An investigation into the efficiency of biocides in controlling algal biofouling in seawater industrial cooling towers

Al-Bloushi Mohammed,Saththasivam Jayaprakash,Jeong Sanghyun,Al-Refaie Abdullah,Raju S. Arun Kumar1,Choon NG Kim,Amy L. Gary,Leiknes TorOve 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.6

Biofouling in the open recirculating cooling water systems may cause biological corrosion, which can reduce the performance, increase the energy consumption and lower heat exchange resulting in reduced efficiency of the cooling tower (CT). Seawater CTs are prone to bio-fouled due to the presences of organic and inorganic compounds which act as nourishment for various microorganisms like (algae, fungi, and bacteria) for their growth under certain environmental conditions. The most commonly being used method to control the biofouling in CT is by addition of biocides such as chlorination. In this study, diatom and green algae were added to the CT basin and its viability was monitored in the recirculating cooling seawater loop as well as in the CT basin. Three different types of oxidizing biocides, namely chlorine, chlorine dioxide (Chlorine dioxide) and ozone, were tested by continuous addition in pilot-scale seawater CTs and it was operated continuously for 60 d. The results showed that all biocides were effective in keeping the biological growth to the minimum regardless of algal addition. Amongst the biocides, ozone could reduce 99% of total live cells of bacteria and algae, followed by Chlorine dioxide at 97%, while the conventional chlorine showed only 89% reduction in the bioactivities.

Protective efficacy of Coriandrum sativum seeds against arsenic induced toxicity in Swiss albino mice

Kumar Arun,Kumar Vikas,Akhouri Vivek,Kumar Ranjit,Ali Mohammad,Rashmi Tuhin,Chand Gyanendra Bahadur,Singh Sushil Kumar,Ghosh Ashok Kumar 한국독성학회 2022 Toxicological Research Vol.38 No.4

Arsenic poisoning in ground water is one of the most sensitive environmental pollutant causing serious pollution all over the world. Chronic arsenic exposure through drinking water to humans leads to major public health related issues. There have been very meagre studies which reported that, the plant constituents proved to exhibit protective effect from arsenicosis. Therefore, the present study aims to evaluate the protective efficacy of Coriandrum sativum seeds extract against sodium arsenite induced toxicity in Swiss albino mice. In the present study twenty-four male healthy Swiss albino mice (30 ± 5 g) were divided into four groups (n = 6), where the control group received normal diet and water; group II and group III treated with sodium arsenite (2 mg per kg body weight per day) for 2 and 4 weeks respectively. The group IV mice were administered with C.sativum seeds extract at the dose of 150 mg per kg body weight per day for 4 weeks upon sodium arsenite pretreated (2 mg/kg body weight for 4 weeks per day) mice. After the complete dose duration, all the treatment group animals were sacrificed same day for haematological, biochemical and histopathological study. In the arsenic treated mice, there were significant (p < 0.0001) changes in the serum levels of ALT, AST, ALP, urea, uric acid and creatinine as well as in the haematological parameters. In contrast, after the administration with C.sativum seeds extract upon arsenic pretreated mice, there was significant (p < 0.0001) improvement observed in the hepatic and renal biomarker parameters as well as haematological variables. In the arsenic intoxicated mice, after administration with C.sativum seeds extract there was significant (p < 0.0001) reduction in the arsenic concentration in blood, liver and kidney tissues as well as in the serum LPO levels. Furthermore, the histopathological study showed that, C.sativum seeds extract administrated group of mice significantly restored the liver and kidney at cellular level against arsenic induced toxicity. The entire study concludes that C.sativum seeds extract possesses the ameliorative effect against arsenic induced liver and kidney intoxication.

Ruptured mirror DACA aneurysm: A rare case report and review of literature

Deepak Kumar Singh,Prevesh Kumar Sharma,Arun Kumar Singh,Vipin Kumar Chand 대한뇌혈관외과학회 2023 Journal of Cerebrovascular and Endovascular Neuros Vol.25 No.3

Bilateral distal anterior cerebral artery (DACA) aneurysms also called “kissing aneurysms” or “mirror aneurysm” are extremely rare, accounting for only 0.2% of all intracranial aneurysms. There have only been a few examples of mirror DACA aneurysms reported in the literature. Here, we report a rare case of mirror DACA aneurysm in a middle aged female with its successful clipping. Patient was admitted with severe headache and altered sensorium. Computed tomography (CT) head was suggestive of anterior inter-hemispheric hematoma. Digital subtraction angiography (DSA) was done which was suggestive of two distal anterior cerebral artery aneurysms located at same anatomical position. It was treated through microsurgical clipping. Mirror image DACA aneurysms are rare occurrence. All patients with ruptured DACA aneurysms should have angiography with 3D reconstruction studies. This aids in determining the aneurysm’s morphology and planning treatment accordingly.

