Search Results (40,587)

Objective: Peripherally Inserted Central Catheter (PICC) tip migration often occurs after placement despite efforts to position the tip centrally. This study aimed to quantify PICC tip migration within 3–7 h post-insertion and evaluate the effectiveness of manual adjustments for repositioning. Methods: This single-centre retrospective study evaluated the impact of a proactive approach following PICC placement, which included standardized body positioning during X-rays, defined target PICC tip locations, radiological surveillance at 4–6 h post-insertion, and guided manual adjustments. We included all infants receiving PICCs during a five-year period; trained nurses and physicians in vascular access performed the insertions. Results: Of 712 infants included, the median gestational age was 30 weeks, and the median birth weight was 1386 g. PICC tip migration occurred in 211 infants (30%) within 3–7 h post-insertion, with 81% of cases involving inward migration into the cardiac silhouette. Migration was more common in upper limb PICCs (82%). Manual adjustments achieved satisfactory repositioning in 191 infants (83%). None of the infants experienced pericardial effusion. Conclusions: A proactive approach that standardized imaging protocols, timing, and PICC tip positioning detected migration in 30% of infants and successfully facilitated repositioning in 83% of cases. Full article

The [3+2] cycloaddition chemistry of (2S)-5-methylene-2-t-butyl-1,3-dioxolan-4-one, derived from lactic acid, has been examined, and spiro adducts have been obtained with benzonitrile oxide, acetonitrile oxide, diazomethane and diphenyldiazomethane. The structure and absolute stereochemistry of the benzonitrile oxide adduct has been confirmed by X-ray diffraction, and all the adducts have been fully characterised by ¹H and ¹³C NMR. Attempted cycloaddition with a nitrile sulfide, a nitrile imine and azides failed. Pyrolysis results in a range of novel gas-phase reactions, with the nitrile oxide adducts giving pivalaldehyde, CO₂, the nitrile and ketene, the diazomethane adduct losing only N₂ to give a cyclopropane-fused dioxolanone, and the diphenylcyclopropane derived from diphenyldiazomethane giving mainly benzophenone in a sequence involving the loss of pivalaldehyde and methyleneketene. Full article

Large organic molecules and metal complexes are promising candidates for organic electronics, optoelectronics, and spintronics, with interfaces to metals being critical. Clean preparation in ultra-high vacuum (UHV) is ideal, but many systems are fragile and cannot be thermally sublimed. This study details the preparation of thin films of the metallacrown Cu(II)[12-MC_Cu(II)N(Shi)-4] (short: CuCu4) from the liquid phase using electrospray injection (ESI) and, in particular, liquid injection (LI). Both methods produce films with intact CuCu4 complexes, but they differ in the amount of co-adsorbed solvent molecules. Enhancements using an argon stream perpendicular to the molecular beam significantly reduce these contaminants. An additional effect occurs due to the counterions (HNEt₃)₂ of CuCu4. They are co-deposited by LI, but not by ESI. The advantages and limitations of the LI method are discussed in detail. The CuCu4 films prepared by different methods were analyzed with infrared (IR) spectroscopy, ultraviolet and X-ray photoelectron spectroscopy (UPS, XPS), and scanning tunneling microscopy (STM). For thicker films, ex situ and in situ prepared CuCu4 films to exhibit similar properties, but for studying interface effects or ultrathin films, in situ preparation is necessary. Full article

