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Applied chemometric approach in identification sources of air quality pattern in Selangor, Malaysia

Ang KH

Sains Malaysiana, 2018;47:471-479.

In recent years, Malaysia has experienced quite a few number of chronic air pollution problems and it has become a
major contributor to the deterioration of human health and ecosystems. This study aimed to assess the air quality data
and identify the pattern of air pollution sources using chemometric analysis through hierarchical cluster analysis (HCA),
discriminant analysis (DA), principal component analysis (PCA) and multiple linear regression analysis (MLR). The air
quality data from January 2016 until December 2016 was obtained from the Department of Environment Malaysia. Air
quality data from eight sampling stations in Selangor include the selected variables of nitrogen dioxide (NO2
), ozone (O3
),
sulfur dioxide (SO2
), carbon monoxide (CO) and particulate matter (PM10). The HCA resulted in three clusters, namely low
pollution source (LPS), moderate pollution source (MPS) and slightly high pollution source (SHPS). Meanwhile, DA resulted
in two and four variables for the forward stepwise mode and the backward stepwise mode, respectively. Through PCA,
it was identified that the main pollutants of LPS, MPS and SHPS came from industrial and vehicle emissions, agricultural
systems, residential factors and natural emission sources. Among the three models yielded from the MLR analysis, it was
found that SHPS is the most suitable model to be used for the prediction of Air Pollution Index. This study concluded that
a clearer review and practical design of air quality monitoring network would be beneficial for better management of
air pollution. The study also suggested that chemometric techniques have the ability to show significant information on
spatial variability for large and complex air quality data.

Matched MeSH terms: Linear Models
Artificial Light at Night and Cancer: Global Study

Al-Naggar RA, Anil Sh

Asian Pac J Cancer Prev, 2016 10 01;17(10):4661-4664.
PMID: 27892680

Background: Artificial light at night (ALAN) has been linked to increased risk of cancers in body sites like the breast
and colorectum. However exposure of ALAN as an environmental risk factor and its relation to cancers in humans has
never been studied in detail. Objective: To explore the association of ALAN with all forms of cancers in 158 countries.
Materials and Methods: An ecological study encompassing global data was conducted from January to June 2015,
with age-standardized rates (ASR) of cancers as the outcome measure. ALAN, in the protected areas, as the exposure
variable, was measured with reference to the Protected Area Light Pollution Indicator (PALI) and the Protected Area
Human Influence Indicator (PAHI). Pearson’s correlations were calculated for PALI and PAHI with ASR of cancers for
158 countries, adjusted for country populations, electricity consumption, air pollution, and total area covered by forest.
Stratified analysis was conducted according to the country income levels. Linear regression was applied to measure the
variation in cancers explained by PALI and PAHI. Results: PALI and PAHI were positively associated with ASR of all
forms of cancer, and also the four most common cancers (p < 0.05). These positive correlations remained statistically
significant for PAHI with all forms of cancer, lung, breast, and colorectal cancer after adjusting for confounders. Positive
associations of PALI and PAHI with cancers varied with income level of the individual countries. Variation in all forms
of cancers, and the four most common cancers explained by PALI and PAHI, ranged from 3.3 – 35.5%. Conclusion:
Artificial light at night is significantly correlated for all forms of cancer as well as lung, breast, colorectal, and prostate
cancers individually. Immediate measures should be taken to limit artificial light at night in the main cities around the
world and also inside houses.

