Excellent Physical Characteristics Research Articles

Picometer-Scale Atomic Shifts Governing Subdisordered Structures in Diamond.

Diamond is considered the most promising next-generation semiconductor material due to its excellent physical characteristics. It has been more than three decades since the discovery of a special structure named n-diamond. However, despite extensive efforts, its crystallographic structure and properties are still unclear. Here, we show that subdisordered structures in diamond provide an explanation for the structural feature of n-diamond. Monocrystalline diamond with subdisordered structures is synthesized via the chemical vapor deposition method. Atomic-resolution scanning transmission electron microscopy characterizations combined with the picometer-precision peak finder technology and diffraction simulations reveal that picometer-scale shifts of atoms within cells of diamond govern the subdisordered structures. First-principles calculations indicate that the bandgap of diamond decreases rapidly with increasing shifting distance, in accordance with experimental results. These findings clarify the crystallographic structure and electronic properties of n-diamond and provide new insights into the bandgap adjustment in diamond.

The Impact of Adding Dioxane Derivatives to Polyurethane Structures on their Performance and Degradation in the Environment

AbstractThe novel dioxane-polyether polyurethanes underwent a 12-month outdoor soil burial test to look into how they would degrade in a natural setting. The structure, thermal properties, surface features, and mechanical strength of the polyurethane films were compared. The initial chemical structure and subsequent chemical alterations were identified using FTIR spectroscopy. The polyurethane samples were less thermally stable throughout the duration of the soil burial test, according to TG/DTG curves. According to all findings, polyurethanes containing 1,3-dioxane-5,5-dimethanol exhibit excellent physical characteristics and mild degradation levels after being buried in soil for a year. These polyether urethanes can break down if the rigid domain structure is exposed to moisture and if microorganisms can spread into the polymer matrix. The physical properties, surface features, and degradation of polyether polyurethanes can be improved by varying the molar ratios of the hard segment components and the dioxane derivative structures.

Three‐Dimensional Polar Perovskites for Highly Sensitive Self‐Driven X‐Ray Detection

AbstractThree‐dimensional (3D) organic–inorganic hybrid perovskites (OIHPs) have achieved tremendous success in direct X‐ray detection due to their high absorption coefficient and excellent carrier transport. However, owing to the centrosymmetry of classic 3D structures, these reported X‐ray detectors mostly require external electrical fields to run, resulting in bulky overall circuitry, high energy consumption, and operational instability. Herein, we first report the unprecedented radiation photovoltage in 3D OIHP for efficient self‐driven X‐ray detection. Specifically, the 3D polar OIHP MhyPbBr3 (1, Mhy=methylhydrazine) shows an intrinsic radiation photovoltage (0.47 V) and large mobility‐lifetime product (1.1×10−3 cm2 V−1) under X‐ray irradiation. Strikingly, these excellent physical characteristics endow 1 with sensitive self‐driven X‐ray detection performance, showing a considerable sensitivity of 220 μC Gy−1 cm−2, which surpasses those of most self‐driven X‐ray detectors. This work first explores highly sensitive self‐driven X‐ray detection in 3D polar OIHPs, shedding light on future practical applications.

Three-Dimensional Polar Perovskites for Highly Sensitive Self-Driven X-Ray Detection.

Three-dimensional (3D) organic-inorganic hybrid perovskites (OIHPs) have achieved tremendous success in direct X-ray detection due to their high absorption coefficient and excellent carrier transport. However, owing to the centrosymmetry of classic 3D structures, these reported X-ray detectors mostly require external electrical fields to run, resulting in bulky overall circuitry, high energy consumption, and operational instability. Herein, we first report the unprecedented radiation photovoltage in 3D OIHP for efficient self-driven X-ray detection. Specifically, the 3D polar OIHP MhyPbBr3 (1, Mhy=methylhydrazine) shows an intrinsic radiation photovoltage (0.47 V) and large mobility-lifetime product (1.1×10-3 cm2 V-1 ) under X-ray irradiation. Strikingly, these excellent physical characteristics endow 1 with sensitive self-driven X-ray detection performance, showing a considerable sensitivity of 220 μC Gy-1 cm-2 , which surpasses those of most self-driven X-ray detectors. This work first explores highly sensitive self-driven X-ray detection in 3D polar OIHPs, shedding light on future practical applications.