Background: Body composition analysis is crucial in clinical practice, yet few methods are suitable for pediatric patients, and data on young children with obesity are limited. Methods: This study measured body fat percentage (BFP), fat mass (FM), and fat-free mass (FFM) in 26 pediatric patients with obesity (BMI: 35.6±6.9 kg/m²), using two bioelectrical impedance analysis (BIA) devices (TANITA and BIACORPUS), and the results were compared to those of the gold-standard dual-energy X-ray absorptiometry (DXA). Additionally, air displacement plethysmography (BODPOD) was compared with DXA, and all methods were evaluated against each other. Results: Significant differences were observed between all methods and parameters (p < 0.05). For example, Bland–Altman analysis for BFP identified differences between BIACORPUS and DXA (mean: −3.5%; 95% limits of agreement: −16.7% to 9.8%) and between TANITA and DXA (mean: −3.1%; 95% limits of agreement: −12.2% to 6.1%). These differences can be regarded as clinically relevant, especially when considering the 95% limits of agreement. Further, moderate differences between BODPOD and DXA were identified, which could be clinically relevant (mean: 2.1%; 95% limits of agreement: −4.2% to 8.5%). Conclusions: TANITA was the most comparable BIA method to the gold standard, DXA. Therefore, TANITA is recommended for assessing body composition in young patients with obesity to monitor therapy progress in clinical settings. When using BODPOD as an alternative to DXA, caution is warranted since we found relevant differences between both methods. Full article

The design, synthesis, and study of lanthanide coordination compounds with luminescent and magnetic properties attractive in modern technologies is still a pressing and challenging task. In the present work, a series of coordination compounds of tetrakis-carbacylamidophosphate PPh₄[LnL₄] (where HL = diphenyl-N-benzoylamidophosphate) with several lanthanide ions such as Nd^III, Sm^III, Dy^III, and Tm^III was prepared and studied by X-ray analysis and luminescence spectroscopy at 293 and 77 K, as well as by magnetic measurements. Coordination compounds are not isostructural, but the type of coordination is the same. All of them have intense sensitized emission. PPh₄[SmL₄], PPh₄[DyL₄], and PPh₄[TmL₄] chelates are characterized by dual visible and infrared emission and mechanoluminescence. In addition, PPh₄[DyL₄] has multifunctional properties such as Vis and NIR emissions, brilliant mechanoluminescence and single-ion molecular magnet (SIM) properties. This type of compound holds great promise in multifunctional magnetic radiation converters. Full article

The chemical structure of coal is very composite, consisting of a heterogeneous carbonaceous matrix with variable degrees of “turbostratic” order and the inclusion and/or exclusion of mineral matter (ash). The formation of surface oxides on carbon has long been recognized as a key to understanding many chemical and physical properties of carbon materials relevant to their consolidated or emerging applications. The extent and nature of surface oxides can effectively be assessed by high-resolution X-ray photoelectron spectroscopy (XPS), which provides excellent insight into the functional nature of C-O moieties. However, the XPS analysis of ash-bearing carbons may be biased by the interfering effects of inorganics with the most relevant spectral ranges, namely the core levels O_1s and C_1s. The effect of ash components on the spectroscopic characterization of carbon is scrutinized here with reference to a sub-bituminous coal characterized by a fairly large ash content. The coal is subjected to different treatments, including devolatilization, milling, and oxidation. A synthetic carbon (Carboxen) is used as a reference sample for the correct assignment of the carbon–oxygen functionalities in the core-level XPS spectra (C_1s and O_1s) in the absence of mineral matter. On the opposite side, fly ash from an industrial coal boiler is analyzed to investigate the effects of mineral matter. It is shown that the establishment of non-uniform charging of the sample induced by ash provides a key to the interpretation of the XPS spectra of ash-bearing carbon samples. The positive charge on the surface, referred to as the charging effect, brings about a shift of the core-level binding energies towards higher values. Grinding of the samples or partial combustion emphasizes the charging effect. XPS analysis of the fly ash, where carbon is largely consumed and dispersed in the inorganic matter, confirms that charging arises from non-conductive aluminosilicates. These effects may induce remarkable changes in carbon and oxygen peak shapes and need to be accounted for to obtain correct interpretations of the XPS spectra of ash-rich carbonaceous fuels. Full article

