Sustainable super-hard and thick nanodiamond composite film deposited on cemented carbide substrates with an interfacial Al-interlayer.

Super-hard nanodiamond composite (NDC) films, synthesized via cathodic arc plasma deposition on unheated WC−Co substrates, offer an eco-friendly solution for cutting tools. A 100 nm-thick Al-interlayer mitigates Co catalytic effects, improving adhesion and yielding smooth and dense 10 µm-thick films at a deposition rate of 3.3μm/hr. These grain-boundary-rich nanostructured films, with an impressive 58 GPa hardness attributed to a substantial 70% C sp3 fraction, prove optimal for hard coatings. The Al-interlayer effectively suppresses Co catalytic effects, forming a dense Al-oxide layer, enhancing film hardness and adhesion (Lcr=18.6N). NDC films present a promising eco-friendly option for high-performance hard coatings

Wear-resistant and adherent nanodiamond composite thin film for durable and sustainable silicon carbide mechanical seals.

In response to environmental concerns, there is a growing demand for durable and sustainable mechanical seals, particularly in high-risk industries like chemical, petroleum, and nuclear sectors. This work proposes augmenting the durability and sustainability of silicon carbide (SiC) ceramic seals with the application of a nanodiamond composite (NDC) film through coaxial arc plasma deposition (CAPD) in a vacuum atmosphere. The NDC coating, with a smooth surface roughness of Ra = 60 nm as substrate, demonstrated a thickness of 1.1 μm at a deposition rate of 2.6 μm/hr. NDC film has demonstrated exceptional mechanical and tribological characteristics, such as a hardness of 48.5 GPa, Young’s modulus of 496.7 GPa, plasticity index (H/E) of 0.098, and fracture toughness of H3/E2 = 0.46 GPa, respectively. These NDC films showcased commendable adhesion strength (> 60 N), negligible wear, and low friction (≤ 0.18) during dry sliding against a SiC counter material. Raman analysis has confirmed the nanocomposite structure of NDC film, emphasizing the role of highly energetic carbon ions in enhancing film adhesion by forming SiC intermetallic compounds at the interface through the diffusion of silicon atoms from the substrate into the films. The abundance of grain boundaries and rehybridization of carbon sp3 to sp2 bonding is perceived to improve tribological performance. CAPD excels in synthesizing long-life eco-friendly NDC coatings for durable and sustainable mechanical seals, featuring smooth surfaces, superior adhesion, outstanding hardness, and wear resistance, making them high potential candidates for various tribological applications

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

Eco-friendly thick and wear-resistant nanodiamond composite hard coatings deposited on WC–Co substrates.

Nanodiamond composite (NDC) films, synthesized using an environmentally friendly PVD coaxial arc plasma deposition technique on commercial cemented carbide (Co6 wt%) substrates without the need for substrate heating, chemical etching of Co, and chemical gases. These NDC coatings, crafted under specific discharge power conditions (5.2 J/pulse, 120 V, and 1 Hz), with or without a substrate biasing (−100V, 40kHz, and 35% duty cycle), exhibit a distinctive nanostructure characterized by nanodiamond grains embedded in an amorphous carbon (a-C) matrix. Highlighting remarkable mechanical characteristics attributed to highly energetic ejected carbon ion. The coatings boast high hardness (H = 65–82 GPa), Young's modulus (E = 688–780 GPa), plasticity index (H/E = 0.094–0.105), and brittle fracture resistance (H3/E2 = 0.58–0.9 GPa). Additionally, these NDC films manifest a substantial thickness of 7 μm due to low internal stress, along with superior adhesion, anti-wear resistance, and a low friction coefficient (0.1–0.09) through dry sliding against an Al2O3 counterpart. Raman analysis substantiates the nanocomposite structure of the film, underscoring the influential role of biasing in enhancing the characteristics of these environmentally friendly and wear-resistant NDC coatings. Nevertheless, the application of a negative bias led to increased internal stress levels (1.28 to 4.53 GPa), adversely impacting the adhesion between the film and substrate, resulting in a decrease from HF3 to HF6 as per Rockwell C indentation. NDC coatings hold significant potential for extending the lifespan of cutting tools and improving overall machining performance

