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1,901 result(s) for "Martin, Guillermo"
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Nanoengineered polyaniline/carbon black VXC 72 hybridized with woven abaca for superior electromagnetic interference shielding
The growing demand for efficient electromagnetic (EM) shielding materials has driven extensive research into sustainable and functionalized composites for high-frequency applications. This study investigates the electromagnetic (EM) shielding properties of Polyaniline (PAni)-functionalized woven abaca fibers, reinforced with Carbon Black (CB) VXC 72, in the ultrahigh-frequency (UHF) range (500–4500 MHz), as determined using Vector Network Analyzer (VNA). The composite was developed by functionalizing abaca fabric with PAni through in situ chemical oxidative polymerization and depositing CB via a dip-and-dry method. The morphological structure and elemental composition were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), while Fourier-transform infrared (FTIR) spectroscopy was used to confirm functional group interactions. Electrical resistivity was determined using the four-point probe method, and EMI shielding effectiveness (SE) was evaluated in the ultrahigh frequency (UHF) range of 500 MHz to 4500 MHz using a Vector Network Analyzer (VNA). Experimental results indicate that PAni/CB functionalization successfully imparted shielding properties to abaca fabric. PAni/1CB/Abaca exhibited the highest shielding effectiveness with an average SE of 5.96 dB, corresponding to 74.34% attenuation of incident electromagnetic waves, and a peak attenuation of 7.45 dB at 4.5 GHz. In contrast, 2CB/Abaca and PAni/2CB/Abaca showed selective EMI shielding, with peak attenuation values of 8.27 dB at 1.67 GHz and 7.98 dB at 1.69 GHz, respectively. The electrical resistivity measurements revealed that PAni/1CB/Abaca had the lowest resistivity at 891 Ω·cm, whereas 1CB/Abaca exhibited the highest at 5238 Ω·cm. The primary shielding mechanism was absorption rather than reflection, making the composite a lightweight, corrosion-resistant alternative to traditional metal-based EMI shields. These findings demonstrate the potential of natural fiber-based conductive composites for flexible EMI shielding applications in telecommunications, healthcare, and aerospace industries.
Designing Intensive Care Unit Windows in a Mediterranean Climate: Efficiency, Daylighting, and Circadian Response
Hospital intensive care units (ICUs) frequently experience inadequate lighting conditions, with low daytime and excessive nighttime illuminance, which can negatively affect patient recovery and the work performance of health personnel. This study examines the impact of window design parameters—specifically, window-to-wall ratio (WWR) and window position—and interior surface reflectance on visual comfort, lighting performance, energy consumption, and human well-being in intensive care units (ICUs) in Mediterranean climates, according to orientation. Using dynamic lighting metrics, such as daylight autonomy (DA) and circadian stimulus autonomy (CSA), this research quantifies the influence of these design factors. The results suggest that a WWR of 25% is optimal for achieving sufficient DA and CSA values, with centered window configurations preferred for uniform daylight distribution and circadian stimulus. This study further emphasizes the significance of interior reflectance, recommending bright coatings to maximize outcomes, while advising against dark finishes, particularly in north-facing rooms or with smaller WWRs. Although Seville shows slightly better performance than Barcelona, the proposed configurations are effective across both locations, highlighting the prioritization of window sizing, positioning, and reflectance over Mediterranean geographical differences. These findings offer practical guidance for ICU design to enhance natural lighting, supporting patient recovery and overall well-being through improved circadian alignment.
New Approaches in Dynamic Metrics for Lighting Control Systems: A Critical Review
The growing number of daylighting metrics—often overlapping in scope or terminology—combined with the need for prior familiarization to interpret and apply them effectively, has created a barrier to their adoption beyond academic settings. Consequently, this study analyzes a representative set of established and emerging daylighting metrics to evaluate applicability, synergies, and limitations. Particular attention is given to their implications for occupant health, well-being, performance, and energy use, especially within the context of sensorless smart control systems. A virtual room model was simulated using DaySim 3.1 in two contrasting climates—Seville and London—with varying window-to-wall ratios, orientations, and occupancy schedules. The results show that no single metric provides a comprehensive daylighting assessment, highlighting the need for combined approaches. Daylighting Autonomy (DA) proved useful for task illumination, while Useful Daylight Illuminance (UDI) helped identify areas prone to excessive solar exposure. Spatial metrics such as Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE) offer an overview but lack necessary granularity. Circadian Stimulus Autonomy (CSA) appears promising for evaluating circadian entrainment, though its underlying models remain under refinement. Continuous Overcast Daylight Autonomy (DAo.con) shows the potential for sensorless lighting control when adjusted for orientation. A nuanced, multi-metric approach is therefore recommended.