Matched MeSH terms: Linear Models
Fulltext Aggression in adolescents: the biopsychosocial predictors

Fatimah Ahmad Fauzi, Nor Afiah Mohd Zulkefli, Anisah Baharom

Malaysian Journal of Medicine and Health Sciences, 2019;15(104):15-15.
MyJurnal

Introduction: Adolescent aggression has become a serious public health problem with the escalating juvenile cases and violence among secondary school students by inflicting harm to others. The objective of this study was to deter-mine the biopsychosocial predictors of adolescent aggression among Form Four students in Hulu Langat. Methods: Cross-sectional study was conducted by proportionate population sampling method among Form Four students from all public secondary schools in Hulu Langat. Pre-tested questionnaires distributed to measure students’ ag-gression, demographic (ethnicity, family income), biological (sex, head injury, nutritional deficiency, breakfast skip-ping), psychological (attitude towards aggression, normative beliefs to aggression, personality trait, and emotional intelligence), and social factors (family environment, single parent status, domestic violence, peer deviant affiliation, alcohol, smoking, and substance abuse). Data was analysed using multivariate analysis to determine the significant predictors. Results: 480 students from four randomly selected schools participated in the study with response rate of 96.5%. The median aggression score was low, which was 23.00 (IQR=12.00). From simple linear regression, 15 factors had significant relationship with adolescent aggression. The predictors of adolescent aggression were lower family income, Malay ethnicity, nutritional deficiency, attitude towards aggression, and peer deviant affiliation (F [8, 244] =15.980, p-value

Matched MeSH terms: Linear Models
Fulltext Prediction and explanation on adolescent aggression: a study protocol

Fatimah Ahmad Fauzi, Nor Afiah Mohd Zulkefli, Anisah Baharom

Malaysian Journal of Medicine and Health Sciences, 2020;16(1):106-114.
MyJurnal

Introduction: Adolescent aggression is an important public health concern with escalating prevalence of juvenile cases and violence among these age groups including robbery, homicide, and gang fights. The objectives of this study protocol are to determine the biopsychosocial predictors and explore the contextual factors of adolescent ag- gression among secondary school students in Hulu Langat. Methods: Explanatory mixed method study design will be used, consist of quantitative cross-sectional study followed by basic qualitative study. Proportionate population sampling among Form 4 secondary school students from selected public secondary schools in Hulu Langat will be executed. Questionnaires will be distributed to 481 students on aggression as the dependent variable, and several independent variables: demographic (ethnicity, family income), biological (sex, head injury, nutritional deficiency, breakfast skipping), psychological (attitude and normative beliefs, personality trait, emotional intelligence), and so- cial factors (family environment, single parent status, domestic violence, peer deviant affiliation, alcohol, smoking, substance abuse). Subsequently, participants with moderate to high aggression scores will be further explored on the contextual factors of adolescent aggression by in-depth interview. Multiple linear regression will be executed using SPSS to determine significant predictors whereas thematic analysis will be applied for qualitative data analysis on the context of adolescent aggression. Both findings will be further integrated and discussed to give comprehensive description on the phenomena. Conclusion: Better knowledge and understanding on adolescent aggression may generate new framework to drive more effective preventive strategies and unravel adolescent aggressive related Pub- lic Health problems.

Matched MeSH terms: Linear Models
Exhaled carbon monoxide levels among Malaysian male smokers with nicotine dependence

Guan NC, Ann AY

Southeast Asian J. Trop. Med. Public Health, 2012 Jan;43(1):212-8.
PMID: 23082572

We studied the use of exhaled carbon monoxide (CO) to identify nicotine dependence among adult Malaysian male smokers. We conducted a cross-sectional study among 107 male smoking staff at a university hospital. We measured their exhaled CO using a piCO+ Smokerlyzer and diagnosed nicotine dependence using a Mini-International Neuropsychiatric Interview (MINI). The optimal cut-off value for exhaled CO was determined. The correlation between exhaled CO level and the Fagerstrom Test for Nicotine Dependence (FTND) was also assessed. The mean exhaled CO level among subjects with nicotine dependence (15.78 ppm) was significantly higher than subjects without nicotine dependence (9.62 ppm). The cut-off value used to identify smokers with nicotine dependence was set at 10 ppm (specificity = 0.721, sensitivity = 0.731, positive predictive value = 0.817 and negative predictive value = 0.617). Psychometric properties were stable with various durations of smoking. Exhaled CO correlated positively with FTND scores (Pearson's rho = 0.398, p = 0.01). Our findings show exhaled CO can be used to identify nicotine dependence among adult Malaysian male smokers.

