Search

In recent years, amorphous bioglass is used to improve the bioactivity of HA (Ca10(PO4)6(OH)2). Nevertheless, bioglass crystallizes and reacts with the matrix to form a complex phase composition during sintering, resulting in an unclear mechanism for tailoring the properties of HA bioceramics. In this work, TPMS structural HA ceramics fabricated by digital light processing (DLP) were doped by akermanite (Ca2MgSi2O7) to better tailor the porosity, bioactivity and mechanical strength. After sintering above 1000 °C, Mg2+ ions from akermanite substitute Ca2+ ions in HA, leading to the decomposition of HA into β-TCP. This process increases the porosity of bioceramics. Additionally, liquid phases sintering caused by akermanite gives rise to the densification and enhancement of grain bonding, thereby reinforcing the mechanical strength of scaffolds. For in vitro bioactivity, as the content of akermanite increases from 0 wt.% to 20 wt.%, carbonated hydroxyapatite firstly deposits onto the surfaces of scaffolds and then disappears, because excessive Mg2+ prevent the hydroxyapatite crystallization. Finally, bioceramics with 5 wt.% and 10 wt.% of akermanite and sintering at 1100 °C exhibit a high porosity of over 80% and an appropriate compressive strength of over 2 MPa, while achieving an enhanced in vitro bioactivity and good biocompatibility. After optimization, this kind of porous scaffolds can be well applied to the repair of cancellous bone defect.

It is difficult to prepare ceramic cores by traditional technology due to high dependence on mold and the difficulty of manufacturing complex structures. Additive manufacturing technology can solve these problems. In this study, the silica ceramics were prepared by selective laser sintering (SLS) based on particle grading. Adding appropriate amount of fine powder to coarse powder could improve the mechanical properties of silica ceramics. As a result, the flexural strength of silica green bodies reached a maximum of 3.20 MPa when the mass ratio of coarse powder (D50 = 45.6 μm) and fine powder (D50 = 23.3 μm) was 4:5. With the increase of fine powder content, the shrinkage and flexural strength of silica ceramics first increased and then decreased, while the apparent porosity showed an opposite trend. When the mass ratio was 4:5, the maximum of flexural strength was 7.15 MPa with the linear shrinkage of 4.76% and the apparent porosity of 47.28%. Compared with silica ceramics without fine powder, the flexural strength of silica ceramics increased by nearly 550% (from 1.13 MPa to 7.15 MPa) under the optimal particle grading. Therefore, the silica ceramics with good mechanical properties were prepared by SLS via optimizing the particle grading.

Silica ceramic cores have played an important part in the manufacture of hollow blades due to their excellent chemical stability and moderate high-temperature mechanical properties. In this study, silica-based ceramics were prepared with Al2O3 addition by stereolithography, and the influence of Al2O3 content on mechanical properties of the silica-based ceramics was investigated. The Al2O3 in silica-based ceramics can improve the mechanical properties by playing a role as a seed for the crystallization of fused silica into cristobalite. As a result, with the increase of Al2O3 content, the linear shrinkage of the silica-based ceramics first decreased and then increased, while the room-temperature flexural strength and the high-temperature flexural strength first increased and then decreased. As the Al2O3 content increased to 1.0 vol%, the linear shrinkage was reduced to 1.64% because of the blocked viscous flow caused by Al2O3. Meanwhile, the room-temperature flexural strength and the high-temperature flexural strength were improved to 20.38 and 21.43 MPa with 1.0 vol% Al2O3, respectively, due to the increased α-cristobalite and β-cristobalite content. Therefore, using the optimal content of Al2O3 in silica-based ceramics can provide excellent mechanical properties, which are suitable for the application of ceramic cores in the manufacturing of hollow blades.

Increasing the work function of borophene over a large range is crucial for the development of borophene-based anode materials for highly efficient electronic devices. In this study, the effect of fluorine adsorption on the structures and stabilities, particularly on the work function, of α-borophene (BBP), was systematically investigated via first-principles density functional theory. The calculations indicated that BBP was well-stabilized by fluorine adsorption and the work functions of metallic fluorine-adsorbed BBPs (Fn-BBPs) sharply increased with increasing fluorine content. Moreover, the work function of F-BBP was close to that of the frequently used anode material Au and even, for other Fn-BBPs, higher than that of Pt. Furthermore, we have comprehensively discussed the factors, including substrate deformation, charge transfer, induced dipole moment, and Fermi and vacuum energy levels, affecting the improvement of work function. Particularly, we have demonstrated that the charge redistribution of the substrate induced by the bonding interaction between fluorine and the matrix predominantly contributes to the observed increase in the work function. Additionally, the effect of fluorine adsorption on the increase in the work function of BBP was significantly stronger than that of silicene or graphene. Our results concretely support the fact that Fn-BBPs can be extremely attractive anode materials for electronic device applications.

Additive manufacturing is expected to transform and upgrade the traditional foundry industry to realize the integrated manufacturing and rapid and low-cost development of high-performance components with complex shapes. The additive manufacturing technology commonly applied in casting mold preparation (fusible molds, sand molds/cores and ceramic cores) mainly includes selective laser sintering (SLS) and binder injection three-dimensional printing (3DP). In this work, the research status of SLS/3DP-casting processes on material preparation, equipment development, process optimization, simulation and application cases in aerospace, automotive and other fields were elaborated. Finally, the developing trends of the additive manufacturing technology in the future of foundry field are introduced, including multi-material sand molds (metal core included), ceramic core-shell integration and die-casting dies with conformal cooling runners.

Porous Al2O3-based ceramics with improved mechanical strength and different pore size were fabricated using Al2O3 and SiO2 poly-hollow microspheres (PHMs) as raw materials by selective laser sintering (SLS). The effects of different contents of SiO2 PHMs on phase compositions, microstructures, mechanical properties and pore size distribution of the prepared ceramics were investigated. It is found that moderate content of SiO2 PHMs (≤30 wt%) could work as a sintering additive, which could enhance the bonding necks between Al2O3 PHMs. When the content of SiO2 PHMs increased from 0 wt% to 30 wt%, the compressive strength of Al2O3-based ceramics increased from 0.3 MPa to 4.0 MPa, and the porosity decreased from 77.0% to 65.0% with open pore size decreased from 52.0 μm to 38.3 μm. However, SiO2 PHMs could provide pores by keeping its integrity when the content of SiO2 PHMs increased to 40 wt%, which could result in the porosity increasing to 66.8% and pore size decreasing to 30.1 μm. Selective laser sintering of different kinds of ceramic PHMs is a feasible method to fabricate porous ceramics with complex shape, controllable pore size and improved properties.

