Browse Articles

Trimester-specific lipid profile reference intervals in healthy pregnant women; A cross-sectional study at Debre Markos comprehensive specialized hospital, 2022/2023

A unified Haar wavelet collocation framework for fractional volterra integro-differential equations with application to tumor-immune dynamics modeling

Integrated GRM-based efficient multi-performance prediction method for reconfigurable Fabry–Perot antennas

Dissemination of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium between humans and fishes

Abstract Vancomycin-resistant enterococci (VRE) are a major public health concern, yet little is known about their circulation in fish. This study investigated the occurrence, glycopeptide resistance genotypes, virulence characteristics, and sequence types (STs) of VRE isolated from diseased fishes and humans. Isolates were identified using multiplex polymerase chain reaction (PCR) assay and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and tested for antimicrobial susceptibility. VRE isolates were screened for the presence of glycopeptide resistance genes and eight virulence genes. Multilocus sequence typing (MLST) was determined to assess the clonality of VRE isolates from fishes and humans. Among 60 human samples, 20 Enterococcus species isolates (33.33%) including Enterococcus faecalis and Enterococcus faecium (10 of each), were identified. The overall prevalence of E. faecalis was 42.86% (30/70) in Oreochromis niloticus and 48.0% (24/50) in Clarias gariepinus . E. faecium was found in 15.71% (11/70) of Oreochromis niloticus and 14.0% (7/50) of Clarias gariepinus . Over 50% of human isolates were multidrug resistant (MDR) and 30% exhibited an extensive drug resistant (XDR) phenotype. Fish isolates also displayed high MDR (70.83%) and XDR (29.17%) rates. Forty-nine (53.26%; 34 from fish and 15 from human) isolates were VRE including 30 isolates of E. faecalis (VREfs) and 19 isolates of E. faecium (VREfm). The vanA gene was the most frequent among VREfs (83.33%) and VREfm (100%) isolates. The vanB gene was found in 26.67% of VREfs and 15.79% of VREfm. Three out of 10 VREfm (30%) and 2/24 (8.33%) VREfs isolates of fish origin carried both vanA and vanB genes. vanC gene was found in 13.33% (4/30) of VREfs of human and fish origin. One VREfs isolate from human urine carried both vanA and vanC genes. High frequency of the virulence genes  gelE , sprE , asa1 , esp, and cylA were observed;  efa  and ace gene was more associated with VREfs, while hyl  gene was more frequently detected in VREfm. Different combinations of virulence genes suggesting synergistic pathogenic potential. MLST revealed both overlapping and host-specific STs among the examined Enterococcus isolates from humans and fish. Experimental infection of O. niloticus with VREfs and VREfm caused a 100% and 60% mortality rate within 6 days postinfection, respectively with characteristic disease symptoms. The emergence of VRE and the high prevalence of virulence traits could be regarded as an alarming situation. The call for increased infection control and antibiotic stewardship measures is timely and relevant to combat the spread of VRE in fish and humans.

Research on a fuzzy programming model and algorithm for berth allocation considering time-varying water depth

Hydrodynamic and water quality simulation of Yangzonghai Lake, Southwest China, using the two-dimensional CE-QUAL-W2 model

Damping behavior of adaptable shoe under torsional loading at varying angular velocities: replicating the effects on cutting maneuvers

Complex optical properties of single crystal and atomic layer deposited alumina from the terahertz to vacuum ultraviolet spectral range

