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We address the problem of scheduling a set of parts with given processing times and tool requirements on m identical parallel machines. The problem is to find an allocation of the machines to the parts, a proper sequence for the parts assigned to each machine, and a corresponding tool-switching plan for each machine so as to minimize the makespan. It is demonstrated that this problem is np-hard, and three heuristic procedures are proposed for solving it. The first procedure is a multi-start local improvement procedure, and various neighborhood structures and search strategies are discussed in this context. The second procedure is a variation of the list-processing routine that is commonly used for the parallel machine problem. Finally, the last procedure is an adaptation of a well-known constructive procedure for the k-travelling salesman problem. Results of a limited computational experiment are also presented in which the makespan obtained via each heuristic procedure is compared with a proposed lower bound and with other reference values. [ABSTRACT FROM AUTHOR]

We consider alternative sequences of operations for manufacturing a given part. Within each sequence, we study the relationship between the unit-to-unit variation in the machined dimensions and the resulting variation in one or more critical dimensions (i.e. tolerance buildup). We propose an objective criterion for comparing these sequences from the point of view of their impact on the tolerance buildup at the critical dimensions. This criterion, which we refer to as the 'total expected loss' (TEL), is based on the concept of continuous quality loss function. We use TEL as well as the tolerance cost to compare alternative sequences for manufacturing a specific part, and present the results. [ABSTRACT FROM AUTHOR]

We present a mathematical model for scheduling a computer assisted gang-rip saw system. Such systems are typically used within the furniture manufacturing industry for processing (ripping) lumber. This model uses the concept of column generation of linear programming to design appropriate saw arbors, and to select a set of arbors with their corresponding run time, in order to process a given stream of incoming lumber according to a demand schedule for finished cut widths. Results of a limited computational experiment with this model are discussed. [ABSTRACT FROM AUTHOR]

In this paper, we present a novel collaborative Q-Learning based path planning system using Holonic Multi Agent System architecture, and the Fuzzy Inference System, to be used in autonomous mobile robots, represented as head-holons, in order to find the optimal path among any starting point, and a goal in a to 2D grid environment. The decision of the navigation is provided by a fuzzy system controller and then it is verified by a sensor validator. [ABSTRACT FROM AUTHOR]

A lot of projects in real life are subject to some kinds of nonrenewable resources that are not exactly similar to the type defined in the project scheduling literature. The difference stems from the fact that, in those projects, contrary to the common assumption in the project scheduling literature, nonrenewable resources are not available in full amount at the beginning of the project, but they are procured along the project horizon. In this paper, we study this different type of nonrenewable resources. To that end, we extend the resource constrained project scheduling problem (RCPSP) by this resource type (RCPSP-NR) and customize four basic branch and bound algorithms of RCPSP for it, including precedence tree, extension alternatives, minimal delaying alternatives, and minimal forbidden sets. Several bounding and fathoming rules are introduced to the algorithms to shorten the enumeration process. We perform comprehensive experimental analysis using the four customized algorithms and also CPLEX solver. [ABSTRACT FROM AUTHOR]

Bone marrow-derived mesenchymal stem cells (BMSCs) are promising for use in regenerative medicine. Several studies have shown that low-level laser irradiation (LLLI) could affect the differentiation and proliferation of MSCs. The aim of this study was to examine the influence of LLLI at different energy densities on BMSCs differentiation into neuron and osteoblast. Human BMSCs were cultured and induced to differentiate to either neuron or osteoblast in the absence or presence of LLLI. Gallium aluminum arsenide (GaAlAs) laser irradiation (810 nm) was applied at days 1, 3, and 5 of differentiation process at energy densities of 3 or 6 J/cm(2) for BMSCs being induced to neurons, and 2 or 4 J/cm(2) for BMSCs being induced to osteoblasts. BMSCs proliferation was evaluated by MTT assay on the seventh day of differentiation. BMSCs differentiation to neurons was assessed by immunocytochemical analysis of neuron-specific enolase on the seventh day of differentiation. BMSCs differentiation to osteoblast was tested on the second, fifth, seventh, and tenth day of differentiation via analysis of alkaline phosphatase (ALP) activity. LLLI promoted BMSCs proliferation significantly at all energy densities except for 6 J/cm(2) in comparison to control groups on the seventh day of differentiation. LLLI at energy densities of 3 and 6 J/cm(2) dramatically facilitated the differentiation of BMSCs into neurons (p < 0.001). Also, ALP activity was significantly enhanced in irradiated BMSCs differentiated to osteoblast on the second, fifth, seventh, and tenth day of differentiation (p < 0.001 except for the second day). Using LLLI at 810 nm wavelength enhances BMSCs differentiation into neuron and osteoblast in the range of 2-6 J/cm(2), and at the same time increases BMSCs proliferation (except for 6 J/cm(2)). The effect of LLLI on differentiation and proliferation of BMSCs is dose-dependent. Considering these findings, LLLI could improve current in vitro methods of differentiating BMSCs prior to transplantation. [ABSTRACT FROM AUTHOR]

