Fabrication and wear performance of (Cu–Sn) solution/TiCx bonded diamond composites

The Cu(Sn)–TiCx bonded diamond composites were prepared by in situ reaction sintering of Cu, Ti₂SnC and diamond powders. Effect of Ti₂SnC content on the phase composition, microstructure and grinding properties were studied.Вивчено вплив змісту Ti₂SnC на фазовий склад, мікроструктуру і шліфувальні властивості алмазних композитів зі зв’язуючим Cu(Sn)–TiCx, отриманих in situ реакційним спіканням Cu, Ti₂SnC і алмазних порошків.Изучено влияние содержания Ti₂SnC на фазовый состав, микроструктуру и шлифовальные свойства алмазных композитов со связующим Cu(Sn)–TiCx, полученных in situ реакционным спеканием Cu, T₂SnC и алмазных порошков

Axonemal Lumen Dominates Cytosolic Protein Diffusion inside the Primary Cilium

Transport of membrane and cytosolic proteins in primary cilia is thought to depend on intraflagellar transport (IFT) and diffusion. However, the relative contribution and spatial routes of each transport mechanism are largely unknown. Although challenging to decipher, the details of these routes are essential for our understanding of protein transport in primary cilia, a critically affected process in many genetic diseases. By using a high-speed virtual 3D super-resolution microscopy, we have mapped the 3D spatial locations of transport routes for various cytosolic proteins in the 250-nm-wide shaft of live primary cilia with a spatiotemporal resolution of 2 ms and <16 nm. Our data reveal two spatially distinguishable transport routes for cytosolic proteins: an IFT-dependent path along the axoneme, and a passive-diffusion route in the axonemal lumen that escaped previous studies. While all cytosolic proteins tested primarily utilize the IFT path in the anterograde direction, differences are observed in the retrograde direction where IFT20 only utilizes IFT, and approximately half of KIF17 and one third of α–tubulin utilizes diffusion besides IFT

Integrating TSPO PET imaging and transcriptomics to unveil the role of neuroinflammation and amyloid-β deposition in Alzheimer's disease.

PURPOSE Despite the revealed role of immunological dysfunctions in the development and progression of Alzheimer's disease (AD) through animal and postmortem investigations, direct evidence regarding the impact of genetic factors on microglia response and amyloid-β (Aβ) deposition in AD individuals is lacking. This study aims to elucidate this mechanism by integrating transcriptomics and TSPO, Aβ PET imaging in clinical AD cohort. METHODS We analyzed 85 patients with PET/MR imaging for microglial activation (TSPO, [18F]DPA-714) and Aβ ([18F]AV-45) within the prospective Alzheimer's Disease Immunization and Microbiota Initiative Study Cohort (ADIMIC). Immune-related differentially expressed genes (IREDGs), identified based on AlzData, were screened and verified using blood samples from ADIMIC. Correlation and mediation analyses were applied to investigate the relationships between immune-related genes expression, TSPO and Aβ PET imaging. RESULTS TSPO uptake increased significantly both in aMCI (P < 0.05) and AD participants (P < 0.01) and showed a positive correlation with Aβ deposition (r = 0.42, P < 0.001). Decreased expression of TGFBR3, FABP3, CXCR4 and CD200 was observed in AD group. CD200 expression was significantly negatively associated with TSPO PET uptake (r =-0.33, P = 0.013). Mediation analysis indicated that CD200 acted as a significant mediator between TSPO uptake and Aβ deposition (total effect B = 1.92, P = 0.004) and MMSE score (total effect B =-54.01, P = 0.003). CONCLUSION By integrating transcriptomics and TSPO PET imaging in the same clinical AD cohort, this study revealed CD200 played an important role in regulating neuroinflammation, Aβ deposition and cognitive dysfunction

