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For a small satellite, the processor onboard the attitude determination and control system (ADCS) is required to monitor, communicate, and control all the sensors and actuators. In addition, the processor is required to consistently communicate with the satellite bus. Consequently, the processor is unable to ensure all the sensors and actuators will immediately respond to the data acquisition request, which leads to asynchronous data problems. The extended Kalman filter (EKF) is commonly used in the attitude determination process, but it assumes fully synchronous data. The asynchronous data problem would greatly degrade the attitude determination accuracy by EKF. To minimize the attitude estimation accuracy loss due to asynchronous data while ensuring a reasonable computational complexity for small satellite applications, this paper proposes the simplex-back-propagation Kalman filter (SBPKF). The proposed SBPKF incorporates the time delay, gyro instability, and navigation error into both the measurement and covariance estimation during the Kalman update process. The performance of SBPKF has been compared with EKF, modified adaptive EKF (MAEKF), and moving-covariance Kalman filter (MC-KF). Simulation results show that the attitude estimation error of SBPKF is at least 30% better than EKF and MC-KF. In addition, the SBPKF's computational complexity is 17% lower than MAEKF and 29% lower than MC-KF.

Background: There is an increasing public interest in the use of TM internationally, yet there is a paucity of research on the use of TM by the public in the dental setting. This study aimed to explore the views, use of and access to TM in dentistry among different ethnic groups residing in New Zealand., Methods: Qualitative study and in-depth interviews were used. An individual semi-structured questionnaire was used to collect data. Interviews were recorded, transcribed, and analysed using an inductive approach to identify the main themes., Results: Three main themes were extracted from interviews with 14 participants from diverse cultural backgrounds: [1] the perspectives of TM varied among different ethnic groups and included the involvement of spirituality, the environment, knowledge and usage of TM. [2] The TM that was used by different ethnic groups included plants, herbs, massage, and other forms of healing. Reasons for choosing traditional or western medicines generally included family tradition, access to TM, and finding a competent traditional healer. [3] The barriers in accessing TM included the paucity of traditional healers, difficulty accessing plants and cost, therefore most would look for a substitution or alternative treatment., Conclusion: Even though the access to these TM in New Zealand was a challenge for the majority of the participants, they are still considered the first-line treatment for the majority. This study provided dental practitioners an insight into the different sort of TM used by the population. By understanding and acknowledging the use of TM, dental practitioners could create a supportive environment for patients to disclose their use of TM and allow them to educate patients on the use of TM.

This paper presents a new highly accurate gait phase detection system using wearable wireless ultrasonic sensors, which can be used in gait analysis or rehabilitation applications. The gait phase detection system uses the foot displacement information during walking to extract the following gait phases: heel-strike, heel-off, toe-off, and mid-swing. The displacement of foot-mounted ultrasonic sensor is obtained from several passive anchors placed at known locations by employing local spherical positioning technique, which is further enhanced by the combination of recursive Newton-Gauss method and Kalman Filter. The algorithm performance is examined by comparing with a commercial optical motion tracking system with ten healthy subjects and two foot injured subjects. Accurate estimates of gait cycle (with an error of -0.02 ±0.01 s), stance phase(with an error of 0.04±0.03 s), and swing phase (with an error of -0.05±0.03 s) compared to the reference system are obtained. We have also investigated the influence of walking velocities on the performance of the proposed gait phase detection algorithm. Statistical analysis shows that there is no significant difference between both systems during different walking speeds. Moreover, we have tested and discussed the possibility of the proposed system for clinical applications by analyzing the experimental results for both healthy and injured subjects. The experiments show that the estimated gait phases have the potential to become indicators for sports and rehabilitation engineering.

We present the discovery of a new crystal structure polymorph (1) and pseudopolymorph (2) of the Black Dye, one of the world's leading dyes for dye-sensitized solar cells, DSSCs (10.4% device performance efficiency). This reveals that Black Dye molecules can adopt multiple low-energy conformers. This is significant since it challenges existing models of the Black Dye···TiO2 adsorption process that renders a DSSC working electrode; these have assumed a single molecular conformation that refers to the previously reported Black Dye crystal structure (3). The marked structural differences observed between 1, 2, and 3 make the need for modeling multiple conformations more acute. Additionally, the ordered form of the Black Dye (1) provides a more appropriate depiction of its anionic structure, especially regarding its anchoring group and NCS bonding descriptions. The tendency toward NCS ligand isomerism, evidenced via the disordered form 2, has consequences for electron injection and electron recombination in Black Dye embedded DSSC devices. Dyes 2 and 3 differ primarily by the absence or presence of a solvent of crystallization, respectively; solvent environment effects on the dye are thereby elucidated. This discovery of multiple Black Dye conformers from diffraction, with atomic-level definition, complements recently reported nanoscopic evidence for multiple dye conformations existing at a dye···TiO2 interface, for a chemically similar DSSC dye; those results emanated from imaging and spectroscopy, but were unresolved at the submolecular level. Taken together, these findings lead to the general notion that multiple dye conformations should be explicitly considered when modeling dye···TiO2 interfaces in DSSCs, at least for ruthenium-based dye complexes.