Oxidative Stress and Antioxidants in Disease and Cancer: A Review

Gupta, Rakesh Kumar,Patel, Amit Kumar,Shah, Niranjan,Choudhary, Arun Kumar,Jha, Uday Kant,Yadav, Uday Chandra,Gupta, Pavan Kumar,Pakuwal, Uttam Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Reactive oxygen species (ROS), highly reactive molecules, are produced by living organisms as a result of normal cellular metabolism and environmental factors, and can damage nucleic acids and proteins, thereby altering their functions. The human body has several mechanisms to counteract oxidative stress by producing antioxidants. A shift in the balance between oxidants and antioxidants in favor of oxidants is termed as "oxidative stress". Paradoxically, there is a large body of research demonstrating the general effect of oxidative stress on signaling pathways, less is known about the initial and direct regulation of signaling molecules by ROS, or what we term the "oxidative interface." This review focuses on the molecular mechanisms through which ROS directly interact with critical signaling molecules to initiate signaling in a broad variety of cellular processes, such as proliferation and survival (MAP kinases and PI3 kinase), ROS homeostasis, and antioxidant gene regulation (Ref-1 and Nrf-2). This review also deals with classification as well as mechanisms of formation of free radicals, examining their beneficial and deleterious effects on cellular activities and focusing on the potential role of antioxidants in preventing and repairing damage caused by oxidative stress. A discussion of the role of phytochemical antioxidants in oxidative stress, disease and the epigenome is included.

Synthesis and Photoluminescence of Silole Derivatives

Arun Kumar Sharma,Sung-Gi Lee,Sungyong Um,Bomin Cho,Honglae Sohn 조선대학교 기초과학연구원 2013 조선자연과학논문집 Vol.6 No.3

Synthesis and Photoluminescence of Silole Derivatives

Arun Kumar Sharma, Sung-Gi Lee, Sungyong Um, Bomin Cho, Honglae Sohn 조선대학교 기초과학연구원 2013 조선자연과학논문집 Vol.6 No.3

The syntheses of 9,9'-spiro-9-silabifluorene as well as 1,1-dichloro-1-silafluorene and 1,1-dimethyl-1- silafluorene through the formation of 2,2'-dibromobiphenyl have been emphasized with good yields. Their fluorescence spectra are obtained using photoluminescence spectrometer and assumed to be the precursors of the development of polymers.

Numerical Simulation of the Effect of Finite Diaphragm Rupture Process on Micro Shock Tube Flows

Arun Kumar R,Heuy Dong Kim 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5

Recent years have witnessed the use of micro shock tube in various engineering applications like micro combustion, micro propulsion, particle delivery systems etc. The flow characteristics occurring in the micro shock tube shows a considerable deviation from that of well established conventional macro shock tube due to very low Reynolds number and high Knudsen number effects. Also the diaphragm rupture process, which is considered to be instantaneous process in many of the conventional shock tubes, will be crucial for micro shock tubes in determining the near diaphragm flow field and shock formation. In the present study, an axi-symmetric CFD method has been applied to simulate the micro shock tube, with Maxwell’s slip velocity and temperature jump boundary conditions. The effects of finite diaphragm rupture process on the flow field and the shock formation was investigated, in detail. The results show that the shock strength attenuates rapidly as it propagates through micro shock tubes.

Weekly cisplatin or gemcitabine concomitant with radiation in the management of locally advanced carcinoma cervix: results from an observational study

Arun K Verma,Ashok Kumar Arya,Milind Kumar,Anuj Kumar,Sweety Gupta,DN Sharma,GK Rath 대한부인종양학회 2009 Journal of Gynecologic Oncology Vol.20 No.4

Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function. Objective: The use of non-platinum drugs in concurrent chemoradiation in carcinoma cervix has not been well explored and hence a two arm study was planned to compare the outcome of concomitant cisplatin or gemcitabine in locally advanced carcinoma cervix. Methods: Thirty six patients were evaluated in this study for response rates and complications. These patients were divided into two arms, sixteen patients in the cisplatin arm and twenty patients in the gemcitabine arm. Cisplatin and gemcitabine were given as i.v. infusion at doses of 40 mg/㎡ and 150 mg/㎡ respectively for five weeks concomitant with radiotherapy. All patients had received pelvic radiotherapy to a dose of 50 Gy/25 fraction/5 weeks by four field box technique followed by high-dose-rate brachytherapy (3 sessions, each of 7.5 Gy to point A). Results: Median follow up was of 10.4 months (range, 3 to 36 months) and 10.9 months (range, 2 to 49 months) in the cisplatin and gemcitabine arms, respectively. At first follow up, 68.8% in the cisplatin arm and 70% in the gemcitabine arm had achieved complete response (p=0.93). Similar response rates were noted in different stages in both arms. None of the patients except one developed grade 4 toxicity. Similar toxicity profiles were observed in both arms. Local disease control, distant disease free survival and overall survival was 68.8% vs. 70%, 93.8% vs. 85%, 68.8% vs. 60% in the cisplatin and gemcitabine arms, respectively. Conclusion: Weekly gemcitabine had similar disease control and tolerable toxicity profile with cisplatin. Gemcitabine may be used as an alternative to cisplatin in patients with compromised renal function.

CFD Study on Shock-Boundary Layer Interaction Characteristics over a Rough Wall

Arun Kumar R,Heuy Dong Kim 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5

Shock wave boundary layer interaction flows are often occurred in many high speed engineering devices. These interactions bring many salient features on the local as well as the whole flow field. In past few decades, much understanding has been obtained on the major characteristics of the shock wave boundary layer interaction such as boundary layer separation, reattachment, shock unsteadiness, the interaction length, etc. The shock boundary layer characteristics depends on many parameters like upstream Mach number, Reynolds number, boundary layer characteristics etc, which has been pointed out by many past studies. The surface roughness effect can significantly modify the shock boundary layer characteristics which have not been studied much in the past. For the present study a 2-D CFD study was carried out to simulate the experimental study of Inger and to explore the effect of surface roughness on the shock boundary layer interaction flow field such as separation point, interaction length etc. The accuracy of different turbulence model in predicting the flow physics were also compared. It can be observed that the omega based model predicts the shock interaction under roughness effect more accurately compared to the wall function based k-epsilon and Reynolds stress model. From the results it can also be observed that the upstream influence increases and the shock strength decreases as the wall surface roughness increases. The separation zone decreases with increase in surface roughness due to the reduction in shock strength.

Reductive dechlorination of trichloroethylene by polyvinylpyrrolidone stabilized nanoscale zerovalent iron particles with Ni

Kumar, Macharla Arun,Bae, Sungjun,Han, Seunghee,Chang, Yoonseok,Lee, Woojin Elsevier 2017 Journal of hazardous materials Vol.340 No.-

<P><B>Abstract</B></P> <P>We developed a novel stabilized nanoscale zerovalent iron (NZVI) particles with Ni using an electron conducting polymer, polyvinylpyrrolidone (PVP), to selectively dechlorinate trichloroethylene (TCE) to non-toxic intermediates. The size of the PVP stabilized NZVI-Ni ((PVP-NZVI-Ni), average diameter: ∼20nm) is smaller than that of bare NZVI (50–80nm) due to the prevention of agglomeration of the resultant iron particles by PVP. PVP-NZVI-Ni showed a complete removal of TCE in 1h with superior dechlorination kinetics (<I>k<SUB>obs</SUB> </I> =5.702h<SUP>−1</SUP>) and ethane selectivity (98%), while NZVI-Ni showed 5 times slower dechlorination kinetics (1.218h<SUP>−1</SUP>). Other PVP-NZVI-metals (i.e., Cu, Sn, Co, and Mn) also enhanced the TCE dechlorination, but they were much slower (<I>k<SUB>obs</SUB> </I> =0.024−0.411h<SUP>−1</SUP>) than that of PVP-NZVI-Ni. In column test, PVP-NZVI-Ni exhibited better mobility (95% of PVP-NZVI-Ni recovery in the eluent) than NZVI-Ni (1%). In addition, PVP-NZVI-Ni reductively transform TCE to ethane even under 10 cycles of repeated TCE dechlorination treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel NZVI catalyst was synthesized using polyvinylpyrrolidone (PVP) and Ni. </LI> <LI> Size of PVP-NZVI-Ni (20nm) is smaller than that of bare NZVI (50–80nm). </LI> <LI> PVP-NZVI-Ni showed a complete removal of TCE with superior dechlorination kinetics. </LI> <LI> PVP-NZVI-Ni exhibited better mobility than NZVI-Ni nanoparticles in column tests. </LI> <LI> PVP-NZVI-Ni showed a complete TCE removal up to 10 cycles without Ni release. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>