Microscale sensing with NV centers in diamond

Elektroniskā versija nesatur pielikumusNegatīvi lādētais slāpekļa vakances (NV) centrs dimantā ir cietvielu defekts, kam piemīt izcilas spina koherences īpašības pat istabas temperatūrā un kura spina stāvokli iespējams viegli nolasīt optiski. Šajā darbā tika pētīta NV centra relaksācijas īpašības, un defekta-kā-sensora veiktspēja. Eksperimentālie dati liecināja par spēcīgu NV-NV dipola-dipola mijiedarbības lomu T1 relaksācijas procesos augstas koncentrācijas NV centros. Tika identificēti vairāki uzlabojumi NV magnētiskā mikroskopa eksperimentālajā dimantā un visbeidzot tika uzņemts pirms divdimensiju KMR spektrs ar NV KMR spektrometru spiniem, kas atrodas ārpus dimanta matricas. Cik es zinu, šis ir pirmais publicētais šāda tipa eksperimentālais rezultāts. Atslēgas vārdi: cietvielu defekts, kvantu metroloģija, kodolu magnētiskā rezonanse, NV centriThe negatively charged nitrogen vacancy (NV) center in diamond is a solid state defect that possesses both high-spin coherence time at room temperature and a robust optical readout of the spin state. In this work the relaxation dynamics and sensing performance of the nitrogen-vacancy (NV) center were investigated. Strong evidence of NV-NV dipole-dipole couplings playing an important role in T1 relaxation processes in high NV concentration diamonds was found, several key experimental design improvements in a NV diamond magnetic microscope were identified and finally a two-dimensional NMR spectra with a NV NMR spectrometer on an external analyte was observed; the first result of this kind to be reported in literature to the best of my knowledge. Keywords: solid state defects, quantum sensing, nuclear magnetic resonance, NV center

Biomass Properties for Mechanization of Conditioning Processes

Substitution of fossil feedstock for energy and raw materials by biomass is important measure for GHG emission mitigation. Development of energy crop production and agricultural residue utilisation for energy are important goals of the rural policy. As chemical fertiliser production and usage corresponds to the consumption of oil fuel, biomass usage directly for energy production or as fertiliser are activities with equal importance. The main rural resources for biomass eco-technologies in Latvia are cereal straw residues, energy crops, emergent vegetation and peat from wetlands and sediments from lakes. Wide range of biomass properties cause necessity of appropriate mechanization equipment for biomass conditioning accordingly collection, conversion and usage technologies. The ecosystem approach means taking into account the interrelationships among land, air water and all living organisms including humans for mechanization equipment design of biomass technologies. Complex mechanisation of biomass technologies is based on implementation of ecosystem approach and investigation of properties of biomass in conditioning processes. For solid biofuel production densification properties of chopped stalk materials with different additives (peat, rapeseed cake) had been determined

CONDITIONING OF ENERGU CROPS FOR BIOENERGY PRODUCTION

The main steps of rural policy to the development of renewable energy resources are energy crop production. Latvia can provide for the use of approximately 0.36 million ha of the unused now agricultural land for herbaceous energy crop growing. More than 230 million tones of peat are available for solid biofuel production. Peat is recomended as additive because it improves density and burning properties of herbaceous material solid biofuel. Herbaceous stalk material can be harvested in winter season with humidity less than 15% and used for compacting without drying. The aim of experimental investigation is to determine conditioning methods for solid biofuel production with minimum energy consumption. Common reed stalk material is used for experiments, because it experimentally stated ultimate tensile strength is 256 ± 27 N mm-2. This value testifies that common reeds are twice strongest material than cereal crop stalk materials and conditioning mechanization equipment of common reeds would be useful for other energy crops

Fluorsaturošu katjono 1,4-dihidropiridīna un 3,4-dihidropiridona amfifīlu sintēze transmembrānu nogādes pētījumiem