With the rapid growth of the sauce-flavored liquor industry, the treatment of wastewater has become an increasingly critical challenge. This study seeks to assess the catalytic oxidation efficacy of Mn₂Cu₂O_x/Al₂O₃ catalysts in the degradation of organic pollutants present in sauce-flavored liquor wastewater, while also elucidating the mechanisms underpinning their performance. Mn₂Cu₂O_x/Al₂O₃ catalysts were synthesized, and their physicochemical properties were thoroughly characterized using advanced techniques such as Brunauer–Emmett–Teller (BET) analysis, N₂ sorption isotherm analysis, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Moreover, the key active species involved in the catalytic oxidation process, including hydroxyl radicals (•OH) and superoxide anion radicals (•O₂⁻), were identified through hydroxyl radical quenching experiments employing tertiary butyl alcohol (TBA). The contribution of these free radicals to enhancing the ozone catalytic oxidation performance was also systematically evaluated. Based on both experimental data and theoretical analyses, the Mn₂Cu₂O_x/Al₂O₃ catalysts demonstrate remarkable catalytic activity and stability, significantly reducing chemical oxygen demand (COD) levels in wastewater. Furthermore, the catalysts are capable of activating oxygen molecules (O₂) during the reaction, producing reactive oxygen species, such as •O₂⁻ and •OH, which are potent oxidizing agents that effectively decompose organic pollutants in wastewater. The proposed catalysts represent a highly promising solution for the treatment of sauce-flavored liquor wastewater and lays a solid foundation for its future industrial application. Full article

Plastic Concrete is a low-strength ($f_{cm,28\mathrm{d}}$≤ 1.0 MPa), low-stiffness impervious concrete used for cut-off walls in earthen dams worldwide. These properties are achieved through a very high w/c ratio (w/c≥ 3.0) and water-binding additions (e.g., bentonite). To date, the effect of mix design, especially w/c ratio, as well as bentonite content and type, on the long-term time development of the microstructural properties and corresponding compressive strength of Plastic Concrete has yet to be systematically studied. Furthermore, in the literature, mercury intrusion porosimetry (MIP) and X-ray diffractometry (XRD) have yet to be applied systematically to Plastic Concrete for this purpose. The present study closes this gap. Ten Plastic Concrete mixes with two bentonite–cement ratios, three types of sodium bentonite and two swelling times were produced. MIP and XRD measurements and compressive strength tests were performed at sample ages of 7 d, 28 d, 56 d, 91 d and four years. The results show that both MIP and XRD can be successfully used; however, meticulous sample preparation and data analysis must be considered. The porosimetry results show a bi-modal pore size distribution, with two age-dependent peaks at approximately 10,000–20,000 nm and 100–700 nm. The results also exhibit a clear pore refinement over time, with coarse porosity dropping from 26% to 15% over four years. In addition, the fine porosity peak is significantly refined over time and positively correlates with the significant increase in compressive strength. The XRD results show no unexpected crystalline phases over the same period. Overall, this study links MIP and corresponding compressive strength data specifically for Plastic Concrete for the first time, confirming the key role that the mix design of Plastic Concrete plays in defining its long-term microstructural and mechanical properties and ensuring more realistic cut-off wall design in the future. In addition, the experimental boundaries for MIP testing on Plastic Concrete are set out for the first time, enabling future research in this field. Full article

This study investigates the effect of microencapsulated temperature rise inhibitors (TRIs) on the hydration temperature evolution and crack resistance of medium-sized concrete structures. Unlike mass concrete, medium-sized concrete elements such as beams, slabs, and columns pose unique challenges in temperature control due to their moderate volume, limited heat dissipation, and susceptibility to thermal stress-induced cracking. To address this issue, concrete mixtures with TRI dosages of 0%, 0.05%, 0.1%, and 0.15% were evaluated using a sealed foam box method, allowing for precise monitoring of hydration temperature development under insulated conditions. The results indicate that TRIs effectively suppress peak hydration temperature and delays its occurrence, with higher TRI dosages leading to more pronounced effects. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirm that the hydration suppression is attributed to a controlled-release mechanism, where TRIs gradually dissolve, forming a hydration barrier on cement particles. This slows down calcium hydroxide (CH) crystallization, alters C-S-H gel evolution, and reduces early age heat accumulation, mitigating thermal cracking risks. Furthermore, mechanical property tests reveal that, while early age compressive and tensile strength decrease with TRI addition, long-term strength recovery is achieved at optimum TRI dosages. This study identifies 0.1% TRI as the most effective dosage, striking a balance between hydration heat reduction and long-term mechanical performance. These findings provide a scientific basis for optimizing TRI dosages in medium-sized concrete applications, offering a practical solution for thermal cracking prevention. Full article

