Density Measurements Research Articles

Reduced resting-state periodic beta power in adults who stutter is related to sensorimotor control of speech execution

ObjectiveThe primary aim of the current study was to determine whether adults who stutter (AWS) present with anomalous periodic beta (β) rhythms when compared to typically fluent adults in the eyes-open resting state. A second aim was to determine whether lower β power in the RS is related to a measure of β event-related desynchronization (ERD) during syllable sequence execution. MethodsEEG data was collected from 128 channels in a 5 minute, eyes-open resting state condition and from a syllable sequence repetition task. Temporal independent component analysis (ICA) was used to separate volume conducted EEG sources and to find a set of component weights common to the RS and syllable repetition task. Both traditional measures of power spectral density (PSD) and parameterized spectra were computed for components showing peaks in the β band (13-30Hz). Parameterization was used to evaluate separable components adjusted for the 1/f part of the spectrum. ResultsICA revealed frontal-parietal midline and lateral sensorimotor (μ) components common to the RS and a syllable repetition task with peaks in the β band. The entire spectrum for each component was modeled using the FOOOF algorithm. Independent samples t-tests revealed significantly lower periodic β in midline central-parietal and lateral sensorimotor components in AWS. Regression analysis suggested a significant relationship between left periodic sensorimotor β power in the RS and ERD during syllable sequence execution. ConclusionsFindings suggest that periodic β peaks in the spectrum are related to hypothesized underlying pathophysiological differences in stuttering, including midline rhythms associated the default mode network (DMN) and lateral sensorimotor rhythms associated with the control of movement.

Update on Quantitative Computed Tomography.

Quantitative computed tomography (QCT) has important technical advantages for the measurement of bone mineral density, and the technique is well suited for both the diagnosis of osteoporosis and the monitoring of treatment. Its use deserves a wider application than at present. The use of QCT in both research and in the clinic has recently garnered increasing attention. In this review, we update the advances and application of QCT in the study of osteoporosis.

Bait Biomass and Caloric Contribution From the Dungeness Crab (Cancer magister) Fishery in Oregon, USA

ABSTRACTFishery discards worldwide increase the availability of organic materials on the benthos, altering trophic relationships and potentially increasing the abundance of benthic consumers. Expert knowledge from fishers is a valuable yet often underutilized source of information to understand these dynamics. We interviewed Dungeness crab fishers (n = 24) to determine the most‐used bait types and to characterize regional and seasonal bait use strategies that drive inputs of organic matter into Oregon coastal waters during the commercial Dungeness crab fishery each year. Based on bomb calorimetry measurements of caloric densities of 12 commonly reported bait species, total energetic input was 12.99 × 109 kJ (3.10 B kcal) from bait in the 2019–2020 commercial ocean Dungeness season in Oregon, USA. Fishing effort and bait inputs were strongly seasonal, with 88% of effort concentrated in the first 60 days of the 9‐month‐long season but did not vary regionally. This large, temporally concentrated caloric input suggested that bait could contribute substantially to Dungeness crab productivity. Fisher respondents indicated that bait effectiveness was the most important motivating factor in choosing a bait type, more than availability or cost.

Role of Acoustic and Volumetric Properties in View to Estimate the Intermolecular Interactions in the Solutions of Electrolytes and l‐Isoleucine

Abstractl‐Isoleucine is subjected to density and sound velocity measurements in aqueous solutions of potassium (KCl) and sodium chlorides (NaCl) as well as water, from 288.15 to 298.15 K. Through the use of these experimental data, a variety of volumetric and acoustical parameters are calculated, including values for molar volume (Vm), available volume (Va), adiabatic compressibility (β), nonlinear parameters (B/A), Wada constant (W), Rao's constant (R), and van der Wall's constant (a). The findings shed light on many electrostatic and hydrophobic interactions within the binary system involving electrolytes, water, and amino acids. The interactions between the electrolytes and l‐isoleucine are thoroughly examined under varying electrolyte concentrations and temperatures, revealing many interactions. Positive transfer quantities demonstrate the ion‐hydrophilic and solute–solvent interaction in the aqueous medium, particularly between l‐isoleucine and NaCl and KCl. The influence of electrolyte type and temperature on these interactions is discernible. The culmination of the study's outcomes is elaborated through analyzing solute–solvent and solute–solute interactions. In particular, the interaction hierarchy is identified as l‐isoleucine + water + KCl > l‐isoleucine + water + NaCl > l‐isoleucine + swater.

