Engineering Nitrogen-Doped Carbon Quantum Dots: Tailoring Optical and Chemical Properties through Selection of Nitrogen Precursors.

The process of N-doping is frequently employed to enhance the properties of carbon quantum dots. However, the precise requirements for nitrogen precursors in producing high-quality N-doped carbon quantum dots (NCQDs) remain undefined. This research systematically examines the influence of various nitrogen dopants on the morphology, optical features, and band structure of NCQDs. The dots are synthesized using an efficient, eco- friendly, and rapid continuous hydrothermal flow technique. This method offers unparalleled control over synthesis and doping, while also eliminating convention-related issues. Citric acid is used as the carbon source, and urea, trizma base, beta-alanine, L-arginine, and EDTA are used as nitrogen sources. Notably, urea and trizma produced NCQDs with excitation-independent fluorescence, high quantum yields (up to 40%), and uniform dots with narrow particle size distributions. Density functional theory (DFT) and time-dependent DFT modelling established that defects and substituents within the graphitic structure have a more significant impact on the NCQDs' electronic structure than nitrogen-containing functional groups. Importantly, for the first time, this work demonstrates that the conventional approach of modelling single-layer structures is insufficient, but two layers suffice for replicating experimental data. This study, therefore, provides essential guidance on the selection of nitrogen precursors for NCQD customization for diverse applications.

Investigating the effect of N-doping on carbon quantum dots structure, optical properties and metal ion screening.

Carbon quantum dots (CQDs) derived from biomass, a suggested green approach for nanomaterial synthesis, often possess poor optical properties and have low photoluminescence quantum yield (PLQY). This study employed an environmentally friendly, cost-effective, continuous hydrothermal flow synthesis (CHFS) process to synthesise efficient nitrogen-doped carbon quantum dots (N-CQDs) from biomass precursors (glucose in the presence of ammonia). The concentrations of ammonia, as nitrogen dopant precursor, were varied to optimise the optical properties of CQDs. Optimised N-CQDs showed significant enhancement in fluorescence emission properties with a PLQY of 9.6% compared to pure glucose derived-CQDs (g-CQDs) without nitrogen doping which have PLQY of less than 1%. With stability over a pH range of pH 2 to pH 11, the N-CQDs showed excellent sensitivity as a nano-sensor for the highly toxic highly-pollutant chromium (VI), where efficient photoluminescence (PL) quenching was observed. The optimised nitrogen-doping process demonstrated effective and efficient tuning of the overall electronic structure of the N-CQDs resulting in enhanced optical properties and performance as a nano-sensor.

Continuous flow vortex fluidic-mediated exfoliation and fragmentation of two-dimensional MXene.

MXene (Ti2CT x ) is exfoliated in a vortex fluidic device (VFD), as a thin film microfluidic platform, under continuous flow conditions, down to ca 3 nm thin multi-layered two-dimensional (2D) material, as determined using AFM. The optimized process, under an inert atmosphere of nitrogen to avoid oxidation of the material, was established by systematically exploring the operating parameters of the VFD, along with the concentration of the dispersed starting material and the choice of solvent, which was a 1 : 1 mixture of isopropyl alcohol and water. There is also some fragmentation of the 2D material into nanoparticles ca 68 nm in diameter.

Chemical Functionalisation of 2D Materials by Batch and Continuous Hydrothermal Flow Synthesis.

2D materials are single or few layered materials consisting of one or several elements with a thickness of a few nanometres. Their unique, tuneable physical and chemical properties including ease of chemical functionalisation makes this class of materials useful in a variety of technological applications. The feasibility of 2D materials strongly depends on better synthetic approaches to improve properties, increase performance, durability and reduce costs. As such, in the synthesis of nanomaterials, hydrothermal processes are widely adopted through a precursor-product synthesis route. This method includes batch or continuous flow systems, both employing water at elevated temperatures (above boiling point) and pressures to fine-tune the physical, chemical, optical and electronic properties of the nanomaterial. Both techniques yield particles with different morphology, size and surface area due to different mechanisms of particle formation. In this Minireview, we present batch and continuous hydrothermal flow synthesis of a selection of 2D derivatives (graphene, MXene and molybdenum disulfide), their chemical functionalisation as an advantageous approach in exploring properties of these materials as well as the benefits and challenges of employing these processes, and an outlook for further research.

