Valid Reference Research Articles

STEREO-PHOTOGRAMMETRIC MEASUREMENT OF SPATIO-TEMPORAL VELOCITY FIELDS AT LANGE GLACIER, KING GEORGE ISLAND

Abstract. A network consisting of six cameras was set up on both sides of Lange Glacier on King George Island, Antarctica, for a period of two years to monitor changes in the glacier’s motion behaviour. The cameras were observing spatio-temporal glacier surface velocity vector fields as well as the position of the glacier front. Velocity field information was obtained from image sequences by applying subpixel accuracy photogrammetric image sequence analysis techniques. Georeferencing in a superordinate coordinate system was performed via integrated photogrammetric-geodetic network adjustment. As a result, velocity fields were determined with maximum glacier surface velocities in the order of 1.5 meter per day. The results of terrestrial camera image sequence processing can be used as validation and calibration reference for satellite image based glacier velocity dynamics calculations. Moreover, the very high temporal resolution of the image sequences taken at 20 minute time intervals can also be used to analyse highly dynamic processes.

NONPERFUSION AREA QUANTIFICATION IN BRANCH RETINAL VEIN OCCLUSION

To precisely quantify retinal nonperfusion areas (NPAs) in branch retinal vein occlusion using widefield optical coherence tomography angiography (OCTA) and examine their association with neovascular complications. We enrolled 26 patients with treatment-naïve branch retinal vein occlusion and prospectively examined them for 12 months. After 3 monthly ranibizumab injections to treat macular edema, each patient underwent ultra-widefield (UWF) fluorescein angiography (FA) and OCTA. Ultra-widefield FA was additionally performed at Month 12. For UWF FA, the retinal NPA was measured using the equipment's built-in software. For OCTA, we used panoramic image montaged from 5 single 12 × 12 mm2 images and quantified the retinal NPA using a Gullstrand eye with a grid scale at each patient. Measurements were expressed in terms of actual values and disc area units. The retinal NPAs as measured using single OCTA and panoramic OCTA were significantly associated with that measured using UWF FA (P < 0.001 for both). Retinal neovascularization lesions were observed in 4 (15.4%) of 26 eyes. For patients with accompanying neovascularization, the retinal NPA measured using UWF FA, single OCTA, and panoramic OCTA were 187.9 ± 39.5 mm2 (109.9 ± 21.4 disc area), 34.3 ± 13.7 mm2 (19.9 ± 7.7 disc area), and 106.6 ± 24.5 mm2 (62.4 ± 13.6 disc area), respectively, which were larger than for those without neovascularization (P < 0.001, 0.014, and <0.001, respectively). Using widefield OCTA, we could quantify the retinal NPA of eyes with branch retinal vein occlusion. These could serve as valid references to assess the risk of neovascular complications.

Hematological and Chemical Profiles in a Porcine Model of Severe Multiple Trauma

Background: Clinical chemistry and hematological tests are widely used to monitor the clinical course of several diseases. However, these parameters are sparse in large-animal models of multiple trauma (MT). Thus, we aimed to provide these missing data to improve future experimental setups in trauma research. Methods: Male pigs (German Landrace pigs) were randomized into either an MT group (n = 8) including blunt thoracic trauma, tibial fracture, and controlled hemorrhage or a sham group (n = 8) without any trauma. After trauma induction, all animals received intensive care treatment for 72 h under anesthesia, including mechanical ventilation and volume resuscitation. Blood and urine samples were obtained to measure common hematological and chemical parameters before trauma (0 h), after trauma (1.5 h), during resuscitation (2.5 h), after fracture stabilization (3.5 h), and at 12, 24, 48, and 72 h. Statistical analyses were performed using a linear mixed model (group × time) and Welch’s ANOVA. Results: MT led to a perceptible immunological reaction. Between groups, significantly different time courses of leukocyte counts (p = 0.034) and lymphocyte proportions (p = 0.001) were observed. Moreover, MT changed the time course of total protein (p = 0.006). Significantly lower concentrations compared to sham were found in MT at each single time point starting at 1.5 h to the end of the observation period (all p < 0.05). Conclusions: Our results indicate that a traumatic insult leads to significant alterations in the immune system already shortly after trauma. Together with the additional catabolic reactions observed, these alterations might contribute to the occurrence of later complications. The presented data provide valid references for further experimental setups with prolonged observation times, especially in similar porcine models of MT.