This paper presents an unrestrained measurement system based on a wearable wireless ultrasonic sensor network to track the lower extremity joint and trunk kinematics during a squat exercise with only one ultrasonic sensor attached to the trunk. The system consists of an ultrasound transmitter (mobile) and multiple receivers (anchors) whose positions are known. The proposed system measures the horizontal and vertical displacement, together with known joint constraints, to estimate joint flexion/extension angles using an inverse kinematic model based on the damped least-squares technique. The performance of the proposed ultrasonic measurement system was validated against a camera-based tracking system on eight healthy subjects performing a planar squat exercise. Joint angles estimated from the ultrasonic system showed a root mean square error (RMSE) of 2.85° ± 0.57° with the reference system. Statistical analysis indicated great agreements between these two systems with a Pearson's correlation coefficient (PCC) value larger than 0.99 for all joint angles' estimation. These results show that the proposed ultrasonic measurement system is useful for applications, such as rehabilitation and sports.

Distributed transmission rate tuning is important for a wide variety of IEEE 802.15.4 network applications such as industrial network control systems. Such systems often require each node to sustain certain throughput demand in order to guarantee the system performance. It is thus essential to determine a proper transmission rate that can meet the application requirement and compensate for network imperfections (e.g., packet loss). Such a tuning in a heterogeneous network is difficult due to the lack of modeling techniques that can deal with the heterogeneity of the network as well as the network traffic changes. In this paper, a distributed transmission rate tuning algorithm in a heterogeneous IEEE 802.15.4 CSMA/CA network is proposed. Each node uses the results of clear channel assessment (CCA) to estimate the busy channel probability. Then a mathematical framework is developed to estimate the on-going heterogeneous traffics using the busy channel probability at runtime. Finally a distributed algorithm is derived to tune the transmission rate of each node to accurately meet the throughput requirement. The algorithm does not require modifications on IEEE 802.15.4 MAC layer and it has been experimentally implemented and extensively tested using TelosB nodes with the TinyOS protocol stack. The results reveal that the algorithm is accurate and can satisfy the throughput demand. Compared with existing techniques, the algorithm is fully distributed and thus does not require any central coordination. With this property, it is able to adapt to traffic changes and re-adjust the transmission rate to the desired level, which cannot be achieved using the traditional modeling techniques.

Energy is scarce in mobile computing devices including wearable and implantable devices in a wireless body area network. In this paper, an adaptive routing protocol is developed and analyzed which minimizes the energy cost per bit of information by using the channel information to choose the best strategy to route data. In this approach, the source node will switch between direct and relayed communication based on the quality of the link and will use the relay only if the channel quality is below a certain threshold. The mathematical model is then validated through simulations which shows that the adaptive routing strategy can improve energy efficiency significantly compared with existing methods.

Techniques that could be used to monitor human motion precisely are helpful in various applications such as rehabilitation, gait analysis, and athletic performance analysis. This paper focuses on the 3-D foot trajectory measurements based on a wearable wireless ultrasonic sensor network. The system consists of an ultrasonic transmitter (mobile) and several receivers (anchors) with fixed known positions. In order not to restrict the movement of subjects, a radio frequency (RF) module is used for wireless data transmission. The RF module also provides the synchronization clock between mobile and anchors. The proposed system measures the time-of-arrival (TOA) of the ultrasonic signal from mobile to anchors. Together with the knowledge of the anchor's position, the absolute distance that the signal travels can be computed. Then, the range information defines a circle centered at this anchor with radius equal to the measured distance, and the mobile resides within the intersections of several such circles. Based on the TOA-based tracking technique, the 3-D foot trajectories are validated against a camera-based motion capture system for ten healthy subjects walking on a treadmill at slow, normal, and fast speeds. The experimental results have shown that the ultrasonic system has sufficient accuracy of net root-mean-square error ( 4.2 cm) for 3-D displacement, especially for foot clearance with accuracy and standard deviation ( 0.62 ±7.48 mm) compared to the camera-based motion capture system. The small form factor and lightweight feature of the proposed system make it easy to use. Such a system is also much lower in cost compared to the camera-based tracking system.

A major deficit in suitable dyes is stifling progress in the dye-sensitised solar cell (DSC) industry. Materials discovery strategies have afforded numerous new dyes; yet, corresponding solution-based DSC device performance has little improved upon 11% efficiency, achieved using the N719 dye over two decades ago. Research on these dyes has nevertheless revealed relationships between the molecular structure of dyes and their associated DSC efficiency. Here, such structure-property relationships have been codified in the form of molecular dye design rules, which have been judiciously sequenced in an algorithm to enable large-scale data mining of dye structures with optimal DSC performance. This affords, for the first time, a DSC-specific dye-discovery strategy that predicts new classes of dyes from surveying a representative set of chemical space. A lead material from these predictions is experimentally validated, showing DSC efficiency that is comparable to many well-known organic dyes. This demonstrates the power of this approach.