Patterns of Antibiotic Prescription in Children: Tirana, Albania Region.

BACKGROUND: Antibiotics (abx) constitute the most prescribed therapeutic agent in the world. There is little data regarding antibiotic consumption by young children in Albania. AIM: This study aims to evaluate antibiotic prescription in children in quantitative and qualitative terms, and therefore, propose recommendations to improve overall clinical outcomes. METHODS: A retrospective, cross-sectional drug utilisation study was conducted based on unreimbursed prescriptions collected in 25 pharmacies, randomly selected within the district of Tirana, during the period beginning December 2015 to January 2016. They contain at least one antibacterial therapeutic agent prescribed for children 0-15 years old, for systemic use. The data were analysed using SPSS 20. RESULTS: A group of 904 prescriptions meet inclusion criteria, 54.1% patient were female, and 45.9% were male. The most exposed age group were 2-6 years old. The most common diagnosis was respiratory tract infections: bronchitis (59.2%), tonsillitis (17%) followed by bronchopneumonia (9.6%). The most prescribed antibiotic classes are Penicillins (33%), Cephalosporins (33.2%) and Macrolides (21,5%). Amoxicillin (19.4%), Azithromycin (14.7%), the combination of Amoxicillin and Clavulanic acid (13.5%) and Cefaclor (11.7%) were the most commonly prescribed. We observed short duration therapies, with a mean duration of 5.21 days and in 17.4 % of cases with a duration of ≤ 2 days. CONCLUSIONS: We observed a large use of broad-spectrum antibiotics for common respiratory tract infection in children less than 6 years old. We would recommend the creation of an electronic database of patient's record in order to monitor the quality of prescription and education of the healthcare professionals and patient of risks related to antibiotic resistance.

Prevalence and correlates of inappropriate use of benzodiazepines in Kosovo.

BACKGROUND: In post-war Kosovo, the magnitude of inappropriate use of benzodiazepines is unknown to date. OBJECTIVE: The aim of this study was to assess the prevalence and correlates of continuation of intake of benzodiazepines beyond prescription (referred to as "inappropriate use") in the adult population of Gjilan region in Kosovo. METHOD: A cross-sectional study was conducted in Gjilan region in 2015 including a representative sample of 780 individuals attending different pharmacies and reporting use of benzodiazepines (385 men and 395 women; age range 18-87 years; response rate: 90%). A structured questionnaire was administered to all participants inquiring about the use of benzodiazepines and socio-demographic characteristics. RESULTS: Overall, the prevalence of inappropriate use of benzodiazepines was 58%. In multivariable-adjusted models, inappropriate use of benzodiazepines was significantly associated with older age (OR 1.7, 95% CI 1.1-2.7), middle education (OR 1.8, 95% CI 1.2-2.7), daily use (OR 1.4, 95% CI 1.1-2.0) and addiction awareness (OR 2.7, 95% CI 2.0-3.8). Furthermore, there was evidence of a borderline relationship with rural residence (OR 1.2, 95% CI 0.9-1.7). CONCLUSION: Our study provides novel evidence about the prevalence and selected correlates of inappropriate use of benzodiazepines in Gjilan region of Kosovo. Health professionals and policymakers in Kosovo should be aware of the magnitude and determinants of drug misuse in this transitional society.

Selective Calixarene-Directed Synthesis of MXene Plates, Crumpled Sheets, Spheres, and Scrolls.