Abstract: As species extinction rates continue to rise, zoos have adopted a more active role in the conservation of endangered species. A central concern is to preserve genetic diversity of zoological populations. Accordingly, when selecting individuals to transfer to new or existing populations, zoo managers must consider the genetic effects on all populations involved. We propose a quadratic integer programming (IP) model to identify a group of individuals to transfer that maximizes genetic diversity within two subpopulations. We then reduce this model to a linear IP formulation and apply it to the California condor (Gymnogyps californianus) studbook. After simplifying the linear IP model, optimality is achieved within a reasonable time limit when a limited number of individuals are relocated. We also develop a local improvement algorithm (LIA) to efficiently provide near-optimal solutions when we increase the number of transferred individuals. The LIA quickly obtains optimal solutions when few individuals are transferred and in most cases, the LIA outperforms MetaMK, an existing program used to select animals for transfer. [ABSTRACT FROM AUTHOR]

Although the transformation method can essentially be used to generate any distribution, its application to the α‐µ model involves inversion of the incomplete gamma function. Such inversion of a special function does not lead to a closed‐form expression but is usually implemented using iterative methods, which heavily burden any simulation machine. By introducing a novel synthetic α‐µ variant generation method, free from iterations and special functions, the proposed approach will be appropriate for building generalised real‐time fading simulators. [ABSTRACT FROM AUTHOR]

A versatile generalised expression for energy detector performance is derived using the α-µ generalised gamma fading model. The derived expression for probability of detection includes as special cases, Nakagami-m, Weibull gamma and inherently their successors. Furthermore, the new expression accommodates non-integer parameters for the fading model and the detector. [ABSTRACT FROM AUTHOR]

Background: Brucellosis is still a serious public health threat in developing countries, especially in Iran. Brucellosis is an endemic disease in Iran and risk factors increasing its broadcast are prevalent. This study investigated factors influencing brucellosis preventive behaviors amongst marginalized women in Hamadan city, Iran, using the health belief model (HBM)., Methods: In this cross-sectional study, 289 women living in marginal areas were considered from April until May 2018. Via cluster random sampling methods, comprehensive health services where women get health care were selected. Each woman in the selected comprehensive health services was then enrolled by the simple random sampling method. Data were gathered from a face-to-face interview via a questionnaire., Results: Most women had a history of using nonpasteurized dairy products (86.2%). Most women (64.7%) boiled the milk for 3-5 minutes. 61.2% of women put the cheese in a salt-water solution. The results showed that one unit rise in the scores of knowledge, self-efficacy, and cues to action resulted in an increase in the mean score of the protective behavior by 0.189, 209, and 0.150, respectively., Conclusion: The HBM was a helpful model in predicting the influential elements in brucellosis preventive behaviors. Also, recognized effective factors should be taken into account when designing interventions., Competing Interests: No conflicts of interest were reported by the authors., (Copyright © 2022 Majid Barati et al.)