Ultra-low magnetic field systems have attracted increasing attention in recent years because they lack cryocoolers and exhibit lightweight, low cost, and mobilization convenience. In contrast to permanent magnet systems, electromagnetic systems can easily vary background magnetic fields, thus offering opportunities on multiple scales of time and distance to characterize the molecular dynamics and transport properties of complex liquids in bulk or embedded in confined environments. An unconventional ultra-low field bell-shaped head MRI magnet with a dedicated compact structure is needed for applications in clinics, intensive care units, and mobile vans and evaluating stroke in the hyperacute and acute stages. In this work, we use the discrete minimum energy (DME) method to design the ultra-low field bell-shaped head MRI electromagnet. This method involves obtaining a DME current map, initial coil extraction, and coil adjustment. The DME map is used to determine the initial current distribution of the MRI electromagnet over a predefined domain subject to constraints. Then, initial coil extraction aims to extract the initial regularized rectangle coil layout from the DME map. Considering that the extraction process decreases magnetic field homogeneity in the region of interest (ROI), coil adjustment is then implemented. This step adjusts the position and volume of the initial coil layout to meet the homogeneity requirement. A bell-shaped electromagnet ( $$< 20$$ mT, 2 MA/m $$^2$$ ) with a homogeneity of 7 ppm over 260 mm DSV is designed in this work.

This letter reports the fabrication of polycrystalline silicon (poly-Si) tunneling field effect transistors (Tunneling FETs) using green nanosecond laser crystallization (GLC). During the GLC process, the Si is full-melted by laser scanning, hence the recrystallized poly-Si thin films with grain size as large as $1.2~\mu \text{m}$ are attained. This makes it possible to fabricate tunneling FET with high-quali ty poly-Si thin films. Compare with the tunneling FETs fabricated by solid phase crystallization (SPC), the ones via GLC show better subthreshold swing (S.S) of 418 mV/dec. and larger on/off ratio of $6.02 \times 10^{5}$ . Moreover, the activation energy curve is also presented to further demonstrate the con nection between device performance and crystallinity of poly-Si thin films.

Dielectric energy storage materials and capacitors are one of the key components for power electronics. Although strenuous efforts have been made to explore high-performance energy storage materials, the trade-off between the high polarization and high breakdown strength limits the energy density of the materials. In this work, a composition engineering strategy has been proposed to overcome the trade-off between the polarization and the breakdown strength. We introduced (Sr1.05Bi0.3)ScO3 (SBS) into 0.85Bi0.5Na0.5TiO3–0.15NaNbO3 (BNT–NN), where the Sc2O3 embedded in the grains constructs insulating networks to enhance the breakdown strength, while the Sc3+ and Sr2+ ions enter the BNT–NN lattices and smash the R3c domains into ferroelectric polar nanoregions, maintaining the high polarization and decreasing the remnant polarization. As a result, 0.3 SBS doped BNT–NN shows a recoverable energy density (Wrec) of 7.3 J cm−3, one of the highest values for lead-free ferroelectric ceramics with a desirable energy efficiency (η) of 80%. Combined with its favorable temperature and frequency stabilities and discharge ability, the SBS doped 0.85Bi0.5Na0.5TiO3–0.15NaNbO3 could be a promising material for practical energy storage applications.

Indirect selective laser sintering (SLS) was combined with reactive melt infiltration (RMI) to fabricate RB-SiC, and the effects of preform impregnation with different carbon source on the carbonized sample and final RB-SiC were investigated. Results show that the impregnation treatment led to increased bulk density and mechanical strength of samples at all stages. The pore size dwindled and the porosity decreased significantly for the carbonized sample, and the content of Si reduced for the final RB-SiC. The impregnation with PF resin containing 30 % nano carbon black (PFnanoC) seems more promising for the comprehensive properties improvement, the final RB-SiC had a relatively fewer amount of residual pore and carbon and showed superior mechanical properties compared with those of sample impregnated with only PF resin. Kinetics analysis indicates a slower pore-clogging rate under the PFnanoC impregnation condition, which avoided or hindered a too-early infiltration cease during the RMI process.

The effects of low-protein diet (LPD) on kidney function and nutrition in nephropathy are so far unclear.To investigate the effect of LPD on kidney function and nutrition.PubMed, Embase and Cochrane library up to January 2019 and references of retrieved relevant articles.Twenty-nine studies with 1784 individuals in the LPD arm and 1782 individuals in the normal protein diet were identified. Compared with normal protein diet, LPD significantly reduced BUN (WMD -20.756 mg/dl; 95% CI: -33.969 to -7.544 mg/dl; P = 0.002), UREA (WMD -1.400 g/24 h; 95% CI: -1.713 to -1.088 mmol/L; P 0.001), proteinuria (WMD -0.416 g/24 h; 95% CI: -0.715 to -0.117 g/24 h; P = 0.006), body weight (WMD -2.757 kg; 95% CI: -3.890 to 1.623 kg; P 0.001) and BMI (WMD -0.646 kg/mLow-protein diet was significantly associated with improvement of nephropathy, but LPD increases the risk of malnutrition such as BMI. The present meta-analysis provides evidence that LPD was associated with malnutrition, and high-quality RCTs with multi-center and large simple-size should be performed to confirm the present findings.

Electron-phonon coupling affects the properties of two-dimensional (2D) materials significantly, leading to a series of novel phenomena. Inelastic light scattering provides a powerful experimental tool to explore electron-phonon interaction in 2D materials. This review gives an overview of the basic theory and experimental advances of electron-phonon coupling in 2D materials detected by Raman and Brillouin scattering, respectively. In the Raman scattering part, we review Raman spectroscopy studies of electron-phonon coupling in graphene, transition metal disulfide compounds, van der Waals heterostructures, strongly correlated systems, and 2D magnetic materials. In the Brillouin scattering part, we extensively introduce Brillouin spectroscopy in non-van der Waals 2D structures, including temperature sensors for phonons and magnons, interfacial Dzyaloshinsky-Moriya interaction and spin torque in multilayer magnetic structures, as well as exciton-polariton in semiconductor quantum well.

