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Spatial distribution trend of plankton in sungai Pulai estuary, the straits of Johor, Malaysia

Zaleha Kassim, Kamaruzzaman Yunus, Jalal K, Ili Nabilah Jaafar, Nur Suhaila Nordin, Wan Muhamad Amir Wan Ahmad, et al.

Sains Malaysiana, 2015;44:1257-1262.

A spatial distribution study was carried out to investigate the influence of some environmental factors to planktons using collected samples from the Sungai Pulai estuary, near to the Singapore boarder. Six stations chosen for the field sampling were Port Tanjung Pelepas (S1), Tanjung Bin Charcoal Plant (S2), seagrasses of Pulau Merambong (S4) and SecondLink Bridge (S5) and mangrove areas (S3, S6). There is no significant difference of phytoplankton abundance (p>0.05) between stations. Instead, it differs significantly at the level of p<0.05; p= 0.0001 (Two tailed, t=14.10 df=34) between sampling session. In contrast, there is a significant difference of zooplankton abundance (p<0.05) in the sampling stations (χ2 = 17.3,(5)), but there is no significant difference (p>0.05; p=0.8966) between the sampling session (Two tailed, t=0.1310, df=34). Biplot analysis shows that most species are associated with the stations except for Protoperidinium sp., Lithodesmia sp. and Alexendrium sp. Copepod species including Microcalanus sp., Calanus sp. and Temora sp. are associated with S5. Paracalanus sp., Euterpina sp., Tigriopus sp., Oithona sp. and Pseudocalanus sp. are associated with S1, S2 and S4. The planktons are correlated with the temperature (Pearson’s correlation, r2=-0.897) and salinity (Pearson’s correlation, r2=0.9416) in March but no correlation is found in November sampling session. The results indicated the important role of certain environmental factors, namely the salinity and temperature to the distribution of the planktons in Sungai Pulai estuary.
Dynamic connection between inward foreign direct investment, renewable energy, economic growth and carbon emission in China: evidence from partial and multiple wavelet coherence

Arain H, Sharif A, Akbar B, Younis MY

Environ Sci Pollut Res Int, 2020 Nov;27(32):40456-40474.
PMID: 32666445 DOI: 10.1007/s11356-020-08836-8

This paper presents a fresh understanding of the vigorous connection between inward FDI, renewable energy consumption, economic growth and carbon emission in the Chinese economy employing novel Morlet wavelet analysis. Wavelet correlation, continuous wavelet transform and partial and the multiple wavelet coherence analyses are applied on variables under study for data acquired during the period 1979 to 2017. The outcome of these analyses reveals that the connections among the variables progress over frequency and time. From the frequency domain point of view, the current study discovers noteworthy wavelet coherence and robust lead and lag linkages, although time domain reveals inconsistent associations among the considered variables. The wavelet analysis according to economic point of view supports that inward foreign direct investment (FDI) and renewable energy consumption help to enhance economic condition in Chinese economy. The results also suggested that inward FDI enhances the environmental degradation in medium and long run in China. The results emphasize the significance of having organized strategies by the policymakers to cope with huge environmental degradation occurred for a couple of decades in China.
Fulltext Macrolactin A as a Novel Inhibitory Agent for SARS-CoV-2 Mpro: Bioinformatics Approach

Bharadwaj KK, Sarkar T, Ghosh A, Baishya D, Rabha B, Panda MK, et al.

Appl Biochem Biotechnol, 2021 Oct;193(10):3371-3394.
PMID: 34212286 DOI: 10.1007/s12010-021-03608-7

COVID-19 is a disease that puts most of the world on lockdown and the search for therapeutic drugs is still ongoing. Therefore, this study used in silico screening to identify natural bioactive compounds from fruits, herbaceous plants, and marine invertebrates that are able to inhibit protease activity in SARS-CoV-2 (PDB: 6LU7). We have used extensive screening strategies such as drug likeliness, antiviral activity value prediction, molecular docking, ADME, molecular dynamics (MD) simulation, and MM/GBSA. A total of 17 compounds were shortlisted using Lipinski's rule in which 5 compounds showed significant predicted antiviral activity values. Among these 5, only 2 compounds, Macrolactin A and Stachyflin, showed good binding energy of -9.22 and -8.00 kcal/mol, respectively, within the binding pocket of the Mpro catalytic residues (HIS 41 and CYS 145). These two compounds were further analyzed to determine their ADME properties. The ADME evaluation of these 2 compounds suggested that they could be effective in developing therapeutic drugs to be used in clinical trials. MD simulations showed that protein-ligand complexes of Macrolactin A and Stachyflin with the target receptor (6LU7) were stable for 100 nanoseconds. The MM/GBSA calculations of Mpro-Macrolactin A complex indicated higher binding free energy (-42.58 ± 6.35 kcal/mol). Dynamic cross-correlation matrix (DCCM) and principal component analysis (PCA) on the residual movement in the MD trajectories further confirmed the stability of Macrolactin A bound state with 6LU7. In conclusion, this study showed that marine natural compound Macrolactin A could be an effective therapeutic inhibitor against SARS-CoV-2 protease (6LU7). Additional in vitro and in vivo validations are strongly needed to determine the efficacy and therapeutic dose of Macrolactin A in biological systems.
Fulltext The Use of Medicines with Anti-cholinergic Properties and Their Health Impacts among Hospitalised Malaysian Geriatric Patients

