемян ячменя перед посевом, а также сравнение результатов с общепринятымитехнологиями обработки с помощью протравителя семян этими же препаратами. Для полноты исследований обработку производили и химическим препаратом Атик. Высокодисперсный аэрозоль получали с помощью генератора горячего тумана GreenFogBF-130.Обработку производилис помощью устройства с наклонными полками, по которым зерно многократно пересыпалось под действием силы тяжести и подвергалось перемешиванию и воздействию горячего тумана. В результате разницы температур холодного семенного материала и горячего тумана происходил фазовый переход тумана в жидкость, что позволяло получить тонкую плёнку на обрабатываемой поверхности семянячменя.Это способствовало обеззараживанию и активизации физико-химических процессов в зерне. Экспериментальные исследования включали восемь вариантов обработки и один без обработки (контроль). Оценивались результаты продуктивности и структура урожая: число растений на 1 м2, число сорных растений на 1 м2, число продуктивных стеблей (колосьев) на 1 м2, кустистость на 1 м2, продуктивная кустистость на 1 м2,среднее число зерен в колосе, масса 1000 зерен, высота стеблей, биологическая урожайность. В соответствии с ГОСТ 53900-2010 Ячмень кормовой, ГОСТ 5060-86 Ячмень пивоваренный, ГОСТ 28672-90 Ячмень.Требования при заготовках и поставках,ТРТС 021/2011 О безопасности пищевой продукции из качественных показателей рассматривались массовая доля влаги, массовая доля протеина, массовая доля клетчатки, массовая доля сахара, массовая доля жира, массовая доля золы, массовая доля крахмала, обменная энергия, крупность, мелкие зерна, сорная и зерновая примесь, фузариозные зерна, общая токсичность, микотоксиндезоксиниваленол (DON). Лучшие показатели были получены в результате аэрозольной обработки гуминовыми продуктами Гумат калия и Экорост.The aim of the research was to assess the effect of hot mist treatment of the biological preparation Azotovit and humic products potassium HUMATE, barley seeds Ecorost before sowing, as well as to compare the results with conventional technologies of treatment with the help of seed protectant with the same drugs. To complete the research and produce treatment chemicals of Atik. The highly dispersed aerosol was obtained using The greenfogbf-130 hot mist generator. The treatment was carried out using a device with inclined shelves, on which the grain was repeatedly poured under the influence of gravity and was subjected to mixing and the influence of hot fog. As a result of the temperature difference between the cold and hot mist of the seed material, a phase transition of the mist into a liquid occurred, which allowed to obtain a thin film on the treated surface of the barley seeds. This contributed to the disinfection and activation of physical and chemical processes in the grain. Experimental studies included eight treatment options and one without treatment (control). The results of productivity and crop structure were evaluated: the number of plants per 1 m2, the number of weeds per 1 m2, the number of productive stems (ears) per 1 m2, bushiness per 1 m2, productive bushiness per 1 m2, the average number of grains per ear, the weight of 1000 grains, the height of stems, biological yield. In accordance with GOST 53900-2010 barley fodder, barley brewing GOST 5060-86, GOST 28672-90 Barley. Requirements for procurement and supply, TR CU 021/2011 on food safety from qualitative indicators considered the mass fraction of moisture, mass fraction of protein, mass fraction of fiber, mass fraction of sugar, mass fraction of fat, mass fraction of ash, mass fraction of starch, metabolic energy, size, small grains, weed and grain admixture, Fusarium grains, total toxicity, mycotoxindeoxynivalenol (don). The best results were obtained as a result of aerosol treatment with humic products potassium HUMATE and Ecorost.


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