Fabrication of thin film composite forward osmosis hollow fiber membranes

Forward osmosis (FO) has received intensive studies recently for a range of potential applications such as wastewater treatment, water purification and seawater desalination. One of the major challenges to be overcome is the lack of an optimized FO membrane that can produce a high water flux comparable to commercial reverse osmosis (RO) membranes. The objective of the project is to fabricate thin film composite (TFC) hollow fiber membranes which are suitable for FO applications. Specifically, the ultra-filtration hollow fiber substrate was spun using polyethersulfone (PES) by phase inversion method. The substrate is single-skinned on the lumen side. The thin film active layer was formed on the inner surface of the hollow fiber substrate through interfacial polymerization (IP). The two monomers of the polymerization used are M-phenylene-diamine (MPD) and M-phenylene-diamine (TMC). Several IP experimental variables including involvement of additives, MPD concentration in the aqueous solution, polymerization reaction time, etc. were optimized. Hollow fiber substrates and FO membranes were characterized using different analytical methods including scanning electron microscope observation, molecular weight cut-off test, porosity measurement and mechanical strength test, etc. Water and solute permeability of the FO membrane were also measured in an RO setup. It was found that two different chemicals can successfully work together as the additives of aqueous solution to achieve a better performing membrane than applying each additive separately. It was also deduced that, within a feasible range, higher MPD concentration in the aqueous solution is considered more desirable in FO hollow fiber membrane fabrication. The water flux achieved during lab-scale FO test for two membrane orientations using different draw solution concentrations were benchmarked against commercial FO and nanofiltration (NF) membranes. For the fabricated membranes with optimized preparation conditions, water flux can reach 42.6 L/h•m2 using 0.5M NaCl as draw solution and deionized water as feed for the active layer facing draw solution orientation. The performance of the in-house made FO hollow fiber is believed to be superior to all FO membranes reported in the open literature.Bachelor of Engineering (Environmental Engineering

Development of novel composite nanofiltration hollow fiber membranes for niche applications

Due to its unique ability to separate divalent and multivalent ions as well as low molecular weight organic species, nanofiltration (NF) has now become a widely applied separation technology. However, it is challenging to develop NF membranes that remain competent permeation flux at ultrafiltration (UF)-range low operating pressure to reduce energy consumption and membrane fouling tendency. This thesis presents the development of novel composite hollow fiber membranes with NF-like selectivity at low operating pressure, and tailored surface properties and structures for various niche applications including water softening and forward osmosis (FO). Novel composite NF hollow fiber membrane for low-pressure water softening were prepared via interfacial polymerization (IP), and the IP thin film formation process was ameliorated to strengthen the capability for softening of more concentrated and complex water sources. Moreover, novel double-skinned hollow fibers with an NF-like secondary selective skin were produced through either surface modification or layer-by-layer assembly method to mitigate the internal concentration polarization, scale formation and organic fouling for practical FO applications.Doctor of Philosophy (CEE

Feature Transformation Method for Wheel Hub Shape Based on Target Detection and Geometric Analysis

Extracting and transforming shape features has been an important research domain in wheel hub design. The study of wheel hub design based on shape semantics, brand planning, and structural optimization requires regression analysis by using shape features and the corresponding variables to guide wheel hub design through the correlation model. The practical role of feature transformation in design is determined by its effectiveness, accuracy, and convenience. This process, however, has generally been handled manually in previous studies, limiting the universality and comprehensiveness of research outcomes. With the development of artificial intelligence, the automation of this process has become possible, ushering in the era of big data research for feature extraction and transformation. Hence, this study proposes a wheel hub feature transformation method based on target detection and geometric analysis. This method implements feature transformation in the following automation steps: (1) wheel hub feature point detection based on the YOLO model; (2) wheel hub feature grouping based on morphological parameters and position parameters; (3) feature point grooming based on geometric relations; and (4) parameter construction and transformation based on morphological features. Thus, an automatic, bidirectional, and morphological mechanism for transforming the parameters of a wheel hub shape can be developed. With the proposed transformation model, parameters related to the wheel hub shape and features can be transformed quickly, and the generative design of the wheel hub can be conducted based on big data