Anisotropic optical properties of single crystal Al2O3 and atomic layer deposited (ALD) thin film alumina have been studied from 0.42 meV to 8.5 eV using spectroscopic ellipsometry. Generalized spectroscopic ellipsometry is used to obtain the complex dielectric function (ɛ = ɛ1 ± iɛ2) and complex refractive index (N = n + ik) spectra of Al2O3 single crystals for electric fields oscillating parallel (extraordinary) and perpendicular (ordinary) to the optic axis from the terahertz (THz) to vacuum ultraviolet (VUV) spectral ranges. Spectra in ɛ in the infrared (IR) spectral range show four transverse optical (TO) phonon modes at 385.5, 441.1, 568.6, and 633.1 cm−1 and four longitudinal optical (LO) phonon modes at 386, 481.5, 629, and 903.34 cm−1 along the ordinary direction. Two TO modes at 400.1 and 583.9 cm−1 and two LO phonon modes at 510.79 and 887.209 cm−1 are observed in the extraordinary direction. Birefringence is ∼0.011 in the near-IR to VUV and ∼0.34 in the THz spectral ranges. The refractive index (n) for amorphous ALD thin film alumina is smaller than that obtained for both directions of single crystal alumina, except from ∼6.8 to 7.6 eV where n for ALD alumina is greater due to an absorption onset at lower photon energies and Kramers–Kronig consistency. The single IR vibrational mode observed at 586 cm−1 for the ALD film is broader and has a smaller amplitude than that for all TO phonon modes observed for single crystal alumina along both principal directions.

Implementation of mathematical and machine learning models in handheld glucometer to predict whole blood viscosity

Blood viscosity depends mainly on hematocrit and shear rate, and its low-cost and real-time estimation in handheld devices can enable rapid cardiovascular diagnostics and might revolutionize the translational research in healthcare. We developed a synergistic shear-dependent blood viscosity model by integrating and parametrically optimizing the Krieger–Dougherty (KD) and Carreau–Yasuda (CY) formulations to accurately match experimental observations. Furthermore, we calculated relative blood viscosity η(rel) for the amperometric dataset by incorporating the KD–CY model. The amperometric dataset contains peak current (Ip), corresponding time to the peak current (Tp), glucose concentration (Gc), and hematocrit volume (Hv). Besides, we developed a predictive model by utilizing several machine learning models to predict blood viscosity. The models were evaluated through the analysis of statistical parameters, namely, R-squared (R2) score, mean squared error (MSE), and root-mean squared error (RMSE). Moreover, the reliability of the models was tested via relative error (RE) and K-fold cross-validation techniques. It was concluded that the XGBoost and ANN outperformed other models because they have very relative errors (nearly 1%–3%). Our finding was consolidated by the 5-fold cross-validation technique, wherein the R-squared (R2) scores for XGBoost and ANN were observed to be 0.998 ± 0.000 and 0.999 ± 0.000, respectively.

Comparative analysis of surface morphologies for porous structure development under ion beam irradiation in GaSb, InSb, and Ge

In this study, ion beam irradiation was applied to GaSb, InSb, and Ge surfaces under the same conditions to form porous structures ranging from nanoscale to submicrometer scale. Such structures result from the migration of point defects generated by cascade damage and from redeposition induced by sputtering. By comparing the structural changes in these three materials, the dominant mechanisms underlying the formation of a porous structure were investigated. The results indicated that point defect migration plays a primary role in GaSb and Ge, whereas redeposition by sputtering is the main factor influencing InSb. Furthermore, oblique ion irradiation of GaSb confirmed that sputtering contributes to structural formation, indicating that multiple mechanisms may act simultaneously. In addition, the reasons why these phenomena are observed only in limited materials such as GaSb, InSb, and Ge were examined by classifying structure formation (presence or absence) using material properties through logistic regression analysis. Consequently, the melting point was found to influence structure formation.

Intrinsic emittance properties of an Fe-doped β-Ga2O3(010) photocathode: Ultracold electron emission at 300 K and the polaron self-energy

Measurements of the spectral emission properties of an iron-doped a β-Ga2O3(010) photocathode at 300 K reveal the presence of an ultracold contribution to the total electron beam emission with a 6 meV mean transverse energy (MTE) in the 3.5–4.4 eV photon energy range (282–354 nm). This extreme sub-thermal photoemission signal is consistent with direct emission of electrons photoexcited from the Fe dopant states into the low effective mass and positive electron affinity primary conduction band, and it is superimposed on a stronger signal with a larger MTE associated with an (optical)phonon-mediated momentum-resonant Franck–Condon (FC) emission process from a thermally populated and negative electron affinity upper conduction band. For photon energies above 4.5 eV, a transition from a long to a short transport regime is forced by an absorption depth reduction to below 100 nm and both MTE signals exhibit spectral trends consistent with phonon-mediated FC emission if the polaron formation self-energy is included in the temperature of the initial thermalized photoexcited electron distribution.