Speed and accuracy investigations of neural network algorithms for ionospheric modelling at an equatorial region

Neural networks are very efficient tools for modeling, including ionospheric modeling. The training algorithm is important for achieving the optimum performance of the trained network. This research is therefore meant to evaluate and compare the performances of ten neural network training algorithms based on their prediction accuracies, and the duration/times taken by each of the algorithms to establish the optimum result. The neural networks were trained using electron density measurements by Radio Occultation (RO) technique from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. Data for the period 2006 through 2021 was used. The networks were trained using about 2.9 million data points collected from the Kano region, Nigeria (5-degree rectangular region around geographic: 12.00° N, 8.59° E) after performing data quality control. The training algorithms considered in the work include: Bayesian Regularization (BR); Broyden-Fletcher-Goldfarb-Shanno Quasi-Newton (BFG); Conjugate Gradient with Powell/Beale (CGB); Fletcher-Reeves Conjugate Gradient (CGF); Gradient descent with momentum and adaptive learning rate (GDX); Levenberg Marquardt (LM); One Step Secant (OSS); Polak-Ribiére Conjugate Gradient (CGP); Resilient Backpropagation (RP); and Scaled Conjugate Gradient (SCG). The results showed that the BR and the LM algorithms gave the best performances in minimizing the errors of prediction (the mean RMSEs are respectively 112 and 114 ×103 electrons/cm3), but the RP algorithm, which came third in terms of accuracy, was significantly faster than both the LM and BR algorithms. The worst-performing algorithm in terms of accuracy was the GDX algorithm, although it was the fastest algorithm. The BFG algorithm was the worst-performing algorithm in terms of a combination of speed and accuracy. The developed neural network model was validated using ionosonde electron density measurements obtained from Ilorin, Nigeria (geographic: 8.5° N, 4.5° E; geomagnetic: 1.8° S). A comparison of the neural network, the NeQuick, and the IRI model predictions relative to the ionosonde measurements indicate that the neural network model was the best-performing model; the NN model predictions minimized the mean absolute errors (MAEs) in ∼44% of 399 ionosonde profiles investigated, the IRI model did so in ∼32%, and the NeQuick did so in ∼24%. The MAEs of the NeQuick however exhibited the best (least) variance. In overall, the NN model gave the least (best) mean of the MAEs (∼73 × 103 cm−3), compared to ∼82 × 103 cm−3 given by both the NeQuick and the IRI models, further supporting the idea that neural networks are excellent for present-day ionospheric modeling.

Reducing tree volume overestimation in quantitative structure models using modeled branch topology and direct twig measurements