To investigate the effect of ALA intake on blood lipid profiles, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein (VLDL-C) and ratio of TC to HDL-C. We systematically searched randomized controlled trials of ALA intervention on PubMed, Embase, Cochrane library and related references up to March 2018. The final values were calculated as weighted mean difference (WMD) by using a random effects model. Subgroup analysis and meta-regression were used to explore the source of heterogeneity. Generalized least square was performed for dose-response analysis. Forty-seven studies with 1305 individuals in the ALA arm and 1325 individuals in the control arm were identified. Compared with control group, dietary intake of ALA significantly reduced the concentrations of TG (WMD -0.101 mmol/L; 95% CI: -0.158 to -0.044 mmol/L

Selective laser sintering was combined with reactive melt infiltration to fabricate SiSiC part, and the effects of carbon fiber (Cf) on the properties of the SLS green body, the carbonized and final SiSiC sample were investigated. Results show that the addition of an appropriate amount of Cf (1.59 wt%~2.97 wt%) can increase the bulk density and geometric precision of the sample at all stages, and improve the mechanical properties of green and carbonized samples. The main phases composed of the SiSiC composite were free Si, a-SiC, β-SiC, plus a very small amount of Al–Si alloy. With 1.59 wt% Cf addition, a relatively comprehensive favorable macro-properties of both the green sample and carbonized sample was achieved, and the homogeneous microstructure of the latter favored the decreased free Si content and increased β-SiC content of the final composite. The evolution mechanism of Cf added to the raw material is inferred to be the mutual diffusion of [C] and [Si] that occurred at the Cf/Si melt boundary leading to the formation of the siliconized Cf with relatively large diameter size (24.3 μm) and high aspect ratio (>30). Amorphous C, which derived from the pyrolysis of epoxy resin E12, undergone a dissolution-precipitation mechanism with the formation of fine-grain β-SiC.

The manipulation of defects during selective laser melting plays a key role in forming dense ceramic parts with complex shapes. In this study, selective laser melting of alumina with pressure assistance was performed on powder bed, and the defects during selective laser melting, including balling and cracks, were investigated. It was found that, unlike the competition mechanism between spreading and solidification in the metal system, the balling phenomenon of alumina was dominated by the spreading process. According to the calculation, the spreading time of alumina melt was less than 1/5 of the solidification time. Even the alumina powder was fully melted without splashing, the balling phenomenon could still occur. Although lower scanning speed could increase laser dwell time and improve the stability of the molten pool, the efficiency and surface roughness were sacrificed. Severe balling occurred in this condition. When pressure treatment was applied, the balling phenomenon was greatly alleviated. However, surface cracks were observed. There are mainly two reasons for the formation of surface cracks: the shrinkage of the melt and the shear stress in the edge between partially melted zone and fully melted zone. To alleviate the surface cracks, the distribution of the density of powder bed, the laser parameters, and the particle size should be well controlled. This paper provided an experimental reference for the manipulation of balling phenomenon and surface cracks of alumina melt in the SLM process performed on powder bed.

In this paper, high-porosity Al2O3 ceramic foams called Al2O3 PHM ceramics were fabricated through selective laser sintering (SLS) via Al2O3 poly-hollow microspheres (Al2O3 PHMs). SLS parameters were optimized by an orthogonal experiment as to be laser power = 6 W, scanning speed = 1800 mm/s, and scanning space = 0.15 mm. The effect of sintering temperature on microstructure, shrinkage, porosity, phase composition, mechanical properties and pore size distribution of Al2O3 PHM ceramics were investigated. When sintering temperature increased, Al2O3 PHM ceramics contained only Al2O3 phase and were gradually densified. With the raise of sintering temperature, the porosity of Al2O3 PHM ceramics decreased gradually from 77.09% to 72.41%, but shrinkage in H direction and compressive strength of Al2O3 PHM ceramics increased from 6.63% and 0.18 MPa to 13.10% and 0.72 MPa, respectively. Sintering temperature had little effect on pore size distribution of Al2O3 PHM ceramics, which only declined from 24.2 to 21.4 μm with the increase of sintering temperature from 1600 to 1650 °C. This method can not only directly prepare ceramic foams with complex shapes, but also control properties of ceramic foams. It provides a simple preparation method for many kinds of ceramic foams with complex structure and high porosity by using PHMs with different composition.

Complex structural Si3N4 ceramics with ultra-high porosity were innovatively formed by selective laser sintering (SLS) technology without any binder. Due to rapid cooling rate, the high temperature phase constituent and microstructure of the SLSed Si3N4 poly hollow microspheres (PHMS) were preserved, thus revealing the bonding mechanism of Si3N4 under the nonequilibrium heat source. Si3N4 PHMS are bonded by microvilli composed of bamboo-structure SiO2 nanofiber clusters, stacked SiO2 nanospheres and smooth α-Si3.72N4 nanowires. Finally, the pre-sintered Si3N4 ceramics with a porosity of 80% are directly fabricated in the atmosphere by SLS, which have the enough strength to satisfy the post-treatment requirements.

