Search Results (30,430)

Low-frequency mobile bands remain essential for wide-area and penetration-limited wireless coverage, but their limited channel bandwidth constrains the achievable capacity. This paper presents a measurement-supported extrapolation framework for assessing how lowband MIMO and future AAS-assisted operation can enhance coverage and single-user throughput-oriented capacity in wireless networks. The motivation is to evaluate whether such deployments can strengthen the lower-frequency layer as a robust coverage-and-capacity support layer for general traffic and reduce the load on midband and higher-frequency resources. Controlled radiated SISO and $2\times 2$ MIMO measurements were performed with a base-station simulator and commercial user equipment in representative lowband and midband frequency bands. Measured RSRP, CQI, BLER, MAC-layer throughput, and IP-layer throughput thresholds for a 25 Mbit/s downlink target were used for coverage estimation and conditional extrapolation. Under the Extended Hata model, the measured $2\times 2$ MIMO thresholds yielded a 43% larger estimated radius at 800 MHz than at 1800 MHz, while the same model indicated a 93% radius increase for a representative 10 dB AAS-related beamforming gain scenario. Conditional $4\times 4$ MIMO extrapolations indicated data rates above 100 Mbit/s in 10 MHz and above 200 Mbit/s with 10 MHz two-component-carrier aggregation under ideal high-CQI conditions. The results support the potential of future lowband AAS deployments. The AAS and higher-order MIMO results are scenario-based estimates rather than direct field validation. Full article

A robust procedure for compensating for inaccuracies caused by 3-D positioning errors in the measurement of the near-field (NF) data required by the non-redundant (NR) spherical near-to-far-field (NtFF) transformations for long antennas is presented in this article. These errors may arise from hardware defects and positioners’ controlling inaccuracies, which may cause the probe to deviate from the intended spherical scan surface and prevent it from reaching the NR sampling points required by either of the two NR representations for long antennas. To account for these errors, the method proceeds through two steps. The first step, called spherical wave correction, compensates for the phase shifts due to radial displacements from the intended scanning sphere. As a result of this correction, the NF samples belong to the intended scanning sphere, but at points different from those required by the adopted NR representation, thus impairing the subsequent NF reconstruction via the optimal sampling interpolation (OSI) algorithm. Such an algorithm enables one to efficiently build the iterative scheme used in the second step, which makes it possible to effectively retrieve the NF samples at the prescribed NR positions. Test results are shown to numerically validate the capability of the developed two-step compensation technique to correct even significant and pessimistic 3-D positioning errors affecting the collection of the NF data. Full article

With the advancement of cognitive radar, applying deep neural networks to radar jamming recognition has become an indispensable research direction. However, as a common anti-jamming measure, the agility of radar waveform parameters degrades the effectiveness of jamming recognition, creating a trade-off between jamming recognition and anti-jamming agility. Specifically, for the same type of jamming, radar agility in frequency, pulse width, and bandwidth alters the profile and scale features of the jamming, posing challenges to conventional CNN-based jamming recognition. To address this challenge, this paper proposes an Adaptive Feature-Focusing CNN (AFF-CNN). A pre-trained AFF module is designed to establish a mapping between agile parameters and adaptive feature scales. Operating on time-domain high-resolution range profiles (HRRP) and time–frequency domain short-time Fourier transform (STFT) data, this module calibrates deviations induced by radar inter-pulse parameter agility and enhances the capability of salient signal feature-focusing. Furthermore, a lightweight 1D-2D feature fusion CNN is designed to process these adaptive features and recognize jamming using single-pulse signals, thereby enhancing the network’s adaptability to inter-pulse parameter agility in radar systems. Simulation results demonstrate superior recognition accuracy and generalization capability compared to five comparative approaches, confirming effective adaptation to inter-pulse agility scenarios. Full article