Abstract Quantitative Structure Models (QSMs) are fit to tree point clouds to represent the topology of trees as a network of cylinders. QSMs allow for the calculation of metrics difficult to measure without destructive sampling, including total tree volume. Current limitations in terrestrial laser scanning technology make small branches difficult to accurately resolve, causing overestimation of small branch volume in QSMs, which can translate into overestimating tree biomass. We present a new method called Real Twig to correct overestimated small branch and twig cylinders in QSMs. Real Twig differs from current methods by using twig diameters measured directly from corresponding tree species to model a unique taper for every path in the QSM, using the QSM’s inherent branching topology, but without relying on predefined mathematical or allometric relationships. To test Real Twig, we generated QSMs for different sets of trees that had detailed dry mass and density measurements obtained via felling after scanning. QSM-based biomass estimates were obtained by multiplying the tree’s QSM-based volume estimate by the tree’s specific basic density value. We trained our method with high-quality data consisting of five northern red oak (Quercus rubra L.) and five red maple (Acer rubrum L.) trees, using two different versions of TreeQSM, a widely used algorithm for generating QSMs. We further tested our method on three publicly available datasets, including managed forests and large tropical trees, collected with both phase-shift or time-of-flight sensors. QSMs corrected with our Real Twig method showed a very large improvement in tree biomass estimation, with a relative mean error of −1.2%, a relative root mean square error of 10.5%, and a concordance correlation coefficient of 0.999, compared to a relative mean error 76.8%, a relative root mean square error of 48.7%, and a concordance correlation coefficient of 0.982, when using the standard outputs of TreeQSM.

Density-profile imaging using a second harmonic dispersion interferometer configured with reflective-beam expanders.

A Second-Harmonic Dispersion Interferometer (SHDI) is assembled to measure the two-dimensional, line-integrated density profile of a pulsed-plasma jet using probe-beam diameters well beyond the 1mm diameters typically used in such instruments. An initial prototype demonstrated the technique using 7mm beam diameters, which are now increased to 35mm diameter using two types of beam expanders: an achromatic-beam expander (ABE) or a reflective-beam expander (RBE). ABEs were found to add a periodic background to the measured-phase image with a magnitude of the order of Δϕ ∼ 2π radians, compared to the background phase noise level in the system configured without beam expanders at Δϕbg ∼ 0.025 radians. Subtraction of the background phase in a sample image reduced the effect of the ABE phase offset to a level of Δϕ ∼ 0.1 radians, enhancing the quality of the density measurements. Reflective-beam expanders (RBEs) did not modify the background phase appreciably and were a significant improvement, allowing the instrument to be used for 2D (r, z) density-profile measurements of a 3cm diameter × 5cm long, pulsed-plasma jet. Variations in the timing parameters for the plasma gun, specifically the gas valve opening time and the gas-injection delay, for a constant discharge current were used to map the plasma gun's performance, indicating a nominal line-integrated electron density of Nedl ≳ 3 × 1015 cm-2 and a volumetric density of Ne ≃ 9 × 1015cm-3. The results obtained for the RBE configuration demonstrate that the 2D-SHDI platform may be scaled to even larger sample areas and a rep-rated system, with the ability to potentially provide for a reproducible, time-resolved (∼1 ns), high resolution (∼100μm) measurement of 2D plasma-density profiles.

Effect of replacing B2O3 with CuO on the structural, optical absorption, thermal, mechanical, and gamma-ray shielding properties of B2O3–Bi2O3–K2O glass

This paper delves into the effect of replacing B2O3 with CuO on the structural, optical absorption, thermal, mechanical, and gamma(γ)-ray shielding properties of four CKB glasses formulated as (65-y)B2O3–15Bi2O3–20K2O-yCuO (where y = 0, 0.3, 0.6, and 1.2 mol%). The glasses were created using the melt-quenching technique, and their non-crystalline structure was verified by X-ray diffraction (XRD) analysis. Fourier-transform infrared (FTIR) spectroscopy identified several structural groups, predominantly consisting of BO3, BO4 units, and B–O–B linkages. Thermal properties, assessed via Differential Scanning Calorimetry (DSC), indicated that the glass transition temperature was highest for the 0.3 mol% CuO sample (CKB0.3), demonstrating enhanced thermal stability in comparison to other compositions. Density measurements correlated positively with CuO concentration, peaking at 1.2 mol%, while molar volume, boron molar volume, oxygen packing density, and boron-boron separation distances showed a decreasing trend with increased CuO concentration. UV–Vis absorption spectroscopy indicated a decline in the optical energy gap and an increase in Urbach energy, attributed to the conversion of BO3 into BO4 units in the glass matrix. Mechanical properties, evaluated using the Makishima-Mackenzie model, demonstrated enhancements in elastic moduli and micro-hardness with rising CuO concentration. The γ-ray shielding properties (γ-RPs) were examined at energies of 0.662, 1.173, and 1.333 MeV, revealing that both the linear attenuation coefficient and effective atomic number reached their maximum values at 1.2 mol% CuO (CKB1.2). While CKB1.2 exhibited excellent mechanical and γ-ray shielding performance, CKB0.3 excelled in thermal stability and demonstrated γ-ray shielding efficiency comparable to CKB1.2. This suggests that CKB0.3 is a promising candidate for radiation shielding applications requiring a balanced combination of thermal stability and effective γ-ray attenuation properties, particularly at 0.662 MeV.