Wahab IA, Akbar B, Zainal ZA, Che Pa MF, Naina B

Malays J Med Sci, 2019 Mar;26(2):77-87.
PMID: 31447611 MyJurnal DOI: 10.21315/mjms2019.26.2.9

Background: Studies have shown that the use of medicines with anti-cholinergic (Ach) properties can increase elderly patients' risk of experiencing falls, confusion, and longer hospital stays (LOS). These adverse effects are preventable with appropriate intervention. Little is known about the use of medicines with Ach properties and their impact on Malaysian elderly patients. This study aimed to investigate the use of medicines with Ach properties and their impact on fall risk, confusion, and longer LOS among hospitalised elderly patients.
Methods: This study utilised a cross-sectional design and was conducted at a single centre where convenience sampling was employed to collect data from elderly patients (> 60 years) admitted to geriatric and medical wards at Hospital Tuanku Ja'afar during a 2-month period (July 2017-August 2017). Patients were excluded from this study if their hospital admission was planned for an elective procedure or if neurocognitive and hepatic impairment were diagnosed prior to the hospital admission. Medicines with Ach properties were identified and classified according to the anti-cholinergic drug scale (ADS). Univariate and multiple logistic regression statistical analyses were performed to assess its impacts on falls, confusion, and LOS.
Results: A total of 145 elderly patients with a mean age of 71.59 years old (SD = 8.02) were included in the study. Fifty-two percent of the participants were female, and the average hospital stay was 6 days (SD = 2.09). Medicines with Ach properties were administered in 62% (n = 90) of the cases. The most commonly prescribed medicine with Ach properties was furosemide (n = 59), followed by ranitidine (n = 44), warfarin (n = 23), and methylprednisolone (n = 22). Compared to patients who did not receive medicines with Ach properties, patients who received them had a significantly higher risk of falls [odds ratios (OR) = 2.61; 95%CI: 1.18, 5.78; P = 0.018], confusion (OR = 3.60; 95%CI: 1.55, 8.36; P = 0.003), and LOS (OR = 4.83; 95%CI: 2.13, 10.94; P < 0.001). Multiple comorbidities also showed a significantly increased risk of falls (OR = 3.03; 95%CI: 1.29, 7.07; P = 0.010).
Conclusion: Medicines with Ach properties had a significant impact on elderly patients' health. Strategies for rationally prescribing medicines with Ach properties to Malaysian elderly patients need to be improved and be recognised as an important public health priority.
Fulltext Investigation of Heat Transfer and Pressure Drop in Microchannel Heat Sink Using Al2O3 and ZrO2 Nanofluids

Khan MZU, Uddin E, Akbar B, Akram N, Naqvi AA, Sajid M, et al.

Nanomaterials (Basel), 2020 Sep 09;10(9).
PMID: 32916991 DOI: 10.3390/nano10091796

A new micro heat exchanger was analyzed using numerical formulation of conjugate heat transfer for single-phase fluid flow across copper microchannels. The flow across bent channels harnesses asymmetric laminar flow and dean vortices phenomena for heat transfer enhancement. The single-channel analysis was performed to select the bent channel aspect ratio by varying width and height between 35-300 μm for Reynolds number and base temperature magnitude range of 100-1000 and 320-370 K, respectively. The bent channel results demonstrate dean vortices phenomenon at the bend for Reynolds number of 500 and above. Thermal performance factor analysis shows an increase of 18% in comparison to straight channels of 200 μm width and height. Alumina nanoparticles at 1% and 3% concentration enhance the Nusselt number by an average of 10.4% and 23.7%, respectively, whereas zirconia enhances Nusselt number by 16% and 33.9% for same concentrations. On the other hand, thermal performance factor analysis shows a significant increase in pressure drop at high Reynolds number with 3% particle concentration. Using zirconia for nanofluid, Nusselt number of the bent multi-channel model is improved by an average of 18% for a 3% particle concentration as compared to bent channel with deionized water.
Fulltext Development of a Linear Acoustic Array for Aero-Acoustic Quantification of Camber-Bladed Vertical Axis Wind Turbine

Butt AH, Akbar B, Aslam J, Akram N, Soudagar MEM, García Márquez FP, et al.

Sensors (Basel), 2020 Oct 21;20(20).
PMID: 33096774 DOI: 10.3390/s20205954

Vertical axis wind turbines (VAWT) are a source of renewable energy and are used for both industrial and domestic purposes. The study of noise characteristics of a VAWT is an important performance parameter for the turbine. This study focuses on the development of a linear microphone array and measuring acoustic signals on a cambered five-bladed 45 W VAWT in an anechoic chamber at different tip speed ratios. The sound pressure level spectrum of VAWT shows that tonal noises such as blade passing frequencies dominate at lower frequencies whereas broadband noise corresponds to all audible ranges of frequencies. This study shows that the major portion of noise from the source is dominated by aerodynamic noises generated due to vortex generation and trailing edge serrations. The research also predicts that dynamic stall is evident in the lower Tip speed ratio (TSR) region making smaller TSR values unsuitable for a quiet VAWT. This paper compares the results of linear aeroacoustic array with a 128-MEMS acoustic camera with higher resolution. The study depicts a 3 dB margin between two systems at lower TSR values. The research approves the usage of the 8 mic linear array for small radius rotary machinery considering the results comparison with a NORSONIC camera and its resolution. These observations serve as a basis for noise reduction and blade optimization techniques.