Correlation between electromechanical, piezo-sensing, and ferroelectric response for energy harvesting applications of PVDF-based polymers

Searching for sustainable power sources suitable for scavenging mechanical energy is an area of intense research. For this purpose, flexible piezoelectric energy harvesters are suitable candidates to cater to the sustainability demand. In this study, devices composed of uniaxially and biaxially stretched polyvinylidene fluoride (PVDF) films were used as pressure sensors. Various mechanical stimuli-based tests were employed to extract and compare the output voltage. A better electro-mechanical response was extracted from the poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] films, which were simply prepared by solvent casting without any post-synthesis treatment such as poling or stretching. Detailed characterization revealed that P(VDF–TrFE) exhibited improved crystallinity and ferroelectric response, making it a better energy harvester. A mechanical energy conversion protocol is utilized to generate output voltage from a P(VDF–TrFE) based device. Based on this measurement, response to the external force and the piezoelectric sensitivity values have been quantified.

Modeling roles and trade-offs in multiplex networks

Magnetotransport in high-mobility metamorphic InGaAs/InAlAs heterostructures with high InAs content

Magnetotransport studies of high-mobility metamorphic heterostructures containing InxGax−1As quantum well (QW) with a high InAs content (x ≥ 0.85) have been carried out. The scattering rate can be effectively controlled by adjusting the spacer thickness between the QW and the δ-doping layer. By analyzing the temperature and angle dependences of the Shubnikov–de Haas oscillations, the effective mass m∗, the quantum lifetime τq, the effective g∗-factor, and the nature of the scattering potential were determined. Estimates were also carried out within the framework of the kp Kane model, which confirm a significant manifestation of nonparabolicity in the measured values of m∗.

High-resolution, high-throughput detection of hidden antibiotic resistance with the dilution-and-delay (DnD) susceptibility assay

Abstract Rising rates of antibiotic treatment failure highlight the complexity of resistance mechanisms. While genetically encoded resistance is well established, recent clinical studies have uncovered noncanonical mechanisms driven by phenotypic heterogeneity, such as heteroresistance, persistence, or adaptive resistance. Yet, standard susceptibility tests lack the resolution or throughput to detect these diverse phenotypic mechanisms. To address these limitations, we develop a scalable, high-resolution assay—Dilution-and-Delay (DnD)—by implementing two basic principles of bacterial growth. DnD detects rare drug-insensitive cells at frequencies as low as 1 in 100 million, while also reporting bulk population inhibition as the conventional MIC. We demonstrate this capability across synthetic communities, heteroresistance, persistence, and evolutionary progression. These high-resolution data expose how traditional susceptibility assays are constrained by statistical detection limits. Scaling up DnD for high-throughput application to ~120 clinical isolates reveals that under-the-radar multidrug resistance or tolerance is common. By combining resolution with scalability, DnD provides an advanced platform for antibiotic susceptibility testing with broad impact on basic research, clinical practice, and epidemiological surveillance. It supports a new framework for measuring, defining, and understanding antibiotic resistance.

Ion irradiation-driven unit-cell expansion and strain accumulation behavior in magnesium oxide

