Chemical and physical transformations by milling are attracting enormous interest for their ability to access new materials and clean reactivity, and are central to a number of core industries, from ...mineral processing to pharmaceutical manufacturing. While continuous mechanical stress during milling is thought to create an environment supporting nonconventional reactivity and exotic intermediates, such speculations have remained without proof. Here we use in situ, real-time powder X-ray diffraction monitoring to discover and capture a metastable, novel-topology intermediate of a mechanochemical transformation. Monitoring the mechanochemical synthesis of an archetypal metal-organic framework ZIF-8 by in situ powder X-ray diffraction reveals unexpected amorphization, and on further milling recrystallization into a non-porous material via a metastable intermediate based on a previously unreported topology, herein named katsenite (kat). The discovery of this phase and topology provides direct evidence that milling transformations can involve short-lived, structurally unusual phases not yet accessed by conventional chemistry.
Honey liqueur is an alcoholic drink derived from honey and strong fruit brandy of suitable type, traditionally made in Serbia and other Balkan countries. Although European Union has regulated the ...levels of neonicotinoid insecticides in honey and pollen, there is an increased risk of the presence of these compounds in traditional products made from honey. The objective of this study was to develop an optimized LC–MS/MS analytical method with dispersive liquid–liquid microextraction (DLLME) and QuEChERS sample preparation procedures for analysis of seven neonicotinoids (dinotefuran, nitenpyram, thiamethoxam, clothianidin, imidacloprid, acetamiprid and thiacloprid) in honey liqueur. The LC–MS/MS conditions were optimized to unequivocally provide good chromatographic separation, selectivity and specificity of developed method. The method was validated to fulfill the requirements of SANCO/12495/2011 for both sample pretreatment procedures providing results for accuracy (R, 69.2–113.4% for DLLME; 71.8–94.9% for QuEChERS), precision (RSD expressed in terms of repeatability (3.21–10.20% for DLLME; 4.19–12.81% for QuEChERS) and within-laboratory reproducibility (9.11–16.63% for DLLME; 11.32–16.40% for QuEChERS)), limits of detection (LOD, 0.5–1.5μgL−1 for DLLME; 1.0–2.5μgL−1 for QuEChERS) and quantification (LOQ, 1.0–5.0μgL−1 for DLLME; 2.5–10.0μgL−1 for QuEChERS). Matrix effects were compensated by the use of matrix-matched calibration. Analysis of real honey liqueur samples obtained from local markets showed the presence of clothianidin or thiacloprid in four of the analyzed samples, therefore implicating the necessity of ongoing control of this type of traditional product.
•A LC–MS/MS method for neonicotinoids determination in honey liqueur is proposed.•Sample preparation with DLLME and QuEChERS was tested.•Good performance was obtained in terms of selectivity, precision and accuracy.•Honey liqueur samples were analyzed using the developed method.
Selectivity in mechanochemical cocrystal formation between nicotinamide and anthranilic acid or salicylic acid was studied using tandem in situ reaction monitoring by powder X-ray diffraction (PXRD) ...and Raman spectroscopy. Selectivity was probed by offering a competing cocrystal coformer to a previously prepared cocrystal or under competitive reaction conditions where all cocrystal coformers, in different stoichiometric ratios, were introduced together in the starting reaction mixture. Reaction paths were dependent on the starting mixture composition, and we find that the formation of intermediates and the final product can be predicted from solid-state ab initio calculations of relative energies of possible reaction mixtures. In some cases, quantitative assessment revealed different reaction profiles derived from PXRD and Raman monitoring, directly indicating, for the first time, different mechanochemical reactivity on the molecular and the bulk crystalline level of the reaction mixture.