Analytical performance evaluation of a commercial next generation sequencing liquid biopsy platform using plasma ctDNA, reference standards, and synthetic serial dilution samples derived from normal plasma

BackgroundCirculating tumor (ct) DNA assays performed in clinical laboratories provide tumor biomarker testing support for biopharmaceutical clinical trials. Yet it is neither practical nor economically feasible for many of these clinical laboratories to internally develop their own liquid biopsy assay. Commercially available ctDNA kits are a potential solution for laboratories seeking to incorporate liquid biopsy into their test menus. However, the scarcity of characterized patient samples and cost of purchasing validation reference standards creates a barrier to entry. In the current study, we evaluated the analytical performance of the AVENIO ctDNA liquid biopsy platform (Roche Sequencing Solutions) for use in our clinical laboratory.MethodIntra-laboratory performance evaluation of AVENIO ctDNA Targeted, Expanded, and Surveillance kits (Research Use Only) was performed according to College of American Pathologists (CAP) guidelines for the validation of targeted next generation sequencing assays using purchased reference standards, de-identified human plasma cell-free (cf) DNA samples, and contrived samples derived from commercially purchased normal and cancer human plasma. All samples were sequenced at read depths relevant to clinical settings using the NextSeq High Output kit (Illumina).ResultsAt the clinically relevant read depth, Avenio ctDNA kits demonstrated 100% sensitivity in detecting single nucleotide variants (SNVs) at ≥0.5% allele frequency (AF) and 50% sensitivity in detecting SNVs at 0.1% AF using 20–40 ng sample input amount. The assay integrated seamlessly into our laboratory’s NGS workflow with input DNA mass, target allele frequency (TAF), multiplexing, and number of reads optimized to support a high-throughput assay appropriate for biopharmaceutical trials.ConclusionsOur study demonstrates that AVENIO ctDNA liquid biopsy platform provides a viable alternative for efficient incorporation of liquid biopsy assays into the clinical laboratory for detecting somatic alterations as low as 0.5%. Accurate detection of variants lower than 0.5% could potentially be achieved by deeper sequencing when clinically indicated and economically feasible.

Identification of valid reference genes for quantitative RT-PCR in Caragana microphylla under salt and drought stresses.

Caragana microphylla is a leguminosae plant and grows mainly in semi-arid areas of northwest China and Mongolia. However, the lack of studies on C. microphylla reference genes limits the accurate understanding of the molecular biology mechanisms in this crop under abiotic stresses. In this study, we selected nine candidate genes from salt-treated C. microphylla transcriptome data and evaluated their stability by using geNorm, NormFinder, BestKeeper, and RefFinder in salt and drought conditions. In addition, the relative expressions of Delta 1-pyrroline-5-carboxylate synthase 2 (P5CS2) and Catalase 2 (CAT2) were examined to confirm the stability of the candidate reference genes. As a results, glyceraldehyde-3-phosphate dehydrogenase C2 (GAPC2) and 26S proteasome regulatory subunit (RPN5) were the most stable in both salt and drought treatments. The relative expression of P5CS2 and CAT2 also showed more stable levels in normalization by GAPC2 and RPN5 than the most unstable gene, Ubiquitin 4 (UBQ4). Therefore, it is believed that these candidate reference genes selected and validated in our study could be used to study the molecular biological study of response to salt and drought stress in C. microphylla.

A Multivariate Approach to the Selection and Validation of Reference Conditions in KwaZulu-Natal Rivers, South Africa

The use of reference conditions is essential to the monitoring and management of aquatic ecosystems. We examined existing and potential reference sites through historical data, maps and field data collected from river sites in KwaZulu-Natal (KZN), South Africa. In our study, we applied nine criteria that best reflect the characteristics of South African rivers on 24 a priori selected reference sites. These nine criteria comprised of catchment conditions (flow modification and natural landscape) and site-specific attributes (water quality, human disturbance, river channel, water abstraction, riparian vegetation, riparian zone modification and instream habitat quality). The a priori selected reference sites were subjected to validation using multivariate methods such as analysis of similarities (ANOSIM), similarity percentages (SIMPER) and non-parametric multidimensional scaling (MDS) based on the macroinvertebrate fauna by applying a SASS5 threshold considered to be an indicator of undisturbed sites in South African rivers. We identified differences in the macroinvertebrate assemblages of the reference conditions for each river group based on their ecoregions, geomorphology and seasonal variations. Ecoregions and river geomorphology were better in the grouping of sites with similar reference conditions than the seasons. Our findings indicated that all of the selected sites could be considered as valid reference sites; however, caution should be taken in applying this method to lowland rivers because of their noticeable seasonal variability and habitat instability which tend to alter their reference states. We recommend that a type-specific reference condition be developed for lowland rivers. Also, statistical validation of reference conditions should be a continuous process in river biomonitoring.

