bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of Two Paediatric Rotary Systems: Kedo-SG Blue™ and Prime Pedo™ Files in Primary Mandibular Molars: A Randomised Clinical Trial
Authors: Jeepalyam Saranya , Nirmala SVSG , Nuvvula Sivakumar
Published: January 2024

Introduction: The success of root canal procedures depends on cleaning and shaping of canals. There are several instrumentation techniques available for root canal preparation. Recently, exclusive rotary file systems called Kedo-SG Blue and Prime-Pedo have been introduced for root canal preparation in primary teeth. The inherent flexibility of these files allows them to preserve the anatomy of curved canals in primary molars. Aim: To compare the instrumentation time, obturation time, and quality of obturation using two paediatric rotary file systems, KedoSG BlueTM and Prime-PedoTM, in mandibular primary molars. Materials and Methods: A randomised clinical trial was conducted in the outpatient Department of Paediatric and Preventive Dentistry, Narayana Dental College and Hospital, Nellore Andhra Pradesh, India, from February 1, 2019 to January 20, 2020. Fifty primary molars with necrotic pulp were included and randomly divided into two groups, with 25 teeth in each group. Group 1 and Group 2 were instrumented with Kedo-SG BlueTM and Prime-PedoTM, respectively. The time taken for instrumentation and obturation was noted in minutes, and the quality of root canal filling was recorded as optimal, underfilled, or overfilled. The data were statistically analysed using an independent Student’s t-test for time measurements and a Chi-square test for the quality of obturation. Results: There was a statistically significant difference in instrumentation time and obturation time between the two groups (p-value=0.009; 0.011). The Kedo-SG BlueTM rotary system showed a better quality of obturation compared to the Prime-PedoTM rotary system, although the difference was not statistically significant (p-value=0.22). Conclusion: The Kedo-SG BlueTM rotary system demonstrated shorter instrumentation and obturation times, as well as a higher number of optimally filled canals compared to the Prime-PedoTM rotary system. Therefore, the Kedo-SG BlueTM rotary system exhibited better clinical performance in primary molars than the Prime-PedoTM rotary system.
Association between Nocturnal Hypoxemia and COPD Severity: A Cross-sectional Study
Authors: Raman Rohan , Khound Nilom , Sarmah Kripesh Ranjan , Nair Gayatri S , Sharma Bhuwan
Published: January 2024

Introduction: Globally, Chronic Obstructive Pulmonary Disease (COPD) is the third most common cause of mortality. More than 80% of these fatalities happened in low- and middleincome nations. Transient desaturation during sleep occurs in healthy persons during Rapid Eye Movement (REM) sleep. This phenomenon is aggravated in COPD patients. As Nocturnal Desaturation (NOD) in COPD has been suggested to increase mortality, its early identification will aid in early initiation of treatment and prevention of associated complications. Aim: To estimate the prevalence of nocturnal hypoxemia in COPD and determine its association with COPD severity. Materials and Methods: A cross-sectional study was carried out at the Department of General Medicine, Apollo Hospitals, Guwahati, Assam, India during January to December 2021 involving 100 patients who had COPD symptoms. Continuous oxygen saturation monitoring with transcutaneous finger probe was done for the entire duration of sleep at night. Patients whose oxygen saturation falls below 90% for at least 30% of recording time in sleep were classified as desaturators. Statistical Package for Social Sciences (SPSS) Version 26.0 was used for data analysis. Using the Chi-square test, the relationship between the qualitative variables was evaluated. The Mann-Whitney test or the unpaired t-test was used to analyse the quantitative data between the two groups. A p-value of less than 0.05 was considered significant. Results: Prevalence of NOD among cases of COPD was observed as 26% in present study. A significant association was observed between presence of NOD in COPD cases with severity of COPD and with desaturation in 6-Minute Walk Test (6-MWT) (p<0.01). Severe cases had a prevalence of NOD as 65% as compared to 28.2% and 4.9% in moderate and mild cases respectively (p<0.01). A total of 61.9% cases with desaturation during 6-MWT showed NOD as compared to 38.1% without desaturation (p<0.01). Conclusion: One fourth of the normoxemic COPD patients had significant NOD. NOD episodes were observed to be positively associated with increasing severity of COPD. Assessing variations in oxygen saturation during a 6-MWT can be helpful in identifying COPD patients who may be at risk for severe night time desaturation.
A Review of Silo Temperature Field Studies
Authors: Zhang Zijie
Published: January 2024

Silo is a large thin-walled structure, due to the operation period will be affected by different temperatures, such as sunshine temperature difference, seasonal temperature difference and the temperature difference between inside and outside the silo wall, of which the most influential is the sunshine temperature difference, silo due to the unevenness of the temperature distribution is prone to stress concentration and more likely to occur damage. This paper briefly introduces the three-dimensional heat transfer theory and ASHRAE solar radiation model, and discusses in detail the research progress of different experts and scholars at China and abroad on the temperature effect of silos. Finally, it is concluded that there are fewer temperature regulations in China codes, and there is a need to develop a perfect temperature theory to prevent silos from damage caused by temperature inhomogeneity.
An Assessment of the Viability of Haematological and Haemostatic Parameters of Blood under certain Storage Conditions at the Rivers State University Teaching Hospital Blood Bank in Port Harcourt, Nigeria
Authors: Nkabari Nwika Goodnews , Mgbeoma Eze Evelyn , Obioma Azuonwu , Ken-Ezihuo Stella U.
Published: January 2024

Introduction: Despite significant advances in transfusion medicine, concerns about the inherent risks of blood transfusion persist, even under optimal temperature and duration of storage. This makes the evaluation of blood viability a global task (1). Maintenance of adequate temperature is considered a key factor in the viability and quality of stored blood in healthcare institutions. Evaluating the haematological and haemostatic functionality of blood elements at different storage temperature and duration is therefore imperative for improving patient care and resource utilization in Rivers State University Teaching Hospital (RSUTH) blood bank in Port Harcourt.

