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International audience; A zinc(II) complex of polypyazole containing ligand namely, [Tp*ZnCl] (Zn1) {Tp* = tris(3,5-dimethylpyrazolyl)borate}, along with its zinc(II) bound hydroxo complex [Tp*Zn–OH] (Zn2) were synthesized and characterized by FT-IR, Raman, 1H NMR techniques and elemental analysis. In alkaline solution (0.1 M KOH), the Zn2 modified glassy carbon (GC), namely GC–Zn2, was investigated as a molecular electrocatalyst for the hydrogen evolution reaction (HER). Different quantities (ca. 0.1–0.5 mg cm–2) of Zn2 were loaded on GC electrodes to make various GC–Zn2 electrodes. These electrodes were utilized as cathodes in 0.1 M KOH to produce H2 using linear sweep voltammetry (LSV) measurements. The HER electrocatalytic activity of the GC–Zn2 catalyst was found to be quite high and it increased with the catalyst loading density. The top performing electrocatalyst, GC–Zn2 (0.5 mg cm–2), demonstrated considerable HER catalytic performance with a low HER onset potential (EHER) of –33 mV vs. RHE and a high exchange current density of 0.59 mA cm–2. Moreover, the top performing electrocatalyst had a Tafel slope of –152 mV dec–1 and consumed an overpotential of 135 mV to generate a current density of 10 mA cm–2. Under the same operating conditions, these HER electrochemical kinetic parameters were found to be not remarkably far from those determined for commercial Pt/C (–10 mV vs. RHE, 0.88 mA cm–2, 108 mV dec–1 and 110 mV to yield a current density of 10 mA cm–2). In addition, the most active molecular electro-catalysts for H2 production from aqueous alkaline electrolytes were found to be comparable to the HER electrochemical kinetic parameters reported here for the GC–Zn2 electrocatalyst. Using 5000 cycles of repetitive cyclic voltammetry and 48 h of chronoamperometry measurements, the best electrocatalyst’s stability and long term durability were tested. It exhibited high stability for the HER catalytic activity.

In this paper aims, we found the fluid concentration after calculating the velocity and temperature of the fluid with a variable viscosity that depends on the fluid moving through an inclined porous channel. We examined the influences of certain parameters that are active on fluid velocity by analyzing the graphs obtained after we reached the momentum equation solution, and used the MATHEMATICA program for plot the velocity and temperature of the fluid for two types of flow (Poiseuille and Couette).

The widespread presence of microplastics has caused significant concerns on their potential effects on marine ecosystems. Microplastics are classified as plastic products of less than 5 mm in size and are known to be one of the most dangerous aquatic debris to marine species. Sea cucumbers are deposit feeders living in sediment regions and benthic zone that may collect microplastics in low-energy environments. This research aims to evaluate the types of microplastic isolated from the intestine of Stichopus horrens in Malaysia. This species is selected because it is mainly found in this island. Pulau Pangkor is one of the leading tourism destinations on the small islands is facing increasing numbers of tourists and development and it is useful for sustainable study. A total of 20 S. horrens samples collected from Pulau Pangkor, Malaysia were dissected, and their intestines were collected for digestion. Microplastics were extracted using NaOH and filtered using filter paper. Microplastic identification was conducted on the based of the physical characteristics (colour, shape, size) and chemical characterisation was evaluated using FTIR for polymer functional groups. A total of 1446 unit of microplastics were found in S. horrens. Among various types and colours, fibre (90%) and black (59%) were dominant amongst the various particles identified. The majority of microplastics sizes were 0.51 μm and 1-2 μm. Two polymer materials were identified, namely polyethylene and poly(methyl methacrylate). As a conclusion, the findings of the study will serve as primary data for pollution indicators in respective islands. The microplastics could impact the immune system and upset gut's balance of human.