To date, decoding limb kinematic information mostly relies on neural signals recorded from the peripheral nerve, dorsal root ganglia (DRG), ventral roots, spinal cord gray matter, and the sensorimotor cortex. In the current study, we demonstrated that the neural signals recorded from the lateral and dorsal columns within the spinal cord have the potential to decode hindlimb kinematics during locomotion. Experiments were conducted using intact cats. The cats were trained to walk on a moving belt in a hindlimb-only condition, while their forelimbs were kept on the front body of the treadmill. The bilateral hindlimb joint angles were decoded using local field potential signals recorded using a microelectrode array implanted in the dorsal and lateral columns of both the left and right sides of the cat spinal cord. The results show that contralateral hindlimb kinematics can be decoded as accurately as ipsilateral kinematics. Interestingly, hindlimb kinematics of both legs can be accurately decoded from the lateral columns within one side of the spinal cord during hindlimb-only locomotion. The results indicated that there was no significant difference between the decoding performances obtained using neural signals recorded from the dorsal and lateral columns. The results of the time-frequency analysis show that event-related synchronization (ERS) and event-related desynchronization (ERD) patterns in all frequency bands could reveal the dynamics of the neural signals during movement. The onset and offset of the movement can be clearly identified by the ERD/ERS patterns. The results of the mutual information (MI) analysis showed that the theta frequency band contained significantly more limb kinematics information than the other frequency bands. Moreover, the theta power increased with a higher locomotion speed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Fathi and Erfanian.)

Deep brain stimulation (DBS) has become an effective therapeutic solution for Parkinson's disease (PD). Adaptive closed-loop DBS can be used to minimize stimulation-induced side effects by automatically determining the stimulation parameters based on the PD dynamics. In this paper, by modeling the interaction between the neurons in populations of the thalamic, the network-level modulation of thalamic is represented in a standard canonical form as a multi-input multi-output (MIMO) nonlinear first-order system with uncertainty and external disturbances. A class of fast and robust MIMO adaptive fuzzy terminal sliding mode control (AFTSMC) has been presented for control of membrane potential of thalamic neuron populations through continuous adaptive DBS current applied to the thalamus. A fuzzy logic system (FLS) is used to estimate the unknown nonlinear dynamics of the model, and the weights of FLS are adjusted online to guarantee the convergence of FLS parameters to optimal values. The simulation results show that the proposed AFTSMC not only significantly produces lower tracking errors in comparison with the classical adaptive fuzzy sliding mode control (AFSMC), but also makes more robust and reliable outputs. The results suggest that the proposed AFTSMC provides a more robust and smooth control input which is highly desirable for hardware design and implementation., (© 2021. The Author(s).)

Objective . The main objective of this research is to record both sensory and motor information from the ascending and descending tracts within the spinal cord to decode the hindlimb kinematics during walking on a treadmill. Approach . Two different experimental paradigms (i.e. active and passive) were used in the current study. During active experiments, five cats were trained to walk bipedally while their hands were kept on the front frame of the treadmill for balance or to walk quadrupedally. During passive experiments, the limb was passively moved by the experimenter. Local field potential (LFP) activity was recorded using a microwire array implanted in the dorsal column (DC) and lateral column (LC) of the L3-L4 spinal segments. The amplitude and frequency components of the LFP formed the feature set, and the elastic net regularization was used to decode the hindlimb joint angles. Main results. The results show that there is no significant difference between the information content of the signals recorded from the DC and LC regions during walking on the treadmill, but the information content of the DC is significantly higher than that of the LC during passively applied movement of the hindlimb in the anesthetized cats. Moreover, the decoding performance obtained using the recorded signals from the DC is comparable with that from the LC during locomotion. However, the decoding performance obtained using the recording channels in the DC is significantly better than that obtained using the signals recorded from the LC. The long-term analysis shows that robust decoding performance can be achieved over 2-3 months without a significant decrease in performance. Significance . This work presents a promising approach to developing a natural and robust motor neuroprosthesis device using descending neural signals to execute the movement and ascending neural signals as the feedback information to control the movement., (© 2021 IOP Publishing Ltd.)

Objective: Providing accurate and robust estimates of limb kinematics from recorded neural activities is prominent in closed-loop control of functional electrical stimulation (FES). A major issue in providing accurate decoding the limb kinematics is the decoding model. The primary goal of this study is to develop a decoding approach to model the dynamic interactions of neural systems for accurate decoding. Another critical issue is to find reliable recording sites. Up to now, neural recordings from spinal neural activities were investigated. In this paper, the neural recordings from different vertebrae in decoding limb kinematics are investigated., Approach: In the current study, a new generative probabilistic model with explicit considering the joint density is developed. Then, an adaptive discriminative learning algorithm is proposed for learning the model. It will be shown that the proposed generative process can be implemented by a recurrent neural network (RNN) with specific structure. We record the neural activities from dorsal horn neurons by using three electrodes placed in the L4, L5, and L6 vertebrae in anesthetized cats., Main Results: Information theoretic analysis on single-joint movement and multi-segment recordings implies the rostrocaudal distribution of kinematic information. It is demonstrated that during hip movement, best decoding performance is achieved by L4 recordings. For knee and ankle movements, best decodings are achieved by L5, and L6 recordings respectively. It is also shown that the decoding accuracy using multi-segment recordings outperforms decoding accuracy obtained by single-segment recording in multi-joint movement. The results also confirm the superiority of the proposed probabilistic recurrent neural network (PRNN) over the conventional recurrent neural network and Kalman filter ([Formula: see text])., Significance: Multi-segment recordings from dorsal horn neurons as well as the proposed probabilistic recurrent network model provide a promising approach for robust and accurate decoding limb kinematics.