Methods: In this cohort study design, a total of sixteen (16) male and female blood donors in equal proportion of sex and ABO blood groups were randomly selected from the Port Harcourt blood donors' population and recruited as study subjects for this research. A well-structured questionnaire and the immunoassays were used to assess the donors' health and serological status respectively. Also the sample obtained were analayzed by automation and data statistically analyzed using ANOVA.

Results: The results of this study shows a statistically significant decrease in white blood cell count from 4.93×109/L ± 0.33 to 2.79×109/L ± 1.68 (p=0.00) and platelet count from 227.38×109/L ± 32.17 to 153.75×109/L ± 58.39 (p=0.00) at day 7. Also, a significant decrease in platelet count from 227.38×109/L ± 32.17 to 141.50±60.92 at day 14. A significant decrease in Fibrinogen from 340.75mg/L±18.69 to 281.2575 mg/L ±46.41 at day 1 and day 14 respectively, and rise in PT and aPTT from 17.02s ±1.28 to 24.31s ±6.67 and 41.25s±3.23 to 46.63s±6.28 at day 14th to day 21 respectively (p=0.00).

Conclusion and Implications for Translation: Pooled plasma at 4-60C contain clinically significant amount of coagulation factors up to day 21 in storage. The WBC and platelet is lost within seven day of storage at 4-60C. Lower temperatures, especially freezing at -60°C accelerate the loss of haematological viability of blood especially the depletion of white blood cells and platelets (p=0.00). Antihaemophilic factor and fibrinogen is maintained in FFP at 180 day in storage at -600C.
Characterization of Dominant Hydrogeochemical Processes in Groundwater in Onitsha Area, Southeastern Nigeria
Authors: Okolo C. M.  , Onuora I. D.  , Madu F. M.  , Obasi P. N.
Published: January 2024

The characterization of the dominant hydrogeochemical processes in groundwater in Onitsha area, southeastern Nigeria was carried out. This is to identify the dominant mechanisms responsible for the evolution and the chemical composition of the water sources. A total of fifteen (15) groundwater samples were collected from different locations in the study area in August 2022 and these samples were subjected to chemical analysis using standard methods. The results indicated that the water quality parameters were within the World Health Organization acceptable limits for drinking quality although turbidity in six of the samples exceeded the guideline values. The hydrochemical facies were determined using various plots. Piper diagrams indicated that Ca2+ - Mg2+ - Cl- – SO42- was the dominant facies with Ca2+ and Cl- as the dominant ions. The Durov diagram indicate recharge water in limestone and sandstone aquifers and influenced by important ion exchange reactions. However, the Gibbs plots mainly plotted in the rock dominance zone indicating that the major processes controlling water chemistry in the study area were water-rock interaction and dissolution of rock minerals. The ionic ratio plots were employed to determine the mechanisms and reactions prevalent in the study area that influenced the water chemistry. Na/Cl plot indicated that the excess of Cl- over Na+ was balanced by Ca2+ and Mg2+ while the depletion of Na+ with respect to Clindicated ion exchange reaction which could be attributed to silicate weathering confirming the Na/Cl plot conclusions. The relative abundance of anionic facies shows that Cl- + SO42- were more abundant than HCO3- and the plot of Ca2+ + Mg2+ ions against HCO3- ions depict samples with excess Ca2+ + Mg2+. However, Ca2+ +Mg/HCO3 ratio was less than one (<1) and indicated fresh recharge water.
An Investigation on the Occurrence of Brinjal Wilt Caused by Sclerotium rolfsii in Northern Karnataka, India
Authors: Kirankumar S. J. , Yadahalli K. B. , Hegde G. M. , Purushotham Pooja
Published: January 2024

Aims: The Sclerotium wilt of brinjal caused by S. rofsii is an important disease and occurs severely in the brinjal growing areas of northern Karnataka. To gain knowledge about the prevalence of sclerotium wilt of brinjal in different districts of northern Karnataka.  And also to study the factors that contribute to the disease occurrence following research was conducted.

Study Design:  Roving survey.

Place and Duration of Study: The laboratory studies were conducted in the Department of Plant Pathology, College of Agriculture, University of Agricultural Sciences, Dharwad during rabi 2020-21.

Methodology: A roving survey was conducted in five northern Karnataka brinjal growing districts during rabi 2020-21, observing Sclerotium wilt incidence and calculating percentages. The survey collected data was used to reveal a correlation between disease incidence and soil type, irrigation type, mulch type, and crop stage.