With microscopic thermogravimetric analysis, it is difficult to prepare metastable intermediate phases with precise water contents during the dehydration process of hydrates, making it a challenge to acquire their related spectra. The gradual dehydration process of ZnSO₄·7H₂O proceeds through 7 → 6 → 4 → 1 → 0. Vibrational spectra of ZnSO₄ hydrates, especially ZnSO₄·6H₂O and ZnSO₄·4H₂O, have not been previously reported. By macroscopic thermogravimetric analysis of ZnSO₄·7H₂O, the dehydration process can be precisely controlled to produce a variety of ZnSO₄ hydrates with specific water contents. In this study, powder X-ray diffraction confirmed the purities of 7H₂O, 6H₂O, 4H₂O, 1H₂O and anhydrous ZnSO₄. IR and Raman spectra of ZnSO₄ hydrates were obtained and compared for the first time. Spectroscopic and crystallographic analysis revealed that structural similarity plays a key role in the 7 → 6 → 4 → 1 → 0 dehydration process. Macroscopic thermogravimetric analysis combined with powder X-ray diffraction is a valuable method for investigating the intermediate phases in the hydrate dehydration process. Full article

In response to the issue of the insufficient adhesion strength of polypropylene materials, a plasma–ultrasonic treatment is proposed. Plasma treatment is first conducted to activate the polypropylene adherends, and then ultrasonic vibration is applied to the adhesive to facilitate the interface contact, enhancing the bonding performance of polypropylene. The shear strength of the test specimens was assessed using single-lap shear tests. The bonding samples were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), contact angle, and infrared analysis to explore the bonding mechanism of plasma–ultrasonic treatment. The results show that compared to untreated polypropylene specimens, the plasma treatment process increased the shear strength of the polypropylene specimens by 370.3%, and the addition of ultrasonic-assisted technology further increased the shear strength of the polypropylene specimens by 10.6%. The coefficient of variation decreased from 0.53 in the untreated sample to 0.32 for the plasma–ultrasonic treatment, enhancing the stability of adhesion. Plasma treatment introduces active groups, such as hydroxyl groups, onto the surface of polypropylene and increases the surface roughness of polypropylene. Ultrasonic treatment promotes the penetration of adhesive microstructures on the surface of polypropylene, enhancing the anchoring effect of the adhesive, thereby improving bonding performance. Furthermore, through molecular dynamics analysis, compared to the untreated polypropylene bonding system, the bonding energy of the bonding system under the plasma–ultrasonic treatment was increased by 57%, effectively enhancing the shear strength of polypropylene bonding. Plasma–ultrasonic treatment can effectively improve the bonding strength of polypropylene, providing a new idea for the study of polymer bonding. Full article

Condensation-type polysiloxane composites with montmorillonite (MMT) of different organic modifications were prepared in this study. X-ray diffraction (XRD) characterization revealed that the higher degree of organic modification in Cloisite 20A, compared to that in Cloisite 30B, resulted in a larger interlayer spacing between the clay platelets. This facilitates the insertion of elastomer chains between the layers, enabling easier exfoliation and dispersion in the elastomeric matrix. Differential scanning calorimetry (DSC) showed that the reinforcing agents used reduced the cold crystallization temperature of the condensation-type polysiloxane while leaving the glass transition and melting temperatures nearly unaffected. Additionally, the nanocomposites exhibited slightly lower crystallization and melting enthalpies compared to pure silicone. Thermogravimetric analysis (TGA) showed that incorporating the two organically modified clays (Cloisite 20A and Cloisite 30B) into the condensation-type polysiloxane significantly improved the thermal stability of the resulting nanocomposites. This improvement was reflected in the significant increase in the onset and maximum degradation rate temperatures across all examined reinforcement ratios. It was observed that a higher degree of organic modification in MMT (Cloisite 20A) resulted in a more efficient dispersion in the PDMS matrix and enhanced the thermal stability of the composites. These PDMS nanocomposites could be suitable as protective coatings for devices exposed to elevated temperatures. Full article