The importation of hepatitis B virus (HBV) variants through migration challenges elimination efforts in low-endemicity countries. This study evaluated the seroprevalence, occult hepatitis B infection (OBI), and molecular signatures of HBV among 537 international migrants from 46 countries who arrived in St. Petersburg, Russia. HBsAg, anti-HBs, and anti-HBc were measured by ELISA. This was followed by nested real-time PCR targeting viral genes (S, X) and a human housekeeping gene (HPRT, internal control), amplification of overlapping fragments covering the complete HBV genome, and Sanger sequencing. HBsAg prevalence was 2.61% (95% CI: 1.43–4.34), while anti-HBc was detected in 16.39% (95% CI: 13.36–19.79). HBV DNA was found in 8.19% (44/537; 95% CI: 6.02–10.04) of migrants. Notably, OBI (HBsAg-negative/HBV DNA-positive) was identified in 33 individuals, yielding a prevalence of 6.15% (33/537; 95% CI: 4.27–8.52) in the entire cohort and 6.31% among HBsAg-negative subjects. The findings among OBI cases were as follows: the majority (54.5%) had no detectable anti-HBc or anti-HBs; 30.3% were positive for anti-HBs only; 6.06% were positive for anti-HBc IgG only; 9.09% of cases featured both anti-HBc and anti-HBs. Viral loads in OBI cases were uniformly low (14–53 IU/mL). Genotype D predominated (86.36%, 38/44). The distribution of subgenotypes among all sequenced isolates was as follows: D1 in 36.36% (16/44), D2 in 36.36% (16/44), D3 in 13.64% (6/44), while genotypes A2 (6.82%, 3/44), B4 (4.55%, 2/44), and C2 (2.27%, 1/44) were rare. In the major hydrophilic region (MHR), the most frequent amino acid substitutions were at positions T127P/I (61.4%) and T118R/M/V/A (45.5%). Immune escape mutations were significantly associated with OBI (81.82% of OBI cases versus 18.18% of HBsAg-positive cases; p = 0.003). Drug resistance mutations (L180M + M204V ± T184A) were detected in 11.4% of isolates (all genotype D2). In the precore region, stop codon mutation W28* was found in 31.82% of samples, and the A1762T/G1764A double substitution in the basal core promoter occurred in 25.0%. The high prevalence of OBI, coupled with the accumulation of escape and drug resistance mutations in imported HBV variants, highlights the urgent need to include molecular HBV screening in mandatory medical examinations for arriving migrants to prevent undetected transmission and inform clinical management in receiving countries. Full article

Background: Vitamin D is a key regulator of skeletal homeostasis, and hypovitaminosis D is highly prevalent among postmenopausal women, who are at increased risk of osteoporosis, sarcopenia, and related complications. Accurate assessment of serum 25-hydroxyvitamin D [25(OH)D] is therefore essential. However, substantial variability exists among analytical methods, particularly between automated chemiluminescent immunoassays (CLIA) and liquid chromatography–tandem mass spectrometry (LC-MS/MS), the latter considered the reference technique. This study aimed to compare four analytical methods, three CLIA platforms, and LC-MS/MS for measuring circulating 25(OH)D levels in a cohort of menopausal and postmenopausal women. Methods: A total of 425 serum samples from menopausal and postmenopausal women representing the real-world distribution of vitamin D levels in this population were analyzed using three automated CLIA systems and LC-MS/MS. Method comparison, agreement, precision through quality control assessment, total error, and sigma were evaluated. Results: The evaluated CLIA platforms (Abbott, Snibe, and Siemens) showed strong correlation with LC-MS/MS, with r = 0.919, r = 0.978, and r = 0.879. Furthermore, all assays showed excellent precision (CV < 5%), with good-to-acceptable total error (TE) and Sigma-metric performance. Conclusions: In conclusion, these findings demonstrate that while CLIA platforms offer a reliable and precise alternative for routine clinical use, these findings underscore the importance of method selection and result interpretation in the clinical assessment of vitamin D status in postmenopausal women. Furthermore, it highlights the ongoing need to minimize inter-assay variability and ensure consistent vitamin D assessment. Full article

