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Fulltext Heuristics for multiobjective optimization of two-sided assembly line systems

Jawahar N, Ponnambalam SG, Sivakumar K, Thangadurai V

ScientificWorldJournal, 2014;2014:458959.
PMID: 24790568 DOI: 10.1155/2014/458959

Products such as cars, trucks, and heavy machinery are assembled by two-sided assembly line. Assembly line balancing has significant impacts on the performance and productivity of flow line manufacturing systems and is an active research area for several decades. This paper addresses the line balancing problem of a two-sided assembly line in which the tasks are to be assigned at L side or R side or any one side (addressed as E). Two objectives, minimum number of workstations and minimum unbalance time among workstations, have been considered for balancing the assembly line. There are two approaches to solve multiobjective optimization problem: first approach combines all the objectives into a single composite function or moves all but one objective to the constraint set; second approach determines the Pareto optimal solution set. This paper proposes two heuristics to evolve optimal Pareto front for the TALBP under consideration: Enumerative Heuristic Algorithm (EHA) to handle problems of small and medium size and Simulated Annealing Algorithm (SAA) for large-sized problems. The proposed approaches are illustrated with example problems and their performances are compared with a set of test problems.
Fulltext Parapharyngeal and retropharyngeal abscess: anatomical complexity and etiology

Brito-Mutunayagam S, Chew YK, Sivakumar K, Prepageran N

Med J Malaysia, 2007 Dec;62(5):413-5.
PMID: 18705479 MyJurnal

The differential diagnoses of an abscess deep in the neck are retropharyngeal abscess and parapharyngeal abscess. We report a case each of these deep neck space abscesses to highlight their difference with emphasis on its anatomy and possible etiologies.
Evaluation of tracheal diameter after surgical tracheostomy

Sivakumar K, Prepageran N, Raman R

Am J Otolaryngol, 2006 Sep-Oct;27(5):310-3.
PMID: 16935173 DOI: 10.1016/j.amjoto.2006.01.007

PURPOSE: The aim of this study was to evaluate the narrowing of the trachea in head and neck surgical patients who had undergone elective tracheostomy.
MATERIALS AND METHODS: This is a prospective study. Twenty-five patients were included in this study. All these patients had a preoperative elective tracheotomy, preceding major head and neck surgery for head and neck malignancies. An x-ray of the lateral soft tissue neck was taken after a minimum of 6 weeks after the dissimulation of tracheotomy tube. Diameter of the trachea above the stoma (around 2 cm below the cricoid ring that can be clearly seen in lateral x-ray corresponding to the second tracheal ring) was taken as controls. Data were entered into a computer database and statistically analyzed using SPSS for Windows (version 12.0; SPSS, Chicago, Ill). In addition to descriptive statistics for all patients, inferential statistics were used to compare the 2 tracheal diameters across all patients and within the subgroups of men and women. Associations between outcome and other variables were evaluated statistically using an chi 2 test for the categorical data. Other parametric and nonparametric statistical tests were used when appropriate. Criterion for statistical significance was set at P < .05 (Student t test and 2-tailed test).
RESULTS: From this study, 92% (23/25) patients developed narrowing of trachea, all less than 50%. Very early decanulation of tracheotomy shows low or no narrowing at all. There is gradual narrowing in patients in whom dissimulations were performed after 14 days. Ethnicities of Indian decent (13/25) predominate in this study population. Male patients in this study have shorter decanulation period compared with female.
CONCLUSIONS: Elective surgical tracheotomy is a relatively safe procedure resulting in minimum asymptomatic tracheal stenosis.
Study site: University Malaya Medical Centre, Kuala Lumpur, Malaysia
Fulltext Investigations on the generation of oil-in-water (O/W) nanoemulsions through the combination of ultrasound and microchannel

Manickam S, Sivakumar K, Pang CH

Ultrason Sonochem, 2020 Dec;69:105258.
PMID: 32702637 DOI: 10.1016/j.ultsonch.2020.105258

O/W nanoemulsions are isotropic colloidal systems constituted of oil droplets dispersed in continuous aqueous media and stabilised by surfactant molecules. Nanoemulsions hold applications in more widespread technological domains, more crucially in the pharmaceutical industry. Innovative nanoemulsion-based drug delivery system has been suggested as a powerful alternative strategy through the useful means of encapsulating, protecting, and delivering the poorly water-soluble bioactive components. Consequently, there is a need to generate an emulsion with small and consistent droplets. Diverse studies acknowledged that ultrasonic cavitation is a feasible and energy-efficient method in making pharmaceutical-grade nanoemulsions. This method offers more notable improvements in terms of stability with a lower Ostwald ripening rate. Meanwhile, a microstructured reactor, for instance, microchannel, has further been realised as an innovative technology that facilitates combinatorial approaches with the acceleration of reaction, analysis, and measurement. The recent breakthrough that has been achieved is the controlled generation of fine and monodispersed multiple emulsions through microstructured reactors. The small inner dimensions of microchannel display properties such as short diffusion paths and high specific interfacial areas, which increase the mass and heat transfer rates. Hence, the combination of ultrasonic cavitation with microstructures (microchannel) provides process intensification of creating a smaller monodispersed nanoemulsion system. This investigation is vital as it will then facilitate the creation of new nanoemulsion based drug delivery system continuously. Following this, the fabrication of microchannel and setup of its combination with ultrasound was conducted in the generation of O/W nanoemulsion, as well as optimisation to analyse the effect of varied operating parameters on the mean droplet diameter and dispersity of the nanoemulsion generated, besides monitoring the stability of the nanoemulsion. Scanning transmission electron microscopy (STEM) images were also carried out for the droplet size measurements. In short, the outcomes of this study are encouraging, which necessitates further investigations to be carried out to advance a better understanding of coupling microchannel with ultrasound to produce pharmaceutical-grade nanoemulsions.
Bis[N,N-bis(2-hydroxyethyl)dithiocarbamato]dimethyltin(IV)