A photolytically Cl-initiated oxidation reaction of 2-phenylethanol (2PE) was carried out at the Advanced Light Source (ALS) in the Lawrence Berkeley National Laboratory. Using the multiplex photoionization mass spectrometer, coupled with the tunable vacuum ultraviolet radiation of the ALS, data were collected at low pressure (4-6 Torr) and temperature (298-550 K) regimes. Data analysis was performed via characterization of the reaction species photoionization spectra and kinetic traces. Products and reaction pathways are also computed using the CBS-QB3 composite method. The present results suggest primary products m/ z = 30 (formaldehyde), 106 (benzaldehyde), and 120 (phenylacetaldehyde) at 298 K, and m/ z = 120 (phenylacetaldehyde) at 550 K. Branching fractions at room temperature are 27 ± 6.5% for formaldehyde, 24 ± 4.5% for benzaldehyde, and 25 ± 5.8% for phenylacetaldehyde and 60 ± 14% for phenylacetaldehyde at 550 K.

Decoding continuous hind limb joint angles from sensory recordings of neural system provides a feedback for closed-loop control of hind limb movement using functional electrical stimulation. So far, many attempts have been done to extract sensory information from dorsal root ganglia and sensory nerves. In this work, we examine decoding joint angles trajectories from the single-electrode extracellular recording of dorsal horn gray matter of the spinal cord during passive limb movement in anesthetized cats. In this study, a processing framework based on ensemble learning approach is propose to combine firing rate (FR) and interspike interval (ISI) information of the neuronal activity. For this purpose, a stacked generalization approach based on recurrent neural network is proposed to enhance decoding accuracy of the movement kinematics. The results show that the high precision neural decoding of limb movement can be achieved even with a single electrode implanted in the spinal cord gray matter.

Background: Operating room personnel are at high risk of needlestick injuries (NSIs) and exposure to blood and body fluids., Objective: To investigate the predictors of NSIs preventive behaviors during surgery among operating room personnel based on a health belief model (HBM)., Methods: This cross-sectional study was conducted on 128 operating room personnel in Hamadan, western Iran. Participants were selected, by census sampling, from teaching hospitals, completed a self-reported questionnaire including demographic characteristics, knowledge and HBM constructs., Results: The levels of knowledge and perceived self-efficacy for the NSIs preventive behaviors among operating room personnel were not satisfactory. However, the levels of perceived benefits, susceptibility and severity were reported to be relatively good. The results showed that the perceived susceptibility (β ‑0.627) and cues to action (β 0.695) were the most important predictors of the NSIs preventive behaviors., Conclusion: The framework of the HBM is useful to predict the NSIs preventive behaviors among operating room personnel.

The O-( 3 P)-initiated oxidation of 2-methylfuran (2-MF) was investigated using vacuum-ultraviolet synchrotron radiation from the Advanced Light Source at Lawrence Berkeley National Laboratory. Reaction species were studied by multiplexed photoionization mass spectrometry at 550 and 650 K. The oxygen addition pathway is favored in this reaction, forming four triplet diradicals that undergo intersystem crossing into singlet epoxide species that lead to the formation of products at m/z 30 (formaldehyde), 42 (propene), 54 (1-butyne, 1,3-butadiene, and 2-butyne), and 70 (2-butenal, methyl vinyl ketone, and 3-butenal). Mass-to-charge ratios, photoionization spectra, and adiabatic ionization energies for each primary reaction species were obtained and used to characterize their identities. In addition, by means of electronic structure calculations, potential energy surface scans of the different species produced throughout the oxidation were examined to further validate the primary chemistry occurring. Branching fractions for the formation of the primary products were calculated at the two temperatures and contribute 81.0 ± 21.4% at 550 K and 92.1 ± 25.5% at 650 K.