It is difficult to fabricate lightweight ceramic parts with well pore control and high structural complexity. In this paper, lightweight mullite ceramics with controlled porosity and enhanced properties were prepared via selective laser sintering (SLS) using mechanical mixed FAHSs/PA12 (Fly ash hollow spheres/polyamide 12) composites. Crack-free ceramic green bodies were prepared through SLS using the optimized process parameters: 7.2 W in laser power, 1600 mm/s in scanning velocity and 0.11 mm in hatch spacing. The influence of PA12 content on porosity, size distribution of open pore, mechanical properties and thermal property were studied. The pores in ceramic foams consisted of the closed pores from sphere core-shell structures, the open pore channels in the middle of stacking spheres and the special gaps in the middle of spheres related to SLS. It was found that the total porosity of lightweight mullite ceramics increased slightly from 85.1 ± 0.3% to 85.2 ± 0.4% with PA12 content increasing from 10 to 15 wt%, and then increased obviously to 86.7 ± 0.5% with further increasing PA12 addition to 25 wt%. This porosity increase was mainly attributed to the open pores resulted from the PA12 addition. The PA12 were firstly filled into the interspaces between stacking spheres and when the stacking volume reached the maximum, the interspaces expanded to form the special gaps between spheres with further PA12 addition. Thus, the size distribution of open pore in lightweight FAHS ceramics increased from 31.5 to 34.5 μm gradually with PA12 content increasing from 10 to 25 wt%. Finally, low thermal conductivity of 0.06 W/(m·K) was obtained, which probably resulted from the high porosity and the special pore structures of the SLS-formed ceramic foams. The understanding of the unique pore structures and microstructures will help the pore control and strength improvement of SLS-formed ceramic foams using the ceramic hollow spheres.

A disposable upper gastrointestinal endoscope can effectively decrease infectious outbreaks associated with endoscope reuse. In the present study, we aimed to evaluate the feasibility and safety of a disposable endoscope for upper gastrointestinal examination.In a prospective, randomized trial, 144 upper endoscopic procedures were allocated to either the disposable endoscope group or the conventional endoscope group. The primary outcomes were rates of excellent and good image qualities and maneuverability satisfaction. The second outcome included procedure duration, endoscopic diagnosis, and adverse events.A total of 144 subjects were enrolled in the present analysis and prospectively randomized to 2 study groups. Finally, 70 and 69 subjects were enrolled in the novel disposable endoscope group and the conventional endoscope group, respectively, due to the schedule cancellation of 5 subjects. The baseline characteristics of the patients were similar in both groups. The excellent and good image quality rates and maneuverability satisfaction of the novel disposable endoscope were not inferior to the conventional endoscope (p = 0.99 and p = 0.99, respectively). Moreover, no significant between-group difference was observed in the endoscopic results and adverse events (p = 0.30 and p = 1, respectively). However, the procedure duration in the novel disposable endoscope was longer compared with the conventional endoscope (8.40 ± 4.28 minThe novel disposable endoscope was as safe, effective, and maneuverable as a conventional endoscope. However, the novel disposable endoscope was associated with a longer procedure duration.Einweg-Endoskope für den oberen Gastrointestinaltrakt können Infektionsausbrüche, die auf die Wiederverwendung von Endoskopen zurückzuführen sind, wirksam verringern. In der vorliegenden Studie sollte die Durchführbarkeit und Sicherheit von Einweg-Endoskopen bei der Untersuchung des oberen Gastrointestinaltrakts bewertet werden.In einer prospektiven, randomisierten Studie wurden 144 endoskopische Eingriffe des oberen Gastrointestinaltrakts entweder der Einweg-Endoskop-Gruppe oder der konventionellen Endoskop-Gruppe zugewiesen. Die primären Endpunkte waren die Rate der guten Bildqualität sowie die Zufriedenheit mit der Manövrierfähigkeit. Zu den zweiten Endpunkten gehörten die Dauer des Eingriffs, die endoskopische Diagnose und unerwünschte Ereignisse.Insgesamt wurden 144 Probanden in die vorliegende Studie aufgenommen und prospektiv auf zwei Studiengruppen randomisiert. Da fünf Probanden ausfielen, wurden schließlich 70 Probanden in die Einweg-Endoskop-Gruppe und 69 in die konventionelle Endoskop-Gruppe eingeschlossen. Die Patienten beider Gruppen zeigten ähnliche Ausgangscharakteristika. Die Bildqualität und die Zufriedenheit mit der Manövrierfähigkeit des neuartigen Einweg-Endoskops waren nicht schlechter als bei einem konventionellen Endoskop (P=0,99 bzw. P=0,99). Außerdem wurde bei den endoskopischen Ergebnissen und unerwünschten Ereignissen kein signifikanter Unterschied zwischen den Gruppen beobachtet (P=0,30 bzw. P=1). Allerdings dauerte der Eingriff mit dem neuartigen Einweg-Endoskop länger als mit dem konventionellen Endoskop (8,40 ± 4,28 min vs. 5,12 ± 2,65 min, P0,001).Das neuartige Einweg-Endoskop war genauso sicher, effektiv und manövrierfähig wie das konventionelle Endoskop. Allerdings war das neuartige Einweg-Endoskop mit einer längeren Verfahrensdauer verbunden.

In this study, we propose a deep-learning approach to establish the lithographic model for i-line photolithography and develop an optical proximity correction (OPC) algorithm to increase the resolution limit. The applications of RETs are not only on CMOS semiconductor, but also on some metasurface which used to patterning by electron beam lithography. With the OPC algorithm, we are able to manufacture a near-infrared metalens patterning by i-line photolithography in a more efficient and less expensive way.

Background Non-alcohol fatty liver disease (NAFLD) is the most common chronic liver disease in the world, with a high incidence and no effective treatment. At present, the targeted therapy of intestinal microbes for NAFLD is highly valued. Lycium barbarum polysaccharide (LBP), as the main active ingredient of Lycium barbarum, is considered to be a new type of prebiotic substance, which can improve NAFLD by regulating the gut microbiota. The purpose of this study is to evaluate the safety and efficacy of LBP supplementation in modulating gut microbiota for NAFLD patients. Methods This randomized, double-blind, placebo-control study will be conducted in the physical examination center of the Ningxia Hui Autonomous Region People’s Hospital. A total of 50 patients with NAFLD confirmed by abdominal ultrasound, laboratory tests, and questionnaire surveys will be recruited and randomly assigned into the control group (maltodextrin placebo capsules) and the intervention group (LBP supplementation capsules) for 3 months. Neither patients, nor investigators, nor data collectors will know the contents in each capsule and the randomization list. The primary outcome measure is the level of ALT concentration relief after the intervention. Secondary outcomes include gut microbiota abundance and diversity, intestinal permeability, patient’s characteristic demographic data and body composition, adverse effects, and compliance from patients. Discussion LBPs are potential prebiotics with the property of regulating host gut microbiota. Our previous studies have documented that LBP supplement can improve the liver damage and the gut microflora dysbiosis in NAFLD rats. This treatment would provide a more in-depth understanding of the effect of this LBP supplementation. Trial registration Chinese Clinical Trial Register, ChiCTR2000034740. Registered on 17 July 2020.