Matched MeSH terms: Linear Models
QbD-Driven Development and Validation of Liquid Chromatography Tandem Mass Spectrometric Method for the Quantitation of Sildenafil in Human Plasma

Hasnain MS, Ansari SA, Rao S, Tabish M, Singh M, Abdullah MS, et al.

J Chromatogr Sci, 2017 Jul 01;55(6):587-594.
PMID: 28335023 DOI: 10.1093/chromsci/bmx010

The present work was employing the Quality by Design approach for the development and validation of a LC-MS-MS method to support the clinical advancement in determination of sildenafil in human plasma using lorazepam as an internal standard. Sample preparation involved solid phase extraction and calibration range observed between 3 and 1,700 ng/mL. The method was systematically optimized by employing Box-Behnken design and used mobile phase flow rate, pH and composition of mobile phase as the critical factors, and assessing the design for retention time and peak area as the responses. A substantial decrease in the variability associated with the method variables was shown in optimization studies and confirmed enhanced method robustness. The present studies revealed that developed method achieves all the regulatory requirements for linearity, accuracy, precision, selectivity, sensitivity and stability for the determination of sildenafil in human plasma. There was not any significant change in the stability of the drug shown by stability studies, performed in human plasma through freeze-thaw cycles, bench-top stability, short-term stability, long-term stability and auto sampler stability. In short, this method shows satisfactory results for the analysis of sildenafil in human plasma and possesses high degree of utility in pharmacokinetic and bioequivalence studies.

Matched MeSH terms: Linear Models
Fulltext Higher Dietary Cost Is Associated with Higher Diet Quality: A Cross-Sectional Study among Selected Malaysian Adults

Pondor I, Gan WY, Appannah G

Nutrients, 2017 Sep 16;9(9).
PMID: 28926947 DOI: 10.3390/nu9091028

Food price is a determining factor of food choices; however its relationship with diet quality is unclear in Malaysia. This study aimed to examine socio-economic characteristics and daily dietary cost (DDC) in relation to diet quality in the state of Selangor, Malaysia. Dietary intake was assessed using a Food Frequency Questionnaire (FFQ) and diet quality was estimated using a Malaysian Healthy Eating Index (M-HEI). DDC in Malaysian Ringgit (RM) was calculated from dietary intake and national food prices. Linear regression models were fitted to determine associations between DDC and M-HEI scores and predictors of diet quality. The mean M-HEI score of respondents was 61.31 ± 10.88 and energy adjusted DDC was RM10.71/2000 kcal (USD 2.49). The highest quintile of adjusted DDC had higher M-HEI scores for all respondents (Q1: 57.14 ± 10.07 versus Q5: 63.26 ± 11.54, p = 0.001). There were also positive associations between DDC and M-HEI scores for fruits (p < 0.001) and vegetables (p = 0.017) for all respondents. Predictors of diet quality included carbohydrate (β = 0290; p < 0.001) and fat intakes (β = -0.242; p < 0.001) and energy adjusted DDC (β = 0.196; p < 0.001). Higher dietary cost is associated with healthy eating among Malaysian adults.

Matched MeSH terms: Linear Models
Effects of soil chemical properties and seasonality on mycorrhizal status of prickly pear (opuntia ficus-indica) planted in hot arid Steppe rangelands

Souad Neffar, Haroun Chenchouni, Arifa Beddiar

Sains Malaysiana, 2015;44:671-680.