Minéralisation in situ de nano-hydroxyapatite sur nanofibre de cellulose bifonctionnelle / alcool polyvinylique / hydrogel d'alginate de sodium par impression 3D

International audienceThis paper reports the manufacturing by 3D printing of scaffolds for in-situ mineralization of hydroxyapatite using aqueous suspensions of alginate and polyvinyl alcohol (PVA)-grafted cellulose nanofibers (CNF). Bifunctional CNF with carboxyl and aldehyde moieties were prepared from bleached bagasse pulp and crosslinked with PVA. Aqueous hydrogels for 3D printing were prepared by directly mixing PVA-grafted CNF with sodium alginate, with and without the addition of phosphate ions. A calcium chloride solution was sprayed during the printing process in order to partially crosslink alginate and to increase the dimensional stability of the printed gel. At the end of the printing process, the prepared scaffolds were dipped into a CaCl 2 solution to: i) complete alginate crosslinking and ii) promote hydroxyapatite nucleation and growth by reaction with phosphate ions. In order to better understand the mechanisms governing manufacturing of scaffolds by 3D printing, the rheological behavior of alginate/PVA-grafted CNF and the mechanical properties of unit filaments obtained by direct hydrogel extrusion were investigated. The final scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). This study shows that 3D printed sodium alginate/PVA-grafted CNF hydrogels are promising scaffold materials for bone tissue engineering.Cet article rapporte la fabrication par impression 3D d'échafaudages pour la minéralisation in-situ d'hydroxyapatite à l'aide de suspensions aqueuses de nanofibres de cellulose (CNF) greffées à l'alcool polyvinylique (PVA) et d'alginate. Des CNF bifonctionnels avec des fragments carboxyle et aldéhyde ont été préparés à partir de pâte de bagasse blanchie et réticulés avec du PVA. Des hydrogels aqueux pour l'impression 3D ont été préparés en mélangeant directement du CNF greffé au PVA avec de l'alginate de sodium, avec et sans addition d'ions phosphate. Une solution de chlorure de calcium a été pulvérisée pendant le processus d'impression afin de réticuler partiellement l'alginate et d'augmenter la stabilité dimensionnelle du gel imprimé. A la fin du processus d'impression, les échafaudages préparés ont été plongés dans une solution de CaCl2 pour: i) compléter la réticulation d'alginate et ii) promouvoir la nucléation d'hydroxyapatite et la croissance par réaction avec des ions phosphate. Afin de mieux comprendre les mécanismes de fabrication des échafaudages par impression 3D, le comportement rhéologique du CNF greffé alginate / PVA et les propriétés mécaniques des filaments unitaires obtenus par extrusion directe d'hydrogel ont été étudiés. Les échafaudages finaux ont été caractérisés par microscopie électronique à balayage (MEB), spectroscopie infrarouge à transformée de Fourier (FTIR) et analyse thermogravimétrique (TGA). Cette étude montre que les hydrogels CNF greffés d'alginate de sodium / PVA imprimés en 3D sont des matériaux d'échafaudage prometteurs pour l'ingénierie tissulaire osseuse

Unveiling a 72.5 GPa peak hardness in sustainable nanodiamond composite hard coatings via discharge energy control: a nanoindentation-Raman approach.

Sustainable nanodiamond composite (NDC) films hold promise for high-performance hard coatings thanks to coaxial arc plasma deposition (CAPD). This eco-friendly technique eliminates the need for external heating, chemical reactions, or Co substrate pre-treatment. CAPD boasts lower energy consumption and faster deposition rates, making it a sustainable solution for the growing demand for high-quality, environmentally friendly coatings. This study investigates the influence of discharge energy on the nanostructure and mechanical properties of these NDC films. Optimal discharge energy, ranging from 2.3 to 12 J/pulse, was meticulously explored. A combined nanoindentation-Raman approach reveals a significant correlation between discharge energy and film properties. Remarkably, at 7 J/pulse, a peak hardness of 72.5 GPa is achieved, surpassing other energy levels. Raman spectroscopy confirms maximum nanodiamond content at this energy level (evidenced by maximized Adia/AG ratio, indicating a higher diamond-to-graphite ratio), along with minimal graphitization. Additionally, the presence of trans-polyacetylene (t-PA) peaks (denoted as At-PA) revealed the existence of maximum grain boundaries ratio (At-PA/AG), contributing to enhanced mechanical properties. Optimizing discharge energy tailors NDC film nanostructure, enhancing mechanical performance for advanced hard coatings