Background The optimal analgesia regimen after open cardiac surgery has been unclear. The aim of this study was to investigate the beneficial effects of continuous pecto-intercostal fascial blocks (PIFB) initiated before surgery on outcomes after open cardiac surgery. Methods A group of 116 patients were randomly allocated to receive either bilateral continuous PIFB (PIF group) or the same block with saline (SAL group). The primary endpoint was postoperative pain at 4, 8, 16, 24, 48, and 72 hours after extubation at rest and during exercise. The secondary outcome measures included analgesia requirements (sufentanil and flurbiprofen consumption), time to extubation, length of stay in the intensive care unit, incidence of postoperative nausea and vomiting, time until return of bowel function, time to mobilization, time to urinary catheter removal, and the length of hospital stay. Results The length of stay in the intensive care unit (29 ± 7 hours vs 13 ± 4 hours, P Conclusion Bilateral continuous PIFB reduced the length of hospital stay and provided effective postoperative pain relief for 3 days.

The L-shaped tunnel field-effect transistor (LTFET) improves current drivability significantly by transforming the path of the band-to-band tunnelling from point-tunnelling to line-tunnelling, but meanwhile, the gate-source overlapped structure of LTFET brings about a larger active area of interface trap charges (ITCs). In this paper, the impact of ITCs on LTFET's characteristics is investigated in terms of the electric field, dc, analogue/RF, linearity and transient performance. From TCAD simulation results, it is found that for conventional LTFET, different types of ITCs lead to distinct variations in I–V characteristics, subthreshold swing, transconductance, parasitic capacitances, cut-off frequency, linearity parameters such as V IP 2 , V IP 3 , I IP 3 , and I MD 3 and the fall propagation delay ( t pHL ) . To improve the device stability, heterogeneous gate dielectric (HGD) structure is introduced into LTFET. From comparison results, it is found that benefiting from the improved gate controllability near the tunnelling junction, HGD-LTFET not only improves dc, analogue/RF, linearity and transient performance but also effectively suppresses the variation caused by ITCs thus has better stability. Therefore, HGD-LTFET is a very attractive choice in future low-power and high-frequency applications.

A novel method to fabricate high-performance Al2O3 Ceramics by indirect Selective Laser Sintering (idSLS) based on particle packing optimization was reported. Al2O3 ceramics with the particle size distribution (PSD) being adjusted based on a particle packing model was prepared with the idSLS method, and the effects of PSD on the macro-performance and microstructure of the idSLSed ceramics part was investigated. Results show that an appropriate PSD of raw material is not only essential to the good SLS formability of powder bed but also contribute to the favorable sintering characteristics of the SLSed green body through an ideal particle packing. The improvement of overall properties including mechanic strength, dimensional accuracy, and surface flatness of the SLSed green body and the final parts were achieved with a fine-tuned PSD exponent. When the raw material has a PSD exponent of 0.5–0.6, the final ceramic parts showed relatively balanced comprehensive properties of bulk density >2.0 g cm−3, linear change 3.97 MPa, compressive strength >5.25 MPa and surface altitude difference

Background Fire-needle acupuncture, an important kind of acupuncture therapy, has been clinically used to treat upper limb spastic paralysis (ULSP) after stroke. Clinical experience has indicated that fire-needle acupuncture treatment takes less time, requires fewer visits, and has more rapid results and fewer side effects compared to chemical medicine alternatives. This study will evaluate the effects of fire-needle acupuncture for ULSP in the context of standardized clinical research and provide high-quality data to inform clinical procedures and future study design. Methods/Design A randomized controlled trial will be carried out to evaluate the effects of fire-needle acupuncture therapy in patients with ULSP from stroke. ULSP patients (n = 120) will be recruited at Changhai Hospital in Shanghai, China. Patients will be randomly divided into three groups, including fire-needle acupuncture group (FAG), filiform-needle acupuncture group (FFAG) and rehabilitation treatment group (RTG). During the 3-week treatment, the FAG will be treated every two days, while FFAG and RTG will be treated 5 d in a row and then rest for 2 d. The Simplified Fugl-Meyer Motor Function Scale and Modified Ashworth Scale will be used as the primary outcome measures. Statistical analysis will be conducted by an independent statistician. Discussion Through this study, the utility of fire-needle acupuncture in treating ULSP after stroke will be tested, and some specific claims of fire-needle acupuncture therapy will be evaluated, such as relieving spasm and muscular tension, improving activities of daily living, rapidity of response and less frequency of treatment compared with other treatments. Trial registration Chinese Clinical Trial Registry (identifier: ChiCTR-IOR-17013875; registration date: 28 December 2016).

The low-pressure die-casting process (LPDC) is widely used in fabricating aluminum alloy automotive wheels. With good castability and mechanical properties, A356 alloys are important and common materials for LPDC wheels. However, in practical casting process, defects often appear, especially porosities in the wheel thick-walled parts (i.e., spoke) due to inadequate interdendritic feeding, which greatly decreases the mechanical properties. In this investigation, to deal with this problem, local squeeze (LS) was added in conventional LPDC to enhance the interdendritic feeding. The practical A356 alloy wheel castings were fabricated with different LS velocities and times. The quantitative characteristics of α-Al cells, Si particles, and porosities with and without the LS analyzed by optical microscope, scanning electron microscope, and 3D x-ray computed tomography were compared. Their effects on the tensile and impact properties were discussed. The results have shown that the LS can increase the cooling rate and feed shrinkage of spoke parts, hence resulting in finer grains and denser microstructure. In result, the properties of spoke parts were improved with the LS.