Comparisons of longitudinal radiographic measures of keel bones, tibiotarsal bones, and pelvic bones versus post-mortem measures of keel bone damage in Bovans Brown laying hens housed in an aviary system.

Keel bone damage, include deviations and fractures, is common in both white and brown laying hens, regardless of the housing system. Radiography for assessing birds' keel bones is was proposed by previous studies. However, radiographs show only 2 out of 3 dimensions of the dissected keel bones. The current study aimed to (1) investigate the association of radiographic optical density (keel and tibiotarsal) and geometry (keel) with dissected keel bone pathology. Previous studies suggested that keel bone fractures may result from internal pressure exerted by pelvic cavity contents. The current study also aimed to (2) investigate the potential associations between pelvic dimensions and measures of keel bone damage. A sample of 200 laying hens on a commercial farm were radiographed at 16, 29, 42, 55, and 68 weeks, and culled at the end of the laying period (week 74). The birds were examined post-mortem for pelvic dimensions and underwent whole-body radiography, followed by keel and tibiotarsal bone dissection and radiography, and keel bone scoring. The radiographs were used to estimate radiographic optical density (keel and tibiotarsal bone) and keel bone geometry (ratio of keel bone length to mid-depth). The method for on-farm radiography of laying hens, including live bird restraint, positioning for live keel imaging, and post-imaging measurements, was developed, tested, and found to be reproducible. The radiographs (1,116 images of 168 birds) and the respective measurements and post-mortem scores of keel bones are also provided for further development of radiographic metrics relevant to keel bone damage. Some longitudinal radiographic measurements of keel geometry (ratio of length to mid-depth) and optical density (keel and tibiotarsal) showed associations with the damage (deviations/fractures) observed on the dissected keel bones. The associations of keel damage were clearer with the radiographic keel geometry than with keel and tibiotarsal optical density, also clearer for the keel deviations than for keel fractures. The higher radiography ratio of keel length to mid-depth at weeks 42, 55 and 68 of age, the larger deviations size observed on the dissected keels at age of 74 weeks. The higher the tibiotarsal radiographic optical density at week 55 of age, the lower deviations size and fractures count observed on the dissected keels at age of 74 weeks. Pelvic dimensions showed a positive correlation with body weight, but a larger pelvic cavity was associated with increased keel bone damage. These findings lay the foundations for future use of on-farm radiography in identifying appropriate phenotypes for genetic selection for keel bone health.

Retinal vascular changes after Silicon Oil removal in the Eye with Rhegmatogenous Retinal detachment