In this paper, a low-cost motion analysis system using a wireless ultrasonic sensor network is proposed and investigated. A methodology has been developed to extract spatial-temporal gait parameters including stride length, stride duration, stride velocity, stride cadence, and stride symmetry from 3D foot displacements estimated by the combination of spherical positioning technique and unscented Kalman filter. The performance of this system is validated against a camera-based system in the laboratory with 10 healthy volunteers. Numerical results show the feasibility of the proposed system with average error of 2.7% for all the estimated gait parameters. The influence of walking speed on the measurement accuracy of proposed system is also evaluated. Statistical analysis demonstrates its capability of being used as a gait assessment tool for some medical applications.

In this paper, a new method for measuring and monitoring human body joint angles, which uses wearable ultrawideband (UWB) transceivers mounted on body segments, is proposed and investigated. The model is based on providing a high ranging accuracy (intersensor distance) between a pair of transceivers placed on the adjacent segments of the joint center of rotation. The measured distance is then used to compute the joint angles based on the law of cosines. The performance of the method was compared with a flexible goniometer by simultaneously measuring joint flexion-extension angles at different angular velocities, ranging between 8 and 90(°) /s. The measurement errors were evaluated by the average differences between two sets of data (ranging from 0.8(°) for slow movement to 2.8(°) for fast movement), by standard deviation (ranging from 1.2(°) to 4.2(°) for various movement speeds) and by the Pearson correlation coefficient (greater than 0.99) which demonstrates the very good performance of the UWB-based approach. The experimental results have shown that the system has sufficient accuracy for clinical applications, such as rehabilitation.

In this paper, an ultrasonic-based system for foot parameters measurement has been proposed and investigated. An extended Kalman filtering-based methodology has been developed to extract foot parameters including step length, stride length and cycle time from horizontal displacement during walking. The system comprises of one ultrasonic transmitter (mobile) and four ultrasonic receivers (anchors) with fixed known positions. A Radio Frequency (RF) module is used in our system not only to provide synchronization clock between the mobile and anchors, but also to transmit collected data wirelessly to reduce the wires used. To evaluate the performance of the proposed system, the 2-dimensional foot displacement and the foot parameters were measured and validated against the reference camera motion capture system. These experiment results demonstrate the capability of the proposed system being used as a gait analysis tool for rehabilitation and other medical applications.

This paper introduces a novel method for arm flexion/extension angles measurement using wireless ultrasonic sensor network. The approach uses unscented Kalman filter and D-H kinematical chain model to retrieve the joint angles. This method was experimentally validated by calculating the 2-dimensional wrist displacements from one mobile, placed on the point of subject's wrist, and four anchors. The performance of the proposed ultrasonic motion analysis system was bench-marked by commercial camera motion capture system. The experimental results demonstrate that a favorable performance of the proposed system in the estimation of upper limb motion. The proposed system is wireless, easy to wear, to use and much cheaper than current camera system. Thus, it has the potential to become a new and useful tool for routine clinical assessment of human motion.

Ru L(2,3) edge x-ray absorption near-edge spectroscopy spectra of four compounds [Ru(SO(2))(NH(3))(4)X]Y (X =  water, Y = (±)-camphorsulfonate(2); X =water, Y = tosylate(2); X =isonicotinamide, Y = tosylate(2); X =pyridine, Y = triflate(2)) are reported before and after optical excitation, which causes photoinduced linkage isomerism of the SO(2) ligand. Principal component analysis reveals consistent changes in the spectra upon photoisomerization, suggesting a partial oxidation of the Ru ion. These results demonstrate that x-ray absorption near-edge spectroscopy is an effective means of probing photoinduced linkage isomerism.

This paper proposes a wearable system using UWB transceivers to measure the knee flexion/extension angle parameter, who is known to be of clinical importance. First, a pair of very small and light antennas is placed on the adjacent segments of knee joint. Then, the range data between these two antennas is acquired using Time of Arrival (TOA) estimator. We further use the measured distance to compute the flexion/extension angle using the law of cosines. The performance of the method was compared with a flexible goniometer by simultaneously measuring knee flexion-extension angle. The experimental results show that the system has reasonable performance and has sufficient accuracy for clinical applications.

Foot clearance above ground is a key factor for a better understanding of the complicated relationship between falls and gait. This paper proposes a wearable system using UWB transceivers to monitor the vertical heel/toe clearance during walking. First, a pair of very small and light antennas is placed on a point approximating to the heel/toe of the foot, acting as a transmitter and receiver. Then, the reflected signal from ground is captured and propagation delay is detected using noise suppressed Modified-Phase-Only-Correlator (MPOC). The performance of the UWB-based system was compared with an ultrasound system for stationary movements. The experimental results show that an overall mean difference between these two systems is about 0.634mm with correlation coefficient value of 0.9604. The UWB-based system is then used to measure foot clearance during walking which shows promising results for gait events detection.

