Local Piezoelectric Properties of Doped Biomolecular Crystals

Piezoelectricity is the ability of certain crystals to generate mechanical strain proportional to an external electric field. Though many biomolecular crystals contain polar molecules, they are frequently centrosymmetric, signifying that the dipole moments of constituent molecules cancel each other. However, piezoelectricity can be induced by stereospecific doping leading to symme-try reduction. Here, we applied piezoresponse force microscopy (PFM), highly sensitive to local piezoelectricity, to characterize( 010) faces of a popular biomolecular material, α-glycine, doped with other amino acids such as L-alanine and L-threonine as well as co-doped with both. We show that, while apparent vertical piezoresponse is prone to parasitic electrostatic effects, shear piezoelectric activity is strongly affected by doping. Undoped α-glycine shows no shear piezoelectric response at all. The shear response of the L-alanine doped crystals is much larger than those of the L-threonine doped crystals and co-doped crystals. These observations are rationalized in terms of host–guest molecule interactions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research (RFBR), grant № 3-16492, and directly by the RFBR (grant № 19-52-06004 MNTI_a). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU was used. A.K. acknowledges the Ministry of Science and Higher Education of the Russian Federation for the support under the project № 075-15-2021-588 from 1.06.2021. The work was also developed within the scope of the project CICECO at the Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. I.L. expresses his gratitude to the Estate of Olga Klein–Astrachan fund, grant № 721977

The sero-epidemiology of Coxiella burnetii (Q fever) across livestock species and herding contexts in Laikipia County, Kenya

Coxiella burnetii, the causative agent of Query fever (Q fever), is among the most highly infectious zoonotic pathogens transmitted among livestock, with chronic effects challenging to veterinary and medical detection and care systems. Transmission among domestic livestock species can vary regionally due to herd management practices that determine which livestock species are raised, whether or not livestock are in contact with wildlife, and the susceptibility of these livestock to infection. To explore how different livestock management practices are associated with the risk of infection in multispecies environments, we carried out a comparative study of three types of herd management systems in the central Kenyan county of Laikipia: agro‐commercial, mixed conservancy/commercial, and smallholder ranches. We tested C. burnetii antibody seroprevalence in four common livestock species. Across all management types, the highest seroprevalence was in camels (20%), followed by goats (18%), sheep (13%), and cattle (6%). We observed a lower odds of testing seropositive for young compared to adult animals (adjusted OR = 0.44 [95% CI 0.24, 0.76]), and for males compared to females (adjusted OR = 0.52 [95% CI 0.33, 0.80]). Animals from mixed conservancy/commercial and smallholder operations had a higher odds of testing seropositive compared to animals from agro‐commercial ranches (adjusted OR = 5.17 [95% CI 2.71, 10.44] and adjusted OR = 2.21 [95% CI 1.17, 4.43] respectively). These data suggest that herd management practices might affect the transmission dynamics of C. burnetiiin arid African ecosystems like those seen in Kenya where several transmission modes are possible, risk of drought has promoted new livestock species such as camels, and multiple wildlife species may co‐occur with livestock on the landscape. Further longitudinal studies are needed to disentangle the mechanisms underlying these patterns, and further explore transmission patterns between wildlife, domestic animal, and human populations

Surface piezoelectricity and pyroelectricity in centrosymmetric materials: A case of α-glycine

Surface pyroelectricity and piezoelectricity induced by water incorporation during growth in α-glycine were investigated. Using the periodic temperature change technique, we have determined the thickness (~280 µm) of the near surface layer (NSL) and its pyroelectric coefficient (160 pC/(K × cm2) at 23◦C) independently. The thickness of NSL remains nearly constant till 60◦C and the pyroelectric effect vanishes abruptly by 70◦C. The piezoelectric effect, 0.1 pm/V at 23◦C measured with an interferometer, followed the same temperature dependence as the pyroelectric effect. Abrupt disappearance of both effects at 70◦C is irreversible and suggests that water incorporation to α-glycine forms a well defined near surface phase, which is different form α-glycine because it is polar but it too close to α-glycine to be distinguished by X-ray diffraction (XRD). The secondary pyroelectric effect was found to be <14% of the total, which is unexpectedly small for a material with a large thermal expansion coefficient. This implies that water incorporation infers minimal distortions in the host lattice. This finding suggests a path for the control of the piezoelectric and pyroelectric effects of the crystals using stereospecific incorporation of the guest molecules. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.This work was supported by the collaborative program of the Israeli Ministry of Science with the Russian Foundation for Basic Research, grant № 3-16492. This research was made possible in part by RFBR (Grant No. 19-52-06004 MNTI_a), and the Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under Project № 3.9534.2017/8.9. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU was used. I.L. expresses his gratitude to Estate of Olga Klein–Astrachan fund, grant № 721977

Multiple-scattering effects on incoherent neutron scattering in glasses and viscous liquids