Mycorrhizal fungi are an essential component to consider for better management of soil fertility, particularly in
degraded rangelands of drylands. The present article presents a field survey of colonization and intensity of arbuscular
mycorrhizal fungi (AMF) on prickly pear (Opuntia ficus-indica) roots from young (5 years old) and old (more than 20
years) plantations. The results observed were explained by seasonality and edaphic factors. Prickly pear roots showed
a mycorrhizal frequency (F%) up to 100% of colonization and a mycorrhizal intensity (M%) that may exceed 70%.
According to ANOVAs, both F% and M% varied significantly between Prickly pear plantation ages, but only M% between
seasons. The Generalized linear model showed that edaphic factors have no effect on the variation of F%. However
the statistical model showed that M% were significantly influenced by active CaCO3
, organic matter, carbon, nitrogen,
phosphorus contents and C/N. Our findings highlight the importance of mycorrhization in rehabilitation programs of
degraded rangelands by prickly pear plantations in semiarid and arid lands, particularly during early plant ages and
under environmental abiotic stresses such as climate and soil type.

Matched MeSH terms: Linear Models
Water quality assessment and analysis of spatial patterns and temporal trends

Gazzaz NM, Yusoff MK, Juahir H, Ramli MF, Aris AZ

Water Environ Res, 2013 Aug;85(8):751-66.
PMID: 24003601

This study investigated relationships of a water quality index (WQI) with multiple water quality variables (WQVs), explored variability in water quality over time and space, and established linear and non-linear models predictive of WQI from raw WQVs. Data were processed using Spearman's rank correlation analysis, multiple linear regression, and artificial neural network modeling. Correlation analysis indicated that from a temporal perspective, the WQI, temperature, and zinc, arsenic, chemical oxygen demand, sodium, and dissolved oxygen concentrations increased, whereas turbidity and suspended solids, total solids, nitrate nitrogen (NO3-N), and biochemical oxygen demand concentrations decreased with year. From a spatial perspective, an increase with distance of the sampling station from the headwater was exhibited by 10 WQVs: magnesium, calcium, dissolved solids, electrical conductivity, temperature, NO3-N, arsenic, chloride, potassium, and sodium. At the same time, the WQI; Escherichia coli bacteria counts; and suspended solids, total solids, and dissolved oxygen concentrations decreased with distance from the headwater. Lastly, regression and artificial neural network models with high prediction powers (81.2% and 91.4%, respectively) were developed and are discussed.

Matched MeSH terms: Linear Models
Fulltext Novel calcium infusion regimen after parathyroidectomy for renal hyperparathyroidism

Tan JH, Tan HC, Loke SC, Arulanantham SA

Nephrology (Carlton), 2017 Apr;22(4):308-315.
PMID: 26952689 DOI: 10.1111/nep.12761

AIM: Calcium infusion is used after parathyroid surgery for renal hyperparathyroidism to treat postoperative hypocalcaemia. We compared a new infusion regimen to one commonly used in Malaysia based on 2003 K/DOQI guidelines.
METHODS: Retrospective data on serum calcium and infusion rates was collected from 2011-2015. The relationship between peak calcium efflux (PER) and time was determined using a scatterplot and linear regression. A comparison between regimens was made based on treatment efficacy (hypocalcaemia duration, total infusion amount and time) and calcium excursions (outside target range, peak and trough calcium) using bar charts and an unpaired t-test.
RESULTS: Fifty-one and 34 patients on the original and new regimens respectively were included. Mean PER was lower (2.16 vs 2.56 mmol/h; P = 0.03) and occurred earlier (17.6 vs 23.2 h; P = 0.13) for the new regimen. Both scatterplot and regression showed a large correlation between PER and time (R-square 0.64, SE 1.53, P

Matched MeSH terms: Linear Models
LC-MS/MS quantitation of antimalarial drug piperaquine and metabolites in human plasma

Aziz MY, Hoffmann KJ, Ashton M

J Chromatogr B Analyt Technol Biomed Life Sci, 2017 Sep 15;1063:253-258.
PMID: 28863865 DOI: 10.1016/j.jchromb.2017.06.035

PURPOSE: This study aimed to develop a sensitive, quantitative assay for the antimalarial piperaquine (PQ) and its metabolites M1 and M2 in human plasma.
RESULTS: Analytes were gradiently separated on a C18 column and detected with a Sciex API 4000 MS/MS with an ESI source operated in the positive ion mode with deuterated PQ as internal standard. The response was linear in the range 3.9-2508nM with a runtime of 7.0min per sample. The method was applied to clinical samples from healthy volunteers.
CONCLUSION: This LC-MS/MS method for the simultaneous quantitation of PQ and two of its metabolites in plasma may prove helpful for assessment of metabolite safety issues in vivo.