September 2020 at a glance: focus on heart failure with preserved ejection fraction and medical therapy.

Type 2 diabetes mellitus and obesity increase heart failure (HF) risk.1-4 Dang et al.5 showed that delivery of longevity-associated variant of the human BPIFB4 gene in obese mice with diabetes improves cardiac function. Usefulness of biomarker measurements may be lower in patients with HF and preserved ejection fraction (HFpEF).6, 7 Henkens et al.8 performed a systematic review of studies investigating the diagnostic value of novel biomarkers for HFpEF. The risk of bias was high in all studies. The main limitations were use of case-control designs, poor diagnosis of HFpEF, absence of pre-specified cut-off points, lack of external validation, inadequate and variable reference standards. An analysis of TOPCAT Americas showed that spironolactone treatment was associated with a reduction in loop diuretic and thiazide doses. The reduction in the risk of HF hospitalizations with spironolactone (hazard ratio 0.77, 95% confidence interval 0.62–0.96; P = 0.021) was, however, independent of multiple variables, including loop diuretic dose and serum creatinine, thus showing it was not mediated by its diuretic effects.9 Elderly age, renal dysfunction and hyperkalaemia are major causes of spironolactone discontinuation.10 An analysis of TOPCAT Americas confirmed these data and also showed that these patients received lower spironolactone, but not placebo, doses. Spironolactone reduced the primary endpoint also in these subgroups while its withdrawal was associated with a two to four-fold higher risk of events. Thus, a low-dose strategy should be preferred instead of discontinuation.11 Larsen et al.12 showed that metformin can improve myocardial efficiency in insulin-resistant patients with HFrEF without diabetes. Sacubitril/valsartan improves outcome in HFrEF.13 An analysis of PARADIGM-HF showed that liver dysfunction is an independent predictor of outcomes in HFrEF patients and sacubitril/valsartan improved liver function, compared with enalapril.14 Oxidative stress and inflammation have a key role in HF.15 Vericiguat treatment was associated with reduction in inflammatory- and oxidative stress-related markers, such as high-sensitivity C-reactive protein and uric acid, and this may have a role for its beneficial effects.16 Inotropic drugs did not improve survival in HF.17, 18 Better results can be expected from drugs not acting through an increase in intracellular calcium. Danicamtiv, a novel cardiac myosin activator, improved stroke volume, global longitudinal and circumferential strain and left atrial function in experimental models and in a phase 2a trial in patients with HFrEF.19 In patients hospitalized for acute HF, istaroxime had beneficial effects on left ventricular function, without hypotension, tachycardia, or serious cardiac adverse events.20 Lung congestion is a leading cause of dyspnoea and exercise intolerance.21 Transient receptor potential vanilloid 4 (TRPV4) channel regulates fluid exchange in the lungs. A novel transient TRPV4 antagonist (GSK2798745) was tested in a pilot randomized, placebo-controlled trial aimed at the reduction of lung water content. The new drug was well tolerated and showed a trend towards improved gas transfer.22

Engineered food supplement excipients from bitter cassava for minimisation of cassava processing waste in environment