Understory mosses modify near-surface soil conditions, but how elevation regulates their influence on active and mineral-associated soil organic carbon (SOC) remains unclear. We compared independently selected moss-covered and non-moss-covered soils across a 3200–3500 m elevational gradient and integrated soil physicochemical measurements, microbial biomass (MB), dissolved organic matter (DOM), microbial necromass carbon (MNC), particulate organic carbon (POC), mineral-associated organic carbon (MAOC), metagenomic profiling, and piecewise structural equation modeling. Moss-covered soils consistently contained higher SOC and MAOC, but lower DOM, MB, and generally lower POC, than non-moss-covered soils. MNC showed an elevation-dependent reversal, with higher values under moss cover at 3200 m but lower values under moss cover at 3300–3500 m. Elevation was not a significant uniform driver of MB, DOM, MNC, POC, or MAOC; instead, its influence was mainly reflected in interactions with surface cover and in elevation-related changes in moss-layer structure, diversity, and hydrothermal conditions. Core carbon-fixation and degradation functions remained broadly stable, whereas specific functional modules shifted within moss-covered soils: acetate and acetyl-CoA metabolism genes (ackA and abfD) were relatively abundant at 3300–3400 m, while the polysaccharide-reprocessing gene SGA1 and oxidative-transformation gene katG increased toward higher elevations, and pmoC/amoC rebounded at 3500 m. Structural equation models linked the microbial functional gene system more strongly to POC, whereas MNC was positively associated with MAOC, and the direct POC-to-MAOC pathway was not significant. These findings indicate that moss cover is associated with contrasting SOC allocation patterns and stronger microbial necromass–MAOC coupling, while elevation modulates these relationships indirectly through changes in moss communities, soil microenvironment, and microbial functional potential. Full article

An interlaboratory comparison of RF power measurements using automatic power measurement software was carried out among partners of the European Partnership on Metrology project titled “Development of RF and microwave metrology capability II” (RFMicrowave2). The absolute RF power output of a travelling signal generator was measured at six frequencies between 2 GHz and 18 GHz and at three nominal power levels of −10 dBm, 0 dBm, and 10 dBm. Comparison results were evaluated in terms of comparison reference values, degrees of equivalence, and normalised errors. Uncertainty evaluations were performed using both the Guide to the Expression of Uncertainty in Measurement and Monte Carlo simulation methods. The results demonstrate an acceptable level of agreement among participating laboratories and confirm the applicability of automatic power measurement software for interlaboratory RF power comparisons. Full article

This study examines the relationship between higher education development, innovation capacity, and regional economic performance across Kazakhstan’s regions during the 2010–2024 period. The analysis is motivated by the growing role of higher education institutions within regional innovation systems and by ongoing debates regarding the economic effects of university modernization and innovation-policy reforms in transition and resource-dependent economies. Despite substantial higher education reforms implemented in Kazakhstan since the 2010s, including Bologna-process modernization and the post-2018 expansion of university autonomy, empirical evidence regarding the regional economic transmission of these reforms remains limited. The study employs a regional panel-data framework combining Two-Way Fixed Effects estimation with a Difference-in-Differences specification anchored on the post-2018 reform period. The empirical strategy is complemented by robustness procedures, spatial-dependence diagnostics, and tests for serial correlation and cross-sectional dependence within harmonized regional boundaries covering sixteen regions of Kazakhstan. The findings indicate that the relationship between higher education expansion and regional economic development in Kazakhstan is considerably weaker and more institutionally contingent than is frequently assumed in simplified human-capital frameworks. Individual higher-education indicators show weak or statistically insignificant independent associations with regional GRP per capita after controlling for regional and temporal fixed effects. Given the substantial overlap among several higher-education measures, these findings should not be interpreted as evidence against the broader contribution of higher education to regional development. Wage dynamics and fixed capital investment remain the strongest correlates of regional economic performance. The analysis also identifies a negative and statistically significant association between R&D personnel and regional output, which the paper interprets jointly through a regional innovation paradox in which research-capacity expansion outpaces absorptive demand, alongside alternative explanations including reverse causality, compositional features of regional R&D statistics, and within-block multicollinearity. The Difference-in-Differences estimations provide limited evidence of statistically significant short-run regional economic effects around the post-2018 reform period; the design evaluates post-2018 divergence between higher-capacity and lower-capacity regions rather than identifying a clean causal reform effect, and the null result is consistent with absence of divergence, implementation lags, low statistical power in the small-cluster panel, and limited sensitivity of regional GRP per capita to early reform transmission. The study contributes to the regional economics, innovation-systems, and transition-economy studies by providing regional panel evidence from a resource-dependent post-Soviet context characterized by substantial territorial heterogeneity. The findings suggest that higher education expansion and institutional modernization do not automatically generate measurable regional economic transformation in the absence of complementary commercialization mechanisms, diversified industrial structures, and stronger regional innovation ecosystems. Full article

