1,288 research outputs found
Perspectives on alternatives to phthalate plasticized poly(vinyl chloride) in medical devices applications
Poly(vinyl chloride) (PVC) is one of the most important polymeric materials available today and is used to manufacture many items, ranging from packaging and toys to healthcare devices. PVC is per se a rigid material but it is made softer by compounding with plasticizers, particularly phthalate esters such as di-(2-ethylhexyl) phthalate (DEHP). In flexible plasticizer PVC (P-PVC), phthalates are not chemically bound to PVC and they are released into the external environment. In particular, prolonged contact of P-PVC based medical devices with body fluids or tissues has been shown to be associated with severe health risks. Major concerns regarding the safety of P-PVC in medical plastic items have been raised, and several alternatives to phthalates and to P-PVC itself as well as chemical/physical treatments of P-PVC to reduce DEHP migration have been proposed. This review outlines recent scientific approaches for preventing DEHP contamination of humans by P-PVC medical devices, highlighting the impact of the proposed alternative materials on human health and strategies for implementing them
High Temperature Stability of Onion-Like Carbon vs Highly Oriented Pyrolytic Graphite
Abstract
The thermodynamic stability of onion-like carbon (OLC) nanostructures with respect to highly oriented pyrolytic graphite
(HOPG) was determined in the interval 765â1030 K by the electromotive force (emf) measurements of solid electrolyte
galvanic cell: (Low) Pt|Cr3C2,CrF2,OLC|CaF2s.c.|Cr3C2,CrF2,HOPG|Pt (High). The free energy change of transformation
HOPG = OLC was found positive below 920.6 K crossing the zero value at this temperature. Its trend with temperature was
well described by a 3rd degree polynomial. The unexpected too high values of
LDrHT
LT
P
~DcPĂ°TĂ jointly to the HR-TEM,
STEM and EELS evidences that showed OLC completely embedded in rigid cages made of a Cr3C2/CrF2 matrix, suggested
that carbon in the electrodes experienced different internal pressures. This was confirmed by the evaluation under constant
volume of
dP
dT
by the
a
k
ratio for OLC (0.5 MPa K21) and HOPG (8 Pa K21) where a and k are the isobaric thermal expansion
and isothermal compressibility coefficients, respectively. The temperature dependency of the pressure was derived and
utilized to calculate the enthalpy and entropy changes as function of temperature and pressure. The highest value of the
internal pressure experienced by OLC was calculated to be about 7 GPa at the highest temperature. At 920.6 K, DrH and
DrS values are 95.8 kJ mol21 and 104.1 JK21 mol21, respectively. The surface contributions to the energetic of the system
were evaluated and they were found negligible compared with the bulk terms. As a consequence of the high internal
pressure, the values of the enthalpy and entropy changes were mainly attributed to the formation of carbon defects in OLC
considered as multishell fullerenes. The change of the carbon defect fraction is reported as a function of temperature
Sc substitution for Mg in MgB2: effects on Tc and Kohn anomaly
Here we report synthesis and characterization of Mg_{1-x}Sc_{x}B_{2}
(0.12T_{c}>6 K.
We find that the Sc doping moves the chemical potential through the 2D/3D
electronic topological transition (ETT) in the sigma band where the ``shape
resonance" of interband pairing occurs. In the 3D regime beyond the ETT we
observe a hardening of the E_{2g} Raman mode with a significant line-width
narrowing due to suppression of the Kohn anomaly over the range 0<q<2k_{F}.Comment: 8 pages, 4 EPS figures, to be published in Phys. Rev.