As part of an effort to design more efficient dyes for dye-sensitized solar cells (DSCs), structure-property relationships are established in the world's best-performing chemical series of dyes: 2,2'-bipyridyl-4,4'-carboxylatoruthenium(II) complexes. Statistical analysis, based on crystallographic data from the Cambridge Structural Database, is used to determine common structural features and the effects of structural change to its salient molecular constituents. Also included is the report of two new crystal structures for tris(2,2'-bipyridyl)dichlororuthenium(II)hexahydrate and tris(2,2'-bipyridyl)iron(II)dithiocyanate; these add to this statistical enquiry. Results show that the metal (M) core exhibits a distorted octahedral environment with M-N π-backbonding effects affording the propensity of the metal ion towards oxidation. The same characteristics are observed in iron-based analogues. The role of carboxylic groups in this series of dyes is assessed by comparing complexes which contain or are devoid of COOH groups. Space-group variation and large molecular conformational differences occur when COOH groups are present, while such structural features are very similar in their absence. The nature of the anion is also shown to influence the structure of COOH-containing complexes. These structural findings are corroborated by solution-based UV-vis absorption spectroscopy and DSC device performance tests. The presence of COOH groups in this series of compounds is shown to be mandatory for dye-uptake in TiO(2) in the DSC fabrication process. Throughout this study, results are compared with those of the world's most famous DSC dye, N3 (N719 in its fully protonated form): cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II). Overall, the molecular origins of charge-transfer in these complexes are ascertained. The findings have important implications to the materials discovery of more efficient dyes for DSC technology.

The photoinduced O-bound coordination mode in RuSO(2) complexes, previously observed only at 13 K, has been generated at 100 K in tetraammineaqua(sulfur dioxide)ruthenium(II) (±)-camphorsulfonate. This coordination state, often denoted MS1, decays to the η(2)-bound MS2 state, with an estimated half-life of 3.4(8) h and a long-lived population of 2.9(4)% at 120 K.

This paper studies the possibility of distinguishing between benign and malignant masses by exploiting the morphology-dependent temporal and spectral characteristics of their microwave backscatter response in ultra-wideband breast cancer detection. The spiculated border profiles of 2-D breast masses are generated by modifying the baseline elliptical rings based upon the irregularity of their peripheries. Furthermore, the single- and multilayer lesion models are used to characterize a distinct mass region followed by a sharp transition to background, and a blurred mass border exhibiting a gradual transition to background, respectively. Subsequently, the complex natural resonances (CNRs) of the backscatter microwave signature can be derived from the late-time target response and reveal diagnostically useful information. The fractional sequence CLEAN algorithm is proposed to estimate the lesions' delay intervals and identify the late-time responses. Finally, it is shown through numerical examples that the locations of dominant CNRs are dependent on the lesion morphologies, where 2-D computational breast phantoms with single and multiple lesions are investigated. The analysis is of potential use for discrimination between benign and malignant lesions, where the former usually possesses a better-defined, more compact shape as opposed to the latter.

Objective: The current study explored family and individual variables associated with dieting and binge eating., Method: 581 college females completed questionnaires exploring the amount of criticism and preoccupation with weight and food they experienced in their families, their current levels of depression, external attributions, and body esteem, and their degree of focus on dieting and binge eating., Results: A structural equation model incorporating previous research and theoretical considerations was evaluated. The data were consistent with a model in which family variables were mediated by individual variables of depression, external attributions, and negative body esteem to predict dieting and bingeing. Dieting was influenced by all three individual variables, and in turn, dieting and depression were associated with binge eating., Discussion: These results are consistent with an internalization model of family issues. Family dysfunction and values lead to depressive symptoms, external attributions, and negative body esteem. Dieting may be a "solution" that leads to additional eating problems such as binge eating when depression is present.

Background: Sentinel node (SN) biopsy for breast cancer is becoming more common owing to its lower morbidity when compared with full axillary dissection. However, the optimal method of finding and the number of SN to be dissected are still subject to conjecture. The aim of this study was to determine the optimal number of SN required to accurately stage an axilla after the i.d. injection of isotope and blue dye., Method: Prospective data from all patients undergoing SN biopsy from April 2000 to September 2004 were analysed. For positive SN, the order in which they became positive was then tabulated., Results: During the 4 years, 113 patients who fulfilled the selection criteria had undergone SN biopsy with 216 SN harvested. Of these, 33 patients had positive SN results. If only the first SN was analysed, 87.9% of those positive biopsies would have been discovered. Two SN raised the predictive value to 97.0%., Conclusion: Two SN would seem to be the optimal number to harvest after i.d. injection of both isotope and blue dye.

This study describes an investigation using tropical water lilies (Nymphaea spontanea) to remove hexavalent chromium from aqueous solutions and electroplating waste. The results show that water lilies are capable of accumulating substantial amount of Cr(VI), up to 2.119 mg g(-1) from a 10 mg l(-1) solution. The roots of the plant accumulated the highest amount of Cr(VI) followed by leaves and petioles, indicating that roots play an important role in the bioremediation process. The maturity of the plant exerts a great effect on the removal and accumulation of Cr(VI). Plants of 9 weeks old accumulated the most Cr(VI) followed by those of 6 and 3 weeks old. The results also show that removal of Cr(VI) by water lilies is more efficient when the metal is present singly than in the presence of Cu(II) or in waste solution. This may be largely associated with more pronounced phytotoxicity effect on the biochemical changes in the plants and saturation of binding sites. Significant toxicity effect on the plant was evident as shown in the reduction of chlorophyll, protein and sugar contents in plants exposed to Cr(VI) in this investigation.

