Electronic states spectroscopy of Hydroxyapatite ceramics

Photoluminescence, surface photovoltage spectroscopy and high-resolution characterization methods (Atomic Force Microscopy, Scanning Electron Microscopy, X-ray spectroscopy and DC conductivity) are applied to nanostructured Hydroxyapatite (HAp) bioceramics and allowed to study electron (hole) energy states spectra of the HAp and distinguish bulk and surface localized levels. The measured trap spectra show strong sensitivity to preliminary heat treatment of the ceramics. It is assumed that found deep electron (hole) charged states are responsible for high bioactivity of the HAp nanoceramics

Photoluminescence and Surface Photovoltage Spectroscopy Studies of Hydroxyapatite Nano-Bio-Ceramics

Photoluminescence (PL) and surface photovoltage spectroscopy applied to nanostructural bioceramics hydroxyapatite (HAp) allowed to study electron (hole) energy states spectra of HAP and distinguish bulk and surface localized levels. Studied PL excitation spectra allowed obtaining an exact value of the energy band gap in HAP: Eg=3.95 eV.This result is consistent with Eg value determined by the contact potential difference (ΔCPD) curves treatment method as Eg=3.94 eV. Comparison between ΔCPD and PL spectra indicates that the energy spectra of electron – hole levels studied by two different experimental spectroscopy techniques are very similar. This comparison enables to conclude that all HAp samples have identical electron – hole states structures consisting of five bulk states and one surface state. It is assumed that the deep electron (hole) charged states may be responsible for high bioactivity of the HAp nanoceramics

Electronic States Spectroscopy of Hydroxyapatite Ceramics

Photoluminescence, surface photovoltage spectroscopy and high-resolution characterization methods (Atomic Force Microscopy, Scanning Electron Microscopy, X-ray spectroscopy and DC conductivity) are applied to nanostructured Hydroxyapatite (HAp) bioceramics and allowed to study electron (hole) energy states spectra of the HAp and distinguish bulk and surface localized levels. The measured trap spectra show strong sensitivity to preliminary heat treatment of the ceramics. It is assumed that found deep electron (hole) charged states are responsible for high bioactivity of the HAp nanoceramics

Photoluminescence and surface photovoltage spectroscopy studies of hydroxyapatite nano-Bio-ceramics

Photoluminescence (PL) and surface photovoltage spectroscopy applied to nanostructural bioceramics hydroxyapatite (HAp) allowed to study electron (hole) energy states spectra of HAP and distinguish bulk and surface localized levels. Studied PL excitation spectra allowed obtaining an exact value of the energy band gap in HAP: Eg=3.95 eV.This result is consistent with Eg value determined by the contact potential difference (ΔCPD) curves treatment method as Eg=3.94 eV. Comparison between ΔCPD and PL spectra indicates that the energy spectra of electron – hole levels studied by two different experimental spectroscopy techniques are very similar. This comparison enables to conclude that all HAp samples have identical electron – hole states structures consisting of five bulk states and one surface state. It is assumed that the deep electron (hole) charged states may be responsible for high bioactivity of the HAp nanoceramics

Viral and Bacterial Respiratory Pathogens during the COVID-19 Pandemic in Israel

Background: previous worldwide reports indicated a substantial short-term reduction in various respiratory infections during the early phase of the SARS-CoV-2 pandemic. Aims: exploring the long-term impact of the COVID-19 pandemic on respiratory pathogens. Methods: retrospective analysis of bacterial and viral positivity rate in respiratory samples, between 1 January 2017–30 June 2022 in a tertiary hospital in Jerusalem, Israel. Results: A decline in overall respiratory tests and positivity rate was observed in the first months of the pandemic. Respiratory isolations of Hemophilus influenza and Streptococcus pneumoniae were insignificantly affected and returned to their monthly average by November 2020, despite a parallel surge in COVID-19 activity, while Mycoplasma pneumoniae was almost eliminated from the respiratory pathogens scene. Each viral pathogen acted differently, with adenovirus affected only for few months. Human-metapneumovirus and respiratory-syncytial-virus had reduced activity for approximately a year, and influenza A virus resurged in November 2021 with the elimination of Influenza-B. Conclusions: After an immediate decline in non-SARS-CoV-2 respiratory infections, each pathogen has a different pattern during a 2-year follow-up. These patterns might be influenced by intrinsic factors of each pathogen and different risk reduction behaviors of the population. Since some of these measures will remain in the following years, we cannot predict the timing of return to pre-COVID-19 normalcy