Role of bulge epidermal stem cells and TSLP signaling in psoriasis
Psoriasis is a common inflammatory skin disease involving a cross‐talk between epidermal and immune cells. The role of specific epidermal stem cell populations, including hair follicle stem cells (HF‐SCs) in psoriasis is not well defined. Here, we show reduced expression of c‐JUN and JUNB in bulge HF‐SCs in patients with scalp psoriasis. Using lineage tracing in mouse models of skin inflammation with inducible deletion of c‐Jun and JunB, we found that mutant bulge HF‐SCs initiate epidermal hyperplasia and skin inflammation. Mechanistically, thymic stromal lymphopoietin (TSLP) was identified in mutant cells as a paracrine factor stimulating proliferation of neighboring non‐mutant epidermal cells, while mutant inter‐follicular epidermal (IFE) cells are lost over time. Blocking TSLP in psoriasis‐like mice reduced skin inflammation and decreased epidermal proliferation, VEGFα expression, and STAT5 activation. These findings unravel distinct roles of HF‐SCs and IFE cells in inflammatory skin disease and provide novel mechanistic insights into epidermal cell interactions in inflammation. Synopsis Lineage tracing in models of skin inflammation reveals that thymic stromal lymphopoietin (TSLP) activates pro‐inflammatory cues in mutant hair follicle stem cells (HF‐SCs) and keratinocytes (KCs) (1). Primed non‐mutant HF‐SCs also produce TSLP, thus contributing to the disease (2). Scalp psoriasis was associated with a reduction of c‐JUN/JUNB in bulge hair follicle stem cells (HF‐SCs) in psoriatic patients. Specific deletion of c‐Jun/JunB in bulge HF‐SCs (mutant GFP HF‐SCs) was sufficient for the development of psoriasis‐like disease in mice. Keratinocytes derived from mutantGFPHF‐SCs survived, while keratinocytes from mutantGFP inter‐follicular epidermal cells (IFE) were lost during psoriasis progression. TSLP was an important mediator for epidermal hyper‐proliferation and pro‐inflammatory signaling in keratinocytes. Neutralization with anti‐TSLP reduced epidermal cell proliferation and psoriasis‐like progression in mice. TSLP was highly expressed in the epidermis and hair follicles of scalp psoriasis. Graphical Abstract Lineage tracing in models of skin inflammation reveals that thymic stromal lymphopoietin (TSLP) activates pro‐inflammatory cues in mutant hair follicle stem cells (HF‐SCs) and keratinocytes (KCs). Primed non‐mutant HF‐SCs also produce TSLP, thus contributing to the disease.
2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.
Syntrichia laevipila Brid., a Bryophyta from Northwest Argentina as a Source of Antioxidants and Antimicrobials
In recent years, numerous studies have emerged on the biological activities of bryophytes and their potential for therapeutic use. However, mosses appear to be a relatively overlooked group. The objective of this study was to conduct a phytochemical analysis of one hydroalcoholic extract of Syntrichia laevipila and to evaluate its potential as an antioxidant and antimicrobial agent. The moss was collected in the Chaco Serrano region of Argentina, specifically on Jacaranda mimosifolia, and subsequently extracted by maceration in ethanol/water. UHPLC/ESI/MS/MS analysis identified 32 peaks, including phenolic compounds (phenolic acids, lignans, chalcones, and flavonoids) and non-hydrophilic compounds (terpenoids, fatty acids, and brassinosteroids). Maslinic and oleanolic acids, two triterpenoids present in S. laevipila, were also detected in J. mimosifolia, a substrate of this moss. The concentration of phenolic compounds was 19.05 ± 0.21 µg GAE/mL, while the total flavonoid concentration was 13.13 ± 0.33 µg QE/mL. The determination of reducing and total sugars yielded 0.22 ± 0.03 mg GE/mL and 1.26 ± 0.24 mg GE/mL, respectively, while the concentration of soluble proteins was 90.60 ± 4.50 µg BSAE/mL. The extract exhibited antioxidant properties by scavenging ABTS•+, H2O2, AAPH, and HO• radicals. Additionally, it demonstrated antibacterial activity by inhibiting the growth of four strains of Staphylococcus aureus. The data obtained suggest that the hydroalcoholic extract of S. laevipila possesses significant potential as a natural antioxidant and antimicrobial agent, making it a promising candidate for the development of phytotherapeutic and cosmetic products.