Unchecked large-scale rudimentary upstream (sub-merged and solid state) fermentation processes of bitter cassava roots into alcohol have often contributed significantly to agricultural wastes into environment. Thus, the study explored a proven valorisation methodology, Simultaneous Release Recovery Cyanogenesis (SRRC) along with intact bitter cassava polysaccharide-rich derivatives (CWF), as an apt to find alternative materials for food supplement excipients.Triplicate CWF powder, peeled or intact bitter cassava roots, were produced and analysed to determine critical properties suitable in tablet making. Exclusion approach, using SRRC and compaction, was performed to select desired powder properties for tablet formulation. Microcrystalline cellulose, with known properties for developing drug excipients, was used as a validation reference material. Tablets, for disintegration time and in-vitro dissolution rates studies were produced using wet-granulation, and their potential to release and bio-avail Iron-Zinc investigated in-vitro (pHs 1.2 and 6.8 solutions, 37⁰C). Morphology and Iron-Zinc dissolution-release mechanisms were examined. Kinetic models were used to describe matrix dissolution and Iron-Zinc release mechanisms.Intact root powder compaction capacity, depicted by hardness, was 4.3, 4.4 and 4.6 KG at 200, 500 and 700 MPa respectively. Scanning Electron Microscopy (SEM) showed Iron-Zinc inclusion altered tablet morphology. Efficient matrix dissolution and Iron and Zinc release were achieved, showing apex recovery efficiency (98%, 30–45 min). Fitted models well-explained dissolution and release mechanisms (mean R² = 0.95), demonstrating adequacy.SRRC-improved intact bitter cassava was confirmed as potential alternative excipient's matrix for Iron and Zinc release and bioavailability. Thus, this approach is practical for indirect waste elimination, and can promote strategy for sustainable valorisation of agricultural wastes and alternative functional food supplements delivery system.

Analysis of Molecular Heterogeneity in Therapeutic IFNα2b from Different Manufacturers by LC/Q-TOF.

Recombinant human IFNα2b (rhIFNα2b), as an important immune-related protein, has been widely used in clinic for decades. It is also at the forefront of the recent emergence of biosimilar medicines, with numerous products now available worldwide. Although with the same amino acid sequence, recombinant proteins are generally heterogeneous due to post-translational modification and chemical reactions during expression, purification, and long-term storage, which could have significant impact on the final product quality. So therapeutic rhIFNα2b must be closely monitored to ensure consistency, safety, and efficacy. In this study, we compared seven rhIFNα2b preparations from six manufacturers in China and one in America, as well as four batches of rhIFNα2b preparations from the same manufacturer, measuring IFNα2b variants and site-specific modifications using a developed LC/Q-TOF approach. Three main forms of N-terminus, cysteine, methionine, and acetylated cysteine were detected in five rhIFNα2b preparations produced in E. coli (1E~5E) and one in Pseudomonas (6P), but only the native form with N-terminal cysteine was found in rhIFNα2b preparation produced in Saccharomyces cerevisiae (7Y). Two samples with the lowest purity (4E and 6P), showed the highest level of acetylation at N-terminal cysteine and oxidation at methionine. The level of oxidation and deamidation varied not only between samples from different manufacturers but also between different batches of the same manufacturer. Although variable between samples from different manufacturers, the constitution of N-terminus and disulfide bonds was relatively stable between different batches, which may be a potential indicator for batch consistency. These findings provide a valid reference for the stability evaluation of the production process and final products.

Validation of a spectrophotometric method for the determination of paracetamol in plasma applicable for toxicological emergencies in laboratories with limited resources

Acute paracetamol poisoning remains very problematic because of its insidious and rapid progression to fulminant hepatitis, even death, in the absence of adequate medical care. The latter depends in particular on the dosage of paracetamolemia that can be carried out by several methods, some of which are time-consuming, expensive or depend on the presence of specific reagents. The present work proposes to validate a plasma paracetamol assay method by UV/visible spectrophotometry applicable for toxicological emergencies, which can be used in laboratories with limited resources. Analytical optimizations were carried out based on the method of Glynn and Kendal for the determination of paracetamol on plasma by spectrophotometry. The guide of the European Medicines Agency (EMA) was taken as the main reference for the analytical validation of the method. Good linearity was obtained in the assay range from 40 to 400 μg/mL with a correlation coefficient r = 0.9941. The accuracy and fidelity obtained fulfilled the requirements of the validation protocol. The detection and quantification limits are respectively 10 μg/mL and 40 μg/mL. Analysis by the validated method is 20 times cheaper than the enzyme immunoassay method in terms of chemicals and reagents consumed. The method has been validated according to the requirements of the EMA and can therefore be used routinely. It is a low-cost method and is a good alternative when conventional methods are not available.