Matched MeSH terms: Linear Models
Fulltext Association of the lupus low disease activity state (LLDAS) with health-related quality of life in a multinational prospective study

Golder V, Kandane-Rathnayake R, Hoi AY, Huq M, Louthrenoo W, An Y, et al.

Arthritis Res Ther, 2017 03 20;19(1):62.
PMID: 28320433 DOI: 10.1186/s13075-017-1256-6

BACKGROUND: Systemic lupus erythematosus (SLE) is associated with significant impairment of health-related quality of life (HR-QoL). Recently, meeting a definition of a lupus low disease activity state (LLDAS), analogous to low disease activity in rheumatoid arthritis, was preliminarily validated as associated with protection from damage accrual. The LLDAS definition has not been previously evaluated for association with patient-reported outcomes. The objective of this study was to determine whether LLDAS is associated with better HR-QoL, and examine predictors of HR-QoL, in a large multiethnic, multinational cohort of patients with SLE.
METHODS: HR-QoL was measured using the Medical Outcomes Study 36-item short form health survey (SF-36v2) in a prospective study of 1422 patients. Disease status was measured using the SLE disease activity index (SLEDAI-2 K), physician global assessment (PGA) and LLDAS.
RESULTS: Significant differences in SF-36 domain scores were found between patients stratified by ethnic group, education level and damage score, and with the presence of active musculoskeletal or cutaneous manifestations. In multiple linear regression analysis, Asian ethnicity (p

Matched MeSH terms: Linear Models
Fulltext Aqueous Extract of Nypa fruticans Wurmb. Vinegar Alleviates Postprandial Hyperglycemia in Normoglycemic Rats

Yusoff NA, Ahmad M, Al-Hindi B, Widyawati T, Yam MF, Mahmud R, et al.

Nutrients, 2015 Aug;7(8):7012-26.
PMID: 26308046 DOI: 10.3390/nu7085320

Nypa fruticans Wurmb. vinegar, commonly known as nipa palm vinegar (NPV) has been used as a folklore medicine among the Malay community to treat diabetes. Early work has shown that aqueous extract (AE) of NPV exerts a potent antihyperglycemic effect. Thus, this study is conducted to evaluate the effect of AE on postprandial hyperglycemia in an attempt to understand its mechanism of antidiabetic action. AE were tested via in vitro intestinal glucose absorption, in vivo carbohydrate tolerance tests and spectrophotometric enzyme inhibition assays. One mg/mL of AE showed a comparable outcome to the use of phloridzin (1 mM) in vitro as it delayed glucose absorption through isolated rat jejunum more effectively than acarbose (1 mg/mL). Further in vivo confirmatory tests showed AE (500 mg/kg) to cause a significant suppression in postprandial hyperglycemia 30 min following respective glucose (2 g/kg), sucrose (4 g/kg) and starch (3 g/kg) loadings in normal rats, compared to the control group. Conversely, in spectrophotometric enzymatic assays, AE showed rather a weak inhibitory activity against both α-glucosidase and α-amylase when compared with acarbose. The findings suggested that NPV exerts its anti-diabetic effect by delaying carbohydrate absorption from the small intestine through selective inhibition of intestinal glucose transporters, therefore suppressing postprandial hyperglycemia.

Matched MeSH terms: Linear Models
Fulltext Health-related quality of life and its predictors among adults living with HIV/AIDS and receiving antiretroviral therapy in Pakistan

Ahmed A, Saqlain M, Bashir N, Dujaili J, Hashmi F, Mazhar F, et al.