The Role of Large Language Models (LLMs) in Providing Triage for Maxillofacial Trauma Cases: A Preliminary Study
Background: In the evolving field of maxillofacial surgery, integrating advanced technologies like Large Language Models (LLMs) into medical practices, especially for trauma triage, presents a promising yet largely unexplored potential. This study aimed to evaluate the feasibility of using LLMs for triaging complex maxillofacial trauma cases by comparing their performance against the expertise of a tertiary referral center. Methods: Utilizing a comprehensive review of patient records in a tertiary referral center over a year-long period, standardized prompts detailing patient demographics, injury characteristics, and medical histories were created. These prompts were used to assess the triage suggestions of ChatGPT 4.0 and Google GEMINI against the centerâs recommendations, supplemented by evaluating the AIâs performance using the QAMAI and AIPI questionnaires. Results: The results in 10 cases of major maxillofacial trauma indicated moderate agreement rates between LLM recommendations and the referral center, with some variances in the suggestion of appropriate examinations (70% ChatGPT and 50% GEMINI) and treatment plans (60% ChatGPT and 45% GEMINI). Notably, the study found no statistically significant differences in several areas of the questionnaires, except in the diagnosis accuracy (GEMINI: 3.30, ChatGPT: 2.30; p = 0.032) and relevance of the recommendations (GEMINI: 2.90, ChatGPT: 3.50; p = 0.021). A Spearman correlation analysis highlighted significant correlations within the two questionnaires, specifically between the QAMAI total score and AIPI treatment scores (rho = 0.767, p = 0.010). Conclusions: This exploratory investigation underscores the potential of LLMs in enhancing clinical decision making for maxillofacial trauma cases, indicating a need for further research to refine their application in healthcare settings
Tetris Genioplasty: A New Paradigm for Chin Asymmetries Correction
The chin plays a crucial role as a fundamental structural component that contributes to the overall aesthetics and harmony of the face. Recognizing its central position, medical science has seen the evolution of numerous surgical techniques over the years, all aimed at correcting the range of structural irregularities that can affect the chin. In this contribution, the authors introduce an innovative osteotomy technique, aimed at cases of chin asymmetry in which the skeletal median diverges from the dental median. This technique, called âTetris genioplastyâ, involves performing the classic rectangular osteotomy, but includes an additional vertical osteotomy in order to obtain two distinct segments. Finally, these segments are translocated and repositioned to obtain a realignment between the skeletal median and the dental median. The results were entirely satisfactory for the patients, aligning perfectly with the expected appearance after the operation. Furthermore, no complications were reported, proving the success and safety of the procedure. The Tetris genioplasty aligns itself with this progressive trend by offering a minimally invasive method that nevertheless is able to achieve excellent results with a high impact on the patientâs quality of life, presenting a promising path in the pursuit of optimal aesthetic results with minimized patient morbidity and greater overall safety
Vertical Greenery as Natural Tool for Improving Energy Efficiency of Buildings
The European Construction Sector Observatory outlined that green building envelopes as green roofs and walls contribute to the reduction of energy demand and CO2 emissions due to the air conditioning in summer periods, and the mitigation of heat islands in urban areas. For this reason, the understanding about the contribution of urban greening infrastructures on buildings to sustainable energy use for air conditioning is urgent. This paper focuses on the analysis of a vertical surface provided with a Parthenocissus quinquefolia (L.) Planch., a winter deciduous species, as green cover of a building, assessing the reduction of the solar radiation energy absorbed by the facade and, consequently, the heat flux (HF) transmitted into the internal ambient. This research shows that, in July, surface temperatures (STs) on the vegetated facade were up to 13 degrees C lower than on the unvegetated (bare) facade. Under the climate and environmental conditions of the green wall located at ENEA Casaccia Research Center, a saving of 2.22 and 1.94 kWh(e)/m(2) , respectively in 2019 and 2020, for the summer cooling electricity load, was achieved. These energy reductions also allowed the saving of 985 and 862 g CO2/m(2) emissions, respectively, in 2019 and 2020. Ultimately, a green factor named K-v* was also elaborated to evaluate the influence of vegetation on the STs as well as on HFs transmitted into the indoor ambient and adapted to the case of a detached vertical green cover. Measurements of K-v* factor lasting three years showed the suitability of this index for defining the shading capacity of the vegetation on the building facade surfaces, which can be used to predict thermal gains and effects in a building endowed of a vertical green system
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