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Fulltext A simple route to vertical array of quasi-1D ZnO nanofilms on FTO surfaces: 1D-crystal growth of nanoseeds under ammonia-assisted hydrolysis process

Ali Umar A, Abd Rahman MY, Taslim R, Mat Salleh M, Oyama M

Nanoscale Res Lett, 2011 Oct 25;6:564.
PMID: 22027275 DOI: 10.1186/1556-276X-6-564

A simple method for the synthesis of ZnO nanofilms composed of vertical array of quasi-1D ZnO nanostructures (quasi-NRs) on the surface was demonstrated via a 1D crystal growth of the attached nanoseeds under a rapid hydrolysis process of zinc salts in the presence of ammonia at room temperature. In a typical procedure, by simply controlling the concentration of zinc acetate and ammonia in the reaction, a high density of vertically oriented nanorod-like morphology could be successfully obtained in a relatively short growth period (approximately 4 to 5 min) and at a room-temperature process. The average diameter and the length of the nanostructures are approximately 30 and 110 nm, respectively. The as-prepared quasi-NRs products were pure ZnO phase in nature without the presence of any zinc complexes as confirmed by the XRD characterisation. Room-temperature optical absorption spectroscopy exhibits the presence of two separate excitonic characters inferring that the as-prepared ZnO quasi-NRs are high-crystallinity properties in nature. The mechanism of growth for the ZnO quasi-NRs will be proposed. Due to their simplicity, the method should become a potential alternative for a rapid and cost-effective preparation of high-quality ZnO quasi-NRs nanofilms for use in photovoltaic or photocatalytics applications.PACS: 81.07.Bc; 81.16.-c; 81.07.Gf.

Matched MeSH terms: Orientation, Spatial
Fulltext Novel macromolecules derived from coumarin: synthesis and antioxidant activity

Al-Amiery AA, Al-Majedy YK, Kadhum AA, Mohamad AB

Sci Rep, 2015;5:11825.
PMID: 26134661 DOI: 10.1038/srep11825

The rational design of 4-hydroxycoumarins with tailor-made antioxidant activities is required nowadays due to the wide variety of pharmacologically significant, structurally interesting of coumarins and researcher orientation toward green chemistry and natural products. A simple and unique coumarins have been achieved by reaction of 4-hydroxycoumarin with aromatic aldehyde accompanied with the creation of a macromolecules have 2-aminothiazolidin-4-one. The molecular structures of the compounds were characterized by the Fourier transformation infrared and Nuclear magnetic resonance spectroscopies, in addition to CHN analysis. The scavenging abilities of new compounds against stable DPPH radical (DPPH•) and hydrogen peroxide were done and the results show that the compounds exhibited high antioxidant activates.

Matched MeSH terms: Orientation, Spatial
Fulltext A comparative study between self-perception of walking ability, balance and risk of fall with actual clinical assessment

Nurulaini, A., Syahnaz, M.H., Shamsul, A.S., Teh Rohaila, J.

Medicine & Health, 2018;13(2):133-144.
MyJurnal

Gait and balance disorder are among the most common causes of falls in elderly and often lead to injury, disability and loss of independence. However, there might be a discrepancy between elderly’s perception of their own walking ability, balance, risk of fall with doctor’s evaluation. The aim of this study was to compare perception of the elderly’s walking ability, balance and risk of fall with clinical assessment. This cross sectional study was done in a Primary Care Clinic which involved elderly > 60 years using systematic random sampling. Participants completed a self-administered questionnaire comprising of sociodemographic data and question assessing their perception of ability of walking, balance and risk of fall. Actual clinical assessment was done using Tinetti Performance Oriented Mobility Assessment. Most of the participants perceived they had good walking (84.4%) and balance ability (77%). A small proportion (11.5%) agreed that they are at risk of fall. There was a good agreement in walking ability (k: 0.702, p:

Matched MeSH terms: Orientation, Spatial
Fulltext Synthesis of Ge1-xSnx Alloy Thin Films by Rapid Thermal Annealing of Sputtered Ge/Sn/Ge Layers on Si Substrates

Mahmodi H, Hashim MR, Soga T, Alrokayan S, Khan HA, Rusop M

Materials (Basel), 2018 Nov 12;11(11).
PMID: 30424494 DOI: 10.3390/ma11112248

In this work, nanocrystalline Ge1-xSnx alloy formation from a rapid thermal annealed Ge/Sn/Ge multilayer has been presented. The multilayer was magnetron sputtered onto the Silicon substrate. This was followed by annealing the layers by rapid thermal annealing, at temperatures of 300 °C, 350 °C, 400 °C, and 450 °C, for 10 s. Then, the effect of thermal annealing on the morphological, structural, and optical characteristics of the synthesized Ge1-xSnx alloys were investigated. The nanocrystalline Ge1-xSnx formation was revealed by high-resolution X-ray diffraction (HR-XRD) measurements, which showed the orientation of (111). Raman results showed that phonon intensities of the Ge-Ge vibrations were improved with an increase in the annealing temperature. The results evidently showed that raising the annealing temperature led to improvements in the crystalline quality of the layers. It was demonstrated that Ge-Sn solid-phase mixing had occurred at a low temperature of 400 °C, which led to the creation of a Ge1-xSnx alloy. In addition, spectral photo-responsivity of a fabricated Ge1-xSnx metal-semiconductor-metal (MSM) photodetector exhibited its extending wavelength into the near-infrared region (820 nm).