Medical Visual Question Answering (MedVQA) is a crucial intersection of artificial intelligence and healthcare. It enables systems to interpret medical images—such as X-rays, MRIs, and pathology slides—and respond to clinical queries. Early approaches primarily relied on discriminative models, which select answers from predefined candidates. However, these methods struggle to effectively address open-ended, domain-specific, or complex queries. Recent advancements have shifted the focus toward generative models, leveraging autoregressive decoders, large language models (LLMs), and multimodal large language models (MLLMs) to generate more nuanced and free-form answers. This review comprehensively examines the paradigm shift from discriminative to generative systems, examining generative MedVQA works on their model architectures and training process, summarizing evaluation benchmarks and metrics, highlighting key advances and techniques that propels the development of generative MedVQA, such as concept alignment, instruction tuning, and parameter-efficient fine-tuning (PEFT), alongside strategies for data augmentation and automated dataset creation. Finally, we propose future directions to enhance clinical reasoning and intepretability, build robust evaluation benchmarks and metrics, and employ scalable training strategies and deployment solutions. By analyzing the strengths and limitations of existing generative MedVQA approaches, we aim to provide valuable insights for researchers and practitioners working in this domain. Full article

In this research, polymer composite sheets were developed by blending poly (vinylidene fluoride-co-hexafluoropropylene) or P(VDF-HFP) with varying concentrations of barium sulfate (BaSO₄) for X-ray shielding applications. The photon counting technique was used to evaluate the composite shielding characteristics through the linear attenuation coefficient. Surface properties, including surface morphology, hydrophobicity, and surface energy, were analyzed using an atomic force microscope (AFM) and a water contact angle machine. Scanning electron microscopy (SEM) was employed to investigate the microstructural distribution and dispersion of BaSO₄ particles within the polymer matrix, providing insights into the composite’s uniformity and structural integrity. Additionally, the bulk properties of the composite polymer sheets, such as crystal structures, tensile strength, and thermal stability, were examined. The results demonstrate that increasing the concentration of BaSO₄ in BaSO₄/P(VDF-HFP) composite sheets significantly improves their X-ray attenuation capabilities. Moreover, higher BaSO₄ concentrations enhance the material’s hydrophobicity, flexibility, and thermal stability, highlighting the potential of these composites for advanced radiation shielding applications. Full article

Background: Microbeam radiation therapy (MRT) is an advanced preclinical approach in radiotherapy that utilizes spatially fractionated dose distributions by collimating x-rays into micrometer-wide, planar beams. While the benefits of temporal fractionation are well established and widely incorporated into conventional radiotherapy protocols, the interplay between MRT and temporal dose fractionation remains largely unexplored. In this study, we investigate the effects of combining temporal and spatial dose fractionation by assessing clonogenic cell survival following temporally fractionated MRT with varying irradiation angles, compared to conventional broad-beam (BB) irradiation. Methods: A lung tumor cell line (A549) and a normal lung cell line (MRC-5) were irradiated with a total number of four fractions with a 24 h interval between each fraction. We compared a temporally fractionated BB regime to two temporally fractionated MRT schemes with either overlapping MRT fields or MRT fields with a 45° rotation per fraction. Subsequently, the clonogenic cell survival assay was used by analyzing the corresponding survival fractions (SFs). Results: The clonogenic survival of A549 tumor cells differed significantly between microbeam radiation therapy with rotation (MRT + R) and overlapping MRT. However, neither MRT + R nor overlapping MRT showed statistically significant differences compared to the broad-beam (BB) irradiation for A549. In contrast, the normal tissue cell line MRC-5 exhibited significantly higher clonogenic survival following both MRT + R and overlapping MRT compared to BB. Conclusions: This study demonstrates that combining temporal and spatial fractionation enhances normal tissue cell survival while maintaining equivalent tumor cell kill, potentially increasing the therapeutic index. Our findings support the feasibility of delivering temporally fractionated doses using different MRT modalities and provide clear evidence of the therapeutic benefits of temporally fractionated MRT. Full article