Results: The survey conducted in five districts of northern Karnataka (Belagavi, Bagalkot, Dharwad, Haveri and Gadag) revealed that maximum disease incidence of 35.07 percent was recorded in Narendra village of Dharwad district followed by Nulageri village (17.71%) of Haveri district. No disease incidence was observed in Hanchinal village of Belagavi district and Pettur village of Bagalkot district. The average mean of district for Sclerotium wilt of brinjal was also recorded and results revealed that, Dharwad district showed maximum percent disease incidence (12.39%) followed by Haveri (9.03%), Gadag (7.93%) and the least percent disease incidence (6.89%) was recorded in Bagalkot district.

Conclusion: A study on brinjal sclerotium wilt found that edaphic factors and agronomic practices, such as flooded irrigation and lack of mulching, contribute to high disease incidence in all five districts. Flooding spreads inoculum, while mulching improves soil temperature and restricts sclerotial germination. The fruiting and flowering stages of crops are most susceptible to disease due to nutrient imbalance and S. rolfsii invasion, urging the need for integrated management strategies to reduce brinjal sclerotium wilt.
Effect of Pruning on Morpho-physiological Characters and Yield of Pumpkin (Cucurbita moschata)
Authors: Nath Barsha , Gautam B. P. , Buragohain N. , Goswami R. K. , Bora B.
Published: January 2024

The present study was carried out at the Instructional cum Research Farm, Department of Horticulture, Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali with an aim to study the morpho-physiological characters and yield as influenced by pruning in pumpkin. Pumpkin is an important commercial vegetable crop of Assam which is cultivated mainly during rabi season.The treatments were: T1(Trimming of growing tip of the primary vine at 8th node stage), T2(Trimming of growing tip of the primary vine at 10th node stage), T3(Trimming of growing tip of the primary vine at 12th node stage), T4(Trimming of growing tip of the secondary vine at 6th node stage), T5(Trimming of growing tip of the secondary vine at 8th node stage), T6(Removal of all tertiary vines), T7(Retention of two tertiary vines) and T8(control without pruning). The study revealed that among the treatments, T4 recorded the highest primary vine length and inter-nodal length of primary vine at 60, 90 DAS and at 1st harvest. Number of primary vine was found to be highest under T5 whileT3 recorded maximum number of secondary vines, inter-nodal length of secondary vines, the highest total leaf chlorophyll content, relative leaf water content, leaf area index and maximum fruit yield. Therefore, trimming of growing tip of the primary vine at 12th node stage can be suggested for pumpkin to get maximum yield.
An Ex-post Impact Assessment of Seed-to-Seed Mechanization in Maize in Telangana State, India
Authors: Sunitha G. , Sunandini G. P. , Reddy D. Srinivasa , Meena A.
Published: January 2024

In Telangana, India, maize is cultivated in large areas next to rice and cotton. Considering the importance of the crop, Professor Jayashankar Telangana state Agricultural University (PJTSAU) is focusing on the development of new maize hybrids and agro-technologies that increase yield and income for farmers and reduce input and management costs. In order to evaluate the impacts of seed-to-seed mechanization technology, the Economic Surplus (ES) approach was applied in the present study that quantifies aggregate social benefits which includes producer and consumer surplus. Results revealed a total surplus of Rs. 19.61 lakhs, mainly benefiting producers (72.09 per cent) and consumers (27.91 per cent). The investment in seed-to-seed mechanization demonstrated a promising 23 per cent internal rate of return (IRR), a net present value (NPV) of Rs. 3.2 lakhs, and a favorable BC ratio of 1.67:1. The results of study found that the adoption of novel technology increased farm income and reduced the labour cost.
Effect of Socio-economic Characteristics on Pomegranate Productivity of Farmer Producer Organizations Member Farmers
Authors: Kolekar Pallavi , Chavan R. V. , Bharati S. V.
Published: January 2024

The Investigation was carried out during 2022 to study the socio-economic status of Farmer producer organizations member farmers.  The multistage sampling method was used for selection 26 samples from the Western Region of Maharashtra. The results revealed that, Overall Average age of the farmers was 39.98 years with 8.76 years of experience. The education level of farmer was up to higher secondary i.e.,10.53 years. The average family size was 6.94 number of person with land holding of 3.56 years. Study showed that, the explanatory parameters successfully explained 99.8% of the overall variance in the pomegranate yield, with random errors accounting for the remaining 1%. The findings indicated that age, education, income, and investment all played crucial roles in increasing productivity, while other socio-economic factors including land ownership, experience, and family size did not show significant affect on yield.
Performance of Post-Emergence Herbicide Combinations on Weed Management and Crop Yield in Direct Seeded Rice (Oryza sativa L.)
Authors: Saikia Nilutpal , Singh Manoj Kumar , Aakash  , Lakshmi Dendukuri Udaya , Nithinkumar Kadagonda , Bagrecha Shreyas , Biswakarma Niraj , Bhatt Kanika , Ali Sk. Asraful , Kumar Vikash
Published: January 2024