BackgroundThis study aims to examine vessel density changes in the optic nerve and macula following silicone oil removal (SOR) surgery in eyes with rhegmatogenous retinal detachment (RRD) at different time points by Optical Coherence Tomography Angiography (OCTA) in compared to the contralateral eye.MethodsA total of 43 eyes from 43 patients with silicone oil in their eyes for 3–9 months underwent OCT-A using AngioVue and optic disc-associated vessel density (VD) and thickness, macular-associated VD and thickness, Foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), Acircularity index (AI), vessel density within a 300 μm wide region of the FAZ were compared between eyes. OCTA scans were performed one week before SOR and one month and three months after SOR.ResultsThe mean age of participants was 52.8 years (SD = 15.85) and a median visual acuity was 0.8 (range: 0.5-1.0). Notably, male participants constituted 67.4% of the sample. The preoperative mean value BCVA (logMAR) of patients was 0.73, and 3 months post-oil removal was 0.7727. Regarding optic disc parameters, RNFL thickness and vessel density (VD) measurements Peripapillary, whole disc, inside disc, and Disc Angio (superior, Nasal, inferior, temporal) did not change.In analyzing macular thickness parameters, all of them (Whole and Fovea, parafoveal, and Perifovea) remained unchanged. Examining macular vessel density parameters revealed no significant changes across superficial and deep retinal layers. Finally, the comparison of the foveal avascular zone (FAZ) area and flow density (FD) parameters demonstrated consistent measurements with non-significant alterations observed in FAZ size (p = 0.6) and FD values (p = 0.49) over the monitored duration.ConclusionThere was no change in peripapillary VD and macular vessel density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) after silicone oil removal. FAZ and full retinal thickness remained stable 3 month after SOR. Clinical trial number: Not applicable.

First Thomson scattering results from AWAKE’s helicon plasma source

Abstract We present the first results of electron density and temperature measurements obtained from Thomson scattering at the helicon plasma source (HPS) for the AWAKE project. These measurements are compared to simulation results from a 1D power and particle balance model (PPM), confirming that the plasma can be fully sustained by collisional power dissipation. The variations in plasma parameters under different experimental conditions are evaluated in the PPM framework. We discuss current limitations of the model and propose possible improvements. Additionally, we suggest modifications to the existing HPS setup to enhance axial plasma homogeneity.

The Effect of a 12-week Plyometric Training on Growth Hormone, IGF-1 and Bone Health Indexes in Adolescent Boys

Background: During adolescence, physical activity influences bone mass, which is determined by both genetic and environmental factors. Objectives: This study examines the effect of plyometric exercises on serum markers in male adolescents, including growth hormone, vitamin D, parathyroid hormone, phosphate, and calcium. Methods: The study involved a sample of 30 male adolescents aged 15 years ± 6 months. The participants were divided into two groups: the first group, named the plyometric group (PG), included 15 adolescents who underwent plyometric training sessions three times a week for a duration of 12 weeks. The second group, called the control group (CG), consisted of 15 adolescents who only attended their normal school lessons without any physical training. Resting levels of GH, IGF-1, vitamin D, calcium, phosphate, and PTH were measured before and 48 hours after the last training session, along with bone mass density (BMD) measurements of the femoral neck, lumbar spine, and total body. To evaluate power, the vertical Sargent jump test was used. Results: The results indicate that the PG demonstrated significant improvements in BMD, explosive strength, GH, IGF-1, and vitamin D levels compared to the CG group (P < 0.05). Changes in phosphate, calcium, and PTH were not significant in the PG compared to the CG after 12 weeks of plyometric training (P > 0.05). Conclusions: The 12-week plyometric program resulted in notable enhancements in bone health, explosive strength, and anabolic hormones such as GH and IGF-1, as well as 25-hydroxyvitamin D serum levels.

Formulation and Characterization of Deep Eutectic Solvents and Potential Application in Recycling Packaging Laminates.