KOPSAVILKUMS. Fluorsaturošu katjono 1,4-dihidropiridīna un 3,4-dihidropiridona amfifīlu sintēze transmembrānu nogādes pētijumiem. Smits R., Dr. Ķīm. Prof. G.W. Buchanan, Dr. Ķīm. Vīgante B., Doktora disertācija , 163 lappuses, 48 attēli, 54 shēmas, 6 tabulas, 266 atsauces. Angļu valodā. 1,4-DIHIDROPIRIDĪNS, 3,4-DIHIDROPIRIDONS, FLUORĒTIE ESTERI, KATJONIE AMFIFĪLI, DNS TRANSFEKCIJA, ZĀĻU PĀRNESE, BROMĒŠANA, OKSIDĒŠANA, HLORO-FORMILĒŠANA, ŪDEŅRAŽA SAITES VEIDOŠANA, PAŠAGREGĒŠANĀS, RENTGENSTARU DIFRAKCIJA, 19F-KMR. Šajā darbā apskatīta 1,4-dihidropiridīnu un 3,4-dihidropiridonu farmakoloģiskā un sintētiskā daudzveidība. Kombinācijā ar garu fluorētu alkilesteru unikālajām īpašībām veidoti iespējami transmembrānu aģenti, risinot līdz šim zināmo sistēmu pašagregēšanās, stabilitātes, toksicitātes un gēnu transfekcijas problēmas ar būtisku priekšrocību – šie nesēji var tikt izsekoti in vivo ar maz agresīvu 19F-magnētisko rezonansi. Darba gaitā izskaidroti vairāki fundamentāli 1,4-dihidropiridīnu un 3,4-dihidropiridonu ķīmijas aspekti, tādi kā stereospecifiska bromēšana, ūdeņraža saites veidošanās un heterocikla oksidēšanās. Lai neapšaubāmi pierādītu sintezēto savienojumu struktūru un iegūtu molekulāro iedarbību datus, izmantota rentgenstruktūras analīze.ABSTRACT. Synthesis of novel 1,4-dihydropyridine and 3,4-dihydropyridone based fluorous cationic amphiphiles for possible transmembrane delivery applications. Smits R., Dr. Chem. Prof. G.W. Buchanan, Dr. Chem. Vigante B., Doctor’s Thesis , 163 pages, 48 figures, 54 schemes, 6 tables, 266 references. In English language. 1,4-DIHYDROPYRIDINE, 3,4-DIHYDROPYRIDONE, FLUOROUS ESTERS, CATIONIC AMPHIPHILES, DNA TRANSFECTION, DRUG DELIVERY, BROMINATION, OXIDATION, CHLORO-FORMYLATION, HYDROGEN BONDING, SELF-ASSEMBLY, X-RAY DIFFRACTION, 19F-MRI. In this work both the pharmacologically and synthetically versatile 1,4-dihydropyridines and 3,4-dihydropyridones in combination with the unique properties of fluorous long chain alkyl esters allow the generation of novel putative transmembrane delivery agents, addressing the self- assembly, stability, toxicity and gene transfection problems of current systems with the added advantage that these carriers can be tracked in vivo by non-invasive 19F-magnetic resonance imaging. Along the way some fundamental chemistry aspects, such as stereo-specific bromination, hydrogen bonding and oxidation of the 1,4-dihydropyridine and 3,4-dihydropyridone heterocycles are explored. X-ray diffraction is used throughout the work to provide molecular interaction data and unequivocal structural proofs of the synthesized compounds

Public-private partnership role during the pandemic : A case of COVID-19 testing in the Republic of Latvia 2020