Incoherent neutron scattering experiments are simulated for simple dynamic models: a glass (with a smooth distribution of harmonic vibrations) and a viscous liquid (described by schematic mode-coupling equations). In most situations multiple scattering has little influence upon spectral distributions, but it completely distorts the wavenumber-dependent amplitudes. This explains an anomaly observed in recent experiments

Population pharmacokinetics of colistin and the relation to survival in critically ill patients infected with colistin susceptible and carbapenem-resistant bacteria

Objectives: The aim was to analyse the population pharmacokinetics of colistin and to explore the relationship between colistin exposure and time to death. Methods: Patients included in the AIDA randomized controlled trial were treated with colistin for severe infections caused by carbapenem-resistant Gram-negative bacteria. All subjects received a 9 million units (MU) loading dose, followed by a 4.5 MU twice daily maintenance dose, with dose reduction if creatinine clearance (CrCL) 2 mg/L in 94% (195/208) and 44% (38/87) of patients with CrCL ≤120 mL/min, and >120 mL/min, respectively. Colistin methanesulfonate sodium (CMS) and colistin clearances were strongly dependent on CrCL. High colistin exposure to MIC ratio was associated with increased hazard of death in the multivariate analysis (adjusted hazard ratio (95% CI): 1.07 (1.03–1.12)). Other significant predictors included SOFA score at baseline (HR 1.24 (1.19–1.30) per score increase), age and Acinetobacter or Pseudomonas as index pathogen. Discussion: The population pharmacokinetic model predicted that >90% of the patients had colistin concentrations

Antimicrobial use and antimicrobial resistance in broiler farms in peri-urban Wakiso, Uganda

Objective: A cross sectional study was carried out to 1) describe the antimicrobial use patterns among poultry farmers in Wakiso 2) establish resistant profiles of Salmonella, E. coli and Enterococci among poultry farms in Wakiso. Methods: A cross sectional study in Wakiso district was carried out in October and November 2021 for a period of 6 weeks. A semi structured questionnaire was used to collect data on antimicrobial use on the farms. Boot sock sampling was used to collect samples from the whole poultry house. A composite sample of faecal material was also collected from the poultry house. The information on antimicrobial use is being analyzed for descriptive statistics. The faecal samples were cultured in the laboratory for Isolation of Salmonella, E. coli and Enterococci. The Isolates will further be tested to establish their resistant profiles. The composite sample was used to quantify resistant coliforms against cefotaxime and colistin Results: A total of 200 poultry farms in Wakiso were visited, 211 boot sock samples and 211 composite samples were collected. 29.85% of the respondents were male while 70.15% were female.37.38% had attained secondary level of education. There was observed widespread use of antimicrobials on the farms for treatment of different conditions as well as prevention of disease. The most used groups of antibiotics were, Penicillins, Tetracyclines and Aminoglycosides while Sulphonamides were the least used. From the laboratory analysis, out of the 211 samples collected, Salmonella was isolated at a rate of 8.5%, E. coli at 77.3% and Enterococcus at 62.6%. Resistant coliforms to cefotaxime (5I.7%) and colistin (45.5%) were also identified. Conclusion: There are indications of resistant coliforms among poultry farms in Wakiso. This is attributed to the observed continuous use of antibiotics on the poultry farms. There is need to improve antimicrobial use among farmers. Proper diagnosis of conditions is one possible way that will reduce the use of different antibiotics at farm level

Vancomycin exposure and acute kidney injury outcome: A Snapshot From the CAMERA2 Study

Among patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia from a prospective randomized clinical trial, acute kidney injury (AKI) rates increased with increasing vancomycin exposure, even within the therapeutic range. AKI was independently more common for the (flu)cloxacillin group. Day 2 vancomycin AUC ≥470 mg·h/L was significantly associated with AKI, independent of (flu)cloxacillin receipt

Dissolving the Dichotomies Between Online and Campus-Based Teaching: a Collective Response to The Manifesto for Teaching Online (Bayne et al. 2020)

This article is a collective response to the 2020 iteration of The Manifesto for Teaching Online. Originally published in 2011 as 20 simple but provocative statements, the aim was, and continues to be, to critically challenge the normalization of education as techno-corporate enterprise and the failure to properly account for digital methods in teaching in Higher Education. The 2020 Manifesto continues in the same critically provocative fashion, and, as the response collected here demonstrates, its publication could not be timelier. Though the Manifesto was written before the Covid-19 pandemic, many of the responses gathered here inevitably reflect on the experiences of moving to digital, distant, online teaching under unprecedented conditions. As these contributions reveal, the challenges were many and varied, ranging from the positive, breakthrough opportunities that digital learning offered to many students, including the disabled, to the problematic, such as poor digital networks and access, and simple digital poverty. Regardless of the nature of each response, taken together, what they show is that The Manifesto for Teaching Online offers welcome insights into and practical advice on how to teach online, and creatively confront the supremacy of face-to-face teaching