Design high performance field-effect, strain/gas sensors of novel 2D penta-like Pd2P2SeX (X= O, S, Te) pin-junction nanodevices: A study of transport properties

In the realm of modern nanodevices, attaining high-switching performance and fulfilling sensing detection functions in high-precision environments are of paramount importance. Two-dimensional (2D) Pd2P2SeX (X = O, S, Te) have excellent geometric, physical, and chemical characteristics, and can crystallize into orthogonal structures with indirect band gaps. Based on these fundamental properties, 2D Pd2P2SeX pin-junction devices were modeled via first principles to simulate field-effect transistors, strain sensors with high-switching ratios, and chemisorption-based gas sensors. The Pd2P2SeX pin-junction device exhibited significant gate-voltage control over current, with current changes over nearly three orders of magnitude for Pd2P2SeO. Moreover, the application of a biaxial strain could close the band gap of Pd2P2SeX and significantly enhance transport characteristics, leading to substantial switching effects in devices, such as a 1.44 × 108 switching ratio for Pd2P2SeS. The chemisorption of NO and NO2 produced interfacial electronic coupling that generated an impurity band crossing the Fermi level, thereby inducing a semiconducting to metallic transition. Pd2P2SeO- and Pd2P2SeS-based pin-junction devices exhibited 49.01 and 23.80 s recovery times, respectively, when detecting NO and NO2. Hence, they could be used as high-sensitivity and -selectivity gas sensors. Overall, 2D Pd2P2SeX materials have a vast potential for the development of low-dimensional electronic devices.

Radiochemistry and In Vivo Imaging of [45Ti]Ti-THP-PSMA.

Titanium-45 (45Ti) is a radionuclide with excellent physical characteristics for use in positron emission tomography (PET) imaging, including a moderate half-life (3.08 h), decay by positron emission (85%), and a low mean positron energy of 0.439 MeV. However, challenges associated with titanium chemistry have led to the underdevelopment of this radionuclide for incorporation into radiopharmaceuticals. Expanding on our recent studies, which showed promising results for the complexation of 45Ti with the tris hydroxypyridinone (THPMe) chelator, the current work aimed to optimize the chemistry and imaging attributes of [45Ti]Ti-THP-PSMA as a new PET radiopharmaceutical. Methods. Radiolabeling of THP-PSMA was optimized with [45Ti]Ti-citrate at varying pHs and masses of the precursor. The stability of the radiolabeled complex was assessed in mouse serum for up to 6 h. The affinity of [45Ti]Ti-THP-PSMA for prostate-specific membrane antigen (PSMA) was assessed using LNCaP (PSMA +) and PC3 (PSMA -) cell lines. In vivo imaging and biodistribution analysis were performed in tumor-bearing xenograft mouse models to confirm the specificity of the tumor uptake. Results. > 95% of radiolabeling was achieved with a high specific activity of 5.6 MBq/nmol under mild conditions. In vitro cell binding studies showed significant binding of the radiolabeled complex with the PSMA-expressing LNCaP cell line (11.9 ± 1.5%/mg protein-bound activity) compared to that with the nonexpressing PC3 cells (1.9 ± 0.4%/mg protein-bound activity). In vivo imaging and biodistribution studies confirmed specific uptake in LNCaP tumors (1.6 ± 0.27% ID/g) compared to that in PC3 tumors (0.39 ± 0.2% ID/g). Conclusion. This study showed a simple one-step radiolabeling method for 45Ti with THP-PSMA under mild conditions (pH 8 and 37 °C). In vitro cell studies showed promise, but in vivo tumor xenograft studies indicated low tumor uptake. Overall, this study shows the need for more chelators for 45Ti for the development of a PET radiopharmaceutical for cancer imaging.

Gross, organoleptic and histologic assessment of cadaveric equine heads preserved using chemical methods for veterinary surgical teaching.

