•LIPMD is proposed to improve the quality and accuracy of laser drilling of CFRP plates.•The comparative analysis on machinability and surface integrity of CFRP plate by LIA and LIPMD is ...conducted.•Taper, recast layer, and roundness of CFRP micro-holes are significantly improved.•Smooth kerf and small taper of CFRP micro-holes are obtained.
Carbon fiber reinforced plastic (CFRP) is being widely used due to its excellent mechanical properties and corrosion resistance. However, CFRP with the characteristics of anisotropy and inhomogeneous result in difficulty to drill micro-holes. Traditional methods are used to drill micro-holes resulting in poor performance, such as fiber pull-out, tool wear, and bad processed surface quality. Laser machining has great potential on drilling CFRP micro-holes without tool wear and fiber pull-out, but leads to large taper and recast layer. In this study, laser induced plasma micro-drilling (LIPMD) was proposed to reduce the taper as well as improve the processed surface integrity. A comprehensive analysis processed sidewall surface quality, taper, roundness and surface integrity were conducted, and LIPMD process showed more advantages over laser in air (LIA). It is concluded that the processed sidewall machined by the LIPMD has less epoxy recast layer, and the surface of fiber is smoother than that of in the LIA process, diameter difference between the top and bottom of micro-holes is reduced by about 24.83%-32.02%, and the taper is reduced by 32.02%-47.44% compared with the LIA process. This investigation demonstrates the applicability of the LIPMD as a potential process for improved machinability and surface integrity of CFRP material.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Highly sensitive reflective-type fiber hydrogen sensor based on an enlarged taper cascaded with a tilted fiber grating (TFBG) was proposed. Hydrogen-sensitive Au-Pd nanofilm was coated on the TFBG ...surface by magnetron sputtering means. By cascading an enlarged taper upstream to the TFBG, cladding modes and Ghost mode of the TFBG could be coupled into the core to form a reflective-type TFBG-based hydrogen sensor. As the hydrogen was absorbed by the Au-Pd nanofilm, the effective refractive index of the cladding of the TFBG will change accordingly, so as to the reflective spectra of the TFBG. The hydrogen concentration was obtained through the intensity changing of the ghost mode in the reflective spectra of TFBG. The proposed sensor showed a high sensitivity of 4.83 dB/% with a calculated LOD of 0.07% for the hydrogen concentration range from 0% to 0.7% at room temperature with the rapid response time of 26 s and recovery time of 40 s, respectively.
Background Pharmacologic immunosuppression regimes are commonly employed in stem cell clinical trials to mitigate host immune rejection and promote survival and viability of transplanted cells. ...Immunosuppression and cell survival has been extensively studied in retinal and spinal tissues. The applicability of stem cell therapy is rapidly expanding to other sensory organs such as the ear and hearing. As regenerative therapy is directed to new areas, a greater understanding of immunosuppression strategies and their efficacy is required to facilitate translation to organ-specific biologic microenvironments. Objective This systematic review appraises the current literature regarding immunosuppression strategies employed in stem cell trials of retinal and neural cells. Methods This systematic review was performed in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria included studies presenting data on neural or retinal cells as part of an in-human clinical trial that detailed the immunosuppression regime used. Exclusion criteria included non-English language studies, animal studies, review articles, case reports, editorials, and letters. The databases Medline, Embase, Scopus, Web of Science, and the Cochrane Library were searched from inception to February 2024. Risk of bias was evaluated using the ROBINS-I tool. Results Eighteen articles fit the inclusion criteria. Nine articles concerned retinal cells, 5 concerned spinal cord injury, and 4 concerned amyotrophic lateral sclerosis. A multi-drug and short-term immunosuppression regime were commonly employed in the identified studies. Detected immune responses in treated patients were rare. Common immunosuppression paradigms included tacrolimus, mycophenolate mofetil and tapering doses of steroids. Local immunosuppression with steroids was employed in some studies concerning retinal diseases. Discussion A short-term course of systemic immunosuppression seemed efficacious for most included studies, with some showing grafted cells viable months to years after immunosuppression had stopped. Longer-term follow-up is required to see if this remains the case. Side effects related to immunosuppression were uncommon.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study, some key new developments in nanoscience which highlight the problem of nanoparticles in blood flow through mild stenosis in the presence of a blood clot have been presented. The blood ...flow behavior through the stenosed artery is considered using the Prandlt fluid model and the flow of blood is considered as suspension of nanoparticles. An appropriate non-linear system of equations governing blood flow is represented in a cylindrical coordinate system and solved exactly under mild stenotic conditions using the geometry of the stenotic artery in the presence of a clot. Heat transfer phenomena have been examined for the physical features of the flow of blood through a stenosed artery, which is tapered in shape and with the presence of a clot. The temperature profile has been discussed with graphs for several different parameters of clot size, stenosis height, heat source, and sink parameter. Tapering phenomena has been analyzed for temperature profile. It is examined that in converging tapering the temperature provides greater values as estimated together with the non-tapered arteries and diverging tapering arteries. In this work, it is also analyzed that with a rise in the clot size (σ) the temperature (θ) increases, whereas the radius of the artery with stenosis h(z) decreases and heat source and sink parameter (
D)
increases.