The applicability of COBIT processes representation structure for quality improvement in healthcare: a Delphi study

In healthcare, a variety of quality management practices are used. Although they are important sources for quality improvement initiatives, they do not focus on each particular process. On the other hand, 'Control Objectives for Information and Related Technologies' (COBIT) offers a well-defined process representation structure for representing potential process improvements. The objective of this study was to adopt the COBIT structure for healthcare processes and assess the applicability of such process representations. A two-round Delphi technique was applied: in round 1, open-ended interviews were performed with the participants; in round 2, the participants responded to the web questionnaire. The participants provided their opinion between 11 September 2018 and 26 June 2019. It included 37 members of an expert panel from 8 European countries. N/A. In round 1, strengths, weaknesses, opportunities and threats indicators of using the proposed structure in healthcare were identified. These were evaluated on a 9-point Likert scale in round 2. All participants noted that elements of the COBIT process representation structure were suitable for representing healthcare processes. The consensus was reached only for strengths and opportunities indicators. A set of processes represented with the suggested structure has the potential to become a valid reference in healthcare quality improvements initiatives, as COBIT in IT domain. Despite the fact that the expert panel members confirmed the applicability of the COBIT process representation structure for healthcare processes, the identified weaknesses and threats cannot be ignored.

Use of Remote Sensing Tools to Measure a Fluvial Geomorphic Design-Input Parameter for Land Reclamation

Fluvial geomorphic approaches for reclamation landform design have been applied since 2000, mostly in mined lands, as an alternative to conventional landform design methods. Those approaches aim to reconstruct mature landforms and drainage networks that would develop within a natural catchment, after thousands of years of work performed by geomorphic processes. Some fluvial geomorphic design methods take specific measurements from natural and stable reference areas for initial input values for reclamation design. Valid reference areas can be difficult to find, can be in highly anthropized environments, or may be difficult to access. This paper evaluates the use of remote sensing tools to measure morphometric parameters in upper sections of agricultural land catchments considered for use as reference areas. The ridge to head of channel distance (Xrh) was the parameter of interest. We used land surface profiles developed from LiDAR (Laser Imaging Detection and Ranging) data and planimetric measurements from orthoimages to estimate Xrh. The results obtained by the two methods were encouraging but showed a significant difference. Ground truthing showed that ploughing obliterated between 19.5 and 22.4 m (on average) of the headwater section of first-order channels, reducing the channel length by 15.1 to 32.4%. Using a greater Xrh value than appropriate for near steady-state conditions as a design input for a geomorphic reclamation project would be expected to result in active erosion processes in the constructed reclamation to regain their missing channel length. We recognize the advantages and limitations of remote sensing methods for measuring the morphometric parameters of the landform relief design inputs. We show how these tools may be used to help select and prioritize reference areas, and warn about the use of disturbed landscapes as reference areas to assure the geomorphic stability of the constructed reclamation designs.

Free vibration analysis of a porous rotor integrated with regular patterns of circumferentially distributed functionally graded piezoelectric patches on inner and outer surfaces

This article studies dynamic characteristics of a novel porous cylindrical hollow rotor based on the first-order shear deformation theory and Hamilton’s principle. The proposed model is made from a core including aluminum with porosity integrated with an arrangement of functionally graded piezoelectric patches placed on its inner and outer surfaces with a customized circumferential orientation. The piezoelectric patches are subjected to applied electric potential as sensor and actuator. The kinematic relations are developed based on the first-order shear deformation theory. Hamilton’s principle is used to derive governing equations of motion with calculation of strain and kinetic energies and external work. Solution procedure of the partial differential equations of motion is developed using Galerkin technique for simple boundary conditions. The accuracy and trueness of this work is justified using a comprehensive comparison with previous valid references. A large parametric study is presented to show influence of significant parameters such as dimensionless geometric parameters, porosity coefficient, angular speed, inhomogeneous index, and characteristics of patches on the mode shapes, natural frequencies, and critical speeds of the structure.

Prescriptive Reference Standards of Third-Trimester Cerebroplacental Ratio and Its Physiological Determinants

Objective: To construct valid reference standards reflecting optimal cerebroplacental ratio and to explore its physiological determinants. Methods: A cohort of 391 low-risk pregnancies of singleton pregnancies of nonmalformed fetuses without maternal medical conditions and with normal perinatal outcomes was created. Doppler measurements of the middle cerebral artery and umbilical artery were performed at 24–42 weeks. Reference standards were produced, and the influence of physiological determinants was explored by nonparametric quantile regression. The derived standards were validated in a cohort of 200 low-risk pregnancies. Results: Maternal body mass index was significantly associated with the 5th centile of the cerebroplacental ratio. For each additional unit of body mass index, the 5th centile was on average 0.014 lower. The derived 5th, 10th, and 50th centiles selected in the validation cohort were 5, 9.5, and 51% of the measurements. Conclusions: This study provides methodologically sound prescriptive standards and suggests that maternal body mass index is a determinant of a cutoff commonly used for decision-making.