Highly porous mullite ceramics with bimodal pore structures were fabricated by selective laser sintering (SLS), in which the closed pores were provided by core-shell structure of fly ash hollow spheres (FAHSs) and the open pore channels were created by spherical polyamides (PA12). With increasing sintering temperature, the total porosity of mullite ceramics decreased, in which the average closed pore size reduced and the average open pore size distribution kept constant, however, the compressive strength of ceramic foams increased. This strength enhancement was mainly attributed to the reinforced sintering necks between FAHSs when sintered below 1350 °C, which resulted from the liquid phase diffusion of K, Ca and Ti, while the densification and thickening of sphere shell walls played a key role when above 1350 °C. Our findings illustrate that understanding pore structure characteristics and strength enhancement mechanism changes will be helpful for designing highly porous mullite ceramics with high mechanical performance.

To realize electro-induced shape memory effect for poly (lactic acid) (PLA)-based material, a liquid crystalline, poly [4,4’-bis(6-hydroxyhexyloxy) biphenyl phenylsuccinate] (PBDPS), was introduced in its main chain, which can not only provide high flexibility but also make carbon nanotubes (CNT) distribute selectively in the polymer matrix via π-π interaction. The presence of CNT resulted in the obvious enhancement of tensile strength as well as highly electrical conductivity. Notably, the as-prepared nanocomposites showed good shape memory performance with high recovery rate, high shape fixation and recovery ratios.

Additive manufacturing (AM) technology is showing great potential in dental restorations. In this paper, 3Y-TZP ceramics which are widely used in the fabrication of dental restorations were fabricated by selective laser sintering (SLS) combined with cold isostatic pressing (CIP) technology, and the effect of sintering temperature on phase composition, microstructure and mechanical properties of 3Y-TZP ceramics was investigated. 3Y-TZP/MgO/Epoxy resin E12 composite powder with good flowability and homogeneity was prepared by mechanical mixing method. The SLSed samples were obtained with optimum parameters (laser power = 7 W, scanning speed = 2600 mm/s, hatch spacing = 0.15 mm and layer thickness = 0.09 mm). Then they were densified by CIP (280 MPa, 5 min) process and sintered to obtain 3Y-TZP ceramics. It was found that the sample had the highest flexural strength of 279.50 ± 10.50 MPa and the maximum relative density of 86.65 ± 0.20% when sintered at 1500 °C due to the appropriate grain size and phase composition. Finally, some all-ceramic dental restorations were successfully fabricated by this technology. This work provides a new way for the manufacture of individualized all-ceramic dental restorations. Keywords: Selective laser sintering, 3Y-TZP dental ceramics, Cold isostatic pressing, Microstructure, Mechanical properties

This letter reports of the fabrication of high-performance p-channel polycrystalline germanium (poly-Ge) thin-film transistors (TFTs) using continuous-wave laser crystallization (CLC). During the CLC process, the direction of crystallization matches the direction of laser scanning due to a strong temperature gradient in the melting region. This makes it possible to fabricate high-quality poly-Ge thin films with 1-D longitudinal grains as large as $2\,\,\mu \text{m}\,\,\times 20\,\,\mu \text{m}$ . We fabricated the proposed p-channel CLC Ge TFTs with channel width of $0.7~\mu \text{m}$ and a channel length each of $0.7~\mu \text{m}$ . Consequently, the proposed p-channel CLC Ge TFTs with single-crystal-like channel fabricated on a longitudinal grain with biaxial tensile strain achieved a superior field-effect mobility of 1014.9 cm2/V-s.

To investigate whether dendritic superstructures can be formed from random copolymers, the morphological evolution of a random copolymer, poly(p-dioxanone-co-butylene-co-succinate) (PPBS), is tracked at different crystallization temperatures by optical microscopy. The crystal morphology is regulated by controlling the molecular structure of PPBS as well as the crystallization temperatures, that is, from rounded spherulite for the homopolymer counterpart to dendrites for the copolymer with high p-dioxanone (PDO) content and crystallization temperature. Different from previous works on dendritic crystals, interestingly, film thickness shows no obvious effect on the formation of dendrites. While we find that the crystal growth rate is seriously frustrated by the random structures of PPBS copolyester. Besides, small-angle X-ray scattering (SAXS) analysis indicated that the inter-lamellar region of PPBS copolyester is highly affected by the crystallization temperature. The PDO content, random structure, and high crystallization temperature were believed to be the main factors for the crystals transition from well-rounded spherulite to dendritic crystals.

Direct selective laser sintering (dSLS) is a promising method for the fabrication of complex-shaped ceramic parts. In this paper, boron carbide (B 4 C) was used as an inorganic additive to improve the laser sintering behavior of alumina. The effects of B 4 C addition on the microstructure and mechanical properties of porous alumina ceramics were investigated. Mixture of alumina powders and different amount of B 4 C were directly sintered using different SLS parameters. Results indicated that the process window of alumina could be expanded by the addition of B 4 C. Furthermore, the amount of B 4 C played an important role in surface morphologies of alumina ceramics. It could be explained by the increase of mass transfer due to the addition of B 4 C, which enhanced the densification process. The compressive strength of sintered samples increased with the increase of B 4 C, which reached its maximum value when the content of B 4 C was 7 wt% and the density of the samples after post treatment could reach 1.4 g/cm 3 . In addition, a size expansion phenomenon was observed. The size expansion could reach 5% after SLS, which could be attributed to the pin effects and oxidation behavior of B 4 C particles.

We report a compact, scalable, and high-performance superconducting nanowire single-photon detector (SNSPD) array by using a multichannel optical fiber array-coupled configuration. For single pixels with an active area of 18 µm in diameter and illuminated at the telecom wavelength of 1550 nm, we achieved a pixel yield of 13/16 on one chip, an average system detection efficiency of 69% at a dark count rate of 160 cps, a minimum timing jitter of 74 ps, and a maximum count rate of ∼ 40 M c p s . The optical crosstalk coefficient between adjacent channels is better than − 60 d B . The performance of the fiber array-coupled detectors is comparable with a standalone detector coupled to a single fiber. Our method is promising for the development of scalable, high-performance, and high-yield SNSPDs.