This study examines the low-speed impact response of Nomex honeycomb-core sandwich structures using an approach combining experimental tests and three-dimensional numerical modeling. A finite element model was developed using Abaqus/Explicit to predict contact force, displacement, damage evolution, and absorbed energy under different impact configurations. The influence of core density, skin thickness, and impactor geometry was analyzed to identify the parameters governing impact resistance and energy dissipation mechanisms. The numerical results show good agreement with experimental measurements, with maximum relative differences between 7.3% and 8.3% for the maximum force and between 1.8% and 4.3% for the absorbed energy. Core density appears to be a determining factor: the D144 configuration reaches a maximum force of approximately 4400 N, compared to 2600 N for the D80 configuration, representing an increase of approximately 69%. However, sensitivity analysis indicates that skin thickness exerts the most dominant overall influence on load-bearing capacity; increasing this thickness from 0.2 mm to 1.2 mm leads to a fivefold increase in maximum force (from 1800 N to over 10,000 N) and a significant rise in absorbed energy (from 20 J to 105 J). The geometry of the impactor strongly controls the damage modes and stress distribution. A 60° conical impactor promotes localized deformation and rapid perforation, while a 70° angle offers a better compromise between local resistance and progressive energy absorption. At 80°, the stresses are distributed over a larger surface area, which delays perforation. The geometry of the impactor strongly controls the spatial distribution of damage modes. A sharper 60° conical impactor induces highly localized core crushing and rapid skin perforation, while a 70° angle offers a better compromise between local resistance and progressive energy absorption. At 80°, the stresses are distributed over a wider area, promoting diffuse damage and delaying perforation. These results show that the combined optimization of core density, skin thickness, and the impactor–structure interaction is an effective way to improve the impact tolerance of lightweight sandwich structures intended for aerospace, automotive, and marine applications. Full article

Background/Objectives: T cells within solid tumors often switch from a recirculating to a tissue-resident state, which may blunt antitumor activity, but the signal driving this switch in vivo remains unclear. We asked whether alterations in sphingosine-1-phosphate (S1P) signaling in tumor or the surrounding stromal cells are associated with T cell residency in glioblastoma (GBM). Methods: We analyzed five single-cell RNA-sequencing cohorts: three human glioma datasets, an in-house mouse CT2A glioblastoma cohort, and a human melanoma tumor-infiltrating lymphocyte cohort. T cell egress and tissue-residency programs, together with stromal S1P production and degradation, were scored per cell using curated gene modules. Cell-state contrasts were quantified as Cohen’s d, and sample-level coupling as Spearman ρ. Results: In human GBM, T cell residency programs were elevated in CD4+ helper and regulatory T cells in tumors compared with low-grade glioma controls. In mouse CT2A-derived GBM tumors, stromal S1P production correlated negatively with T cell residency across four independent stromal cell types. In human GBM microglia, S1P production was reduced compared with control microglia. The same CD8+ residency phenotype was replicated in CD3-sorted GBM tumor-infiltrating lymphocytes (TILs) and in melanoma TILs. Conclusions: A loss of stromal S1P production accompanies T cell tissue residency in GBM. Thus, stromal S1P metabolism is a candidate axis for modulating T cell recirculation and TIL biology in GBM. These findings are transcriptomic associations from single-cell RNA sequencing that do not directly measure S1P metabolite levels or signaling activity and will require functional and lipidomic validation. Full article