Deep Eutectic Solvents (DESs) show promising abilities for the delamination of multilayer packaging films that are used in food packaging and in pharmaceutical blister packs. Due to the complexity of their structure, the recycling of such materials is a challenging task, leading to the easiest or cheapest disposal option of either landfill or incineration. Towards the development of 'green' solvents for efficient waste management and recycling, this research focuses on the preparation of a range of hydrophobic and hydrophilic DESs based on carboxylic acids in combination with various naturally derived aliphatic and aromatic organic compounds as well as amino acids. Chemical and physical characterization of the solvents was undertaken using differential scanning calorimetry, rheometry, and density measurements for the determination of their properties. Subsequently, batches of solvent were tested against different types of consumer packaging to evaluate the ability of the DES to delaminate these structures into their component materials. The laminate packaging waste products tested were Al/PE, PE/Al/PET, Al/PE/paper, and PVC/PE/Al. Separated films were collected and studied to further examine the effect of solvent delamination on the materials. Depending on the DES formulation, the results showed either partial or full delamination of one or more of the packaging materials, albeit there were challenges for certain solvent systems in the context of delivering a broad delamination efficiency. Variables including temperature, agitation rate, mixing time, and solvent ratios were investigated via a Design of Experiments process to assess the effects of these parameters on the delamination outcome. The results showed that the DESs presented in this research can offer an efficient, low-energy, affordable, and green option for the delamination of laminate packaging materials.

The role of microsleeps to estimate sleepiness at the wheel and near-miss accidents in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is considered a risk factor for sleepiness at the wheel (SW) and near-miss accidents (NMA). To date, there are subjective and objective methods such as the Maintenance of Wakefulness Test (MWT) to investigate sleepiness. However, these methods have limitations. Therefore, a new analysis of the MWT was introduced based on the identification of microsleeps (MS). So, we tested MS analysis to improve the discriminative ability of MWT in recognizing individuals at risk for SW and NMA in a population with OSA. The study was conducted on 100 naïve patients with suspected OSA referred to our Sleep Medicine Unit. All patients performed a full-standard polysomnography and MWT. The MWT was analyzed according to standard criteria, and the presence of MS episodes, the mean MS latency and the MS density (the mean absolute or relative number of MS) were assessed. Microsleeps were observed in 100% of alert or sleepy patients and 47% of the fully alert (P <0.0001). Almost 90% of patients reporting NMA showed episodes of MS during MWT. The occurrence of NMA was related to EDS, MS latency and MS density (P <0.001). The discriminative power for the NMA of MS density measures was higher than that derived from latency analysis, particularly in patients without EDS and with a simultaneous mean sleep latency >33 minutes. MS analysis provides objective evidence of sleepiness and, therefore, could improve the discriminative ability of the MWT in recognizing individuals at high risk for accidents.

A Novel Primary Care-Based, Practice Nurse-Led Bone Health Service for People in Long Term Care

Abstract Background 11% of all Irish hip fractures originate in the long-term care (LTC) setting and LTC residents are at the highest risk of reduced bone density. Risk is poorly managed as no primary care framework exists. A novel practice nurse-prescriber-led service is described in which risk estimation directs stratification, investigation, and treatment of fragility fracture risk. Methods Baseline assessment uses FRAX (fracture risk assessment tool) to risk-stratify using NOGG (National Osteoporosis Guideline Group) risk charts and inform the need for bone mineral density (BMD) measurement. A bone health drug optimisation process ensured patients were offered treatment at appropriate intensity. Results 107 residents of mean age 86.2 were newly admitted to long-term care in 2023. 92 were included and 15 were excluded due to poor prognosis. 10 of the 92 residents included died in 2023. 91 patients were risk-stratified into NOGG categories as follows: Low 22%, n=20; intermediate, below intervention threshold 23%, n=21; intermediate, above intervention threshold 16%, n=15; high 19%, n=17; very high 20% n=18. 84% (n=77) of those in risk categories indicating anti-resorptive treatment were not prescribed a bisphosphonate at baseline and none were prescribed Denosumab. 84% (n=42) were prescribed Vitamin D either with or without supplemental calcium and 16% were prescribed nothing to improve bone health. Post-intervention, 100% (n=43) of patients at a risk level of NOGG ‘intervention threshold’ or above were prescribed either Vitamin D with or without supplemental calcium and 58% (n=25) were prescribed anti-resorptive therapy (denosumab =47%, n=20 or bisphosphonate = 9%, n=5). Discussion of treatment with the primary care and LTC team is periodic. At the time of data capture, 88% of residents were discussed and 12% were planned for discussion. Conclusion A practice nurse-prescriber led service targeting LTC residents is effective in optimising screening and prescribing. Future work could include replication in the national LTC community.