Generally, a superconducting nanowire single-photon detector (SNSPD) is composed of wires with a typical width of ~100 nm. Recent studies have found that superconducting strips with a micrometer-scale width can also detect single photons. Compared with the SNSPD, the superconducting microstrip single-photon detector (SMSPD) has smaller kinetic inductance, higher working current, and lower requirement in fabrication accuracy, providing potential applications in the development of ultra-large active area detectors. However, the study on SMSPD is still in its infancy, and the realization of its high-performance and practical use remains an opening question. This study demonstrates a NbN SMSPD with a saturated system detection efficiency (SDE) of ~92.2% at a dark count rate of ~200 cps, a polarization sensitivity of ~1.03, and a minimum timing jitter of ~48 ps, at the telecom wavelength of 1550 nm when coupled with a single mode fiber and operated at 0.84 K. Furthermore, the detector's SDE is over 70% when operated at a 2.1-K closed-cycle cryocooler., 10 pages,7 figures, 2 tables

For the first time, ultrafast laser annealed BEOL gate-all-around (GAA) transistor and FeFET memory were demonstrated with monolithic 3D near-memory-computing (NMC) circuit. The GAA MOSFETs employing ultrafast picosecond visible laser dopant activation exhibit record-high Ion (nFETs=407 uA/um, pFETs=345 uA/um). The BEOL FeFETs memory exhibits large memory window ΔV th = 1.2V, more than 106 cycle endurance. Moreover, the 3D stackability of the GAA MOSFETs and FeFET memory bit cell enable reduces the area of the NMC circuitry and improve the readout throughput.

Tim-3, which is expressed on a variety of innate immune cells including NK cells, plays a key role in many autoimmune diseases. However, the immunomodulatory actions of Tim-3 on NK cells in primary biliary cholangitis (PBC) remain uncertain. Using a murine model of PBC we evaluated the expression of Tim-3 and its ligand Gal-9 in peripheral blood, liver, and spleen. Additionally, we studied Tim-3 regulation of chemokine receptors (CXCR1 and CXCR3) in vitro. Flow cytometric analysis indicated large numbers of infiltrating NK cells in the liver which exhibited high expression of Tim-3 and CXCR3. Moreover, we found overexpression of CXCR1 in liver tissue and liver-derived NK cells in PBC mice. We also observed lower levels of soluble Tim-3 in the serum of PBC mice. In vitro experiments with liver-derived NK cells from PBC mice indicated that CXCR3 was up-regulated by treatment with recombinant mouse TIM-3 Fc (rmTim-3 Fc) to activate the Tim-3 pathway. Furthermore, stimulating normal mouse spleen NK cells with poly I:C resulted in elevated expression of CXCR1 and interferon-γ release. Nonetheless, adding rmTim-3 Fc or rmGal-9 significantly down-regulated CXCR1 expression and IFN-γ release in NK cells activated by poly I:C, proposing a means to exploit the Tim-3 pathway to reverse responses in NK cells. In conclusion, our data demonstrate that dysregulation of Tim-3/Gal-9 is involved in modulating the local immune microenvironment in PBC mice. Our findings highlight the potential of Tim-3 pathway to modulate chemokine responses in NK cells during autoimmunity.

Heart disease is the leading cause of death worldwide. Due to the limited regenerative ability of native myocardium, damaged myocardium cannot be restored. Advanced therapeutic approaches such as tissue engineering and regenerative medicine provides potential biological solutions to restore the function of damaged myocardium. Despite progresses in cardiac tissue engineering over the past decades, it is still far from mimicking the native myocardium. Some design considerations for engineering cardiac tissue includes inducing cell alignment, and attaining high cell density within a construct. Bioprinting, a computer-assisted technology, can potentially achieve the abovementioned considerations. In the native myocardium, fibre and cell orientation varies across different planar level. Bioprinting can potentially recapture this complexity through designing print path. The purpose of this project is to fabricate an engineered cardiac tissue via bioprinting. Extrusion-based bioprinting was investigated in terms of printing parameters and material properties to achieve required print resolution for efficient nutrient exchange in bioprinted cell-hydrogel construct. Next, a design framework was developed to characterize and formulate materials for bioprinting. The design framework was applied for material formulation in extrusion printing of C2C12 cells. Following which, a bioprinting strategy, termed support-assisted bioprinting, was established to produce three dimensionally defined constructs. Support-assisted bioprinting is a bioprinting strategy that uses a secondary material (support material) to provide mechanical stability for the primary material (build material) prior to crosslinking of the build material. Support-assisted bioprinting has demonstrated printing of three dimensionally defined cell-hydrogel, where hydrogel struts showed distinct 0o-90o angular difference at different height level. Cell alignment was achieved along the longitudinal axis of printed construct. The mechanism of cell-hydrogel remodelling process towards cell alignment in bioprinted construct was mapped for inducing cell alignment along strut orientation. Lastly, enabling technologies in data and cell processing were developed as translational measures towards organ printing. In data processing, machine readable print path using G-code was generated to reflect the differences in fibre orientation of left ventricle wall. This shows the feasibility of fabricating bioprinted construct that better mimics the architecture of myocardium. In cell processing towards high throughput cell aggregates formation, the use of 3D printed microfluidics was studied. These findings ascertained the potential of bioprinting towards directing cell alignment in a dimensionally defined construct. Doctor of Philosophy (MAE)

Aligned cells provide direction-dependent mechanical properties that influence biological and mechanical function in native tissues. Alignment techniques such as casting and uniaxial stretching cannot fully replicate the complex fibre orientation of native tissue such as the heart. In this study, bioprinting is used to direct the orientation of cell alignment. A 0°-90° grid structure was printed to assess the robustness of the support-assisted bioprinting technique. The variation in the angles of the grid pattern is designed to mimic the differences in fibril orientation of native tissues, where angles of cell alignment vary across the different layers. Through bioprinting of a cell-hydrogel mixture, C2C12 cells displayed directed alignment along the longitudinal axis of printed struts. Cell alignment is induced through firstly establishing structurally stable constructs (i.e. distinct 0°-90° structures) and secondly, allowing cells to dynamically remodel the bioprinted construct. Herein reports a method of inducing a macroscale level of controlled cell alignment with angle variation. This was not achievable both in terms of methods (i.e. conventional alignment techniques such as stretching and electrical stimulation) and magnitude (i.e. hydrogel features with less than 100 µm features). Nanyang Technological University National Research Foundation (NRF) This research is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Medium-Sized Centre funding scheme. This work is also supported by NTU start up grant and is funded by the Research Student Scholarship (NTU).