Background and Objectives: Faricimab, the first bispecific antibody targeting VEGF-A and angiopoietin-2, has demonstrated durable efficacy in pivotal phase 3 trials for neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME). Real-world data on treatment-naïve patients managed with fixed-interval maintenance protocols, particularly from South-Eastern Europe, remain limited. This pilot study evaluated 24-month outcomes of intravitreal faricimab in treatment-naïve nAMD and DME, using a standardized four-injection loading phase followed by fixed every-16-week (Q16W) maintenance. Materials and Methods: This study conducted a retrospective, observational, single-center pilot cohort study of 20 consecutive treatment-naïve eyes (9 nAMD, 11 DME). All patients received four monthly loading injections followed by a fixed every-16-week (Q16W) maintenance schedule, supplemented by discretionary additional injections for residual or recurrent disease activity (215 injections total; mean 10.75 ± 0.79 per patient; range 9–12). Primary outcomes were changes in central foveal thickness (CFT) and best-corrected visual acuity (BCVA; Snellen lines with ETDRS letter equivalents) at months 4 and 24. Prespecified secondary analyses included bootstrap 95% confidence intervals, a linear mixed-effects model with a time × disease-group interaction, Bayesian credible intervals with weakly informative priors, false-discovery-rate (FDR) correction, and a minimum detectable effect-size analysis. Results: All 20 eyes completed 24-month follow-up. In nAMD, mean CFT decreased by 186.9 ± 71.9 µm (35.9%; bootstrap 95% CI 148.1–236.0; p < 0.001; d = 2.60), and BCVA improved by 3.89 ± 0.78 Snellen lines (~19 ETDRS letters; 95% CI 3.44–4.33; p < 0.001; d = 4.97). In DME, CFT decreased by 197.7 ± 65.7 µm (39.3%; 95% CI 162.5–237.3; p < 0.001; d = 3.01), and BCVA improved by 4.55 ± 1.04 lines (~23 ETDRS letters; 95% CI 4.00–5.09; p < 0.001; d = 4.39). All 20 eyes (100%) achieved ≥ 3 Snellen lines gain and ≥20% CFT reduction; 80% reached final BCVA ≥ 7 lines. A linear mixed-effects model showed a significant time effect (p < 0.001) but no time × group interaction (CFT p = 0.84; BCVA p = 0.51), indicating concordant trajectories across diseases. Bayesian analysis with weakly informative priors yielded posterior P(|d| > 0.8) ≥ 0.99 for all primary outcomes. After FDR correction, all pre-specified primary comparisons remained significant. The minimum detectable effect size with the realized sample sizes (Cohen’s d ≈ 0.66 combined, 1.07 nAMD, 0.94 DME at 80% power) was substantially below all observed effect sizes. No ocular or systemic adverse events were recorded. Conclusions: In this small, single-center, treatment-naïve pilot cohort, a fixed Q16W faricimab maintenance schedule with discretionary additional injections was associated with durable anatomical and functional improvements over 24 months in both nAMD and DME, with no adverse events recorded across 215 injections. Given the limited sample, these findings should be regarded as hypothesis-generating. The high responder rates likely reflect the cohort’s substantial baseline visual impairment (mean baseline BCVA ~20/120–20/200), which provides greater absolute capacity for measurable gain than in higher-acuity registration trial populations. These pilot data support fixed-interval faricimab as a logistically feasible candidate strategy in resource-constrained settings and should be confirmed in larger multicenter cohorts using standardized ETDRS acuity assessment. Full article

The contribution of this paper is to propose the design and experimental validation of split-type dual- and tri-band bandpass filters (BPFs) based on highly miniaturized substrate-integrated coaxial cavities (SICCs). The proposed split-type multiband filter design achieves exceptional circuit-area efficiency within the SIW-related (substrate-integrated waveguide) split-type filter category. The size-reduced SICCs are fabricated using two substrates of different thicknesses. The coupling matrix method is employed to synthesize the responses of the example dual- and tri-band filters. The proposed dual-band filter achieves a circuit size of 0.17 λ_d × 0.17 λ_d, with insertion losses of 0.78 and 0.89 dB for the two passbands, and isolation between the passbands exceeding 15 dB. For the tri-band filter, the circuit size is 0.27 λ_d × 0.34 λ_d, with the insertion losses of 0.96, 2.6, and 1.21 dB across the three passbands, accompanied by similarly effective isolation. Experimental results validate the circuit designs and performance, demonstrating strong agreement between measured and simulated data. Full article