Fully exploiting the electronic and mechanical properties of 2D laminar materials not only requires efficient and effective means of their exfoliation into low dimensional layers, but also necessitates a means of changing their morphology so as to explore any enhancement that this may offer. MXenes are a rapidly emerging new class of such laminar materials with unique properties. However, access to other morphologies of MXenes has not yet been fully realised. To this end we have developed the synthesis of MXenes (Ti2 C) as plates, crumpled sheets, spheres and scrolls, which involves selective intercalation of p-phosphonic calix[n]arenes, with control in morphology arising from the choice of the size of the macrocycle, n=4, 5, 6, or 8. This opens up wider avenues of discovery/design for new morphologies from the wider family of MXenes beyond Ti2 C, along with opportunities to exploit any new physico-chemical properties proffered.

Calixarene Assisted Rapid Synthesis of Silver-Graphene Nanocomposites with Enhanced Antibacterial Activity.

Demonstrated herein is a single rapid approach employed for synthesis of Ag-graphene nanocomposites, with excellent antibacterial properties and low cytotoxicity, by utilizing a continuous hydrothermal flow synthesis (CHFS) process in combination with p-hexasulfonic acid calix[6]arene (SCX6) as an effective particle stabilizer. The nanocomposites showed high activity against E. coli (Gram-negative) and S. aureus (Gram-positive) bacteria. The materials were characterized using a range of techniques including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-vis spectrophotometry, FT-IR, and X-ray powder diffraction (XRD). This rapid, single step synthetic approach not only provides a facile means of enabling and controlling graphene reduction (under alkaline conditions) but also offers an optimal route for homogeneously producing and depositing highly crystalline Ag nanostructures into reduced graphene oxide substrate.

Physicians' perceptions about the quality of primary health care services in transitional Albania.

AIM: To date, the available information regarding the quality of primary health care services in Albania is scarce. The aim of our study was to assess the quality of primary health care services in Albania based on physicians' perceptions towards the quality of the services provided to the general population. METHODS: A cross-sectional study was conducted in January-March 2013 including a representative sample of 132 physicians (59 men aged 41.3±6.9 years and 73 women aged 43.7±4.8 years; overall response rate: 132/150=88%) providing primary health care services in several polyclinics (health centers) of Tirana, the Albanian capital city. A structured self-administered and anonymous questionnaire was applied including physicians' perceptions regarding different dimensions of the quality of primary health care. Binary logistic regression was used to assess the association of self-perceived quality of health care services with baseline characteristics of physicians. RESULTS: Self-perceived adequate quality of health care services was positively related to the age of physicians, their working experience, female gender, a lower population served, and specialization in family medicine. CONCLUSION: Our findings provide useful evidence on the self-perceived quality of health services from primary health care physicians' perspective in transitional Albania. Health authorities in Albania should implement suitable instruments to measure the quality of health care services at all levels.

Level and factors of benzodiazepines misuse in Albania.

BACKGROUND: There is little evidence on benzodiazepine misuse and associated factors in transitional countries of the Western Balkans. OBJECTIVE: The aim of this study was to assess the level and socioeconomic correlates of misuse of benzodiazepine drugs in the Albanian adult population. METHOD: We conducted a cross-sectional study including a representative sample of 422 individuals (158 men and 264 women) who were benzodiazepines users. A structured questionnaire included data on age, gender, type of drug used, and awareness of possibility to develop dependence and continuation of therapy after prescription. RESULTS: 289 individuals reported treatment continuation compared with 89 participants who reported no continuation of benzodiazepine drugs. There were no significant age group (P = 0.351), sex (P = 0.454), or educational differences (P = 0.117) in treatment continuation. Age was inversely related to the awareness of becoming dependent with the prolonged use of benzodiazepines (78.4% of the persons aged ≤40 years were aware of the dependence versus 51.9% in the age group >40 years; P = 0.002). CONCLUSION: Our study provides pioneering evidence on the use and misuse of benzodiazepines in Albania. Findings from this study may influence the reforms and policy formulation related to drug misuse in Albania.

High-throughput continuous hydrothermal flow synthesis of Zn-Ce oxides: unprecedented solubility of Zn in the nanoparticle fluorite lattice.