Ceramic oxides offer a range of advantageous characteristics for withstanding intense mixed radiation fields, and consequently, interest has grown in exploring their behavior for nuclear applications such as fuel matrices and waste forms. In this study, magnesium oxide (MgO) was irradiated with ions of varying species, energies, and fluences, and the resulting structural modifications were characterized using synchrotron-based x-ray diffraction (XRD) combined with grazing-incidence XRD. Across all irradiation conditions, unit-cell expansion was observed, increasing with fluence. The magnitude of expansion was most significant for ions that primarily lose energy through nuclear interactions and lowest for those dominated by electronic excitations, spanning nearly two orders of magnitude. Under highly ionizing conditions, lattice swelling was reduced, but microstrain accumulation was enhanced, suggesting that defects are more localized and contribute less to long-range structural changes. These findings reveal the distinct roles of nuclear and electronic energy loss in defect formation and provide mechanistic insight into radiation-induced modifications in MgO, with implications for the design of radiation-tolerant materials for advanced nuclear technologies. Finally, the framework we present—incorporating an irradiation matrix that spans both nuclear and electronic energy loss dominated regions, strengthened by advanced quantitative XRD characterization—is widely applicable to the study of defect physics in polycrystalline materials.

Cryo-ET comparison of the hierarchical ultrastructure of silkworm, spider, and artificial silk fibers

Probing the modulation of internal stress field on phase transitions in sodium niobate by polarized Raman spectroscopy

Sodium niobate (NaNbO3, NN) serves as an ideal model system for investigating the origins of diverse electrical polarization behaviors owing to its rich polymorphism and complex phase transition sequences. Its intrinsic antiferroelectric character further exhibits significant potential for applications in pulsed power energy storage and multi-state non-volatile memory technologies. In particular, although the P and R phases in NN both display antiferroelectric ordering, they exhibit distinct superlattice behaviors. These structural differences give rise to intriguing physical phenomena during the phase transition process, thereby garnering significant research interest. Previous studies often attribute the complex phase evolution in NN to competitive interactions mediated by a minor Q phase component under internal stress fields. Furthermore, these investigations primarily treat the P phase as the dominant structure, which significantly hinders a thorough understanding of stress field effects on the P–R phase transition process. In this study, NN samples predominantly exhibiting the Q phase at room temperature were prepared through process tuning. Furthermore, by varying defect concentrations, a series of NN systems with graded internal stress gradients were constructed. Furthermore, leveraging the sensitive detection capability of polarized Raman spectroscopy for polarizability changes, we investigated the in situ evolution of various phonons under temperature-field conditions. The study explores the mechanisms of phonon synergistic contributions induced by stress gradients during the heating of NN from the P to the R phase. These findings provide an important research foundation for understanding antiferroelectric behavior evolution in NN and for developing high-performance NN-based antiferroelectric devices.

Frequency-division routing via spin–refractive-index locking

Limitations on activation of high dose Ge implants in <i>β</i> -Ga2O3

Among ultrawide bandgap semiconductors, β-Ga2O3 is particularly promising for high power and frequency applications. For devices, n-type concentrations above 1019 cm−3 are required. Ge is a promising alternative n-type dopant with an ionic radius similar to Ga. Homoepitaxial (010) β-Ga2O3 films were implanted with Ge to form 50 and 100 nm box concentrations of 3 × 1019 and 5 × 1019 cm−3, with damage ranging from 1.2 to 2.0 displacements per atom. For lower damage implants, optimized anneals in ultrahigh purity N2 at 950–1000 °C for 5–10 min resulted in an RS of 600–700 Ω/□, mobilities of 60–70 cm2/V s, and a Ge activation of up to 40%. For higher damage implants, activation dropped to 23% with similar mobilities. Ge diffusion, measured by secondary ion mass spectrometry, showed the formation of a Ge “clustering peak” with a concentration exceeding the initial implant following anneals in N2 or O2 at 950–1050 °C. Beyond this peak, minimal Ge diffusion occurred for N2 anneals at 950 °C, but at 1050 °C, non-Fickian diffusion extended to &amp;gt;200 nm. Electrical activation data suggest that clustered Ge is electrically inactive. To understand Ge clustering, several samples were characterized by synchrotron x-ray diffraction. Second-phase precipitates were observed in as-implanted samples, which then fully dissolved after furnace annealing in N2 at 1050 °C. Diffraction peaks suggest that these implant-induced precipitates may be related to a high pressure Pa3¯ phase of GeO2 and may evolve during anneals to explain the Ge clustering. Ultimately, we believe that Ge clustering limits the activation of implanted Ge at high concentrations.