Evaluating the reliability of U–Pb laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) carbonate geochronology: matrix issues and a potential calcite validation reference material

Abstract. We document that the reliability of carbonate U–Pb dating by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is improved by matching the aspect ratio of the LA single-hole drilling craters and propagating long-term excess variance and systematic uncertainties. We investigated the impact of different matrices and ablation crater geometries using U–Pb isotope analyses of one primary (WC-1) and two secondary reference materials (RMs). Validation RMs (VRMs) include a previously characterised one (ASH-15D) and a new candidate (JT), characterised by ID-TIMS (intercept age: 13.797±0.031 Ma) with excellent agreement to pooled LA-ICP-MS measurements (13.75±0.11 | 0.36 Ma), a U concentration of approx. 1 µg g−1 and 238U∕206Pb ratios from 5 to 460, defining the isochron well. Differences in ablation crater depth to diameter ratios (aspect ratio) introduce an offset due to downhole fractionation and/or matrix effects. This effect can be observed either when the crater size between U–Pb RM and the sample changes or when the ablation rate for the sample is different than for the RM. Observed deviations are up to 20 % of the final intercept age depending on the degree of crater geometry mismatch. The long-term excess uncertainty was calculated to be in the range of 2 % (ASH-15D) to 2.5 % (JT), and we recommend propagating this uncertainty into the uncertainty of the final results. Additionally, a systematic offset to the ID-TIMS age of 2 %–3 % was observed for ASH-15D but not for JT. This offset might be due to different ablation rates of ASH-15D compared to the primary RM or remaining matrix effects, even when the aspect ratios chosen are similar.

Cartografía del aguacate en el sur del estado de México mediante tratamiento digital de imágenes sentinel-2

El cultivo de aguacate (Persea americana Mill.) es uno de los más importantes en México, entre los estados con mayor producción se encuentra el Estado de México, que es el tercer estado productor a nivel nacional. Coatepec Harinas y Donato Guerra son dos de los municipios más representativos en lo respectivo a esta actividad; sin embargo, no existe un censo que especifique la superficie del cultivo, por lo que el objetivo de esta investigación fue probar métodos de índices de vegetación, algoritmos spectral angle mapper (SAM) y spectral information divergence (SID) y la combinación de estos en las imágenes del sensor Sentinel-2 para evaluar su desempeño en la identificación de áreas plantadas con el cultivo de aguacate. Los resultados se validaron con una matriz de confusión y la comparación de los datos de referencia de entrenamiento y validación. El algoritmo SID alcanzó una precisión de 97.5% para detectar aguacate, mientras que el tratamiento SAM obtuvo una precisión de 63.1%. La combinación de SID con el índice Anthocyanin Reflectance Index 1 (ARI1), proporcionó un mejor resultado sobre la cartografía de validación regional con 85% de precisión. Otras combinaciones de índices y tratamientos dieron resultados inferiores al 50% de la precisión por lo que no se recomiendan. Esta metodología podría ser probada para la detección de otros cultivos de interés comercial, dado que Sentinel-2 muestra ser una alternativa viable para este tipo de estudios, teniendo una buena resolución espectral, además de ser de fácil acceso y manipulación.

INTRAORAL DENTAL X-RAY RADIOGRAPHY IN BOSNIA AND HERZEGOVINA: STUDY FOR REVISING DIAGNOSTIC REFERENCE LEVEL VALUE

This paper presents the study that would allow a revision of the currently valid diagnostic reference level in intraoral dental X-ray radiography in Bosnia and Herzegovina. The study was conducted for six procedures that are used to capture incisor, premolar and molar teeth, of both maxilla and mandible, in adults. Measurements were performed on 41 intraoral X-ray devices, 20 of which were systems with digital image receptor and 21 film-based X-ray systems. In this study, incident air kerma (Ki) and air kerma-area product (PKA) were used as patient dose descriptors. The third quartile (Q3) of the measured incident air-kerma values was used to compare with the current national diagnostic reference level (DRL) for intraoral dental procedures. The obtained results of Q3 for both types of devices, with film-based and digital image receptors, have shown that the third quartile values are lower (3.5 and 1.2mGy, respectively) than the current national DRL (7.0mGy). Hence, new data can be used to re-establish the diagnostic reference levels in intraoral dental X-ray examinations in Bosnia and Herzegovina.