In this research work, we synthesised poly(methyl methacrylate) (PMMA) enriched with 2 wt.% zinc oxide nanoparticles (ZnO) through conventional heat polymerisation and characterised its ...microstructure. It was found that the distribution of ZnO nanoparticles was homogeneous through the volume of the PMMA. The mechanical testing of the PMMA-ZnO composite primarily included the determination of the compressive properties on real dentures, while density measurements were performed using a pycnometer. The testing of functional properties involved the identification of the colour of the new PMMA-ZnO composite, where pure PMMA acted as a control. In the second step, the PMMA-ZnO cytotoxicity assays were measured in vitro, which were shown to be similar to the control PMMA. Based on this, it could be concluded that the newly formed PMMA-ZnO composite did not induce direct or indirect cytotoxic effects in L929 cell cultures; therefore, according to ISO/DIN 10993-5:2009, this composite was categorised as non-cytotoxic.
Two strains of classical swine fever virus (CSFV) (SRB/CSFV/1264/2005 and SRB/CSFV/6168/2006), producing serious clinical signs of disease during outbreaks in 2005 and 2006 in Serbia, were isolated ...on porcine kidney cells, and their complete genomes were determined by next-generation sequencing. This first complete genome characterization of Serbian CSFV strains provides new data about the evolution of CSFV in the Balkan region and enables further detailed phylogenetic studies of the various strains.
An urban environment defines a specific micro-climate which directly affects the quality of life in urbanized areas and often has a negative impact on urban populations. Phenomena like urban heat and ...surface heat islands are direct products of an urban lifestyle. Urban meteorological networks (UMNs) are a tool that can help to better understand and analyze the current situation and make the right decisions about future urban development. Deployed to monitor and record different objects and their states inside urban areas, UMNs build a long-term meteorological data time series database. The most commonly used systems for achieving this goal include wireless sensor networks (WSNs). This paper presents a combined experience in deploying three different WSN systems. During seven years of research in this field, the authors have recognized the importance of data reliability in data acquisition. More importantly, due to the lack of research addressing the reliability of the data received from WSNs by the core segment of the server (processes used in receiving, validating, parsing, and storing data into a database instance), the received data are used in scientific studies without questioning their reliability. To determine the possibility of shifting information provided by the data measured from sensor networks before it is stored in a desired form of database, this paper proposes a highly reliable socket server model. The model is built with high reliability and performance in mind and it includes three major processes, which use a combination of signals and control messages to pass information about their states. A case study is performed using high-end hardware, running a Linux operating system stressed to its limits. Repetition testing revealed inconsistency in the information provided by the operating system to the application layer, which could lead to the loss of information about short-term and rarely occurring monitored objects. The results lead to the conclusion that there is a clear need for a higher level of data reliability in the process of data acquisition by UMNs. The proposed socket server should fill this gap within the server’s core segment.
Properties of poly (lactic acid) (PLA) and its nanocomposites, with silica
nanoparticles (SiO2), as filler were investigated. Neat PLA films and PLA
films with different percentage of hydrophobic ...fumed silica nanoparticles
(0.2, 0.5, 1, 2, 3 and 5 wt. %) were prepared by solution casting method.
Several tools were used to characterize the influence of different silica
content on crystalline behavior, and thermal, mechanical and barrier
properties of PLA/SiO2 nanocomposites. Results from scanning electron
microscope (SEM) showed that the nanocomposite preparation and selection of
specific hydrophobic spherical nano filler provide a good dispersion of the
silica nanoparticles in the PLA matrix. Addition of silica nanoparticles
improved mechanical properties, the most significant improvement being
observed for lowest silica content (0.2wt.%). Barrier properties were
improved for all measured gases at all loadings of silica nanoparticles. The
degree of crystallinity for PLA slightly increased by adding 0.2 and 0.5 wt.
% of nano filler.
This research aimed to determine whether an adequate surgical approach can be chosen based on clearly defined values of anatomical landmarks (tentorial angle) and tumor size and extension.