This paper presents a generic framework for the modeling of ultra-wideband (UWB) signal propagation in human breast, which facilitates system-level simulations and provides performance prediction. The clutter associated with the breast tissue heterogeneity is modeled through several key parameters depending on the tissue compositions. Subsequently, important channel properties such as the backscatter energy and the probability density function of time-of-arrival are derived. The modified Hermite polynomials, which fit well into the real pulse shapes, are then used to model the UWB signals. Armed with the channel/signal model preliminaries, three metrics are proposed, namely, the mean clutter response, the clean tumor response, and the worst-case clutter response. The generalized model provides a parsimonious way to study the effects of tissue structures, pulse templates, and array setup on the performance of a specified UWB imaging system. Numerical examples are used to demonstrate the usefulness of the proposed approach.

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare, rescue, and security applications. In this paper, a geometry-based statistical channel model is developed for simulating the reception of UWB signals in the indoor propagation environment. This model enables replication of time-varying multipath profiles due to the displacement of a human chest. Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate. The analytical framework can serve as a basis in the planning and evaluation of future measurement programs.

The sorption characteristics of Cr(VI) and Cu(II) by ethylenediamine modified rice hull from single and binary metal ion solutions were evaluated under various experimental conditions. Optimal Cr(VI) and Cu(II) removal from single metal ion solutions occurred at pH 2.0 and 5.5, respectively. Simultaneous removal of Cr(VI) and Cu(II) occurred at pH greater than 3.0. The sorption kinetics of Cr(VI) and Cu(II) from single and binary metal ion solutions were studied with reference to metal concentration, agitation rate and particle size. Sorption of Cr(VI) was more rapid than Cu(II). The kinetics of metal ion sorption fitted a pseudo-second order expression. The variation in the initial uptake rates was very small at an agitation rate beyond 150 rpm and sorption was generally independent of particle size. Equilibrium sorption data could be fitted into the Langmuir isotherm equation. Maximum sorption capacities of ethylenediamine modified rice hull for Cr(VI) at pH 2 and Cu(II) at pH 4 in single metal solutions were 0.45 and 0.06 mmol g(-1), respectively. This corresponds to an enhancement factor of 2.6 and 3 fold for Cr(VI) and Cu(II), respectively, compared to natural rice hull. A synergistic effect was observed for sorption of these ions in binary metal solutions.

Expression of heat shock proteins (HSPs) as a heat stress response is associated with acquisition of thermotolerance. Herbimycin A is a tyrosine kinase inhibitor that has been shown to induce HSPs. The present study aims to investigate the effects of herbimycin A on thermotolerance in rats subjected to heat stress exposure. Herbimycin A induced hsp70 to peak levels 12 h post-injection in rats without heat stress. No change in hsp70 levels was observed in the vehicle- and saline-treated rats. In rats exposed to heat stress at 45 degrees C for 25 min, 12 h post-treatment, lower peak temperatures were attained in herbimycin A-treated group as compared to the vehicle- and saline-treated groups. Terminal transferase-mediated d-UTP nick end labeling (TUNEL) showed that a significant decrease in apoptosis of hepatocytes in herbimycin A-treated rats as compared to the vehicle- and saline-treated rats. Caspase-3 activation was also lower in herbimycin A-treated rats, compared to the vehicle- and saline-treated rats. The present study has demonstrated that herbimycin A is effective for development of thermotolerance and therefore protects rats from heat stress.

Denture marking is accepted as a means of identifying dentures and persons in geriatric institutions, or post-mortem during war, crimes, civil unrest, natural and mass disasters. Labelling on the acrylic resin component of the denture can easily be damaged or destroyed by fire but on cobalt-chromium components it would be more resistant. A copper vapour laser (CVL) can be used to label the cobalt-chromium components of dentures and metal restorations easily, and legibly, and miniaturised for the incorporation of more personal particulars necessary for the identification of the deceased person. The CVL beam is focussed by its optics and delivered to the material surface by the two-axis scanner mounted with mirrors. A personal computer controls the movement of the scanner and the firing of the CVL. The high peak power of the pulsed CVL is focussed to very high energy density producing plasma ablation of the alloy surface. Very fine markings of a few microns width can be produced enabling the storage of detailed information of the deceased person on a metal surface for the purpose of rapid identification.

Spent bleaching earth, an industrial waste produced after the bleaching of crude palm oil, was investigated for its potential in removing Cr(VI) from aqueous solution. The earth was treated with different amounts of sulfuric acid and under different activation temperatures. Results show that the optimum treatment process involved 10% sulfuric acid at 350 degrees C. The effects of contact time, pH, initial concentration, sorbent dosage, temperature, sorption isotherms and the presence of other anions on its sorption capacity were studied. Isotherm data could be fitted into a modified Langmuir isotherm model implying monolayer coverage of Cr(VI) on acid activated spent bleaching earth. The maximum sorption capacity derived from the Langmuir isotherm was 21.2 mg g(-1). This value was compared with those of some other low cost sorbents. Studies of anion effect on the uptake of Cr(VI) on acid activated spent bleaching earth provided the following order of suppression: EDTA >PO4(3-)>SO4(2-)>NO3(-)>Cl(-).