Assessment of Radio Frequency Electromagnetic Field Exposure from Wi-Fi Routers in LAUTECH Campus, Ogbomoso, Nigeria

Wi-Fi routers play a crucial role in enabling internet connectivity within the academic environment. However, there are concerns that radiofrequency electromagnetic field exposure from Wi-Fi routers may be hazardous to human health. The main objective of the research is to assess the safety of RF-EMF exposure in educational environments. A total of 14 Wi-Fi routers were randomly selected and investigated across LAUTECH campus using stratified random sampling method. Measurement of the power density and the electric field strength from these routers were taken using a hand-held electrosmog, TES-593, radiofrequency meter. Measurement points were selected at various distances of 1.0, 2.0, 3.0, 4.0 and 5.0 m from the Wi-Fi routers, representing typical distances between users and routers. At each measurement point, the TES-593 meter was held 1 m above the ground at a fixed position for 30 seconds to record the E-field strength and the power density. The measured power density and the electric field strength, varied from routers to routers depending on their location and the distance of measurement from the routers. The power density recorded for all the Wi-Fi routers investigated ranged from 0.001 to 3.302 W/m2 with a mean of 0.390 W/m2. For all the Wi-Fi routers investigated. The overall exposure levels for the power density decreases with distances for all the routers. The measured electric field strength also decreases with distance ranging from 0.106 to 3.528 V/m with a mean of 0.981 V/m. The measured power densities and the electric field strengths in this research work were comparable and similar with reports from other research work from different environments including educational, residential, and urban settings. The power densities and the electric field strengths recorded were below the 10 W/m2 and 5 V/m recommended by various regulatory agencies respectively. All the Wi-Fi routers considered in this research work were within safety guidelines set by regulatory agencies for the power density and the electric field strength, thus emitting radiations at a level that are considered safe for human exposure within the academic communities. The operation of RF-EMF exposure from Wi-Fi routers in the academic environment of LAUTECH will no pose any potential health risks on staff and students of the institution. The evidence-based insights into potential health risks associated with prolonged exposure to electromagnetic fields from Wi-Fi routers in this research can guide policymakers in establishing safety regulations that will limit exposure levels. It can also inform guidelines on the optimal placement of routers, frequency of usage, and the implementation of periodic monitoring to ensure compliance with international safety standards.

Biochar-enabled carbon negative aggregate designed by core-shell structure: A novel biochar utilizing method in concrete

Using carbon-negative biochar is promising for the carbon footprints reduction of construction materials; however, directly utilizing biochar in concrete would negatively influence its mechanical properties, particularly when the utilizing volume exceeds a certain threshold. By designing as a core-shell structure through cold-bonding method, a novel carbon-negative core-shell aggregate (CSA) with a biochar core and a cementitious shell was developed in this study. The aggregate was characterized by strength, density, and water absorption measurements, meanwhile, analyzed by hydration heat, XRD, TGA, SEM/BSE, and X-CT. The results showed that the developed MG80 biochar-CSA attained a loose bulk density of 789 kg/m3. It exhibited a crushing strength of 6.84 MPa, a water absorption value of 19.4 %, and a significantly superior strength efficiency of 8669 Pa·m3/kg compared to commercially sintered artificial lightweight aggregates and other cold-bonded aggregates documented in literature. The carbon emission assessment indicated that producing one ton of MG80 biochar-CSA emitted −69 kg CO2, which was much lower than the commercial sintered aggregates. Concrete developed by replacing natural aggregate with 90 % MG80 biochar-CSA exhibited a compressive strength of 42.2 MPa while maintaining lightweight with density of 1866 kg/m3, which conforms to the standard-classified structural lightweight aggregate concrete.