Preservation of biological tissues has been used since ancient times. Regardless of the method employed, tissue preservation is thought to be a vital step in veterinary surgery teaching and learning. This study was designed to determine the usability of chemically preserved cadaveric equine heads for surgical teaching in veterinary medicine. Six cadaveric equine heads were collected immediately after death or euthanasia and frozen until fixation. Fixation was achieved by using a hypertonic solution consisting of sodium chloride, sodium nitrite and sodium nitrate, and an alcoholic solution containing ethanol and glycerin. Chemically preserved specimens were stored at low temperatures (2°C to 6°C) in a conventional refrigerator. The specimens were submitted to gross and organoleptic assessment right after fixative solution injection (D0) and within 10, 20, and 30 days of fixation (D10, D20, and D30, respectively). Samples of tissue from skin, tongue, oral vestibule, and masseter muscle were collected for histological evaluation at the same time points. Physical and organoleptic assessments revealed excellent specimen quality (mean scores higher than 4 on a 5-point scale) in most cases. In some specimens, lower scores (3) were assigned to the range of mouth opening, particularly on D0 and D10. A reduced the range of mouth opening may be a limiting factor in teaching activities involving structures located in the oral cavity. The excellent physical, histologic, and organoleptic characteristics of the specimens in this sample support their usability in teaching within the time frame considered. Appropriate physical and organoleptic characteristics (color, texture, odor, and flexibility) of the specimens in this study support the use of the method described for preparation of reusable anatomical specimens.

Influence of Carbon Nanotubes Concentration on the Mechanical Properties of Cement Mortars

In recent decades, mechanical properties of composite materials containing carbon nanoparticles, in particular single-walled or multi-walled carbon nanotubes (SWCNTs or MWCNTs), have been researched, taking into account their excellent physical and mechanical characteristics. In this work, the influence of the concentration of MWCNTs (0.1, 0.2, 0.3, 0.35 wt.%) on compressive and flexural strengths of the cement mortar was investigated. The results of the research show that the compressive and flexural strengths of the 7 and 28-day curing period samples reach their maximum value at 0.3% of nanotube concentration. In comparison to the control sample, the compressive strength increased by 10.93% within 7 days and by 32.0% within 28 days. And in the case of flexure, the strength of the test samples increased by 33.67% within 7 and by 36.50% within 28 days. It can be concluded that in the case of the selected carbon nanotubes and the material composition at 0.3% of MWCNTs, the compressive and flexural strength reach their maximum values.

Longitudinal-torsional compound ultrasonic vibration end grinding sapphire: A study on surface topography and roughness

Owing to excellent physical and optical characteristics, Sapphire has wide applications in detection, military, photoelectric and other industries. Nevertheless, it's difficult to use the conventional processing methods to process sapphire with high precision and efficiency due to its hardness and brittleness. This study adopted longitudinal-torsional compound ultrasonic vibration end grinding (LTUEG) method to grind sapphire. Firstly, the grinding trajectory equation of single grain under LTUEG was established. Then, combining with the motion state of single grain, the removal mechanism of sapphire under LTUEG was clarified. Finally, a comparative experiment between LTUEG and conventional end grinding (CEG) of sapphire was conducted, and the effects of processing parameters on surface topography and surface roughness were investigated. Results showed that surface roughness declined with grinding speed, enhanced with feed rate and grinding depth, declined first and then went up with amplitude, and the minimum value was 0.522 μm. Compared with CEG, LTUEG could significantly reduce the surface roughness, with a maximum reduction of 20.98 %. LTUEG could reduce the pits size. Meanwhile, when the longitudinal amplitude AL was 0.8 μm, the average pits length and pits depth reached the minimum, which were 33.13 μm and 5.296 μm, respectively. The research found that LTUEG could reduce block spalling, increase the ratio of plastic domain removal as well as improve the surface flatness of workpiece.

The study of tryptophol containing emulgel on fungal reduction and skin irritation

Tryptophol (TOH), a fungal quorum-sensing molecule, that possesses anti-fungal activities for controlling the growth of human pathogenic fungi. In the present study, we developed TOH-containing emulgel formulations and examined the antifungal activities and potential use as topical treatments on the skin. The results showed that TOH-containing emulgel at 1000 μM has excellent physical characteristics as homogenous, stability, and inhibits the growth of 30 species of human pathogenic fungi in vitro. TOH-containing emulgel did not cause skin irritation in mouse model of irritation and in healthy human volunteers. Moreover, an increase in skin hydration and a decrease in trans-epidermal water loss (TEWL) were observed after TOH-containing emulgel treatment on human skin. Our findings indicated that TOH-containing emulgel can be utilize as an antifungal agent for topical treatment against fungal infections on the skin.