We introduce a single-grain gate-all-around (GAA) Si nanowire (NW) FET using the location-controlled-grain technique and several innovative low-thermal budget processes, including green nanosecond laser crystallization, far-infrared laser annealing, and hybrid laser-assisted salicidation, that keep the substrate temperature (Tsub) lower than 400 &deg, C for monolithic three-dimensional integrated circuits (3D-ICs). The detailed process verification of a low-defect GAA nanowire and electrical characteristics were investigated in this article. The GAA Si NW FETs, which were intentionally fabricated within the controlled Si grain, exhibit a steeper subthreshold swing (S.S.) of about 65 mV/dec., higher driving currents of 327 &micro, A/&micro, m (n-type) and 297 &micro, m (p-type) @ Vth &plusmn, 0.8 V, and higher Ion/Ioff (&gt, 105 @|Vd| = 1 V) and have a narrower electrical property distribution. In addition, the proposed Si NW FETs with a GAA structure were found to be less sensitive to Vth roll-off and S.S. degradation compared to the omega(&Omega, )-gate Si FETs. It enables ultrahigh-density sequentially stackable integrated circuits with superior performance and low power consumption for future mobile and neuromorphic applications.

A large-area and scalable monolayer TMD is feasible to employ in monolithic 3D image sensor scheme. For the first time, we represents a prototype $\mathrm{MoS}_{2}$ phototransistor array with ultrahigh responsivity $(> 10^{3}\ \mathrm{A}/\mathrm{W})$ and tunable photogain (10 2 ~10 5 ) which can be directly implemented on a CMOS circuit connected with BEOL fine-pitch vertical interconnects. Electric gate pulse modulation mitigates photo gating (PG) and persistent photoconductance (PPC) effects from layered semiconductor interface. Both three-order-of-magnitude improvements of response speed and fine-pitch vertical interconnects empower block-level compressive sensing circuits and global image-signal processing for gain control and data compression.

In this paper, conductance switching behavior of Pt/HfOx/Ti redox-based memristive devices has been thoroughly investigated. The conduction mechanisms involved during the device operation can be associated with the trap-controlled SCL conduction mechanisms. The extracted parameters suggest the gradual switching behavior achieved by the devices was due to the transition between different trap level within trap-fill SCL regime, which is beneficial for the device implementation as analog synapse in the neuromorphic computing platform.

This research focused on evaluating the mechanical properties change of Welding Metals (WMs) at the turbine-end (hot-end, working beyond 500 °C) of a retired CrMoV bainitic gas turbine rotor serving over 14 years, by comparison to those WMs at the compressor-end (cold-end, working below 300 °C). After long-term service, the room-temperature elastic modulus and the bainitic microstructure of hot-end WMs stayed almost the same as those of cold-end WMs, but the high-temperature elastic modulus and the dislocations density of the former became higher than those of the latter. The above change, especially the change of high-temperature elastic modulus produced significant influences on the tensile, fatigue and creep behaviors of hot-end WMs, which further led to a higher tensile and creep strength but a lower ductility, as well as a better fatigue crack propagation resistance under high-temperature condition. A correlation between the high-temperature elastic modulus change and the tensile/fatigue/creep behaviors change was established for hot-end WMs based on mechanics modelling, which provided a feasible way to monitor the rotor properties change.

A novel method to prepare high-porosity mullite ceramic foams by selective laser sintering (SLS) using fly ash hollow spheres (FAHSs) as raw materials was reported. The complex-shaped FAHS green bodies and ceramic foams without delamination or cracks were prepared by SLS. The influence of sintering temperatures on linear shrinkage, phase composition, porosity and mechanical properties was investigated. With the increase of sintering temperature from 1250 °C to 1400 °C, the compressive strength of ceramic foams increased from 0.2 MPa to 6.7 MPa causing the fracture mechanism change from fracturing along FAHSs to across FAHSs, while the porosity of ceramic foams decreased from 88.7% to 79.9% which was higher than those of ceramic foams prepared by the conventional methods. The relatively high porosity of ceramic foams was resulted from the inner hollow structure of FAHSs, the interspaces between stacking FAHSs, and the gaps between FAHSs directly related to SLS. The results above indicated that the fabrication of high-porosity FAHS ceramic foams by SLS could achieve the advanced utilization of FAHS solid waste.

For the first time, CMOS inverters and 6T-SRAM cells based on vertically stacked gate-all-around complementary FETs (CFETs) are experimentally demonstrated. Manufacturing difficulties of vertically stacked source and drain electrodes of the CFETs have been overcome by using junctionless transistors, thereby reducing the number of lithographic steps required. Furthermore, with post metallization treatments, both the voltage transfer characteristics (VTCs) of CMOS inverters and butterfly curves of SRAM show significant improvements due to the symmetry of nMOS and pMOS threshold voltages. Simulation shows that 3-dimensional CFET inverters have lower input parasitic capacitance than standard 2-dimensional CMOS, leading to reduced gate delay and lower power consumption.

For the first time, below 400°C-fabricated gate-all-around (GAA) transistor fabrication process was demonstrated with monolithic computing-in-memory (CIM) circuit. Key enablers are plasma-assisted atomic layer etching (PA-ALE), plasma immersion ion implantation (PIII) and far-infrared laser activation (FIR-LA). The 3D stackable single-grained Si GAA MOSFETs thus fabricated exhibit record-high I on /I off ratio (~108) with low I off (pFETs

Recent monolithic 3-D integrated-circuit (3D-IC) technology tends to induce stronger driving capability in pMOS transistors, compared to that obtained using existing processes. Thus, conventional 6T SRAMs suffer degradation in access speed and write margin when used in monolithic 3D-ICs. This letter proposes a dual-split-controlled 4P2N (DSC-4P2N) SRAM with corresponding read and write assist schemes capable of providing a larger cell read current and higher write margins compared to 4N2P SRAMs implemented in monolithic 3D-ICs. The proposed DSC scheme improves $4.8\times $ in read stability compared to 4P2N SRAM without DSC. A fabricated DSC-4P2N SRAM in monolithic 3D-IC was shown to outperform the previous 6T SRAMs.