Novel Design of Double Slope Solar Distiller with Prismatic Absorber Basin, Linen Wicks, and Dual Parallel Spraying Nozzles: Experimental Investigation and Energic&ndash;Exergic-Economic Analyses

Increasing the evaporation zone inside the solar distiller (SD) is a pivotal method for augmenting its freshwater production. Hence, in this work, a newly designed prismatic absorber basin covered by linen wicks was utilized instead of the conventional flat absorber basin to increase the surface area of the vaporization zone in a double-slope solar distiller (DSSD). Meanwhile, for further enhancement of modified DSSD performance, dual parallel spraying nozzles are incorporated underneath the glass cover as a saltwater feed supply to minimize the thickness of the saltwater film on the wick, which enhances the heating process of the wick surface and, consequently, the evaporation and condensation processes are improved. Two double slope distillers, namely a double slope solar distiller with wick prismatic basin and dual parallel spraying nozzles (DSSD-WPB&amp;DPSN) and a traditional double slope solar distiller (TDSSD), are made and tested in the outdoor summer conditions of Tanta, Egypt (31&deg; E and 30.5&deg; N). A comparative energic&ndash;exergic-economic analysis of the two proposed solar stills is also conducted, in terms of the cumulative distillation yield, daily energy efficiency, daily exergy efficiency, and cost per liter of distilled yield. The present results show that the cumulative distillation yield of the DSSD-WPB&amp;DPSN was 8.20 kg/m2&middot;day, which is higher than that of the TDSSD by 49.64%. Furthermore, the energy and exergy efficiencies were increased by 48.51% and 118.10%, respectively, relative to TDSSD. Additionally, the life cost assessment reveals that the cost per liter of the distilled yield of the DSSD-WPB&amp;DPSN is decreased by 11.13% compared to the TDSSD

Paretic-Limb-Only Plyometric Training Outperforms Volume-Matched Double-Limb Training for Ameliorating Balance Capability and Gait Symmetry in Adolescents with Unilateral Cerebral Palsy: A Comparative Study

Adolescents with unilateral cerebral palsy (U-CP) experience an asymmetrical posture because the less-affected lower limb is preferred for bodyweight support as a strategy of compensating for the paretic side&rsquo;s muscular weakness. This study was designed to compare the effect of 12 weeks of paretic-limb-only plyometric training (PLPT) and volume-matched double-limb training (DLPT) on balance capability and gait symmetry in adolescents with U-CP. Sixty-nine adolescents with U-CP were randomly assigned to PLPT, DLPT, or a control group (n = 23 each). Treatment was delivered twice/week (with at least 48 h recovery intervals) for 12 weeks in succession. The directional (LoSdirectional) and overall (LoSoverall) limits of stability in addition to the temporal (T-GSI) and spatial (S-GSI) gait symmetry indicis were assessed pre- and post-treatment. The LoSdirectional improved significantly in the PLPT group compared to either the DLPT or control group (for the forward (p = 0.027 and &lt;0.001, respectively), backward (p = 0.037 and &lt;0.001, respectively), affected-side (p = 0.038 and 0.004, respectively), and less-affected-side (p = 0.018 and 0.016, respectively)), and this was also the case for the LoSoverall (p &lt; 0.001). Additionally, The T-GSI and S-GSI scores decreased significantly in the PLPT group compared to the DLPT (p = 0.003 and 0.047, respectively) or control (p = 0.003 and 0.036, respectively) group, indicating the development more symmetrical gait patterns. In conclusion, PLPT is likely more effective for enhancing balance capabilities and promoting symmetrical gait patterns than DLPT. Thereupon, it is worthwhile for physical rehabilitation practitioners to include the PLPT paradigm into the intervention plans for adolescents with U-CP