Chromothripsis Is a Recurrent Genomic Abnormality in High-Risk Myelodysplastic Syndromes
To explore novel genetic abnormalities occurring in myelodysplastic syndromes (MDS) through an integrative study combining array-based comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) in a series of MDS and MDS/myeloproliferative neoplasms (MPN) patients. 301 patients diagnosed with MDS (n = 240) or MDS/MPN (n = 61) were studied at the time of diagnosis. A genome-wide analysis of DNA copy number abnormalities was performed. In addition, a mutational analysis of DNMT3A, TET2, RUNX1, TP53 and BCOR genes was performed by NGS in selected cases. 285 abnormalities were identified in 71 patients (23.6%). Three high-risk MDS cases (1.2%) displayed chromothripsis involving exclusively chromosome 13 and affecting some cancer genes: FLT3, BRCA2 and RB1. All three cases carried TP53 mutations as revealed by NGS. Moreover, in the whole series, the integrative analysis of aCGH and NGS enabled the identification of cryptic recurrent deletions in 2p23.3 (DNMT3A; n = 2.8%), 4q24 (TET2; n = 10%) 17p13 (TP53; n = 8.5%), 21q22 (RUNX1; n = 7%), and Xp11.4 (BCOR; n = 2.8%), while mutations in the non-deleted allele where found only in DNMT3A (n = 1), TET2 (n = 3), and TP53 (n = 4). These cryptic abnormalities were detected mainly in patients with normal (45%) or non-informative (15%) karyotype by conventional cytogenetics, except for those with TP53 deletion and mutation (15%), which had a complex karyotype. In addition to well-known copy number defects, the presence of chromothripsis involving chromosome 13 was a novel recurrent change in high-risk MDS patients. Array CGH analysis revealed the presence of cryptic abnormalities in genomic regions where MDS-related genes, such as TET2, DNMT3A, RUNX1 and BCOR, are located.
Targeting Inflammation and Iron Deficiency in Heart Failure: A Focus on Older Adults
Background/Objectives: Heart failure (HF) is a leading cause of morbidity and mortality worldwide, with a higher prevalence among older adults. Iron deficiency (ID), affecting up to 50% of HF patients, is closely linked to chronic inflammation, exacerbating HF outcomes. This review aims to explore the interplay between inflammation, ID, and HF, focusing on older patients, and to identify therapeutic gaps and emerging treatment strategies. Methods: A comprehensive review of the literature was conducted, emphasizing the pathophysiological mechanisms of inflammation and ID in HF, the challenges of current diagnostic criteria, and the limitations of available treatments. Emerging pharmacological and diagnostic approaches were analyzed. Results: Chronic inflammation in HF, particularly in older adults, promotes functional ID through elevated hepcidin levels, impairing iron availability and worsening anemia. Current diagnostic criteria, relying heavily on ferritin, often misclassify ID due to inflammation. Intravenous (IV) iron therapy shows clinical benefits in patients with <50% left ventricular ejection fraction (LVEF), but the evidence is limited in heart failure with preserved ejection fraction (HFpEF). Emerging therapies, such as Sodium-Glucose Cotransporter-2 inhibitors (SGLT2is) and prolyl hydroxylase inhibitors like Roxadustat, offer promising avenues to improve iron metabolism and outcomes. Conclusions: ID and inflammation significantly impact HF progression, particularly inolder adults. Refining diagnostic criteria and exploring innovative therapies are critical to addressing these challenges. Future research should prioritize personalized approaches targeting inflammation and ID, especially in underrepresented populations, such as HFpEF and elderly patients.
Occupational Prestige and Gender-Occupational Segregation
The purpose of this article is to determine whether there is a relationship between the proportion of women working in an occupation and the prestige assigned to that occupation. Based on a representative sample of Spanish employees from the Spanish Quality of Working Life Survey, pooled-sample data (2007–2010) are used to show that occupations with larger shares of women present lower prestige, controlling for a set of objective individual and work-related variables, and self-assessed indicators of working conditions. However, the results obtained do not support the devaluation theory since an inverted-U relationship between female share and occupational prestige is observed. This conclusion holds even after passing a battery of robustness checks.