Mixed polyamide-based composite nanofiltration hollow fiber membranes with improved low-pressure water softening capability

Mixed polyamide-based composite nanofiltration (NF) hollow fiber membranes with suitable characteristics for water softening under ultrafiltration (UF)-range low operating pressure were successfully developed. The thin-film selective layer of the composite membrane was formed via interfacial polymerization on the inner surface of a microporous polyethersulfone (PES) hollow fiber substrate with trymesoyl chloride (TMC) being the organic phase monomer, and a mixture of branched polyethyleneimine (PEI) and piperazine (PIP) being the monomers in the aqueous phase. In was found that there was a synergetic effect of PEI and PIP on the formation of the selective layer. The water permeability and salt rejection of the resultant membrane were both enhanced with a small amount of PIP added into the PEI aqueous phase, but dropped quickly with a higher PIP to PEI ratio. The optimized NF membrane possessed a molecular weight cut-off (MWCO) of 380 Da, an effective pore diameter of 1.27 nm, and pure water permeability (PWP) of 18.2 l/m2 h bar. Under an operating pressure of 2 bar, the membrane exhibited rejection of 96.3% and 93.8% to 1000 ppm MgCl2 and MgSO4 feed solutions, respectively. The capability of the newly developed membrane for low-pressure water softening was evaluated by employing simulated hard water feed solutions with different ionic compositions and total hardness. By the combining effect of electrostatic repulsion and size exclusion, the mixed PEI/PIP-based composite hollow fiber offered superior water softening performance compared with the membranes made with PEI or PIP alone as the aqueous phase IP monomer.NRF (Natl Research Foundation, S’pore)EDB (Economic Devt. Board, S’pore)Accepted versio

One-Step Electrochemical Polymerization of Polyaniline Flexible Counter Electrode Doped by Graphene

To improve the photoelectric property of polyaniline (PANI) counter electrode using for flexible dye-sensitized solar cell (DSSC), graphene (GN) was doped in PANI films covered on flexible conducting substrate by one-step electrochemical method, and then GN/PANI composites are characterized by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), four probe instrument, and so on. The results show that PANI particles can be electrodeposited on the surface of GN sheets as the potential rising to 2.0 V. This formed unique PANI-GN-PANI lamellar structure owing to the strong interaction of conjugated π electron between GN and PANI results in the superior conductivity and catalytic performance of GN/PANI electrode. The maximum conversion efficiency of dye-sensitized solar cell with this counter electrode reaches 4.31%, which is much higher than that of GN-free PANI counter electrode

MiR-558 inhibits odontogenic differentiation of human periodontal ligament fibroblasts by negatively regulating Jagged-1/Notch signaling pathway

Purpose: To investigate the potential effect and explore the underlying mechanism of action of miR-558 in the odontogenic differentiation of human periodontal ligament fibroblasts (hPLFs). Methods: Human periodontal ligament fibroblasts were treated with osteogenic induction medium to induce odontogenic differentiation. The efficiency of odontogenic differentiation was determined using Alizarin red staining and alkaline phosphatase (ALP) activity assays. The expression levels of osteogenic markers, including Osterix and Runx2, were determined by Western blotting, while mRNA levels of Jagged-1, HES1 and HEY1 were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Results: MiR-558 was down-regulated during the odontogenic differentiation of hPLFs. Alizarin red staining and ALP activity data indicate that miR-558 significantly inhibited the odontogenic differentiation of hPLFs. Osterix and Runx2 expression levels were significantly decreased in the miR-558 mimic group but significantly increased in miR-558 inhibitor group compared with those in NC group (p &lt; 0.01). Moreover, miR-558 regulated Notch signaling by targeting Jagged-1, while Jagged-1 knockdown suppressed the odontogenic differentiation of hPLFs. Conclusion: MiR-558 inhibits the odontogenic differentiation of human periodontal ligament fibroblasts by negatively regulating Jagged-1/Notch signaling pathway, and thus, could serve as a potential target to regulate the odontogenic differentiation of hPLFs