Direct-seeded rice (DSR), an innovative alternative to traditional transplanting, has gained popularity for its cost-effectiveness and labour-saving attributes. Weeds pose a significant threat to DSR. In this study, the effectiveness of various weed management methods, including hand weeding and herbicide applications, was evaluated. Hand weeding proved most effective in controlling weeds, while specific herbicides, such as bispyribac sodium + pyrazosulfuron (T2) and triafamone + ethoxysulfuron (T6) applied at 16 days after sowing (DAS), demonstrated superior weed control efficiency, improved growth parameters, and enhanced yield. Paspalum distichum was effectively controlled by penoxsulam + cyhalofop-butyl (T7). The study emphasizes the importance of customizing weed control to local conditions, with the choice of suitable herbicides and practices aligning with prevalent weed biotypes in the specific farming system. Understanding the nuanced impacts of post-emergence herbicides is crucial in navigating the intricate landscape of weed management in direct-seeded rice.
Effect of Di-tert Butyl Peroxide on Diesel Engine Performance Fuelled by Biodiesel Blends
Authors: Kachot Pareshkumar K. , Vyas D. K. , Chavda S. K.
Published: January 2024

This study is motivated by the fact that the vegetable oils are being considered as the fuel of the future for the internal combustion engines, especially the compression ignition engines which are working with diesel as fuel. Different approaches for using the vegetable oils in CI engines as fuel are either to modify the oils to match with that of diesel to run successfully with these oils. Fuel additives are compounds formulated to enhance the quality and efficiency of the fuels used in motor vehicles. There are several benefits associated with the use of fuel additives. Di-tert butyl peroxide (DTBP) is effective for enhance the quality and efficiency of the fuels used in CI engine. The investigation was to check the feasibility of di-tert butyl peroxide as an additive in different blends of diesel and jetropha bio-diesel on engine performance. The short-term tests on an unmodified diesel engine were conducted using the bio diesel and di-tert butyl peroxide blends (0, 10, 20, 30, 40, 50, and 100 per cent and 0, 0.5, 1.0, 1.5, 2.0, 2.5 per cent) with diesel. The engine performance and emission characteristics were measured during the short-term test. In all types of fuel, with increased percentage of load, brake specific energy consumption (BSEC) of the engine was observed to be decreased, on the other hand brake thermal efficiency, fuel consumption rate, sound level (db.), exhaust temperature, and the engine exhaust emissions like CO2, CO, HC and NOx was increased, respectively.
Effect of Different Phosphorus Levels and Frequency of Boron Levels on Growth and Yield of Summer Green Gram [Vigna radiata (L.)]
Authors: Jakhar Rahul , Rathore K. S. , Jakhar Anil
Published: January 2024

A field experiment was conducted at Agronomy farm, college of Agriculture & Research, (Mahatma Jyoti Roa Phoole University) Achrol, Jaipur during summer season (February-April, 2022) to study the “Effect of different phosphorus levels and frequency of boron levels on growth and yield of summer Green gram (Vigna radiata L.)”. The experiment was laid out in Randomized Block Design (RBD) with twelve treatments thrice replicated. Among the different phosphorus levels and frequency of boron levels treatment T12 i.e., P3 (20:60:20 NPK) + 20 & 35 DAS (0.2% foliar spray of borax) showed the highest performance of all treatments with a plant height (78.47 cm), number of branches/plants (13.2), number of nodules/plant (20.30), plant dry weight (10.12 g), CGR (8.50 g/m2/day), number of pods/plant (33.07), number of seeds/pod (10.33), test weight (30.20), seed yield (18.54 q/ha), straw yield (32.20 q/ha), harvest index (36.54 %). Similarly, maximum gross returns (139050 INR/ha), higher net return (103054 INR/ha) and highest benefit cost ratio (2.86) was also recorded in treatment 12 [P3(20:60:20NPK) + 20 & 35 DAS (0.2% FsB)].
Exploration of Diallel Method for Assessing Heterosis and Combining Ability in Maize (Zea mays L.)
Authors: Verma Vishal , Biswal Manorajan , Yadav Niraj Kumar , Gathiy Gabu Singh
Published: January 2024

During the Kharif season of 2018 and Rabi season of 2018-19, an experimental study was conducted. The selection of seven maize genotypes was based on quantitative traits, growth duration, suitability for the Kharif season, and yield. These genotypes were then crossed in a half diallel mating design, resulting in the production of 21 single-cross hybrids. The cultivation of these hybrids, along with the seven parental inbred lines, totaling 28 genotypes, followed a randomized block design. Each plot had dimensions of 23.10m by 1.0m and maintained a plant density of 240 plants per plot. To assess the quantitative traits, observations were recorded from five randomly selected plants per plot. The analysis of variance indicated significant genetic variability among the genotypes, particularly in traits such as days to 50% germination, silking, maturity, plant height, number of leaves per plant, biological yield, cob ear weight, number of rows per cob, and number of seeds per cob. This variability was attributed to both additive and non-additive genetic components, as evident from significant variances due to general combining ability (GCA) and specific combining ability (SCA). The GCA/SCA ratio was less than unity for most traits. For most traits, parental lines P1, P2, and P4 exhibited high GCA effects. Additionally, F1 hybrids P4x P3, P3x P1, P5x P3, and P7 x P5 were found to be desirable in terms of yield and related traits. In terms of yield, seven crosses (P1 x P6, P2 x P7, P2x P5, P1 x P2, P3x P4, P5 x P7, and P3 x P5) outperformed the check hybrid, demonstrating their potential for future breeding programs aimed at enhancing maize yield.
Inventory of Herbaceous Species and Bioaccumulation of Heavy Metals in Their Various Parts: Case in the Urban Ecosystem of Ngaoundere, Cameroon
Authors: Hareinda Ngoudzeu Lontsi , Boukar Hassana , Nestor Nsoe Mengue Jean Jacques , Dalatou Talba , Adji Mohammadou Bouba , Adamou Ibrahima
Published: January 2024