CCQM-K125 Elements in infant formula : Final report

The Key Comparison CCQM-K125 “Elements in Infant Formula” was undertaken to demonstrate the capability of participating national metrology institutes (NMIs) and designated institutes (DIs) in measuring the mass fraction the analytes at mg/kg levels in a test sample of infant formula by various analytical techniques. According to the Inorganic Analysis Working Group’s (IAWG’s) five-year plan, it was recommended to have a key comparison under the measurement service category of food for the year 2015. In this regards, the Government Laboratory, Hong Kong (GLHK) proposed to coordinate a new key comparison and a parallel-run pilot study (CCQM-K125 and CCQM-P159) for the determination of elements in infant formula. At the CCQM IAWG Meeting held in October 2014, the proposed study was agreed by IAWG members to be organised as the fifth benchmarking exercise. It was important for benchmarking to select two exemplary elements which were reasonably easy for many IAWG members to measure. Having further discussed with concerned IAWG members, potassium and copper were selected as the exemplary elements for examination, whereas iodine was an optional element for analysis. This key comparison facilitates claims by participants on the Calibration and Measurement Capabilities (CMCs) as listed in Appendix C of the Key Comparison Database (KCDB) under the Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA). Participants are requested to complete the pertinent Inorganic Core Capabilities Tables as a means of providing evidence for their CMC claims. For registration of CCQM-K125, total 25 institutes registered for the examination of the exemplary analytes of potassium and copper, while 12 institutes registered for the optional analyte of iodine. For submission of results, 25 institutes submitted the results for potassium, 24 institutes submitted the results for copper and 8 institutes submitted the results for iodine. The information about registration and submission of participants’ results is summarised in Table A. For examination of potassium and copper, most of the participants used microwave-assisted acid digestion methods for sample dissolution. A variety of instrumental techniques including inductively coupled plasma mass spectrometry (ICP-MS), isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), atomic absorption spectrometry (AAS), flame atomic emission spectrometry (FAES) and microwave plasma atomic emission spectroscopy (MP-AES) were employed by the participants for determination. For analysis of iodine, most of the participants used alkaline extraction methods for sample preparation. ICP-MS and ID-ICP-MS were used by the participants for the determination. For this key comparison, inorganic core capabilities were demonstrated by the concerned participants with respect to the methods including ICP-MS (without isotope dilution), ID-ICP-MS, ICP-OES, AAS, FAES and MP-AES on the determination of elements (potassium, copper and iodine) in a food matrix of infant formula

CCQM-K124 Trace elements and ehromium speciation in drinking water : Part A: Trace elements in drinking water Part B: chromium speciation in drinking water. Final report

CCQM-K124 was an activity of the Inorganic Analysis Working Group (IAWG) and was jointly coordinated by the National Metrology Institute of Japan (NMIJ) and the Government Laboratory, Hong Kong SAR (GLHK). The Part A of CCQM-K124 was organized by NMIJ and trace elements in drinking water were the measurands. The Part A of the key comparison was undertaken for NMIs and DIs to demonstrate their capabilities in measuring part-per-billion level (in μg/kg) or part-per-million level (in mg/kg) of trace elements in drinking water. It should also facilitate the acquisition of claims in Calibration and Measurement Capabilities (CMCs) as listed in Appendix C of Key Comparison Database (KCDB) under the Mutual Recognition Arrangement of the International Committee of Weights and Measures (CIPM MRA). Results were submitted by 14 NMIs and nine DIs. The participants used different measurement methods, though most of them used direct measurement using inductively coupled plasma-optical emission spectrometry (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS) and high resolution ICP-MS and isotope dilution technique with ICP-MS. Other methods were graphite furnace atomic absorption spectrophotometry (GFAAS) and flame atomic absorption spectrophotometry (FAAS). The results of B, Ca, Cr, As and Cd show good agreement except some outliers. Concerning Hg, instability was observed when the sample was stored in the light. And some participants observed instability of Mo. Therefore, it was agreed to abandon the Hg and Mo analysis as this sample was not satisfactory for KC. Accounting for relative expanded uncertainty, comparability of measurement results for each of B, Ca, Cr, As and Cd was successfully demonstrated by the participating NMIs or DIs. Furthermore, the results of this key comparison can be utilized along with the IAWG core capability approach. It is expected that arsenic, boron, cadmium, calcium and chromium at mass fractions greater than approximately 0.1 µg/kg, 1 µg/kg, 0.01 µg/kg, 1 mg/kg and 0.1 µg/kg respectively in drinking water and similar matrices (groundwater and river water etc.) can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report