The reaction of potassium tetracyanocupprate(I) with triethyltin bromide in presence of phenanthroline (Phen) and quinoxaline (Qox) in acetonitrile via ultrasonic radiation yielded two new nano-supramolecular coordination polymers (SCP) of the type: [Cu2(CN)4(Et3Sn)2(Phen)2] SCP1 and [Cu2(CN)3(Et3Sn)(Qox)] SCP2. The obtained polymers were characterized using elemental and thermal analyses, as well as FT-IR, UV–vis, fluorescence, 1H NMR, and MS spectroscopes. Spectral and analytical features led to the conclusion that both Phen and Qox behave as bidentate ligands and the proposed formulae of SCP1 and SCP2 have the bimetallic nature, in which the geometry around Cu(I) atoms in SCP1 is tetrahedral and planar trigonal. While in SCP2, the Cu(I) has a trigonal plane geometry. Thermal analysis studies indicated that both SCP1 and SCP2 are thermally stable up to 140 °C. Additional confirmation for the structures of SCP1 and SCP2 was obtained from density functional theory (DFT) and molecular mechanics (MM+) calculations. Transmission electron microscopy (TEM) images of SCP1 and SCP2 show regular spherical-like nano-sized particles in the range of 31.24–62.13 nm and 5.16–23.90 nm, respectively. The inhibitory anti-oxidant activities of both SCP1 and SCP2 were investigated using erythrocyte hemolysis and ABTS methods and their cytotoxicity activities towards different tumor cells were also studied by MTT assay. The results showed that both the two polymers have high inhibitory anti-oxidant activities and SCP2 exhibits a significant decrease in surviving fraction of these cancer cell lines compared to SCP1.

The new host-guest ∞3[Cu2(CN)3HB] supramolecular coordination polymer (SCP1) where HB = imidazole cation, was synthesized and structurally elucidated by X-ray single crystal and elemental analyses as well as spectral investigations. The topology of SCP1 constructs of three-dimensional anionic {[Cu2(CN)3]-}∞ framework based on the mini-cycle [Cu2(μ3-CN)2] motifs with encapsulation of cationic imidazole ring. Nanoscale form (SCP1\) was obtained by ultrasonic irradiation and TEM image shows regular nanostructure with the particle size in the range of 19.25–24.35 nm. Luminescence behavior of SCP1 was investigated to detect its ability as sensor for selective determination of nitrobenzene and metal ions. SCP1 and 1\ were found to have high catalytic and photocatalytic activities for degradation of Indigo Carmine (IC) in presence of H2O2. Each catalyst was recycled without loss of catalytic efficiency. The effect of ultrasonic and UV-irradiation and the degradation mechanism were also investigated.

Aim: The aim of this study is to determine the presence of microbial air contaminants in the operating theatre at a teaching hospital. Objective: Airborne microbial level in operation theatre is one of the significant risks in hospital as it can increase the surgical site infection and nosocomial infections. Background: Duo SAS Super 360 Air Sampler was used to collect the airborne samples in triplicate each for nutrient and MacConkey agar at eight operation rooms and two corridors for morning and evening sessions. Sampling was conducted for three months and repeated every two months. Microbiological culture, gram staining and biochemical tests such as catalase test, oxidase test, coagulase test, Triple Sugar Iron Agar test, urease test, citrate test, Sulfide, Indole, Motility test, Methyl Red Voges-Proskauer test, disc diffusion test, and Albert’s stain were performed on the pure isolated culture. Methods: Sampling was conducted for three months and repeated every two months. Microbiological culture, gram staining and biochemical tests such as catalase test, oxidase test, coagulase test, Triple Sugar Iron Agar test, urease test, citrate test, Sulfide, Indole, Motility test, Methyl Red Voges- Proskauer test, disc diffusion test, and Albert’s stain were performed on the pure isolated culture. Bacteria that were present in the operation rooms were Bacillus spp., Micrococcus spp. and Staphylococcus spp. while Pseudomonas aeruginosa and Acinetobacter baumannii were absent. The bacteria identified in the operation theater may also cause surgical site infections and nosocomial infections to the patients, although the microbial contamination in the air of the operation theatre is low. Results: The bacteria identified in the operation theater may also cause surgical site infections and nosocomial infections to the patients, although the microbial contamination in the air of the operation theatre is low. Conclusion: Strengthening surveillance on the hygienic condition of the operation theatre and routine sampling is strongly recommended to control all possible sources and types of infection.

In the present study, the thermal, mechanical, and biological properties of xAg/Ti-30Ta (x=0, 0.41, 0.82 and 2.48 at%) shape memory alloys (SMAs) were investigated. The study was conducted using optical and scanning electron microscopy (SEM), X-ray diffractometry (XRD), compression test, and shape memory testing. The xAg/Ti-Ta was made using a powder metallurgy technique and microwave-sintering process. The results revealed that the addition of Ag has a significant effect on the pore size and shape, whereas the smallest pore size of 11 µm was found with the addition of 0.41 at% along with a relative density of 72%. The fracture stress and strain increased with the addition of Ag, reaching the minimum values around 0.41 at% Ag. Therefore, this composition showed the maximum stress and strain at fracture region. Moreover, 0.82 Ag/Ti-Ta shows more excellent corrosion resistance and biocompatibility than other percentages, obtaining almost the same behaviour of the pure Ti and Ti-6Al-4V alloys, which can be recommended for their promising and potential response for biomaterial applications.