This study was carried out to inventory herbaceous species and to assess the bioaccumulation of heavy metals in these species. The ecosystem chosen was an area of the city of Ngaoundere (Cameroon) divided into three sites, namely a control site and two sites subject to heavy metal pollution. In order to compare the potential for bioaccumulation, two species were assessed. It shows that out of 19 herbaceous species present in the study area, five are very abundant in all three sites regardless of the degree of pollution. Concerning the bioaccumulation, the two herbaceous plants chosen do not absorb the same amounts of heavy metals. Indeed, the concentrations show that the concentration of cadmium, copper, iron, nickel and lead at all three sites is higher in Commellina benghalensis than in Ageratum conyzoides. The concentration of zinc at the control site and the hospital site is higher in C. benghalensis while at the prison site this concentration is higher in Ageratum A. conyzoides. The concentration of cadmium is higher in the leaves than in the other parts in both species. Copper is stored at the roots in both species. A. conyzoides, mainly accumulates iron in the roots and C. benghalensis, accumulates a significant concentration of Iron throughout the plant. A. conyzoides and C. benghalensis store nickel more in the roots than in the other parts. Regarding lead, the species studied store it more in the roots followed by the leaves and finally the stems. As for Zinc, A. conyzoïdes and C. benghalensis store it more in the roots than in the other parts. The bioaccumulation of these heavy metals in edible herbaceous plants could be a threat if these pollutants enter the human food chain.
Parental Income's Impact on Student Participation in Lesson Activities for Equitable Educational Outcomes
Authors: Careemdeen Jalal Deen
Published: January 2024

Aims: This study aims to investigate the relationship between parental income and student participation in lesson activities among secondary schoolchildren in Sri Lanka. The primary objectives is identifying potential differences based on parental income levels, and providing valuable insights into the broader implications for educational equity.
Study Design:  Employing a survey and quantitative research design, this study gathers data from 1350 secondary school students. The research focuses on diverse aspects of student participation, including group work, discussions with teachers and family, experiments, practical activities, and interactions through social media. A Likert Scale with five response options is utilized to measure student engagement, offering a comprehensive view of their involvement.
Place and Duration of Study: The study is conducted in secondary schools across Sri Lanka. Data collection spans a specified duration, ensuring a representative sample of participants. The diverse geographical and socio-economic landscape of Sri Lanka enriches the study's scope, allowing for a nuanced understanding of the interplay between parental income and student participation.
Methodology: A stratified random sampling technique is employed to select 1350 participants, ensuring a diverse representation of secondary school students. The questionnaire, validated by experts in the sociology of education, comprises two sections: one gathering demographic information and the other assessing students' perceptions of their involvement in lesson activities. Descriptive and inferential statistics, facilitated by the Statistical Package for the Social Sciences (SPSS) Version 23, enable a comprehensive analysis of the data.
Results: Descriptive analysis reveals a moderately high overall level of student participation in various lesson activities. Notably, group activities receive the highest mean value, indicating a strong positive correlation with student engagement. The multivariate analysis of variance (MANOVA) demonstrates significant differences based on parental income levels, with upper-middle-class students exhibiting higher participation than their peers from lower-income backgrounds.
Conclusion: The study concludes by highlighting the crucial role of parental income in shaping students' educational experiences. Findings underscore the disparities in engagement levels, emphasizing the need for targeted interventions and policy initiatives to promote educational equity. Educators, policymakers, and parents are urged to consider these insights to foster a more inclusive and equitable educational system in Sri Lanka.
Spectra of wavelet scale coefficients from process acoustic measurements as input for PLS modelling of pulp quality
Authors: Björk Anders , Danielsson Lars‐Göran
Published: October 2002

Acoustic and vibration signals are captured by simple standard accelerometers. These can often be mounted directly on operative process equipment, creating a completely non‐invasive measurement system. The signals from the accelerometer are then amplified, digitized by an analogue‐to‐digital converter and stored in some suitable format in a PC. The method most often used for signal processing of acoustic data has been to apply variants of fast Fourier transform (FFT) on sampled data to produce a frequency domain representation. An alternative way tried here is to use the fast wavelet transform (FWT) in combination with FFT. The FWT has the advantage that it produces time‐resolved representations and, on each time scale, different features can be extracted. However, in this case, time resolution has no meaning, since the starting points for data acquisitions were not fixed. The wavelet step can be seen as a series of pre‐filters and it is here followed by FFT on coefficients at each wavelet scale. The results are compared to those obtained after FFT on the complete time series. We have used spectra of wavelet scale coefficients in an attempt to model pulp quality with PLS. In this case the number of points in the resulting wavelet multiresolution spectrum (WT‐MRS) can be limited to a low number, e.g. 255 compared to 1025 with direct FFT on the time series. In the PLS modelling step the advantage is that the first two components describeYmuch better than when using the conventional approach, e.g. 72% explainedYvariance compared to 40%. A second advantage is that the model requires fewer coefficients. Copyright © 2002 John Wiley & Sons, Ltd.
PCR/PLSR optimization based on noise covariance estimation and Kalman filtering theory
Authors: Ergon Rolf , Esbensen Kim H.
Published: October 2002