A study on the modification of rice husk by various carboxylic acids showed that tartaric acid modified rice husk (TARH) had the highest binding capacities for Cu and Pb. The carboxyl groups on the surface of the modified rice husk were primarily responsible for the sorption of metal ions. A series of batch experiments using TARH as the sorbent for the removal of Cu and Pb showed that the sorption process was pH dependent, rapid and exothermic. The sorption process conformed to the Langmuir isotherm with maximum sorption capacities of 29 and 108 mg/g at 27 +/- 2 degrees C for Cu and Pb, respectively. The uptake increased with agitation rate. Decrease in sorbent particle size led to an increase in the sorption of metal ions and this could be explained by an increase in surface area and hence binding sites. Metal uptake was reduced in the presence of competitive cations and chelators. The affinity of TARH for Pb is greater than Cu.

Previous studies have shown that naltrexone attenuates morbidity and mortality in heat stress by inhibiting endogenous opioids. In this study, we hypothesized that naltrexone can decrease heat stress by attenuating nitric oxide release. Male Sprague-Dawley rats were pretreated with naltrexone or normal saline, and exposed to 45 degrees C for 25 min; controls were exposed to 25 degrees C. Colonic temperatures were recorded and plasma samples from an in-dwelling i.v. cannula were analyzed for nitrate/nitrite levels. Following heat stress, peak colonic temperature was significantly diminished (P < 0.05) in naltrexone-treated rats compared to saline-treated rats. Plasma nitrate/nitrite levels were significantly lower (P < 0.05) in naltrexone-treated rats compared to saline-treated rats. These findings suggest that naltrexone is able to attenuate the rise in plasma nitric oxide levels commonly observed after heat stress., (Copyright 2002 Elsevier Science B.V.)

Stonustoxin (SNTX) is a lethal factor isolated from the venom of the stonefish Synanceja horrida. Although SNTX exhibits a multitude of biological activities, the primary cause of death upon administration of the toxin is attributed to marked hypotension. We investigated the possible mechanisms underlying the vascular hyporeactivity of this novel toxin. Cumulative doses of SNTX (5-320 ng/mL) induced concentration-dependent relaxation in phenylephrine (PE)--precontracted rat aortic rings with intact endothelium. Endothelium removal abolished the relaxation induced by SNTX. Tetraethylammonium (TEA), an inhibitor of K(+) channels, partially inhibited SNTX-induced relaxation. Similarly, SNTX-induced relaxation was partially attenuated by the SP receptor antagonist (NATB), whereas the inducible iNOS inhibitor, AMT-HCl, completely abolished the relaxation caused by SNTX. From the results obtained, it can be postulated that a component of SNTX-mediated vasorelaxation is via binding of either SNTX or SP to the SP receptors that are located on the endothelial cells. Occupation of these SP receptors causes subsequent production of NO and activation of K(+) channels, thus leading to vasorelaxation of the rat aortic rings.

All-trans-retinoyl-beta-D-glucuronide (RAG) is an endogenous active metabolite of all-trans-retinoic acid (ATRA). In the present study, the pharmacokinetics of RAG was examined after the administration of a single intravenous does (5, 10, or 15 micromol/kg) and of multiple daily intravenous doses (5 micromol/kg) to rats for 8 days. The plasma concentrations of RAG and ATRA were measured by a reverse-phase HPLC method. A rapid distribution phase of approximately 1 h was observed in all of the rats after single or multiple doses. Thereafter, RAG was eliminated through a first-order process, in accord with a typical two-compartment first order pharmacokinetic profile. After single intravenous doses, the AUC of RAG increased proportionally with the dose and the clearance remained unchanged within the tested doses. There was no statistical significant difference in distribution rate constants from central compartment to peripheral compartment (K(12)) and from peripheral compartment to central compartment (K(21)) between different doses. However, as the dose increased from 5 micromol/kg to 10 micromol/kg, the volume of distribution at the steady state (V(ss)) and the volume of peripheral compartment (V(p)) decreased significantly (p < 0.05) from 1.290 +/- 0.269, 0.928 +/- 0.232. L/kg to 0.961 +/- 0.149, 0.647 +/- 0.107 L/kg, respectively. V(ss) and V(p) at a dose of 15 micromol/kg (0.924 +/- 0.187, 0.698 +/- 0.165 L/kg) were not significantly different from that at 10 micromol/kg. Thus, RAG might saturate the tissue-binding sites at higher doses. ATRA was detected as a metabolite of RAG at low levels (usually < 0.05 microM) only in the first 2 h after intravenous administration. RAG clearly was not extensively hydrolyzed to ATRA in our study. After multiple daily intravenous administration of RAG, the clearance (Cl) and the elimination rate constant (K(10)) remained unchanged (p > 0.05), indicating that long-term daily administration of RAG did not induce its accelerated metabolism. However, K(12), V(p), and V(ss) declined significantly (p < 0.05) from 1.67 +/- 0.54 h(-1), 0.928 +/- 0.232 L/kg, and 1.290 +/- 0.269 L/kg to 0.96 +/- 0.48 h(-1), 0.494 +/- 0.147 L/kg, and 0.818 +/- 0.187 L/kg, respectively. Therefore, long-term daily dosing of RAG seemed to decrease its distribution profile. Although the AUC of RAG did not change significantly after multiple dosing, the AUC of ATRA after RAG dosing significantly declined (p < 0.05) from 0.032 +/- 0.019 microM x h to 0.010 +/- 0.006 microM x h. The decline in the AUC of ATRA might reflect an increase in its uptake by tissue and/or in its metabolism. Because enhanced clearance is not associated with RAG after multiple administrations, RAG could be considered as an alternate to ATRA in appropriate clinical applications., (Copyright 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association)