Funding Information: The author(s) reported there is no funding associated with the work featured in this article. Publisher Copyright: © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.The novelty of this research includes public-private partnerships (PPP) in emergency situations, especially during a pandemic, where there are only a few researched topics. The goal of this study is to answer the following research question: What is the role of PPP in achieving quick and effective COVID-19 testing during a new pandemic in a small country? The methods of this paper are based on a case study approach. In the beginning, a related literature review was done (keywords: public-private partnerships in COVID-19, testing of the COVID-19, health systems during the pandemic). The second step contains data collection about COVID19 in Latvia (2020). Finally, an analysis of the case and data was performed with the conclusion in the result. Results: The average number of tests in 2020 was 2355.99 (interval: 4.00–12,091.00) per day and 2141.73 (interval: 7.67–7365.77) per month. The private sector conducted around 95.78% per month to check COVID19 infection. Conclusion: The PPP role of COVID-19 testing during a pandemic in small countries contains extra resources for rapid and previously not established process organization that allows governments and the public sector to pay attention to other important questions. As a result, collaboration can decrease infection prevalence and mortality.Peer reviewe

Photocatalytic Activity of TiO2 Coatings Obtained at Room Temperature on a Polymethyl Methacrylate Substrate

Titanium dioxide (TiO2) coatings have a wide range of applications. Anatase exhibits hydrophilic, antimicrobial, and photocatalytic properties for the degradation of organic pollutants or water splitting. The main challenge is to obtain durable anatase nanoparticle coatings on plastic substrates by using straightforward approaches. In the present study, we revealed the preparation of a transparent TiO2 coating on polymethylmethacrylate (PMMA), widely used for organic optical fibres as well as other polymer substrates such as polypropylene (PP), polystyrene (PS), and polycarbonate (PC). The films were spin-coated at room temperature without annealing; therefore, our approach can be used for thermo-sensitive substrates. The deposition was successful due to the use of stripped ultra-small (<4 nm) TiO2 particles. Coatings were studied for the photocatalytic degradation of organic pollutants such as MB, methyl orange (MO), and rhodamine B (RB) under UV light. The TiO2 coating on PMMA degraded over 80% of RB in 300 min under a 365 nm, 100 W mercury lamp, showing a degradation rate constant of 6 × 10−3 min−1. The coatings were stable and showed no significant decrease in degradation activity even after five cycles. © 2022 by the authors. --//-- This is an open access article Iesalnieks M, Eglītis R, Juhna T, Šmits K, Šutka A. "Photocatalytic Activity of TiO2 Coatings Obtained at Room Temperature on a Polymethyl Methacrylate Substrate", Int J Mol Sci. 2022 Oct 26;23(21):12936. doi: 10.3390/ijms232112936 published under the CC BY 4.0 licence.European Union’s Horizon 2020 FET Open program under Grant Agreement No. 899528; Institute of Solid-State Physics, University of Latvia has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-Teaming Phase 2 under grant agreement No. 739508, project CAMART2

Adherence Level to Arterial Hypertension Treatment: A Cross-Sectional Patient Survey and Retrospective Analysis of the NHS Prescription Database

Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.One of the major problems in cardiology practice is poor adherence to antihypertensive medication. This study aimed to evaluate medication adherence; we also aim to investigate the predictors of intentional and unintentional non-adherence. We issued a survey containing questions about patient demographics, blood pressure control, pharmaceutical care, and adherence level to medication. Retrospective analysis of the prescription database of the National Health Service of the Republic of Latvia was performed. The prevalence of non-adherence was 45.9%. The lowest adherence rate (38.2%) was found among patients taking medication for 2–4.9 years. Even though 84.7% of respondents had a blood pressure monitor at home, only 25.3% of them reported measuring blood pressure regularly. There were differences between the groups of adherent patients in terms of the patients’ net income (p = 0.004), medication co-payments (p = 0.007), and whether the pharmacist offered to reduce the costs of drug therapy (p = 0.002). Roughly half of the prescriptions (50.4%) containing perindopril were purchased by patients from pharmacies. The medication adherence level and blood pressure control at home were assessed as low. Intentionally non-adherent respondents discontinued their medication because of fear of getting used to medicines. The pharmacists’ behaviour in terms of offering to reduce the costs of medications used was influenced by socio-economic factors.publishersversionPeer reviewe