The theoretical connection between principal component regression (PCR) and partial least squares regression (PLSR) on one hand and Kalman filtering (KF) on the other is known from earlier work. In the present paper we investigate the possibilities to use latent variables modeling and KF theory as means for optimization of ordinary PLSR and PCR predictors, based on the prerequisite of prior X noise covariance estimates facilitated e.g. by more X than y observations. The result is a new PLSR optimization method, while the PCR optimization turns out to be identical with an earlier known method. A simulation example and two real‐world data examples supporting the theoretical development are presented. The treatment is limited to cases with only one response variable, although an extension to multiresponse cases is also possible. Copyright © 2002 John Wiley & Sons, Ltd.
Batch statistical processing of 1H NMR‐derived urinary spectral data
Authors: Antti H. , Bollard M. E. , Ebbels T. , Keun H. , Lindon J. C. , Nicholson J. K. , Holmes E.
Published: October 2002

Multivariate statistical batch processing (BP) analysis of 1H nuclear magnetic resonance (NMR) urine spectra was employed to establish time‐dependent metabolic variations in animals treated with the model hepatotoxin hydrazine. Hydrazine was administered orally to rats (at 90 mg kg−1), and urine samples were collected from dosed rats and matched control animals (n = 5 per group) at time points up to 168 h post‐dose. Urine samples were analysed via 1H NMR spectroscopy and partial least squares‐based batch processing analysis, treating each rat as an individual batch comprising a series of timed urine samples. A model defining the mean urine profile was established for the control group, and samples obtained from hydrazine‐treated animals were assessed using this model. Time‐dependent deviations from the control model were evident in all hydrazine‐treated animals, and hepatotoxicity was manifested by increased urinary excretion of taurine, creatine, 2‐aminoadipate, citrulline and β‐alanine together with depletion of urinary levels of citrate, succinate and hippurate. The experiment was repeated at six different pharmaceutical centres in order to assess the robustness of the technology and to establish the natural variability in the data. Results were consistent across the data for all centres. BP plots showed a characteristic pattern for each toxin, allowing the time points at which there were maximum metabolic differences to be determined and providing a means of visualizing the net toxin‐induced metabolic movement of urinary metabolism. BP may prove to be a powerful metabonomic tool in defining time‐dependent metabolic consequences of toxicity and is an efficient means of visualizing inter‐animal variations in response as well as defining multivariate statistical limits of normality in terms of biofluid composition. Copyright © 2002 John Wiley & Sons, Ltd.
Maximum likelihood fitting using ordinary least squares algorithms
Authors: Bro Rasmus , Sidiropoulos Nicholaos D. , Smilde Age K.
Published: October 2002

In this paper a general algorithm is provided for maximum likelihood fitting of deterministic models subject to Gaussian‐distributed residual variation (including any type of non‐singular covariance). By deterministic models is meant models in which no distributional assumptions are valid (or applied) on the parameters. The algorithm may also more generally be used for weighted least squares (WLS) fitting in situations where either distributional assumptions are not available or other than statistical assumptions guide the choice of loss function. The algorithm to solve the associated problem is called MILES (Maximum likelihood via Iterative Least squares EStimation). It is shown that the sought parameters can be estimated using simple least squares (LS) algorithms in an iterative fashion. The algorithm is based on iterative majorization and extends earlier work for WLS fitting of models with heteroscedastic uncorrelated residual variation. The algorithm is shown to include several current algorithms as special cases. For example, maximum likelihood principal component analysis models with and without offsets can be easily fitted with MILES. The MILES algorithm is simple and can be implemented as an outer loop in any least squares algorithm, e.g. for analysis of variance, regression, response surface modeling, etc. Several examples are provided on the use of MILES. Copyright © 2002 John Wiley & Sons, Ltd.
Screening for dioxin contamination in fish oil by PARAFAC and N‐PLSR analysis of fluorescence landscapes
Authors: Pedersen Dorthe Kjœr , Munck Lars , Engelsen Søren Balling
Published: October 2002

A preliminary investigation of fish oils demonstrates that fluorescence excitation–emission landscapes evaluated by three‐way chemometric methods may be a candidate for an inexpensive screening method to indicate the level of contamination by dioxins and PCBs, which are normally analysed by expensive and time‐consuming physicochemical separation techniques such as GC‐MS. Fluorescence landscapes of 88 fish oils have been investigated and showed great variation due to species, season and treatment, depicting a variation in natural fluorescent components. The fluorescence landscapes were analysed by PARAFAC. Samples with similar fluorescence fingerprints were selected from a PARAFAC score plot, and local significant prediction models with PARAFAC/MLR, N‐PLSR and PLSR were established with correlation coefficients in the range from r = 0.69 (n = 10) to r = 0.97 (n = 75) for dioxin and of r = 0.92 (n = 12) for PCB. Application of PARAFAC/MLR and N‐PLSR to fluorescence landscapes of fish oils resulted in local regression models for dioxin determination with prediction errors below 1 ng kg−1, which is comparable to the reference method. In the PARAFAC model, two of the modes give the excitation and emission spectra of the pure underlying fluorophores, while the third mode gives their individual concentrations. Excitation and emission optima for three or four PARAFAC components in each data set were identified, representing both positive and negative (quenching) correlation components. It is hypothesized that the quenching correlation may be effected by the joint contribution of chlorinated organic compounds in the fish oil, including dioxins and PCBs. Other explanations for the results are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Omeprazole and analogue compounds: a QSAR study of activity against Helicobacter pylori using theoretical descriptors
Authors: Bruni Aline Thais , Ferreira Márcia Miguel Castro
Published: October 2002