This study was aimed to establish the possibility of using an eco-friendly plant-based pomelo peel with different concentrations to formulate a novel corrosion green inhibitor for steel applications in 3.5% NaCl and 0.1 M HCl solutions at 30 °C. The corrosion rate and inhibition efficiency were evaluated using weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques corresponded with surface morphology characterization of the corroded steel samples without and with inhibitors using a scanning electron microscope (SEM) and energy-dispersive x-ray analysis (EDS). Based on the Fourier-transform infrared spectroscopy (FTIR) results, it was found that the pomelo peels extract is a mixture of the chemical compounds of naringin (C27H32O14), auraptene (C19H22O3) and naringenin-4′-O-glucoside (C21H22O10). The results were also indicated that there is a remarkable improvement in the inhibition efficiency and corrosion rate of low-carbon steel after the addition of inhibitor, and as well as the immersion time was profound to have a significant effect on the corrosion behavior of the different concentrations of inhibitor. The pomelo peels extract of 8000 ppm concentration gave the best inhibition efficiency of 74.64 and 71.15% in 0.1 M HCl and 3.5% NaCl, respectively. The adsorption isotherm of pomelo peels within different concentrations on the steel surface conforms Langmuir’s isotherm, and the thermodynamic parameters of Kads and ΔG have also been calculated and discussed.

In this work, the influence of microwave sintering time and temperature on the microstructure characterisation, and thermal and mechanical behaviours of Ti–30Ta were investigated. The relative densities of Ti–30Ta samples were in the range of 65–72% and as the sintering times/temperatures increased, the relative density decreased. The pore size averages were in the range of 6–17 µm with different sintering parameters, for instance the smallest pore size of 6.8 µm was observed after being sintered at 900 ℃ for 30 min (Ta2). Two morphologies of plate-like (P) and needle-like (N) structures were observed, as well as two regions – dark region (Ti-rich region) and bright region (Ta-rich region), also two phases – β and α. The DSC results revealed that the Ms to Mf transformation range was 98.86 to 80.5 ℃, respectively, while the range of As to Af transformation was about −22.35 to 92 ℃, respectively. The maximum fracture strength and its strain were acquired in the sintered sample of 900 ℃ for 30 min. The total strain recovery (ɛT) was improved linearly as the sintering temperature increased, correspondingly, the best ɛT was implied in Ti–Ta shape memory alloys after being sintered at 1000 ℃ for 30 min (Ta4).

A new mixed ligand complex, viz., [Ni(Tren)(Barb)(H2O)](Barb)(Barb-H)•2H2O (NiC) {Tren = tris(2-aminoethyl)amine and Barb = 5,5-diethlybarbiturate} has been synthesized and characterized. The nickel(II) complex was grafted to g-C3N4, forming NiC@g-C3N4. The obtained NiC complex and its hybrid material NiC@g-C3N4 were characterized by means of FT-IR, TGA-DSC, UV-vis., SEM-EDX, and XRD. Single crystal X-ray crystallography suggests that NiC exhibits NiN5O octahedral geometry. The results also show that the complex molecules are connected via N–H××××O hydrogen bonds. The complex NiC and its NiC@g-C3N4 composite showed cytotoxic effects on in vivo experiments. They also showed an increase in tissue damage markers that are represented by the increase in tissue levels of malondialdehyde (MDA) in brain, liver, kidney and heart. In parallel, both materials showed inhibitory activity for examined antioxidants such as glutathione-S-transferase (GST), superozide dismutase (SOD), glutathione (GSH), glutathione reductase (GSH-R). The destructive effects were clearer for the NiC@g-C3N4 composite compared to in liver, brain and kidney, respectively. The grafting of NiC complex in g-C3N4 is responsible for improving the catalytic activity, which is due to the synergistic effect of both components and facile recovery, as well recycling of the catalyst.