Kerf taper and delamination are undesirable geometrical defects inherent to abrasive water-jet machining (AWJM) of layered fibre reinforced polymer composites. This is mainly attributed to the ...characteristics of water-jet energy as well as the anisotropic nature of the material. The present research describes an experimental investigation into minimizing the aforementioned defects for hybrid fibre reinforced polymer composites. Experimental results reveal that the kerf ratio was mainly influenced by the stand-off distance and traverse rate. Both sides of delamination were influenced by abrasive flow rate, traverse rate, and hydraulic pressure. Minimum kerf ratio and delamination damage can be achieved by increasing the kinetic energy of abrasive water-jet stream when impinging under a lower cutting speed. Response surface methodology (RSM) was employed for establishing empirical relationships between experimental outputs and controlled parameters. Confirmation tests have a variance of within 5% for both outputs via comparison between experimental values and the regression models.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•Polymer composites effectively reduce the absorbed doses due to computed tomography.•Absorbed doses of fetus of a 24th weeks pregnant phantom was studied in chest imaging.•Poly hydroxyethyl ...methacrylate tungsten oxide reduces brain dose notably at 80 kVp.
Given their desirable shielding properties, 5 polymer composite shields reinforced with tungsten were selected and their effects as gamma shields on fetal dose reduction were investigated. According to the results, the selected shields reduce the fetus brain, the fetus lungs, the fetus kidneys, and the total fetus dose almost 34.17%-41.19%, 20.47%-25.08%, 9.27%-12.13%, and 15.39%-18.69%, respectively, at tube voltage of 80 kVp. At the higher tube potentials, the values of dose reduction were smaller. Moreover, it was observed that polymers named PHEMA-WO3 and RS-U-30 had an excellent shielding ability among the other studied composites.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Thermo-hydraulic performance analysis of a tapered double layer microchannel heat sink (DL-MCHS) is done numerically. Water and Al2O3-H2O nanofluid coolants are used with uniform heat flux at the ...base of DL-MCHS. Comparatively higher heat transfer and lower pressure drop can be achieved considering temperature dependent thermo-physical properties. An overall performance factor is determined which indicates that though the tapered channel gives better thermal performance than straight channel, it is not always advantageous, if hydraulic performance is also considered, due to the increase in pressure drop penalty. Finally, from optimization study, maximum heat transfer is obtained at tapering factor of 0.32.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive ...pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as ‘leak’. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models.
The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p < 0.0001; ＋0.02, 95% CI 0.00 to ＋ 0.22), Qd (r = 0.959, p < 0.0001; −5.2 mL/min, 95% CI −52.2 to ＋13.0) and CMVR (r = 0.624, p < 0.0001; ＋50 Woods Units, 95% CI −325 to ＋2549).
Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data. The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data.
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•We describe a conductivity model of side branch flow, incorporating local pressure•The model computed coronary flow, pressure, and microvascular resistance•The model correlated with established, anatomy dependent, side branch flow techniques•This new technique may enhance coronary side branch flow simulations
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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