Matched MeSH terms: Orientation, Spatial
Effects of the nitric acid concentrations on the etching process, structural and optical properties of porous zinc oxide thin films

C.G. Ching, Leonard Lu, C.I. Ang, P.K. Ooi, S.S. Ng, Z. Hassan, et al.

Sains Malaysiana, 2013;42:1327-1332.

The present study reports on the fabrication of porous zinc oxide by wet chemical etching. ZnO thin films were deposited via radio-frequency magnetron sputtering on p-type silicon with (111) preferred orientation. The etchants used in the present work were 0.1% and 1.0% nitric acid (HNO3) solutions. ZnO were etched at various times and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy to allow the examination of their structural and optical properties. The XRD results revealed that the intensity of ZnO(002) decreased when the thin films were etched in varying HNO3 concentrations over different periods of time. The above observation is attributed to the dissolution of the ZnO(002). The SEM images showed that the thickness of the ZnO layers decreased over the etching time, which resulted from the isotropic etching by the HNO3 solution. The PL emission intensity initially increased with increasing etching time. However, with further etching of the samples, the PL spectra showed a decreasing trend in intensity as a result of the decrease in the surface-to-volume ratio. All results lead to the conclusion that 1.0% HNO3 has the capability to change the ZnO surface significantly.

Matched MeSH terms: Orientation, Spatial
Fulltext Investigation of Fibers Reinforced Engineered Cementitious Composites Properties Using Quartz Powder

Liew MS, Aswin M, Danyaro KU, Mohammed BS, Al-Yacouby AM

Materials (Basel), 2020 May 26;13(11).
PMID: 32466366 DOI: 10.3390/ma13112428

In relation to the use of retrofit materials on damaged constructions, application on earthquake-resistant buildings, and for the strengthening and rehabilitation on weakened regions, there is a need for a more superior material than concrete. Application sites include beam-column joints, corbels, link-slabs, deep beams, support regions and dapped-end areas. Fiber reinforced engineered cementitious composites (FR-ECC) can address this issue, because FR-ECC is one of the composite materials that has high strength, ductility and durability. In order to develop FR-ECC, this study was done to investigate the effect of adding quartz powder on the compressive strength capacity and properties of FR-ECC through the use of polyvinyl alcohol (PVA) and steel fibers. The volume fraction of fiber was set to 0%-2%. To support the friendly environment, FR-ECC uses by-product materials such as fly ash and silica fume, with a cement content less than 600 kg/m3. In terms of the experimental investigation on FR-ECC, this work conducted the fresh property tests showing that PVA fibers have quite an influence on ECC workability, due to their hydrophilic behavior. By adjusting the superplasticizer (SP) content, the consistency and high workability of the ECC mixes have been achieved and maintained. The test results indicated that the PVA and steel fibers-based ECC mixes can be classified as self-compacting composites and high early compressive strength composites. Significantly, addition of quartz powder into the ECC mixes increased the compressive strength ratio of the ECC samples up to 1.0747. Furthermore, the steel fiber-based ECC samples exhibited greater compressive strength than the PVA fibers-based ECC samples with the strength ratio of 1.1760. Due to effect of the pozzolanic reaction, the fibers dispersion and orientation in the fresh ECC mixes, so that the cementitious matrices provided the high strength on the FR-ECC samples. During the compression loading, the bulging effect always occurred before the failures of the fibers-based ECC samples. No spalling occurred at the time of rupture and the collapse occurred slowly. Thus, FR-ECC has provided unique characteristics, which will reduce the high cost of maintenance.

Matched MeSH terms: Orientation, Spatial
Fulltext Effect of Laughter Therapy on Depression and Quality of Life of the Elderly Living in Nursing Homes

Heidari M, Ghodusi Borujeni M, Rezaei P, Kabirian Abyaneh S, Heidari K

Malays J Med Sci, 2020 Jul;27(4):119-129.
PMID: 32863751 DOI: 10.21315/mjms2020.27.4.11

Background: Mental disorders are common among the elderly with serious symptoms of depression and social isolation. This study was conducted to investigate the effect of laughter therapy (LT) on depression and quality of life (QOL) of the elderly living in Abadeh nursing homes.
Methods: This is a controlled semi-experimental study with a pre-test, post-test design. Ninety eligible ones of the elderly living in the Abadeh nursing homes and from July to September 2017, entered the study. Some of the criteria for entering the study include being over 60 years old, orientation, not having blindness and deafness, lack of physical and mental problems. After determining the intervention and control groups, the scale of depression and QOL was administered to the subjects and their scores were collected in the pre-test.
Results: Most of the study samples were in the intervention (35.55%) and control (37.77%) group in the age range of 60-69 years. In both intervention and control groups, respectively, 31.11% and 68.88% elderly were males and females. The mean scores of depression in the intervention group after LT (M = 2.57) were lower than those before the intervention (M = 6.87) [CI = -5.58-(-3.02)] and also the results of independent t-test showed a statistically significant difference before and after the intervention between the two groups (P < 0.001). The mean score of dimensions of QOL after LT was higher than that before in the intervention and there was a statistically significant difference in all dimensions with paired t-test (P < 0.001).
Conclusion: Since the implementation of this programme could improve the mental status and QOL of the elderly, this method of therapy can be used as an alternative or complementary model to enhance the health of the elderly.

Matched MeSH terms: Orientation, Spatial