We ...conducted a retrospective analysis of patients operated on because of pineal tumors. The cohort was divided depending on the surgical approach. On preoperative magnetic resonance imaging, we measured maximal diameters, tumor volume, and tumor propagation. In the group of patients operated with the supracerebellar infratentorial approach, we also tested the correlation of tentorial angle with residual tumor. Differences among groups in resection, complications rate, and outcome were tested by the χ2 test. Finally, in both groups, the correlation of residual tumor with tumor volume, propagation, and diameters was tested using the receiver operating characteristic curve.
In the group operated with a supracerebellar approach, total resection was achieved in 78% of the patients. The critical value of cranio-caudal diameter correlated with tumor residue was 31 mm, for lateral-lateral diameter 25 mm, for the lateral extension 14 mm, and tumor volume 12 cm3. Tentorial angle did not influence the extent of the resection. In the group operated with an occipital transtentorial approach, the critical tumor volume related to tumor residue was 9 mm3, anterior-posterior diameter 29 mm, and cranio-caudal diameter 28 mm. The extent of the resection was significantly higher in the supracerebellar group.
In both approaches, tumors larger than 3 cm show an increased risk of subtotal resection. Except when most tumor volume is localized above the venous system, we advocate a supracerebellar corridor as an effective approach that is not limited by tentorial angle.
Cu-Al-Nishape memory alloys (SMAs) are widely known for their better properties in comparison to other SMAs (lower production costs, increased ductility, enhanced machinability, reduced liquidus ...temperature, and decreased hysteresis), but there is still controversy in terms of the biological properties of these materials. The aim of this study was to evaluate biofunctional performances of Cu-Al-Ni alloy produced by continuous casting. The micro-chemical analysis was investigated by SEM/EDX. Immersion tests performed for seven days were used to estimate the quantity of Cu, Al, and Ni ions released in neutral pH and slightly acidic artificial saliva. To assess the biocompatibility of the Cu-Al-Ni alloy samples, MTT assay on fibroblasts and dental pulp cells was performed in indirect and direct contact with samples after 1,3, and 7 days.The study revealed that continuous casting enables the primary fabrication of Cu-Al-Ni rods with a shape memory effect. Samples immersed in artificial saliva with 6.5 pH value showed no significant amounts of released ions, despite the high concentration of copper in the alloy. However, in the acidic environment, the suppression of Cu was 0.14 µg/cm2, Al 1.9 µg/cm2, and Ni 0.73 µg/cm2, and as expected, it was confirmed that Cu-Al-Ni alloy is not corrosion resistant in an acidic environment. In conclusion, this study showed that biocompatibility concerns are related only to materials with a high Cu content in acidic environments. Oppositely, small doses of Cu ions promote cell proliferation, which might be useful in further attempts to enrich different biomedical materials with copper.
Peri-implantitis is an inflammatory lesion of peri-implant tissues. Eradication of the causative
bacteria and decontamination of the implant surface is essential in achieving predictable and stabile
...clinical results. Photodynamic therapy (PDT) is non-invasive adjuvant therapeutic method to surgery in
the treatment of bacterial infection.
The aim of this study was to evaluate early clinical and microbiological outcomes of periimplantitis
after surgical therapy with adjuvant PDT.
Fifty-two diagnosed peri-implantitis sites were divided into two groups. PDT was used for
decontamination of implant surface in the study group; in the control group, chlorhexidine gel (CHX)
followed by saline irrigation was applied. Several clinical parameters were recorded before the treatment
(baseline values) and three months after surgical treatment. Samples for microbiological identification
were collected before therapy, during the surgical therapy (before and after decontamination of implant
surface), and three months thereafter, and analyzed with identification systems using biochemical
analysis.
The use of PDT resulted in significant decrease of bleeding on probing in comparison to CHX
(p < 0.001). It showed significant decontamination of implant surfaces with complete elimination of
anaerobic bacteria immediately after surgical procedure and three months later.
The results indicate that PDT can be used as an adjuvant therapy to surgery for decontamination
of implant surface and surrounding peri-implant tissues within the treatment of peri-implantitis.