Reevaluation of the Cosmic-Ray Ionization Rate in Diffuse Clouds

All current estimates of the cosmic-ray (CR) ionization rate rely on assessments of the gas density along the probed sight lines. Until now, these have been based on observations of different tracers, with C2 being the most widely used in diffuse molecular clouds for this purpose. However, dust extinction maps have recently reached sufficient accuracy to give an independent measurement of the gas density on parsec scales. In addition, they allow us to identify the gas clumps along each sight line, thus localizing the regions where CR ionization is probed. We reevaluate H3+ observations, which are often considered as the most reliable method to measure the H2 ionization rate ζH2 in diffuse clouds. The peak density values derived from the extinction maps for 12 analyzed sight lines turn out to be, on average, an order of magnitude lower than the previous estimates and agree with the values obtained from revised analysis of C2 data. We use the extinction maps in combination with the 3d-pdr code to self-consistently compute the H3+ and H2 abundances in the identified clumps for different values of ζH2 . For each sight line, we obtain the optimum value by comparing the simulation results with observations. We show that ζH2 is systematically reduced with respect to the earlier estimates by a factor of ≈9 on average, to ≈6 × 10−17 s−1, primarily as a result of the density reduction. We emphasize that these results have profound consequences for all available measurements of the ionization rate.

Influence of the extraction method on functional properties of commercial snail secretion filtrates

Snail secretion is a complex mixture of several components, including proteins, glycoproteins, mucopolysaccharides and smaller molecules. Its growing use in nutraceutical, cosmetic and biomedical applications, as well as a component of edible and green packaging to replace chemical plasticizer, implies more affordable and sustainable extraction methods. We chose four extracts obtained from Cornu aspersum snails, different by origin, extraction medium (namely, citric acid, lactic acid or none) and additives and we performed a series of characterizations including the SDS-page, the measure of pH and density, the evaluation of dry matter and of protein content, supported by structural determinations by means of UV-visible and infrared spectroscopy, X-Rays diffraction and thermogravimetric measurements. Biological assays comprising evaluation of cytotoxicity and antibacterial activity were also carried out. All the tests were performed both on the as received snail filtrates and on the samples after proper dialysis to remove preservatives added by manufacturers. The obtained results put into evidence that the properties and composition of the final extract are strongly influenced by the collection method, that can be relevant for the proper use of snail filtrate in specific applications.

Improved Understanding of PEMFC Stack Durability Testing through Comprehensive In-Situ and Ex-Situ Characterization Techniques

Durability testing of Proton Exchange Membrane Fuel Cells for mobile applications remains a critical challenge. While most academic studies focus on single-cell testing, there are only few publications on stack testing of technical relevant sizes. This study utilizes comprehensive characterization techniques to enhance understanding of PEMFC stack durability, aiming to meet the currently targeted durability targets. A 5,500-hour long-term test, based on the Auto Stack Industry (ASI) test protocol, was performed on a 7-cell short stack of 240 cm² active area. In-situ techniques, such as spatially resolved current density measurement, cyclic voltammetry, and electrochemical impedance spectroscopy, provided real-time degradation insights, while ex-situ methods, including FIB-SEM analysis, infrared thermography or contact angle measurements provided information on material degradation mechanisms. Membrane degradation was found to be negligible. Slight thinning of the cathode indicates carbon corrosion of the catalyst support. Catalyst aging was observed in the form of Pt band formation and Co leaching. Gas diffusion layers showed hydrophobicity loss, and increased resistance in bipolar plates contributed to reduced performance. Our findings demonstrate that PEMFC stacks operated under automotive drive cycle protocols can meet the actual targeted durability objectives. Moreover, it illustrates the degradation phenomena that occur under realistic operating conditions and modes, and how they evolve over the duration of thousands of hours of operation.