Qual Life Res, 2021 Jun;30(6):1653-1664.
PMID: 33582967 DOI: 10.1007/s11136-021-02771-y

BACKGROUND: Health-related quality of life (HRQoL) is considered to be the fourth 90 of UNAIDS 90-90-90 target to monitor the effects of combination antiretroviral therapy (ART). ART has significantly increased the life expectancy of people living with HIV/AIDS (PLWHA). However, the impact of chronic infection on HRQoL remains unclear, while factors influencing the HRQoL may vary from one country to another. The current study aimed to assess HRQoL and its associated factors among PLWHA receiving ART in Pakistan.
METHODS: A cross-sectional descriptive study was conducted among PLWHA attending an ART centre of a tertiary care hospital in Islamabad, Pakistan. HRQoL was assessed using a validated Urdu version of EuroQol 5 dimensions 3 level (EQ-5D-3L) and its Visual Analogue Scale (EQ-VAS).
RESULTS: Of the 602 patients included in the analyses, 59.5% (n = 358) reported no impairment in self-care, while 63.1% (n = 380) were extremely anxious/depressed. The overall mean EQ-5D utility score and visual analogue scale (EQ-VAS) score were 0.388 (SD: 0.41) and 66.20 (SD: 17.22), respectively. Multivariate linear regression analysis revealed that the factors significantly associated with HRQoL were: female gender; age > 50 years; having primary and secondary education; > 1 year since HIV diagnosis; HIV serostatus AIDS-converted; higher CD 4 T lymphocytes count; detectable viral load; and increased time to ART.
CONCLUSIONS: The current findings have shown that PLWHA in Pakistan adherent to ART had a good overall HRQoL, though with significantly higher depression. Some of the factors identified are amenable to institution-based interventions while mitigating depression to enhance the HRQoL of PLWHA in Pakistan. The HRQoL determined in this study could be useful for future economic evaluation studies for ART and in designing future interventions.

Matched MeSH terms: Linear Models
Applying a data duplication technique in linear regression analysis of waiting time to pregnancy

Awang H

J Biosoc Sci, 2005 Jul;37(4):471-9.
PMID: 16082858

This analysis demonstrates the application of a data duplication technique in linear regression with censored observations of the waiting time to third pregnancy ending in two outcome types, using data from Malaysia. The linear model not only confirmed the results obtained by the Cox proportional hazards model, but also identified two additional significant factors. The method provides a useful alternative when Cox proportionality assumption of the hazards is violated.

Matched MeSH terms: Linear Models*
Determinants of waiting time to third pregnancy using censored linear regression

Awang H

J Biosoc Sci, 2003 Jan;35(1):59-70.
PMID: 12537156

The intervals between pregnancies have important effects on fertility and maternal and infant health outcomes. This study uses linear regression with censored observation to assess the determinants of the waiting time to third pregnancy. The analysis is applied to data from the Second Malaysian Family Life Survey consisting of 1172 women who had their second delivery ending in a live birth. Contraceptive use, age of the woman, duration of breast-feeding, length of previous pregnancy interval and education of the woman all affect the waiting time to third pregnancy significantly.

Matched MeSH terms: Linear Models*
Fulltext A Quantum Chemical and Statistical Study of Cytotoxic Activity of Compounds Isolated from Curcuma zedoaria

Hamdi OA, Anouar el H, Shilpi JA, Trabolsy ZB, Zain SB, Zakaria NS, et al.

Int J Mol Sci, 2015 Apr 27;16(5):9450-68.
PMID: 25923077 DOI: 10.3390/ijms16059450

A series of 21 compounds isolated from Curcuma zedoaria was subjected to cytotoxicity test against MCF7; Ca Ski; PC3 and HT-29 cancer cell lines; and a normal HUVEC cell line. To rationalize the structure-activity relationships of the isolated compounds; a set of electronic; steric and hydrophobic descriptors were calculated using density functional theory (DFT) method. Statistical analyses were carried out using simple and multiple linear regressions (SLR; MLR); principal component analysis (PCA); and hierarchical cluster analysis (HCA). SLR analyses showed that the cytotoxicity of the isolated compounds against a given cell line depend on certain descriptors; and the corresponding correlation coefficients (R2) vary from 0%-55%. MLR results revealed that the best models can be achieved with a limited number of specific descriptors applicable for compounds having a similar basic skeleton. Based on PCA; HCA and MLR analyses; active compounds were classified into subgroups; which was in agreement with the cell based cytotoxicity assay.