β-Tricalcium Phosphate-Loaded Chitosan-Based Thermosensitive Hydrogel for Periodontal Regeneration.

The current treatment for periodontitis is aimed at resolving gingival inflammation, whilst complete periodontal tissue regeneration is not predictable, and it represents a therapeutic challenge. Injectable biomaterials hold tremendous potential in dental tissue regeneration. This study aimed to investigate the ability of an injectable thermosensitive β-tricalcium phosphate (β-TCP) and chitosan-based hydrogel to carry cells and promote periodontal tissue regeneration. In this study, different concentrations of β-TCP-loaded chitosan hydrogels were prepared (0%, 2%, 4%, or 6% β-TCP, 10% β-glycerol phosphate, and 1.5% chitosan). The characteristics of the hydrogels were tested using rheology, a scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), degradation, and biological analyses. The new biomaterial showed a sol-gel transformation ability at body temperature and exhibited excellent chemical and physical characteristics, whilst the existence of β-TCP enhanced the structure and the properties of the hydrogels. The SEM confirmed the three-dimensional networks of the hydrogels, and the typical rheological properties of strong gel were observed. The EDX and XRD validated the successful incorporation of β-TCP, and similar patterns between different groups were found in terms of the FTIR spectra. The stable structure of the hydrogels under 100 °C was confirmed via DSC. Biological tests such as Alamar Blue assay and Live/Dead staining confirmed the remarkable biocompatibility of the hydrogels with pre-osteoblast MC3T3-E1 and human gingival fibroblast (HGF) cells for 14 days, and the results were validated with confocal imaging. This preliminary study shows great promise for the application of the β-TCP-loaded thermosensitive chitosan hydrogels as a scaffold in periodontal bone and soft tissue repair.

Dynamic ultrasound molecular-targeted imaging of senescence in evaluation of lapatinib resistance in HER2-positive breast cancer.

Prolonged treatment of HER2+ breast cancer with lapatinib (LAP) causes cellular senescence and acquired drug resistance, which often associating with poor prognosis for patients. We aim to explore the correlation between cellular senescence and LAP resistance in HER2+ breast cancer, screen for molecular marker of reversible senescence, and construct targeted nanobubbles for ultrasound molecular imaging to dynamically evaluate LAP resistance. In this study, we established a new cellular model of reversible cellular senescence using LAP and HER2+ breast cancer cells and found that reversible senescence contributed to LAP resistance in HER2+ breast cancer. Then, we identified ecto-5'-nucleotidase (NT5E) as a marker of reversible senescence in HER2+ breast cancer. Based on this, we constructed NT5E-targeted nanobubbles (NT5E-FITC-NBs) as a new molecular imaging modality which could both target reversible senescent cells and be used for ultrasound imaging. NT5E-FITC-NBs showed excellent physical and imaging characteristics. As an ultrasound contrast agent, NT5E-FITC-NBs could accurately identify reversible senescent cells both in vitro and in vivo. Our data demonstrate that cellular senescence-based ultrasound-targeted imaging can identify reversible senescence and evaluate LAP resistance effectively in HER2+ breast cancer cells, which has the potential to improve cancer treatment outcomes by altering therapeutic strategies ahead of aggressive recurrences.