Insight into filter cake structures using micro tomography: The dewatering equilibrium

In recent years, non-destructive X-ray microscopy (XRM) has become a common method to characterize particle systems in various scientific fields: Besides the size and shape of particles in bulk powders, the insight into filter cake structures provides additional information about micro processes during filtration and dewatering. Distributed particle properties mainly influence the porous network build-up with possible local deviation in vertical and horizontal alignment. This article focusses on the model-based correlation between the distributed particle properties and characteristic network parameters like tortuosity, pore radii and preferred capillaries for dewatering, using tomography data as model input. Therefore, cake-forming filtration experiments were carried out with a down-scaled, self-constructed in-situ pressure nutsch. The entire tomographic dataset consists of seven individual scans at certain desaturation steps at different pressure levels.For the experiments, a lognormal distributed particle system (crushed Al2O3) in the range of 55 to 200 µm inside an aqueous suspension was used, containing additives for contrast enhancement. Image data processing based on reconstructed 360° projections allows the identification of the background, solid particles and liquid phase by a two-step segmentation.The subsequent modelling uses experimentally verified particle size distributions from laser diffraction measurements (integral value), 2D- (limited number of particles) as well as tomographic analysis, based on calculated single-particle volumes given by the voxel-dataset (all particles within the scanned volume). To characterize the porous network, a developed tetrahedron model is first applied to follow the shortest way through the porous matrix, then again to calculate the widest capillary related to the pore entrance. Furthermore, with information about the pore throat distribution and the wetting line from the tetrahedron side faces, the force balance is evaluated. This results in an entrance pressure distribution, the capillary pressure curve. Experimental data according to VDI 2762 built filter cakes and mercury intrusion tests are taken as reference for validation.

Global warming, environmental security and its geo-economic dimensions case study: Caspian Sea level changes on the balance of transit channels.

Global warming and climate change are considered as important environmental problems. Environmental security is more pronounced with regard to the Caspian Sea. Due to the geopolitical and geo-economic dimensions on the one hand, and its unique characteristics on the other, this large lake is considerably fragile against environmental challenges. In fact, the innate isolation of the Caspian Sea makes its conditions with regard to global warming unique. Using a descriptive-analytical method and library and valid article references, this study seeks to answer the question: "what are the effects of global warming on environmental security and what challenges does it pose to the Caspian Sea from the geo-economic point of view?" And Also maps and charts related to the research topic were collected and plotted in the GIS. In the next step, using a descriptive-analytical method based on geopolitical perspectives, especially environmental geopolitical studies and internet searches, we analyze the spatial effects of this universal phenomenon in the context of environmental geopolitical systems. The findings indicate that global warming will pose a large spectrum of challenges and problems to the Caspian Sea from the destruction of its ecosystems to the complete transformation of its nature. This research has studied global warming and its effects on the sea level changes of the Caspian Sea and particularly the level of water in the transit channels of the Caspian Sea from the geo-economic point of view. The results show that fluctuations in the water level of the Caspian Sea, in addition to environmental challenges, narrow the balance of its transit channels and threaten the geo-economics and environmental security of the Caspian Sea.

Study on Inflatable Deployment Characteristics of Flexible Film Wing

The inflation deployment process directly affects the forming and bearing deformation characteristics of the flexible wing. In order to optimize the structural design of the flexible inflatable wing, the inflation deployment process was studied with the finite element simulation calculation for the distribution characteristics of pressure and displacement when the wing is not inflated and after inflation molding. The results show that the inflation process is: for the first stage, when the inflation pressure is lower than the critical forming pressure, due to the effect of gravity, the flexible film wing downward bending, and the skin surface pressure is quite small, while the wing is inflated, the overall deformation and displacement is quite large. for the second stage of inflation molding, the flexible wing has a bearing stiffness, but due to aerodynamic loading upward warping occurred, the pressure of the wing root is large, but the displacement of the wing tip is large, which could provide a valid reference method to study the precision and stability of the flexible wing inflation process.