The potential of quaternized wood (QW) chips in removing hexavalent chromium from synthetic solution and chrome waste under both batch and continuous-flow conditions was investigated. Sorption was found to be dependent on pH, metal concentration, and temperature. QW chips provide higher sorption capacity and wider pH range compared with untreated wood chips. The equilibrium data could be fitted into the Langmuir isotherm model, and maximum sorption capacities were calculated to be 27.03 and 25.77 mg/g in synthetic chromate solution and chrome waste, respectively. The presence of sulfate in high concentration appeared to suppress the uptake of chromium by QW chips. Column studies showed that bed depth influenced the breakthrough time greatly whereas flow rate of influent had little effect on its sorption on the column.

Various species of local wood modified with N-(3-chloro-2-hydroxypropyl)-trimethylammonium chloride showed sorption enhancement for hydrolyzed Reactive Blue 2 (HRB) compared to the untreated samples. The enthalpy of sorption of HRB on Simpoh (Dillenia suffruticosa) was found to be endothermic. Maximum sorption capacity calculated from the Langmuir isotherm was 250.0 mg/g. Under continuous flow conditions HRB could be successfully removed. Dye removal was a function of bed depth and flow rate. However, the bed depth service time model of Bohart and Adams was not applicable in the HRB-quaternized wood system. The modified wood was applied to a sample of industrial textile effluent, and it was found to be able to remove the color successfully under batch conditions.

Bis(N,N-dimethylthiocarbamoylthio)acetic acid, [(CH(3))(2)NC(=S)S](2)CHC(=O)OH or C(8)H(14)N(2)O(2)S(4), exists as a centrosymmetric hydrogen-bonded dimer [O.O 2.661 (3) A].

all-trans-Retinoic acid (ATRA, vitamin A acid, or tretinoin) is a potent chemotherapeutic agent for the treatment of acute promyelocytic leukemia (APL). Its poor aqueous solubility not only affects its oral absorption but also prevents it from forming an aqueous parenteral formulation. Recently, we developed a water-soluble formulation of ATRA with 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD). In present study, this formulation was tested in Sprague-Dawley rats. Kinetic study of ATRA was carried out after oral or intravenous administration. Though there were no statistical differences in any of the estimated pharmacokinetic parameters between ATRA sodium salt and HPbetaCD-based ATRA after intravenous administration, inclusion of ATRA into HPbetaCD was found to greatly improve the oral absorption of ATRA., (Copyright 2000 Wiley-Liss, Inc.)

A comparative study of 164 serum samples was carried out to determine the specificity and sensitivity of the indirect antiglobulin test (IAGT) in three different formulations: physiologic saline, low-ionic solution (RAM), and RAM supplemented with polyethylene glycol (PEG). Serum samples containing mostly weak antibodies (anti-D, -C, -E, -c, -Jka, -Fya, -K, -S, -Lea, -Lua, -M, -Cob, -P1, -I, and -Kna) were used in a 10-minute IAGT in which PEG-IAGTs were compared with saline- IAGTs and RAM-IAGTs. With the exception of anti-P1, anti-I, and an anti-Lea, PEG-IAGTs detected all the antibodies tested compared with 72.3% and 77.4% for saline-IAGTs and RAM-IAGTs, respectively. The end-point titers of at least 82% of antibodies detected by PEG-IAGTs were 1-3 dilutions higher than those by saline- and RAM-IAGTs. When specificity of PEG-IAGTs was tested using 268 randomly selected, fresh (< 1 day old) blood samples, PEG-IAGT detected 11 out of 268 samples as positive compared with 7 out of 268 by both saline-IAGTs and RAM-IAGTs. The four antibodies that were not detected were identified as anti-D, anti-E, anti-Bga, and an autoantibody known previously to be only reactive with papain-pretreated red cells. No nonspecific reactions were detected by PEG-IAGTs and no hemolysis was evident in any of the IAGTs. PEG-IAGTs were more sensitive than saline- and RAM-IAGTs. PEG-IAGTs detected all weak, clinically significant antibodies as well as four antibodies that were otherwise undetected by saline-IAGT or RAM-IAGT. The overall sensitivity of the PEGIAGT was 96.3% compared with 84.1% and 73.2% for the RAM- and saline-IAGT, respectively.