Matched MeSH terms: Linear Models
Multiple linear regression and regression with time series error models in forecasting PM10 concentrations in Peninsular Malaysia

Ng KY, Awang N

Environ Monit Assess, 2018 Jan 06;190(2):63.
PMID: 29306973 DOI: 10.1007/s10661-017-6419-z

Frequent haze occurrences in Malaysia have made the management of PM10 (particulate matter with aerodynamic less than 10 μm) pollution a critical task. This requires knowledge on factors associating with PM10 variation and good forecast of PM10 concentrations. Hence, this paper demonstrates the prediction of 1-day-ahead daily average PM10 concentrations based on predictor variables including meteorological parameters and gaseous pollutants. Three different models were built. They were multiple linear regression (MLR) model with lagged predictor variables (MLR1), MLR model with lagged predictor variables and PM10 concentrations (MLR2) and regression with time series error (RTSE) model. The findings revealed that humidity, temperature, wind speed, wind direction, carbon monoxide and ozone were the main factors explaining the PM10 variation in Peninsular Malaysia. Comparison among the three models showed that MLR2 model was on a same level with RTSE model in terms of forecasting accuracy, while MLR1 model was the worst.

Matched MeSH terms: Linear Models*
High-dimensional QSAR modelling using penalized linear regression model with L1/2-norm

Algamal ZY, Lee MH, Al-Fakih AM, Aziz M

SAR QSAR Environ Res, 2016 Sep;27(9):703-19.
PMID: 27628959 DOI: 10.1080/1062936X.2016.1228696

In high-dimensional quantitative structure-activity relationship (QSAR) modelling, penalization methods have been a popular choice to simultaneously address molecular descriptor selection and QSAR model estimation. In this study, a penalized linear regression model with L1/2-norm is proposed. Furthermore, the local linear approximation algorithm is utilized to avoid the non-convexity of the proposed method. The potential applicability of the proposed method is tested on several benchmark data sets. Compared with other commonly used penalized methods, the proposed method can not only obtain the best predictive ability, but also provide an easily interpretable QSAR model. In addition, it is noteworthy that the results obtained in terms of applicability domain and Y-randomization test provide an efficient and a robust QSAR model. It is evident from the results that the proposed method may possibly be a promising penalized method in the field of computational chemistry research, especially when the number of molecular descriptors exceeds the number of compounds.

Matched MeSH terms: Linear Models*
Fulltext Cantilever Beam with a Single Fiber Bragg Grating to Measure Temperature and Transversal Force Simultaneously

Abushagur AAG, Arsad N, Bakar AAA

Sensors (Basel), 2021 Mar 12;21(6).
PMID: 33809028 DOI: 10.3390/s21062002

This work investigates a new interrogation method of a fiber Bragg grating (FBG) sensor based on longer and shorter wavelengths to distinguish between transversal forces and temperature variations. Calibration experiments were carried out to examine the sensor's repeatability in response to the transversal forces and temperature changes. An automated calibration system was developed for the sensor's characterization, calibration, and repeatability testing. Experimental results showed that the FBG sensor can provide sensor repeatability of 13.21 pm and 17.015 pm for longer and shorter wavelengths, respectively. The obtained calibration coefficients expressed in the linear model using the matrix enabled the sensor to provide accurate predictions for both measurements. Analysis of the calibration and experiment results implied improvements for future work. Overall, the new interrogation method demonstrated the potential to employ the FBG sensing technique where discrimination between two/three measurands is needed.

Matched MeSH terms: Linear Models

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