Absolute photoionization cross sections for cyclopentanone and cyclohexanone, as well as partial ionization cross sections for the dissociative ionized fragments, are presented in this investigation. Experiments are performed via a multiplexed photoionization mass spectrometer utilizing vacuum ultraviolet (VUV) synchrotron radiation supplied by the Advanced Light Source of Lawrence Berkeley National Laboratory. These results allow the quantification of these species that is relevant to investigate the kinetics and combustion reactions of potential biofuels. The CBS-QB3 calculated values for the adiabatic ionization energies agree well with the experimental values, and the identification of possible dissociative fragments is discussed for both systems. Copyright © 2017 John Wiley & Sons, Ltd., (Copyright © 2017 John Wiley & Sons, Ltd.)

This work studies the oxidation of 2-methyl-3-buten-2-ol initiated by O( 3 P) atoms. The oxidation was investigated at room temperature, 550, and 650 K. Using the synchrotron radiation from the Advanced Light Source (ALS) of the Lawrence Berkley National Laboratory, reaction intermediates and products were studied by multiplexed photoionization mass spectrometry. Mass-to-charge ratios, kinetic time traces, photoionization spectra, and adiabatic ionization energies for each primary reaction species were obtained and used to characterize their identity. Using electronic structure calculations, potential energy surface scans of the different species produced throughout the oxidation were examined and presented in this paper to further validate the primary chemistry occurring. Branching fractions of primary products at all three temperatures were also provided. At room temperature only three primary products formed: ethenol (26.6%), acetaldehyde (4.2%), and acetone (53.4%). At 550 and 650 K the same primary products were observed in addition to propene (5.1%, 11.2%), ethenol (18.1%, 2.8%), acetaldehyde (8.9%, 5.7%), cyclobutene (1.6%, 10.8%), 1-butene (2.0%, 10.9%), trans-2-butene (3.2%, 23.1%), acetone (50.4%, 16.8%), 3-penten-2-one (1.0%, 11.5%), and 3-methyl-2-butenal (0.9%, 2.5%), where the first branching fraction value in parentheses corresponds to the 550 K data. At the highest temperature, a small amount of propyne (1.0%) was also observed.

Background: Controversy exists as to whether the lipid-lowering properties of kefir drink (a fermented probiotic dairy product) in animal models could be replicated in humans., Objective: To assess and compare the potential lipid-lowering effects of kefir drink with low-fat milk in a dairy-rich diet in overweight or obese premenopausal women., Methods: In this 8-week, single-center, multiarm, parallel-group, outpatient, randomized controlled trial, 75 eligible Iranian women aged 25 to 45 years were randomly allocated to kefir, milk, or control groups. Women in the control group received a weight-maintenance diet containing 2 servings/d of low-fat dairy products, whereas subjects in the milk and kefir groups received a similar diet containing 2 additional servings/d (a total of 4 servings/d) of dairy products from low-fat milk or kefir drink, respectively. At baseline and study end point, serum levels/ratios of total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDLC and HDLC), triglyceride, Non-HDLC, TC/HDLC, LDLC/HDLC, and triglyceride/LDLC were measured as outcome measures., Results: After 8 weeks, subjects in the kefir group had significantly lower serum levels/ratios of lipoproteins than those in the control group (mean between-group differences were -10.4 mg/dL, -9.7 mg/dL, -11.5 mg/dL, -0.4, and -0.3 for TC, LDLC, non-HDLC, TC/HDLC, and LDLC/HDLC, respectively; all P < .05). Similar results were observed in the milk group. However, no such significant differences were found between the kefir and milk groups., Conclusion: Kefir drink causes a significant yet similar improvement in serum lipid profile, compared with low-fat milk, in a dairy-rich diet in overweight or obese premenopausal women., (Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study is to compare intracoronary (IC) bolus only with IC bolus plus maintenance intravenous (IV) infusion of glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitors with respect to 1-year major adverse cardiac events including mortality, nonfatal myocardial infarction, revascularization, and bleeding events after primary percutaneous coronary intervention (PCI)., Methods: This is an observational study of 233 consecutive patients who presented with ST-elevation myocardial infarction and underwent primary PCI between April 2009 and December 2012. Patients were grouped into (1) patients who received IC bolus only (n = 102) and (2) patients who received IC bolus plus maintenance IV infusion of GP IIb/IIIa inhibitors (n = 131). In-hospital post procedural myocardial infarction occurred in 4 (1.7 %) of patients., Results: Mortality occurred in one patient who was treated with IV infusion. Major bleeding occurred in only 5 patients, among whom 4 patients had received GP IIb/IIIa inhibitors IV infusion. However, the difference was not statistically significant (P = 0.389)., Conclusion: Both univariate analysis and the adjusted model for the potential confounders revealed no significant association between the way of GP IIb/IIIa inhibitors administration and 1-year major adverse cardiac events. Our findings suggested that IV infusion of GP IIb/IIIa inhibitors after the bolus dose is not associated with better 1-year outcome after adjustment for confounding variables. Moreover, IV infusion may increase the risk of major bleedings after primary PCI. This finding implies that the need for IV infusion of GP IIb/IIIa inhibitors in patients undergoing primary PCI is under question.