The SARS-CoV-2 pandemic has posed a tremendous burden globally, highlighting the urgent need for new effective antivirals that are possibly useful against future emerging Coronaviruses (hCoVs). In this context, major efforts were focused on the inhibition of highly conserved and essential targets playing a pivotal role in viral replication. Among them, SARS-CoV-2 nsp13 stands out, being the most conserved enzyme within hCoVs. Following our previous reports describing the identification of indole-based diketo acid (DKA) derivatives as SARS-CoV-2 nsp13 inhibitors endowed with antiviral activity, we applied a scaffold hopping strategy to identify new nsp13 inhibitors. Therefore, we investigated a series of 4-phenyl pyrrolyl DKAs and their structural analogs characterized by molecular simplification or DKA isosteric replacement. The derivatives showed potency against both nsp13-associated activities exhibiting measurable IC₅₀s in the low micromolar/submicromolar range, highlighting a promising dual inhibitory profile accordingly. Structure–activity relationship (SAR) studies were performed, highlighting the main structural features increasing the activity of the different compound classes. Interestingly, SAR trends were confirmed in the presence of the BSA/TCEP system despite variations in potency. To shed light on the interaction of the best acting compounds 13b, 15a, and 17d, docking studies were performed, suggesting a putative binding mode in agreement with our previous findings. Full article

We present in this paper an ultra-low-power impulse radio ultra-wideband (IR-UWB) transmitter intended for short-range, highly energy-efficient, and compact silicon-area applications, such as implantable brain–computer interfaces (iBCIs). The proposed transmitter features effective spectrum tunability, enabling independent adjustments to both the center frequency and −10 dB bandwidth. Fabricated in TSMC 40 nm CMOS technology, the chip occupies a core area of just 0.001 mm². Experimental results demonstrate an energy efficiency of 2.45 pJ/b across a data rate range of 10 to 200 Mbps. The peak-to-peak output voltage amplitude is approximately 310 mV when driving a 50 Ω load. Furthermore, in vitro wireless measurements demonstrate reliable through-tissue transmission at an implantation depth of 18 mm and achieve a distance range exceeding 0.8 m. Full article

Combined intrastromal corneal ring segment implantation with corneal collagen cross-linking (CXL) aims to improve optical regularity and reduce the risk of ectatic progression in selected eyes with keratoconus. In this retrospective, single-center, complete-case longitudinal series, 58 eyes from 40 patients treated at OCULENS Ophthalmology Clinic between 2019 and 2022 were analyzed after same-session KeraRing implantation and conventional epithelium-off CXL, with baseline and 6-, 12-, 24-, and 36-month follow-up data. Outcomes included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), thinnest pachymetry, maximum keratometry (Kmax), the Belin/Ambrosio enhanced ectasia total deviation index (BAD-D), the C and D components of the ABCD classification, and Corvis ST-derived dynamic deformation parameters. Longitudinal continuous outcomes were analyzed as eye-level repeated-measures estimates with Holm-adjusted paired comparisons, and stage distributions were analyzed with the Friedman test. At 36 months, UDVA improved from 0.560 ± 0.151 to 0.469 ± 0.136 logMAR and CDVA from 0.350 ± 0.109 to 0.287 ± 0.092 logMAR (both p < 0.001). Kmax decreased from 56.11 ± 3.17 D to 54.87 ± 2.86 D, BAD-D improved from 5.62 ± 1.89 to 4.70 ± 1.75, and thinnest pachymetry measured 440.7 ± 21.9 µm at 36 months, corresponding to 97.0% of baseline thickness. Corvis ST-derived deformation behavior shifted toward lower deformation amplitude and higher stiffness parameter at first applanation (SP-A1), but these device-derived parameters should be interpreted as indirect deformation response metrics rather than as direct tissue stiffness measurements. Two clinically significant complications were recorded (2/58 eyes, 3.4%): one sterile corneal infiltrate requiring ring explantation and one case of corneal melting requiring ring explantation and referral for keratoplasty. The findings support sustained 36-month visual, tomographic, and Corvis ST-derived changes after combined treatment, while interpretation remains limited by the retrospective complete-case design, unavailable denominator for cases excluded because of incomplete follow-up, eye-level analysis with bilateral cases, lack of a control group, and indirect nature of Corvis ST-derived biomechanical assessment. Full article