Ng SW, Yang Farina AA, Othman AH, Baba I, Sivakumar K, Fun HK

Acta Crystallogr C, 2000 Mar 15;56(Pt 3):E84-5.
PMID: 15263206

The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.S contact [3.0427 (6) A]. The molecules are linked into a linear chain by intermolecular O-H.O hydrogen bonds [O.O 2.646 (3) A].
Intention to reduce food waste: A study among Malaysians

Chun T'ing L, Moorthy K, Gunasaygaran N, Sek Li C, Omapathi D, Jia Yi H, et al.

J Air Waste Manag Assoc, 2021 07;71(7):890-905.
PMID: 33689567 DOI: 10.1080/10962247.2021.1900001

Malaysia, also known as a food haven, is currently facing an excessive food waste problem which poses a threat to the environment. The objective of this research is to study the factors that affect the behavioral intention of Malaysians to reduce food waste. This study employs the Theory of Planned Behavior (TPB) and the Norm Activation Model (NAM) to better understand the behavioral intention of Malaysians toward reducing food waste. A cross-sectional study was conducted, using 352 self-administered survey questionnaires. Data collected were analyzed through PLS-SEM analysis. The results show that awareness of consequences (AC) and ascription of responsibility (AR) influence personal norms, while attitude, perceived behavioral control, and personal norms (PN) have significant effect on behavioral intention (BI) to reduce food waste. Furthermore, PN partially mediates the relationship between AC and BI as well as AR and BI. This study offers critical insights which will benefit the Malaysian Government, Non-Governmental Organizations (NGOs), and other related parties in recognizing factors influencing the intention to reduce food waste which can be adopted to develop practical solutions to curb food waste in Malaysia.Implications: This study offers critical insights to the Malaysian Government, non-governmental organizations (NGOs), and other related parties in recognizing factors influencing the intention to reduce food waste which can be adopted to develop practical solutions to curb food waste in Malaysia.
Anatomical Classification and Posttreatment Remodeling Characteristics to Guide Management and Follow-Up of Neonates and Infants With Coronary Artery Fistula: A Multicenter Study From the Coronary Artery Fistula Registry

Gowda ST, Latson L, Sivakumar K, Hiremath G, Crystal M, Law M, et al.

Circ Cardiovasc Interv, 2021 12;14(12):e009750.
PMID: 34903033 DOI: 10.1161/CIRCINTERVENTIONS.120.009750

BACKGROUND: Coronary artery fistulas (CAFs) presenting in infancy are rare, and data regarding postclosure sequelae and follow-up are limited.
METHODS: A retrospective review of all the neonates and infants (<1 year) was conducted from the CAF registry for CAF treatment. The CAF type (proximal or distal), size, treatment method, and follow-up angiography were reviewed to assess outcomes and coronary remodeling.
RESULTS: Forty-eight patients were included from 20 centers. Of these, 30 were proximal and 18 had distal CAF; 39 were large, 7 medium, and 2 had small CAF. The median age and weight was 0.16 years (0.01-1) and 4.2 kg (1.7-10.6). Heart failure was noted in 28 of 48 (58%) patients. Transcatheter closure was performed in 24, surgical closure in 18, and 6 were observed medically. Procedural success was 92% and 94 % for transcatheter closure and surgical closure, respectively. Follow-up data were obtained in 34 of 48 (70%) at a median of 2.9 (0.1-18) years. Angiography to assess remodeling was available in 20 of 48 (41%). I. Optimal remodeling (n=10, 7 proximal and 3 distal CAF). II. Suboptimal remodeling (n=7) included (A) symptomatic coronary thrombosis (n=2, distal CAF), (B) asymptomatic coronary thrombosis (n=3, 1 proximal and 2 distal CAF), and (C) partial thrombosis with residual cul-de-sac (n=1, proximal CAF) and vessel irregularity with stenosis (n=1, distal CAF). Finally, (III) persistent coronary artery dilation (n=4). Antiplatelets and anticoagulation were used in 31 and 7 patients post-closure, respectively. Overall, 7 of 10 (70%) with proximal CAF had optimal remodeling, but 5 of 11 (45%) with distal CAF had suboptimal remodeling. Only 1 of 7 patients with suboptimal remodeling were on anticoagulation.
CONCLUSIONS: Neonates/infants with hemodynamically significant CAF can be treated by transcatheter or surgical closure with excellent procedural success. Patients with distal CAF are at higher risk for suboptimal remodeling. Postclosure anticoagulation and follow-up coronary anatomic evaluation are warranted.