High-throughput continuous hydrothermal flow synthesis has been used as a rapid and efficient synthetic route to produce a range of crystalline nanopowders in the Ce-Zn oxide binary system. High-resolution powder X-ray diffraction data were obtained for both as-prepared and heat-treated (850 degrees C for 10 h in air) samples using the new robotic beamline I11, located at Diamond Light Source. The influence of the sample composition on the crystal structure and on the optical and physical properties was studied. All the nanomaterials were characterized using Raman spectroscopy, UV-visible spectrophotometry, Brunauer-Emmett-Teller surface area and elemental analysis (via energy-dispersive X-ray spectroscopy). Initially, for 'as-prepared' Ce(1-x)Zn(x)O(y), a phase-pure cerium oxide (fluorite) structure was obtained for nominal values of x=0.1 and 0.2. Biphasic mixtures were obtained for nominal values of x in the range of 0.3-0.9 (inclusive). High-resolution transmission electron microscopy images revealed that the phase-pure nano-CeO(2) (x=0) consisted of ca 3.7 nm well-defined nanoparticles. The nanomaterials produced herein generally had high surface areas (greater than 150 m(2) g(-1)) and possessed combinations of particle properties (e.g. bandgap, crystallinity, size, etc.) that were unobtainable or difficult to achieve by other more conventional synthetic methods.

Rapid automated materials synthesis instrument: exploring the composition and heat-treatment of nanoprecursors toward low temperature red phosphors.

We report on the commissioning experimental run of the rapid automated materials synthesis instrument (RAMSI), a combinatorial robot designed to manufacture, clean, and print libraries of nanocrystal precursor solid compositions. The first stage of RAMSI, parallel synthesis, uses a fully automated high throughput continuous hydrothermal (HiTCH) flow reactor for automatic metal salt precursor mixing, hydrothermal flow reaction, and sample slurry collection. The second stage of RAMSI provides integrated automated cleanup, and the third section is a ceramic printing function. Nanocrystal precursor solid ceramics were synthesized from precursor solutions and collected into 50 mL centrifuge tubes where they were cleaned by multiple centrifugation and redispersion cycles (monitored by intelligent scanning turbidimetry) and printed with an automated pipette. Eight unique compositions of a model phosphor library comprising pure nano-Y(OH)(3) and Eu(3+) doped-yttrium hydroxide, Y(OH)(3):Eu(3+) nanocrystal precursor solid were synthesized (with 2 centrifuge tubes' worth collected per composition), processed, and printed in duplicate as 75, 100, and 125 microL dots in a 21.6 ks (6 h) experiment (note: the actual time for synthesis of each sample tube was only 12 min so up to 60 compositions could easily be synthesized in 12 h if one centrifuge tube per composition was collected instead). The Y(OH)(3):Eu(3+) samples were manually placed in a furnace and heat-treated in air for 14.4 ks (4 h) in the temperature range 200-1200 at 100 degrees C intervals (giving a total of 84 samples plus one as-prepared pure Y(OH)(3) sample). The as-prepared and heat-treated ceramic samples were affixed to 4 mm wide hemispherical wells in a custom-made aluminum well-plate and analyzed using a fluorescence spectrometer. When the library was illuminated with a 254 nm light source (and digitally imaged and analyzed), the 3 mol % Eu(3+) sample heat-treated at 1200 degrees C gave the most intense fluorescence (major red peak at 612 nm); however, an identical nanocrystal precursor heat-treated at only 500 degrees C (identified as Y(2)O(3):Eu(3+) after heat treatment) was the brightest phosphor under illumination of the samples heat-treated at or below 1000 degrees C.

Instant nano-hydroxyapatite: a continuous and rapid hydrothermal synthesis.

Nano-particle hydroxyapatite (HA) rods, were rapidly synthesised using a three pump continuous hydrothermal process (using a water feed at up to 400 degrees C and at 24 MPa): the product was obtained as a highly crystalline and phase pure material, without the need for an ageing step or subsequent heat treatment.