This paper aims to determine the different sources of hydrogen that cause hydrogen embrittlement in ferrous materials. The 316L stainless steel was selected as the research object, and subjected to immersion and electrochemical tests in 1.0M HCl solution. The hardness and tensile strength of the test samples were measured before and after hydrogen embrittlement. The hydrogen, which exists in the form of hydrides, was detected through X-ray diffractometry (XRD), while the fracture profile and microstructure of the samples were observed through optical microscopy and scanning electron microscopy (SEM), respectively. The results show that the hydrogen ions diffused into the surface of the steel, forming iron hydrides. In this way, the hardness of the steel was enhanced, and brittle failure occurred under tensile load; the amount of hydrides and the probability of hydrogen embrittlement increase with the immersion time in the acid solution; the sample immersed in 1.0M HCl for one day presented the most prominent hydrogen embrittlement, i.e. the highest hardness and lowest ductility. The research results provide insights into the occurrence of hydrogen embrittlement in ferrous materials.

The effects of different deformation percentages on the microstructure and mechanical properties of Cu–Al–Ni–xTi shape memory alloys (SMAs) were investigated. The experimental results demonstrated that the mechanical properties varied in accordance with the parent and precipitate phase formations, morphologies, and orientations. Furthermore, an increase in deformation can cause an effect on the density and movement of dislocations and thus influences the functional properties of the shape memory features. The results revealed that applied deformations of 2% and 4% on Cu–Al–Ni–0.5 wt% Ti SMAs attained the highest fracture and recovery strains by the shape memory effect, respectively. It can be also concluded that the significant features of shape memory alloys are susceptible to changes of the dislocation density and movements with respect to deformation and also depend mainly on the Ti concentration of the matrix, which can be modified via the formation and volume fraction of x-phase precipitates.

A new 3D-host-guest supramolecular coordination polymer (SCP); ∞3[(Cu3(CN)3)2.(DAHP)], 1 [1,7-diaminoheptane=.(DAHP)] had been synthesized by self-assembly at ambient conditions. X-ray single crystal diffraction of SCP 1 indicated the formation of two-fold [Cu3(CN)3]2 units containing tetrahedral copper(I) atoms which are arranged in unique way to create 3D-network. The neutral [Cu3(CN)3]2 building blocks create unique complex structure containing the minicycle [Cu2(μ3-CN)2] motif with wide cavities enable to capsulate the long chain DAHP as guest molecule. The topology of 1 had been studied by elemental analysis, IR-spectra and thermogravimetric analyses. The topology of 1 had been compared with the prototype SCP containing different aliphatic diamines which indicated the effect of structural variability and flexibility of aliphatic diamines on the network structure of these SCP. The catalytic and photo-catalytic activity of 1 was studied for mineralization of methylene blue (MB) utilizing H2O2 as an oxidant.

Nowadays, scientific knowledge is being developed frequently to offer versatile, safer, and sound user tendencies. At this time, a large number of prevalent techniques that have been indicated by visually impaired people are intelligent tools; however, it possesses limitations. With the recent technological innovation, it isn’t easy to prolong the assistance acquire for people who have visual disabilities throughout their movability. Thus, this design provides cost-effective ultrasonic-based aids, including a hat, stick, and shoes for visually encountered people today, to achieve exclusive self-reliance and even be exempt from additional assistance. Ultrasonic sensors were able to inspect different heights, and simultaneously the user will be alerted via a buzzer. A vibrator was also implemented as a substitute gadget in minimal signal coverage areas and noisy environments. The buzzer and vibration motor are initialized when the obstacle is identified. A global positioning system (GPS) was also included in the design of aids and synchronized with google map within mounted buttons. The text message unit is also utilized by the user to send out SMS info to the saved phone numbers in the Arduino in an emergency text-request by providing the allocated longitude and altitude position. The results revealed a high accuracy of the system under different circumstances, indoor and outdoor, as feedback of different users. In conclusion, this system is considered an inexpensive, friendly user, and sensible blind assist techniques for the blind and visually impaired people.

Cooperative communication systems can solve the data rate limitations in underwater acoustic channels (UAC) introduced by their half-duplex (HD) nature and bandwidth limitations. In this paper, Hierarchical Modulation (HM) is introduced to both enhance the system throughput and spectral efficiency, as well as to enable various degrees of priority communication links. The proposed system utilizes HM with orthogonal frequency division multiplexing modulation (OFDM) in a two-way relay network (TWRN) using physical layer network coding (PLNC) to exchange information between two nodes operating in HD mode. The performance of the proposed PLNC-TWRN system is analysed via simulations using realistic UAC and numerical results are presented to demonstrate that it can significantly enhance the throughput.