Omeprazole and analogues were studied with respect to their activity as inhibitors of urease Helicobacter pylori. Conformational analysis was performed according to the method proposed by Bruni et al. Theoretical descriptors were calculated by an ab initio method (6–31G** basis set). Since several minimum energy structures were obtained for each compound, and the calculated descriptors proved to be sensitive to the structural conformation, different criteria were proposed for conformation selection. Three data sets were generated wherein conformations were grouped according to minimum heat of formation, minimum electronic energy and structural similarity. For these three sets, experimental per cent of control was used to develop quantitative structure–activity models by PLS. Their cross‐validation and correlation coefficients were very good (Q2 = 0.97 and R2 = 0.99 on average) and the standard error of validation was much smaller in comparison with results from the literature. Copyright © 2002 John Wiley & Sons, Ltd.
Hierarchical experimental design exemplified by QSAR evaluation of a chemical library directed towards the melanocortin 4 receptor
Authors: Andersson Per M. , Lundstedt Torbjörn
Published: October 2002

A design strategy for how to select a smaller subset of compounds to synthesize, test for activity and finally establish a QSAR model was investigated. The biological target of interest was the melanocortin 4 receptor (MC4R), which is assumed to have an important role in the control of feeding behaviour and is therefore of great interest as a drug target. A subset of our in‐house compound collection was used to investigate and illustrate the proposed design strategy. The selected compound set has a phenyl core motif in common with five substituents in the ring, which could be varied independently and therefore represented a suitable design scaffold to investigate. By using statistical molecular design in combination with the proposed hierarchical design approach, a training set of compounds was selected. As design variables for the substituents, principal properties based on a set of 110 substituents characterized with σ, π and Verloop parameters were used. By using measured affinity data towards MC4R as a response variable together with the principal properties, a QSAR model was established which proved to have good predictive ability. Two important conclusions were that none of the compounds in the test set were predicted as false negatives by the QSAR model and that the proposed design approach appears to work well. The strategy is implemented in an ongoing project, and the usefulness of hierarchical design of experiments will be explored further. Copyright © 2002 John Wiley & Sons, Ltd.
Estimation of uncertainty of concentration estimates obtained by image analysis
Authors: Korpelainen M. , Reinikainen S.‐P. , Laukkanen J. , Minkkinen P.
Published: October 2002

Images from the scanning electron microscope (SEM) and the optical microscope are widely used in mineral processing to estimate the concentrations of mineral species. The aim of this study was to optimize the procedure used for the determination of concentration estimates from SEM images of ore and rock samples. The goal was especially to develop a method that would allow the estimation of the concentration uncertainty when the image analysis is still in progress. For this study, samples consisting of chromite (FeCr2O4, density 4.7 g cm−3) and quartz (SiO2, density 2.7 g cm−3) were prepared. The chromite concentration in the sample materials varied from 0.1 to 90 wt%. Four replicate microscopic samples for each chromite concentration were prepared and analysed. The total number of samples was 36. Two hundred images and 20 000–30 000 particles per microscopic sample were analysed. Estimation of the sampling error was based on Pierre Gy's sampling theory. Several error components were studied and the error estimates were found to be relatively reliable when they were based on the fundamental sampling error. Copyright © 2002 John Wiley & Sons, Ltd.
Development of a software sensor for phosphorus in municipal wastewater
Authors: Jansson Åsa , Röttorp Jonas , Rahmberg Magnus
Published: October 2002

Different multivariate techniques were applied to data from a wastewater treatment plant in order to develop a software sensor for phosphorus. The predictive power, measured as root mean square error of cross‐validation (RMSECV) and root mean square error of prediction (RMSEP), of partial least squares (PLS) models was found to be superior to that of multiple linear regression (MLR) and principal component regression (PCR) models. The result from using a static as well as a finite impulse response (FIR) model structure was also investigated. Good estimates of phosphorus were obtained for both kinds of model structure, but the FIR models were slightly better than the static ones. Out of the two different fractions of phosphorus that were modelled, i.e. total phosphorus and phosphate in solution, the best predictions were obtained for soluble phosphorus. Copyright © 2002 John Wiley & Sons, Ltd.
Decomposition using maximum autocorrelation factors
Authors: Larsen Rasmus
Published: October 2002