Hybrid Tribo-Piezo-Electric Nanogenerator with Unprecedented Performance Based on Ferroelectric Composite Contacting Layers

This research was supported by the European Regional Development Fund within the project ‘‘Hybrid energy harvesting systems’’ 1.1.1.1./16/A/013.It was recently reported that more efficient triboelectric nanogenerator (TENG)-like devices can be prepared using inversely polarized ferroelectric films made of same material as the contacting layers. In the present work, a clear correlation between the piezoelectric response of inversely polarized ferroelectric PVDF/BaTiO3 nanocomposite films and the performance of the TENG-like device based on these films is demonstrated. This observation is explained by magnified electrostatic induction that is driven by piezoelectric charges and ferroelectric properties of these films. A double capacitor model is proposed that effectively portrays the interactions between ferroelectric layers during contact-separation and subsequent charge redistributions in the external circuit. The new understanding has allowed the result of 3-fold higher open circuit voltages (2.7 kV from 5 cm2) as compared to that of a state of the art TENG. Furthermore, findings uncover the potential for vast improvement in the field of nanogenerators for mechanical energy harvesting as a significantly better piezoelectric performance of flexible nanogenerators has been reported elsewhere.ERDF 1.1.1.1./16/A/013; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Epidemiology of Suicide Mortality in Paraguay from 2005 to 2019 : A Descriptive Study

Publisher Copyright: © 2024 by the authors.Suicide is an important public health problem, fundamentally affecting the younger population and responding to multiple biological, psychological, and social causes. The objective of this study was to characterize changes in suicide mortality, suicide methods, and years of potential life lost from 2005 to 2019 in Paraguay. This observational, descriptive study used data from the Vital Statistics Information Subsystem of the Ministry of Public Health and Social Welfare. The average mortality rate from suicide was 4.9 per 100,000 inhabitants, with an increase from 4.2 between 2005 and 2009 to 5.8 from 2014 to 2019. Suicide was more common in men (75%) than in women. In men, the highest mortality rate was observed among those 20–24 years old, whereas in women, the ages most affected were the 15–19-year-old age group. The most-used method for suicide was hanging. The most frequent place of suicide occurrence was at home (73%). The seasonality of suicide occurrence showed a slight increase in the spring–summer months compared with autumn–winter (53% vs. 47%). The rate of potential years of life lost statistically significantly increased from 2005 to 2019. Public health measures need to be implemented to investigate the underlying reasons and implement interventions in the population to decrease suicide mortality in Paraguay.Peer reviewe

Mechanical reinforcement of electrospun poly(vinyl alcohol) by α‐FeOOH nanowires

The authors kindly acknowledge the financial support of the Estonian Research Council for the post-doctoral research grants of personal research funding in projects PUT1096 and PUTJD578 as well as Institutional Research Funding Projects, IUT20-17, and IUT23-7.We report the mechanical performance of α‐FeOOH nanowire reinforced poly(vinyl alcohol) (PVA) composite nanofiber mat, fabricated using straightforward aqueous processing methods. Goethite (α‐FeOOH) nanocrystals have a high elastic modulus and –OH rich surface, ensuring strong interactions with hydrophilic polymers and effective reinforcement. Needle‐less electrospinning resulted in alignment of the nanowires along fibre axis, as confirmed by transmittance electron microscopy studies. Produced composite PVA nanofibers containing 10 wt% goethite nanoparticles exhibited an outstanding fivefold increase in Young's modulus and 2.5‐fold improvement of tensile strength compared to mats of neat PVA. The addition of α‐FeOOH had a significant influence on glass transition temperature indicating formation of interphase regions around nanowire inclusions. Observed properties are explained by nanowire grafting in the precursor solution, extensive interactions between the adsorbed PVA chains and the matrix and percolation of interphase regions at 10 wt% α‐FeOOH.Estonian Research Council PUT1096 and PUTJD578; Institutional Research Funding Projects, IUT20-17, and IUT23-7; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART