Showing papers by "University of Jordan published in 2008"

The effect of all-ceramic and porcelain-fused-to-metal restorations on marginal peri-implant soft tissue color: a randomized controlled clinical trial.

Abstract: The aim of this study was to test the color-change effect of all-ceramic restorations compared with porcelain-fused-to-metal (PFM) restorations on marginal peri-implant soft tissue. Thirty patients were randomly divided into 2 groups of 15 subjects each. The all-ceramic group received all-ceramic crowns on aluminum oxide-based abutments, while the PFM group received crowns on titanium or gold abutments. A reflectance spectrophotometer was used to measure the color difference (deltaE(Implant)) between the midfacial peri-implant mucosa before and after restoration insertion. The color difference (deltaE(Tooth-implant)) between the midfacial peri-implant mucosa and the gingival margin of the corresponding neighboring tooth was tested. The mucosal thickness was measured midfacially around the implant (MT(Implant)) and neighboring tooth (MT(Tooth)). deltaE(Implant) values were similar for the all-ceramic (7.4 +/- 2.7) and PFM groups (7.6 +/- 2.8). The all-ceramic group induced significantly less visible mucosal color change (3.4 +/- 1.4) compared to the PFM group (5.2 +/- 2.3). The MT(Implant) value of the all-ceramic group was 3.4 +/- 0.8 mm, while that of the PFM group was 2.9 +/- 0.9 mm, which was not significantly different. Significant differences were found when comparing MT(Implant) (3.1 +/- 0.9) and MT(Tooth) (1.2 +/- 0.3) values for test and control groups. All-ceramic restorations revealed a better color match to the neighboring teeth than PFM restorations.

The Highly Similar Arabidopsis Homologs of Trithorax ATX1 and ATX2 Encode Proteins with Divergent Biochemical Functions

Abstract: Gene duplication followed by functional specialization is a potent force in the evolution of biological diversity. A comparative study of two highly conserved duplicated genes, ARABIDOPSIS TRITHORAX-LIKE PROTEIN1 (ATX1) and ATX2, revealed features of both partial redundancy and of functional divergence. Although structurally similar, their regulatory sequences have diverged, resulting in distinct temporal and spatial patterns of expression of the ATX1 and ATX2 genes. We found that ATX2 methylates only a limited fraction of nucleosomes and that ATX1 and ATX2 influence the expression of largely nonoverlapping gene sets. Even when coregulating shared targets, ATX1 and ATX2 may employ different mechanisms. Most remarkable is the divergence of their biochemical activities: both proteins methylate K4 of histone H3, but while ATX1 trimethylates it, ATX2 dimethylates it. ATX2 and ATX1 provide an example of separated K4 di from K4 trimethyltransferase activity.

Factors affecting medical students in formulating their specialty preferences in Jordan.

Abstract: Background In recent years there has been a growing appreciation of the issues of career preference in medicine as it may affect student learning and academic performance. However, no such studies have been undertaken in medical schools in Jordan. Therefore, we carried out this study to investigate the career preferences of medical students at Jordan University of Science and Technology and determine factors that might influence their career decisions.

Seasonal variations in the chemical composition of camel milk in Jordan

Abstract: The principal chemical components of milk from the Arabian camel (Camelus dromedarius) were monitored in Jordan over one year. The analyses included total solids, fat, protein, vitamins, minerals and organic acids. Large seasonal variations in total solids and fat were apparent, with maxima in mid-winter of 139 and 39.0 g/l, respectively, and minima in August of 102 and 25.0 g/l. These differences may be sufficient to alter the sensory properties of the milk, and the fat: casein ratio may need standardisation for cheesemaking. The mean values of trace elements like zinc (5.8 mg/l), iron (4.4 mg/l) and manganese (0.05 mg/l) in Jordanian camel milk could provide valuable additions to the diet of urban populations, as could the mean concentration of vitamin C (33 mg/l). The levels of organic acids were generally higher than in bovine milk and, as with all the constituents of the milk, there were discernible patterns linking concentration and season of the year.

Estimation of P(Y < X) for the Three-Parameter Generalized Exponential Distribution

Abstract: This article considers the estimation of R = P(Y < X) when X and Y are distributed as two independent three-parameter generalized exponential (GE) random variables with different shape parameters but having the same location and scale parameters. A modified maximum likelihood method and a Bayesian technique are used to estimate R on the basis of independent complete samples. The Bayes estimator cannot be obtained in explicit form, and therefore it has been determined using an importance sampling procedure. An analysis of a real life data set is presented for illustrative purposes.

Assessment of groundwater vulnerability in the coastal region of Oman using DRASTIC index method in GIS environment.

Abstract: A study was carried out to develop a vulnerability map for Barka region in the North Batina of Oman using DRASTIC vulnerability index method in GIS environment. DRASTIC layers were created using data from published reports and the seven DRASTIC layers were processed by the ArcGIS geographic information system. Finally, DRASTIC maps were created for 1995 and 2004 to understand the long-term changes in the vulnerability index. DRASTIC vulnerability maps were evaluated using groundwater quality data such as chemical and biological parameters. DRASTIC vulnerability maps of 1995 and 2004 indicate that the northern part of Barka is more vulnerable to pollution than southern part and the central part of Barka also shows high relative vulnerability which is mostly related to the high conductivity values. Moreover, the changes in water level due to high abstraction rate of groundwater reflect in the vulnerability maps and low vulnerability area is increased in the southern part during 2004 compared to 1995. Moreover, regional distribution maps of nitrate, chloride and total and fecal coliforms are well correlated with DRASTIC vulnerability maps. In contrast to this, even though DRASTIC method predicted the central part of the study region is highly vulnerable, both chemical and biological parameters show lower concentrations in this region compared to coastal belt, which is mainly due to agricultural and urban development. In Barka, urban development and agricultural activities are very high in coastal region compared to southern and central part of the study area. Hence, this study concluded that DRASTIC method is also applicable in coastal region having ubiquitous contamination sources.

Social Support and Stress Among University Students in Jordan

Abstract: The purpose of this study was to examine the relationship between perception of social support and perceived stress among university students in Jordan. A sample of 241 university students from private and government universities in Jordan answered self-report questionnaires including the perceived social support scale and perceived stress scale. The results showed that university students have moderate perception of social support and stress. Female university students had higher perception of stress and social support than male university students. Perceived stress had a negative correlation with perceived social support from family (−0.29, p < 0.05). The perceived social support from family was a better predictor of perceived life event as stressful situations than perceived social support from friends. The study implications for research and intervention were discussed.

Evaluating greywater reuse potential for sustainable water resources management in Oman.

Abstract: This study aims to evaluate the potential of greywater availability in Muscat Governorate in the Sultanate of Oman, to establish a methodology for greywater quantity estimation, to test greywater quality in order to assess reuse potential, and to examine public acceptance for reuse.Total fresh water consumption and greywater generation from different household sources were measured by water meters in five selected households during summer and winter. Additionally, a survey was designed and conducted in five administrative areas of Muscat Governorate, with the objective of testing a methodology for estimating greywater generation potential in these areas. Collected data were compared with that used by the Ministry of Housing, Electricity and Water, Sultanate of Oman. The survey covered a total of 169 houses and 1,365 people. Greywater samples were collected and analyzed from showers, laundries, kitchens and sinks in some of these households to determine their water quality parameters. Statistical analysis results indicated that there is no significant variance in the total fresh water consumption between data used by the ministry and those measured and estimated during this study, highlighting the applicability of the tested method. The study concluded that the average per capita greywater generation rate is 151 Lpcd. Greywater production ranged from 80 to 83% of the total fresh water consumption and most of the greywater is generated from showers. Further, 55 to 57% of the greywater generated in a typical Omani household originated from the shower, 28 to 33% originated from the kitchen, 6 to 9% originated from laundry, and 5 to 7% originated from sink, which constitutes approximately 81% of the total fresh water consumption. The physical, chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids, inorganic constituents, total organic carbon, chemical and biochemical oxygen demands, total Coliforms and Escherichia Coliform bacteria. The public acceptance survey illustrated that approximately 76% of the respondents accepted the reuse of greywater for gardening, 53% for car washing and 66% for toilet flushing.

Pharmacophore modeling, quantitative structure-activity relationship analysis, and in silico screening reveal potent glycogen synthase kinase-3beta inhibitory activities for cimetidine, hydroxychloroquine, and gemifloxacin

Abstract: The pharmacophoric space of glycogen synthase kinase-3beta (GSK-3beta) was explored using two diverse sets of inhibitors. Subsequently, genetic algorithm and multiple linear regression analysis were employed to select optimal combination of pharmacophores and physicochemical descriptors that access self-consistent and predictive quantitative structure-activity relationship (QSAR) against 132 training compounds ( r (2) 123 = 0.663, F = 24.6, r (2) LOO = 0.592, r (2) PRESS against 29 external test inhibitors = 0.695). Two orthogonal pharmacophores emerged in the QSAR, suggesting the existence of at least two distinct binding modes accessible to ligands within GSK-3beta binding pocket. The validity of the QSAR equation and the associated pharmacophores was established by the identification of three nanomolar GSK-3beta inhibitors retrieved from our in-house-built structural database of established drugs, namely, hydroxychloroquine, cimetidine, and gemifloxacin. Docking studies supported the binding modes suggested by the pharmacophore/QSAR analysis. In addition to being excellent leads for subsequent optimization, the anti-GSK-3beta activities of these drugs should have significant clinical implications.

Aflatoxin Decontamination of Artificially Contaminated Feeds by Sunlight, γ-Radiation, and Microwave Heating

Abstract: SUMMARY The efficiency of decontamination of aflatoxin residues in poultry feeds through exposure to sunlight (solar radiation), γ-radiation ( 60 Co), and microwave heating were investigated in artificially contaminated feed samples. Photodegradation of aflatoxin by sunlight has been found to cause a significant (P < 0.05) decrease in both B1 and the total aflatoxins. Moreover, the degrees of aflatoxins were dependent on exposure time. Both aflatoxin B1 and total aflatoxins were decreased when feed samples exposed to sunlight by 42.3, 39.9, 75.5, and 65.9% for 3 and 30 h of direct sunlight of the treatment T1, whereas feed samples subjected to γ-irradiation and microwave heating caused a significant (P < 0.05) decrease in aflatoxin B1 contents by 42.7 and 32.3% for γ-irradiation and microwave heating (T3 of 25 kGy and 10 min of microwave heating), respectively. Therefore, the solar radiation was more effective in aflatoxin B1 reduction when compared with γ-irradiation and microwave heating.

Impacts of land use/cover change on soil properties in the Mediterranean region of northwestern Jordan

Abstract: This study was carried out to evaluate the effects of deforestation on physical and chemical properties of soils under native forest in the Mediterranean region of northwestern Jordan. Land use/cover maps of 1953, 1978 and 2002 were interpreted and analysed within GIS to quantify the shift from forest to rainfed cultivation. Six sites were sampled in a non-changed forest and in cultivated fields, three for each. Different soil properties of texture, bulk density, organic matter, total nitrogen, pH, cation exchange capacity (CEC), phosphorous and potassium were analysed. Results showed that many forests were changed into cultivated lands at a rate more than the reforestation. Subsequently, adverse effects on the studied physical and chemical properties were observed. The most affected properties were particle size distribution, bulk density of surface soil and subsoil. Organic matter and CEC decreased in cultivated soil as compared to the forest soil. Cultivated soils were found to exhibit a significantly lower status in physical and chemical soil properties as compared to forest soils. This general decline in the soil physical and chemical properties, in turn, contributed to soil erosion, reduction of soil fertility and land degradation. There is an urgent need to improve soil quality by developing sustainable land use practices to reduce the rate of soil degradation and to ensure long-term sustainability of the farming system in the study area and in similar biophysical settings. Copyright © 2008 John Wiley & Sons, Ltd.

Virtual Human Technology: Capturing Sex, Race, and Age Influences in Individual Pain Decision Policies

Abstract: Pain assessment is subject to bias due to characteristics of the individual in pain and of the observing person. Few research studies have examined pain assessment biases in an experimental setting. This study employs innovative virtual human technology to achieve greater experimental control. A lens model design was used to capture decision-making policies at the idiographic and nomothetic level. Seventy-five undergraduates viewed virtual humans (VH) that varied in sex, race, age, and pain expression. Participants provided computerized ratings with Visual Analogue Scales on the VH's pain intensity, pain unpleasantness, negative mood, coping, and need for medical treatment. Idiographic analyses revealed that individuals used pain expression most frequently as a significant cue. Nomothetic analyses showed that higher pain expression VH and female VH were viewed as having higher pain intensity, higher pain unpleasantness, greater negative mood, worse coping, and a greater need to seek medical treatment than lower pain expression VH and male VH, respectively. Older VH were viewed as having worse coping and a greater need to seek medical treatment than younger VH. This innovative paradigm involving VH technology and a lens model design was shown to be highly effective and could serve as a model for future studies investigating pain-related decision making in healthcare providers.

Assessment of anxiety and depression after lower limb amputation in Jordanian patients.

Abstract: Objective This study aimed to assess the prevalence of anxiety and depression among Jordanian lower limb amputees with different clinical characteristics and sociodemographic data (gender, marital status, social support, income, type and level of amputation, and occupation). Methods Participants were 56 patients with unilateral lower limb amputation with mean duration (8.4 +/- 5.75 years). They were recruited from inpatient and outpatient clinics of Jordan University hospital, Royal Farah Rehabilitation Center, and Al-basheer hospital in Amman, Jordan. Participants responded to a questionnaire that included a battery of questions requesting brief information about sociodemographic variables and characteristics of amputation. The level of depression and anxiety in each participating patient was assessed by the Hospital Anxiety and Depression Scale (HADS). Results The prevalence of anxiety and depressive symptoms were 37% and 20%, respectively. Factors associated with high prevalence of psychological symptoms included female gender, lack of social support, unemployment, traumatic amputation, shorter time since amputation, and amputation below the knee. These findings were confirmed by a significant reduction of anxiety and depression scores in patients who received social support, patients with amputation due to disease, and patients with amputation above the knee. Presence of pain and use of prosthesis had no effect on the prevalence. Conclusions The findings of the present study highlight the high incidence of psychiatric disability and depression in amputees; it also showed the importance of sociodemographic factors in psychological adjustment to amputation. It is suggested that psychiatric evaluation and adequate rehabilitation should form a part of their overall management.

Using Fourier transform infrared (FT-IR) absorbance spectroscopy and multivariate analysis to study the effect of chlorine-induced bacterial injury in water.

Abstract: The effect of chlorine-induced bacterial injury on spectral features using Fourier transform infrared (FT-IR) absorbance spectroscopy was studied using a mixed bacterial culture of (1:1) ca. 500 CFU/mL each Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 15442 in 0.9% saline. Bacterial cells were treated with 0, 0.3, or 1.0 ppm of initial free chlorine (21 degrees C, 1 h of contact time). Chlorine-injured and dead bacterial cells retained the ATR spectral properties of uninjured or live cells in the region of C-O-C stretching vibrations of polysaccharides, indicative of the cell wall peptidoglycan layer and lipopolysaccharide outer leaflet. This confirms the observations of others that extensive bacterial membrane damage is not a key factor in the inactivation of bacteria by chlorine. The bactericidal effect of chlorine caused changes in the spectral features of bacterial ester functional groups of lipids, structural proteins, and nucleic acids, with apparent denaturation reflected between 1800 and 1300 cm (-1) for injured bacterial cells. Three-dimensional principal component analysis (PCA) showed distinct segregation and clustering of chlorine-treated and untreated cells. Cells exposed to chlorine at 0.3 or 1.0 ppm could be distinguished from the untreated control 73 and 80% of the time, respectively, using soft independent modeling of class analogy (SIMCA) analysis. This study suggests that FT-IR spectroscopy may be applicable for detecting the presence of injured and viable but not culturable (VBNC) waterborne pathogens that are underestimated or not discernible using conventional microbial techniques.

Robust fault estimation of uncertain systems using an LMI‐based approach

Abstract: General recent techniques in fault detection and isolation (FDI) are based on H∞ optimization methods to address the issue of robustness in the presence of disturbances, uncertainties and modeling errors. Recently developed linear matrix inequality (LMI) optimization methods are currently used to design controllers and filters, which present several advantages over the Riccati equation-based design methods. This article presents an LMI formulation to design full-order and reduced-order robust H∞ FDI filters to estimate the faulty input signals in the presence of uncertainty and model errors. Several cases are examined for nominal and uncertain plants, which consider a weight function for the disturbance and a reference model for the faults. The FDI LMI synthesis conditions are obtained based on the bounded real lemma for the nominal case and on a sufficient extension for the uncertain case. The conditions for the existence of a feasible solution form a convex problem for the full-order filter, which may be solved via recently developed LMI optimization techniques. For the reduced-order FDI filter, the inequalities include a non-convex constraint, and an alternating projections method is presented to address this case. The examples presented in this paper compare the simulated results of a structural model for the nominal and uncertain cases and show that a degree of conservatism exists in the robust fault estimation; however, more reliable solutions are achieved than the nominal design. Copyright © 2008 John Wiley & Sons, Ltd.

Combining ligand-based pharmacophore modeling, quantitative structure-activity relationship analysis and in silico screening for the discovery of new potent hormone sensitive lipase inhibitors.

Abstract: Hormone sensitive lipase (HSL) has been recently implicated in diabetes and obesity, prompting attempts to discover new HSL inhibitors. Toward this end, we explored the pharmacophoric space of HSL inhibitors using four diverse sets of compounds. Subsequently, genetic algorithm and multiple linear regression analysis were employed to select optimal combination of pharmacophoric models and 2D physicochemical descriptors capable of yielding a self-consistent and predictive quantitative structure−activity relationship (QSAR) (r = 0.822, n = 99, F = 11.1, rLOO2 = 0.521, rPRESS2 against 23 external test inhibitors = 0.522). Interestingly, two pharmacophoric models emerged in the QSAR equation suggesting at least two binding modes. These pharmacophores were employed to screen the National Cancer Institute (NCI) list of compounds and our in-house built database of established drugs and agrochemicals. Active hits included the safe herbicidal agent bifenox (IC50 = 0.43 μM) and the nonsteroidal anti-inflammatory nap...

Societal perspectives on the role of community pharmacists and over-the-counter drugs in Jordan

Abstract: Objective The aim of this study is to investigate the Jordanian population’s attitudes towards the role of community pharmacist and their use of and their perceptions of OTC drugs. Setting The interviews were carried out in four urban centers in Jordan with the target sample being 1,000 members of the general public. Method This project used the survey methodology administered by structured interviews to general public in four main urban centers in Jordan. The target sample was 1,000. The questionnaire was divided into four sections that measured the knowledge, attitude and practice of the Jordanian population regarding the use of community pharmacy services and OTC drugs. Main outcome measure Perceptions on the professional role of the community pharmacist and the use of OTC drugs as expressed by a sample of the general public in Jordan. Results A total of 1,085 members of the public were interviewed. Proximity to home was the main reason to visit the same pharmacy (26.2%). More than half of the interviewed sample (56.8%) stated that they would always follow the directions on the packet of the OTC product. Males were more likely to increase the dose of the preparation if it did not work within the recommended period of time, while females were more likely to decrease the dose or stop the product (P < 0.05). More than 60% of participants mentioned that they bought antimicrobials from pharmacies without prescriptions. The majority of participants (62.7%) reported that they would seek advice from a pharmacist when the condition was not serious enough to visit the doctor. Conclusions The public in Jordan think highly of the pharmacy profession despite their confusion and uncontrolled consumption of OTC drugs. The findings of this study indicate that drug authorizing bodies in Jordan must be more proactive in promoting appropriate self-medication use and improving pharmaceutical services.

Reasons for choosing dentistry as a career by Arab dental students

Abstract: The aim of this study was to determine the reasons for choosing dentistry as a career in an Arab population of undergraduate dental students in Jordan. An anonymous questionnaire was administered to dental students from year 1 to 5 at the Faculty of Dentistry of the University of Jordan in Amman. The questionnaire comprised 31 items and the students were required to rate the importance of each item for selecting dentistry as a career on a 10 point scale. Parametric tests were used to investigate if statistically significant differences existed between scores for different groups. The response rate for the study was 79% (477 out of 604 students recruited). Two hundred and twenty one students (46%) had dentistry as a first choice. Prestige was given a maximum score by 44.4% of the students recruited and a similar number of students, 43.6% gave a maximum score to the factor representing helping people. There were slight differences in the motivation between male and females with males more motivated by financial factors. It was concluded that ‘prestige’ and ‘helping people’ were important motivating factors in this group of dental students.

Late Neoproterozoic A-type granites in the northernmost Arabian-Nubian Shield formed by fractionation of basaltic melts

Abstract: Geochemical, isotopic and age constraints support a comagmatic origin for Ghuweir Mafics and the Feinan A-type granites. The two rocks types, named collectively in this paper as the Feinan Ghuweir Magmatic Suite (FGMS), formed between 556 and 572 Ma ago according to Rb–Sr whole-rock dating. FGMS has low Sr initial ratios, which preclude a significant contribution of much older crust in the magma genesis. The FGMS has a wide range of silica contents, with a gap at 55–65 wt% SiO2. It has a transalkaline to alkaline character; belongs to the medium to high K calc-alkaline series; it ranges from metaluminous to mildly peraluminous character and belongs to the alkali and alkali-calcic series. The Feinan granites and the Ghuweir rhyolites and rhyodacites are classified as A-type granites and belong to group A2 of Eby [Eby, N.G., 1992. Chemical subdivision of the A-type granitoids: petrogenetic and tectonic iplications. Geology 20, 641–644]. According to geochemical modeling the Ghuweir Mafics were derived from a subduction modified lithospheric mantle by 10% batch modal partial melting of a phlogopite-bearing spinel lherzolite. The intra-suite geochemical variations can be ascribed to fractional crystallization of olivine, pyroxene, and plagioclase. The accumulation of apatite in the most evolved samples is responsible for the high concentrations of REE. The Feinan granites and the Ghuweir rhyolites and rhyodacites were derived from the mafic magma by the fractional crystallization of ≈78% of the original magma to the mineral assemblage olivine+pyroxene+plagioclase+magnetite. The intra-suite geochemical variations in the Feinan A-type granites are due to the fractional crystallization of the mineral phases: amphibole +Na and K-feldspar+apatite +magnetite+zircon+allanite. The FGMS correlates with time-equivalent rocks in many parts of the Arabian-Nubian Shield and the surrounding areas.

Photosynthetic performance of giant clams, Tridacna maxima and T. squamosa, Red Sea

Abstract: Two species of giant clams, Tridacna maxima and T. squamosa, coexist in the Red Sea, but exhibit dis- tinctly different depth distributions: T. maxima mostly occurs in shallow waters (reef flat and edge), while T. squamosa may occur down to the lower fore-reef slope. Giant clams have been described as mixotrophic, capable of both filter-feeding and photosynthesis due to algal symbionts (zooxanthellae), therefore, observed depth preferences were investigated in relation to possible differences in autotrophy vs. heterotrophy. This study was conducted from April to June 2004, at the reef near the Marine Science Station, Aq- aba, Gulf of Aqaba, Red Sea, and in May 2007, at a reef near Dahab, Sinai Peninsula, Egypt. In situ measurements using a submersible pulse amplitude modulated fluorometer (Diving PAM), revealed no significant differences in effective PSII quantum yield (DF/Fm 0 ) and relative electron transport rates (ETR) between the two species; but rapid light curves (ETR vs. light, photosynthetically active irradiance, PAR) showed significant differences in maximum photosynthetic rates (ETRmax), with 20% higher values in T. maxima. Chamber incubations displayed higher net and gross oxygen produc- tion by T. maxima (88.0 and 120.3 lmol O2 cm -2 mantle area day -1 ) than T. squamosa (56.7 and 84.8 lmol O2 cm -2 mantle area day -1 ); even under shading conditions (simu- lated depth of 20 m) T. maxima still achieved 93% of the surface gross O2 production, whereas T. squamosa reached only 44%. A correlation was found between ETR and net photosynthesis measured as oxygen production (T. maxima: R 2 = 0.53; T. squamosa: R 2 = 0.61). Calculated compen- sation depth (CD) (gross photosynthesis equals respiration) in T. maxima (16 m) matches the maximum depth of occurrence in this study (17 m). By contrast, the CD of T. squamosa (9 m) was much shallower than the maximum vertical range (42 m). Findings suggest T. maxima is a strict functional photoautotroph limited by light, whereas T. squamosa is a mixotroph whose photoautotrophic range is extended by heterotrophy.

Detection of sublethal thermal injury in Salmonella enterica serotype typhimurium and Listeria monocytogenes using Fourier transform infrared (FT-IR) spectroscopy (4000 to 600 cm(-1)).

Abstract: Fourier transform infrared (FT-IR) spectroscopy (4000 to 600 cm(-1)) was utilized to detect sublethally heat-injured microorganisms: Salmonella enterica serotype Typhimurium ATCC 14028, a Gram-negative bacterium, and Listeria monocytogenes ATCC 19113, a Gram-positive bacterium. A range of heat treatments (N= 2) at 60 degrees C were evaluated: 0D (control), 2D, 4D, 6D, and 8D using a D(60 degrees C) (S. enterica serotype Typhimurium ATCC 14028 = 0.30 min, L. monocytogenes ATCC 19113 = 0.43 min). The mechanism of cell injury appeared to be different for Gram-negative and Gram-positive microbes as observed from differences in the 2nd derivative transformations and loadings plot of bacterial spectra following heat treatment. The loadings for PC1 and PC2 confirmed that the amide I and amide II bands were the major contribution to spectral variation, with relatively small contributions from C-H deformations, the antisymmetric P==O stretching modes of the phosphodiester nucleic acid backbone, and the C-O-C stretching modes of polysaccharides. Using soft independent modeling of class analogy (SIMCA), the extent of injury could be predicted correctly at least 83% of the time. Partial least squares (PLS) calibration analysis was constructed using 5 latent variables for predicting the bacterial counts for survivors of the different heat treatments and yielded a high correlation coefficient (R= 0.97 [S. enterica serotype Typhimurium] and 0.98 [L. monocytogenes]) and a standard error of prediction (SEP= 0.51 [S. enterica serotype Typhimurium] and 0.39 log(10) CFU/mL [L. monocytogenes]), indicating that the degree of heat injury could be predicted.