This paper presents methods for the analysis and decomposition of multivariate data sets where a given ordering/structure of the observations or the variables exists. Examples of such data sets are found in remote sensing imagery, where observations (pixels) each consisting of a reflectance spectrum are organized in a two‐dimensional grid. Another example is biological shape analysis. Here each observation (e.g. human bone, cerebral ventricle) is represented by a number of landmarks, the co‐ordinates of which are the variables. Here we do not have an ordering of the observations (individuals). However, normally we have an ordering of landmarks (variables) along the contour of the objects. For the case with observation ordering, the maximum autocorrelation factor (MAF) transform was proposed for multivariate imagery (Switzer P. InComputer Science and Statistics, Billard L (ed.). Elsevier: Amsterdam, 1985; 13–16). This corresponds to an R‐mode analysis of the data matrix. We propose to extend this concept to situations with variable ordering. This corresponds to a Q‐mode analysis of the data matrix. We call this method the Q‐MAF decomposition. It turns out that in many situations the new variables resulting from MAF and Q‐MAF analyses can be interpreted as a decomposition of (spatial) frequency. However, contrary to Fourier decomposition, these new variables are located in frequency as well as location (space, time, wavelength, etc.). Copyright © 2002 John Wiley & Sons, Ltd.
Applicational aspects of support vector machines
Authors: Belousov A. I. , Verzakov S. A. , von Frese J.
Published: October 2002

The special emphasis of support vector machines (SVMs) on generalization ability makes this approach particularly interesting for real‐world applications with limited amounts of training data. In this paper we analyse the applicational aspects of SVMs, illustrating them with the step‐by‐step construction of a classifier for polymers by means of their mid‐infrared spectra. With this example we show how the main difficulties of a typical industrial classification task can be addressed using SVMs. Copyright © 2002 John Wiley & Sons, Ltd.
New and old trends in chemometrics. How to deal with the increasing data volumes in R&D&P (research, development and production)—with examples from pharmaceutical research and process modeling
Authors: Wold Svante , Berglund Anders , Kettaneh Nouna
Published: October 2002

Chemometrics was started around 30 years ago to cope with and utilize the rapidly increasing volumes of data produced in chemical laboratories. The methods of early chemometrics were mainly focused on the analysis of data, but slowly we came to realize that it is equally important to make the data contain reliable information, and methods for design of experiments (DOE) were added to the chemometrics toolbox. This toolbox is now fairly adequate for solving most R&D problems of today in both academia and industry, as will be illustrated with a few examples. However, with the further increase in the size of our data sets, we start to see inadequacies in our multivariate methods, both in their efficiency and interpretability. Drift and non‐linearities occur with time or in other directions in data space, and models with masses of coefficients become increasingly difficult to interpret and use. Starting from a few examples of some very complicated problems confronting chemical researchers today, possible extensions and generalizations of the existing chemometrics methods, as well as more appropriate preprocessing of the data before the analysis, will be discussed. Criteria such as scalability of methods to increasing size of problems and data, increasing sophistication in the handling of noise and non‐linearities, interpretability of results, and relative simplicity of use will be held as important. The discussion will be made from a perspective of the evolution of the scientific methodology as driven by new technology, e.g. computers, and constrained by the limitations of the human brain, i.e. our ability to understand and interpret scientific and data analytical results. Quilt‐PCA and Quilt‐PLS presented here address and offer a possible solution to these problems. Copyright © 2002 John Wiley & Sons, Ltd.
Non‐linear partial least squares. Estimation of the weight vector
Authors: Hassel Per A. , Martin Elaine B. , Morris Julian
Published: October 2002

A key issue in non‐linear partial least squares (PLS) is the calculation of the weight vectors. The weight vector can be derived in a number of ways; for example, as in linear PLS, through an optimization routine as in error‐based non‐linear PLS, or through the covariance criterion as in Spline‐PLS. An alternative approach to the estimation of the weight vector in non‐linear PLS is proposed based on the theory of the weighted average, the reciprocal variance criterion. Unlike the covariance‐based criterion that gives equal consideration to both the response and the process variables in the calculation of the weight vector, the proposed approach gives emphasis to the response variables. The new weighting criterion performs well where the variability in the response variables can be captured by a few underlying phenomena. The methodology is illustrated through its application to simulated spectral data and an industrial NIR data set. It is shown that for the case studies the proposed approach outperforms the covariance criteria of PLS in terms of performance on a validation data set. Copyright © 2002 John Wiley & Sons, Ltd.
Generalization of pair correlation method (PCM) for non‐parametric variable selection
Authors: Héberger Károly , Rajkó Róbert
Published: October 2002

The pair correlation method (PCM) has been developed for choosing between two correlated predictor variables (factors) provided that the scatter is caused not only by random effects. The distinction between two variables can be made using an arrangement into a 2 × 2 contingency table. Further on, suitable test statistics can be used to decide the significance of differences between factors. PCM can easily be generalized (GPCM) for variable selection purposes using more than two variables. The comparison of factors can be made pairwise in all possible combinations. If a given statistical test indicates a significant difference between the factors, the following terms are used for the overwhelming and subordinate factors: superior–inferior or winner–loser respectively. Every comparison can mark a factor as superior, inferior or no decision can be made. The following step is ranking of predictor variables. Three ways of ranking have been elaborated: (i) simple ranking, (ii) ranking based on differences and (iii) ranking according to probability‐weighted differences. (Difference here means number of wins minus number of losses.) Suitable examples are presented to show the usefulness and applicability of the method in various conditions. Copyright © 2002 John Wiley & Sons, Ltd.