A Comprehensive Review on Catalytic Activities of Green-Synthesized Selenium Nanoparticles on Dye Removal for Wastewater Treatment

The increase in economic activities and the industrialization of countries have caused the growth of pollution created by waste and sewage. In particular, the textile industry produces large amounts of liquid contaminants due to the large amounts of water employed during the production of fabrics. In addition, dyes are another category of organic compound used in many industries, such as pharmaceuticals and rubber making. The presence of limitations in physico-chemical methods for the degradation of various dyes has stimulated the interest of researchers worldwide. One of the most economical ways is the use of photocatalytic decomposition under UV light radiation by green nanoparticles (NPs). In recent years, various metal NPs have been made using the green method that is cost-effective, eco-friendly, safe, and simple. Selenium (Se) is a crucial semiconductor metal that is widely utilized for its outstanding photovoltaic and optoelectronic attributes. Due to the excellent physical characteristics of Se, such as thermo-conductivity, anisotropy, and high photoconductivity, it has been used for removing various organic dyes. Hence, green SeNPs have attracted much attention in the catalytic decomposition process. The current review focuses on providing comprehensive studies concerning the degradation or reduction of various organic dyes through green SeNPs as an effective and efficient method and their mechanisms. It highlights the importance of utilizing green chemistry and catalytic properties. The aim is to benefit researchers from both academic and industrial backgrounds.

Composition and Flowering Quality of Cacahuacintle Maize Populations from the High Valleys of Mexico.

Cacahuacintle is one of the maize types with great demand for pozole preparation; however, little is known about the variation in chemical composition and flowered grain quality among populations. Physicochemical characteristics, flowered grain quality, pasting properties, and starch microstructure were evaluated in 33 populations of Cacahuacintle maize collected in Valles Altos, Mexico. The seeds samples of corn were obtained in 2017 from local farmers in the states of Mexico, Puebla, and Tlaxcala. Results were analyzed under a completely randomized design, and the ANOVA, Tukey test, and principal components were obtained. The ANOVA showed significance (p ≤ 0.05) in 18 of the 22 variables evaluated. The TE-6, AM-7, and CA-6 populations were outstanding for the good quality of their protein, pasting viscosity, and flowered grain quality. Nine populations collected in Calimaya, estate of Mexico, and Serdan Valley, state of Puebla, presented excellent physical, pasting, and flowery grain characteristics, with reduced protein content and lysine and tryptophan values typical of maize with normal endosperm. The softness of the endosperm grain, starch microstructural, and pasting characteristics of Cacahuacintle maize populations have a fundamental role in reducing the time and increasing the flowered grain volume, properties that were different from those observed in the Chalqueño, included as dent maize check. Variations in grain quality among Cacahuacintle maize populations is an important genetic resource for the improvement of the nutritional and flowering quality of Cacahuacintle maize.

Experimental and Numerical Studies on Bending and Failure Behaviour of Inflated Composite Fabric Membranes for Marine Applications

Owing to their excellent physical characteristics of lightweightiness, compactness and rapid deployment, the inflated membrane structures satisfy the demands of maritime salvage and military transportation for long-distance delivery and rapid response. Exploring the failure behaviour of inflated membrane structures can greatly contribute to their widespread applications in ocean engineering. In this research, the main objective is to comprehensively investigate the bending and failure behaviour of inflated membrane structures. Thus, the Surface-Based Fluid Cavity method is employed to set up the finite element model (FEM) which is compared to the experimental results to verify its reliability. In parallel, the effects of internal pressure and wrinkles are discussed. An empirical expression of the ultimate bending loading was fitted by face-centred composite designs of the Response Surface Methodology. The results of experiments and FEM show that the bearing capacity of the inflated membrane structure is positively correlated with the internal pressure but decreased obviously with the occurrence and propagation of wrinkles. The deformation behaviour and the stress distribution are similar to those of the traditional four-point bending beam, and the local instability induced by wrinkles will cause structural failure. In addition, the numerical model and the proposed expression showed deviations below 5% in relation to the experimental measures. Therefore, the FEM and proposed expression are high of reliability and have important engineering guiding significance for the application of inflated membrane structures in ocean engineering.

Adjusting the interfacial adhesion via surface modification to prepare high-performance fibers

Ultra-high molecular weight polyethylene (UHMWPE) fiber is a new kind of high-performance fiber. Due to its excellent physical and chemical characteristics, it is widely used in various fields. However, the surface UHMWPE fiber is smooth and demonstrates no-polar groups. The weak interfacial adhesion between fiber and resin seriously restricts the applications of UHMWPE fiber. Therefore, the surface modification treatments of UHMWPE fiber are used to improve the interfacial adhesion strength. The modified method by adding nanomaterials elucidates the easy fabrication, advanced equipment and proper technology. Thus, the progress of UHMWPE nanocomposite fibers prepared via adding various nanofillers are reviewed. Meanwhile, the effects of other various methods on surface modification are also reviewed. This work advances the various design strategies about nano technologies on improving interfacial adhesion performance via treatment methodologies.

구리/그래핀 복합재의 전기전도도에 미치는 그래핀 입자 및 체적분율의 영향

Cu is most commonly used as a matrix in composites for high electrical and thermal conductivity. Recently, graphene has been researched to improve mechanical and electrical properties as reinforcing materials of composites owing to its excellent physical characteristics. Therefore, the purpose of this study is to evaluate the effects in electrical conductivity according to the shape, structure, and the volume fraction of the graphene reinforcement for Cu/graphene composites. For the evaluation of the variation in electrical conductivity according to the shape and the volume fraction of graphene platelets, RVE was analyzed for models in the location and orientation of graphene which were randomly arranged or not. The change in electrical conductivity of the volume fraction and aspect ratio of graphene platelets was evaluated by using the ABAQUS program. Depending on the angle of graphene platelets, the electrical conductivity was the highest at 0°. In addition, in a relatively high volume fraction model, the electrical conductivity decreased quickly according to increase in the angle, and the variation was changed at angle 45° for the AR.

Restoration of posterior tooth with single shade composite: A case series

Composite restoration is a popular material to restore tooth structure due to dental caries as there is an increasing demand for aesthetic restoration. With the advancing technologies, it has excellent physical characteristics which increases its longevity. However, the appropriate case selection also influences the outcome as composite is technique sensitive. This material can be offered to patient seeking less time-consuming procedure, better preservation of tooth structure, affordable but acceptable aesthetic outcome. These three cases presented shows the possibility of creating a good aesthetic result in posterior tooth restoration with the use of single shade composite.

Synthesis, Physical Properties, and In Vitro-Simulated Gastrointestinal Digestion of Hydrophilic β-Sitosterol Sugar Esters.

Hydrophilic β-sitosterol sugar esters were synthesized by a two-step biocatalytic approach using β-sitosterol vinyl adipate as an intermediate. The maximum conversion (above 90%) of β-sitosterol vinyl adipate was achieved using the saccharides glucose, sucrose, and raffinose. The chemical structure of the synthesized esters was confirmed by various techniques. The investigation of physical properties revealed that β-sitosterol sugar esters had enhanced water solubility (3.0-8.0 mM at 35 °C), reduced crystallinity, and high wettability. Their lyotropic liquid crystal properties were observed by polarized light microscopy. Furthermore, β-sitosterol sugar esters could be hydrolyzed into β-sitosterol adipate under simulated intestinal conditions at a low rate (2.83-18.14%). Most β-sitosterol sugar esters probably entered into intestinal bile salt micelles with ester bonds intact and showed up to 10-fold higher in vitro bioaccessibility than free β-sitosterol in non-fat systems. The excellent physical and functional characteristics of β-sitosterol sugar esters suggested their great potential application in the food industry.

A Review of the Brazeability of Low-Temperature and Nano-Reinforced Al-Based Brazing Filler Metals

Aluminum and its alloys are some of the most widely used materials for the brazing of parts in aerospace and automotive industries due to their excellent physical characteristics, e.g., good ductility, high strength-to-weight ratio, light weight, good corrosion and oxidation resistance, satisfactory malleability and formability, and excellent thermal and electrical conductivity. Especially during casting operations, high strength and machinability of Al-based alloys are of utmost concern. The quality and strength of casting products are affected by porosity generated due to the dissolution of gases and the effects of modifiers. Thus, unstable properties of Al alloys arising due to such influences should to be controlled by reinforcing suitable elements. Compared to other materials, brazing on Al requires higher control precision as the difference between the melting points of the base metal and the filler remain low even after the addition of melting point suppressants, such as Si. This necessitates the development of novel low-temperature Al-based filler metals. Moreover, the mechanical properties of Al-based alloys can be enhanced by introducing nanoparticles within them to reduce the thickness of Si-needles and IMCs (intermetallic compound) within the Al matrix, thereby refining the nanostructure.