Purpose: Controversy exists regarding whether increasing dairy intake without energy restriction would lead to weight loss. We aimed to compare the potential weight-reducing effects of kefir drink (a probiotic dairy product) and milk in a dairy-rich non-energy-restricted diet in overweight or obese premenopausal women., Methods: One hundred and forty-four subjects were assessed for eligibility in this single-center, multi-arm, parallel-group, randomized controlled trial. Of these, seventy-five eligible women aged 25-45 years were randomly assigned to three groups, labeled as control, milk, and kefir, to receive an outpatient dietary regimen for 8 weeks. Subjects in the control group received a diet providing a maintenance level of energy intake, containing 2 servings/day of low-fat dairy products, while those in the milk and kefir groups received a weight maintenance diet, containing 2 additional servings/day (a total of 4 servings/day) of dairy products from low-fat milk or commercial kefir drink, respectively. Anthropometric outcomes including weight, body mass index (BMI), and waist circumference (WC) were measured every 2 weeks., Results: Fifty-eight subjects completed the study. Using analysis of covariance models in the intention-to-treat population (n = 75), we found that at 8 weeks, subjects in the kefir and milk groups had significantly greater reductions in weight, BMI, and WC compared to those in the control group (all p < 0.01). However, no such significant differences were found between the kefir and milk groups., Conclusions: Kefir drink leads to a similar weight loss, compared with milk, in a dairy-rich non-energy-restricted diet in overweight or obese premenopausal women. However, further studies are warranted.

Objectives: To evaluate, with magnetic resonance imaging (MRI), the occurrence of bone and tendon injuries and their impact on clinical management in athletes with ankle trauma during sports activities having normal radiographs and referred to the orthopedic department as "ankle sprains"., Methods: This was a prospective study of 54 patients. Clinical examination and MR imaging were done in order to have an accurate diagnosis and the incidence of those injuries., Results: Nearly half of the patients were found to have no ligament injury on MRI. Isolated bone bruises and isolated tendon injuries may share the same clinical signs with ankle sprains., Conclusions: MRI-based clinical management has been adjusted for each case; beside the Grade 3 ligament injuries and the rare, but difficult to diagnose osteochondral lesions of the talus, partial weight bearing or short-immobilization were offered as treatment modalities for the rest of the patients avoiding unnecessary long-term treatments and rehabilitation exercises., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Both opioids and calcium channel blockers could affect hypothalamic-pituitary-adrenal (HPA) axis function. Nifedipine, as a calcium channel blocker, can attenuate the development of morphine dependence; however, the role of the HPA axis in this effect has not been elucidated. We examined the effect of nifedipine on the induction of morphine dependency in intact and adrenalectomized (ADX) male rats, as assessed by the naloxone precipitation test. We also evaluated the effect of this drug on HPA activity induced by naloxone. Our results showed that despite the demonstration of dependence in both groups of rats, nifedipine is more effective in preventing of withdrawal signs in ADX rats than in sham-operated rats. In groups that received morphine and nifedipine concomitantly, naloxone-induced corticosterone secretion was attenuated. Thus, we have shown the involvement of the HPA axis in the effect of nifedipine on the development of morphine dependency and additionally demonstrated an in vivo interaction between the L-type Ca2+ channels and corticosterone.