Stonustoxin (8-50 micrograms/ml) produced a rapid and concentration-dependent rise in tension (contracture) of the electrically stimulated mouse hemidiaphragm followed by a gradual waning of tension from the peak to the baseline; the nerve-evoked and the directly (muscle)-evoked twitches of the hemidiaphragm were also progressively and irreversibly blocked in a time- and concentration-dependent manner. Stonustoxin (22 and 44 micrograms/ml) produced a similar rapid rise in tension of the chick biventer cervicis muscle as well as irreversible and concentration-dependent blockade of nerve-evoked twitches and contractures produced by acetylcholine (200 microM), carbachol (8 microM) and KCl (40 mM). The muscle contracture produced by stonustoxin was blocked by dantrolene sodium (6 microM) but not by tubocurarine (15 microM). Moreover, stonustoxin (40 micrograms/ml) did not inhibit nerve conduction in the toad sciatic nerve and stonustoxin (60 micrograms/ml) did not exhibit any anticholinesterase activity. The inhibition of neuromuscular function by stonustoxin in the mouse hemidiaphragm and chick biventer cervicis muscle can therefore be attributed to some irreversible myotoxic action(s) of the toxin, whereas the stonustoxin-induced muscle contractures could have been mediated via depolarization of muscle fibres.

Venoms from stonefish (genus Synanceja) have marked effects on the cardiovascular and neuromuscular systems and on vascular permeability; the venoms also exhibit haemolytic and hyaluronidase activity. Recently, a toxic protein, stonustoxin (SNTX), was purified from the venom of S. horrida: the primary lethal action of SNTX has been attributed to its potent endothelium-dependent vasorelaxant activity causing a rapid, marked and irreversible hypotension; the other actions of SNTX resemble those of the stonefish crude venoms.

Stonefish venom has been documented to cause marked hypotension and respiratory difficulties in envenomed animals. Stonustoxin, a lethal protein recently isolated from the venom of the stonefish Synanceja horrida produced hypotension and, at concentrations above 20 micrograms/kg, death in anaesthetized rats, with no observable effects on nerve-evoked twitches of the tibialis and diaphragm muscles. Stonustoxin (20-160 ng/ml) induced endothelium-dependent relaxations of rat thoracic aortae precontracted with noradrenaline. Higher concentrations induced relaxations followed by contractions. Methylene blue, haemoglobin and the specific NO-synthase inhibitor L-NG-nitro arginine methyl ester inhibited stonustoxin-induced relaxations, while the cyclooxygenase inhibitor indomethacin was without effect. The results of the present study show that stonustoxin causes marked vasorelaxation of the rat isolated aorta, which appears to be due to the release of endothelium-derived relaxing factor (probably nitric oxide or nitric oxide-yielding substances) from the vascular endothelium, and this may be responsible for the in vivo hypotensive and lethal actions of stonustoxin and of stonefish venom.

Documentation on the biological activity (including the lethality) of the venom (BSV) from the black scorpion Heterometrus longimanus is lacking. We have investigated the effects of BSV on adrenergic transmission using the rat isolated anococcygeus muscle (Acm), since the venom from several species of scorpions causes peripheral sympathetic nerve stimulation with enhanced adrenergic responses. The catecholamine content in BSV was also measured by HPLC. The effects of phentolamine (5 microM), guanethidine (5 microM), desipramine (1.5 microM), tetrodotoxin (2 microM) and reserpine pretreatment in vivo (5 mg/kg s.c. x 24 hr and 5 mg/kg i.p. x 3 hr) on contractile responses of the rat Acm to field stimulation, crude BSV (2-10 microliters in 6 ml bath), noradrenaline (3 microM), tyramine (10-15 microM), carbachol (2-3 microM) and potassium chloride (50-75 mM) were investigated. BSV mimicked the agonist actions of noradrenaline (NA) by acting directly on postjunctional alpha-adrenoceptors in the anococcygeus muscle. The LD50 of crude BSV injected i.v. into mice was 0.13 ml per kg mouse. Sequential ultrafiltration of the crude BSV revealed the presence of a substance of low mol. wt which mediates the postjunctional alpha-agonist actions of BSV. HPLC measurements confirmed the presence of noradrenaline (NA; mean concentration of 1.8 +/- 0.3 mM) in BSV; the dopamine concentration (mean of 31 +/- 4 microM) was 60-fold lower than that of NA, whereas adrenaline was not detected in all the 15 samples investigated. Thus, the presence of NA in BSV can account for the postjunctional alpha-agonist actions of the venom in the Acm.

A major variable to consider in the production of biologicals from mammalian cell cultures is the mode of operation, be it a batch, continuous, perfusion, fed-batch or other production method. The final choice must consider a number of fundamental and economic issues. Here we present some antibody production data from different cell lines using different modes of production and discuss the important factors for consideration in choosing a production strategy. It was found that the productivity of batch cultures was lower than that obtained in continuous and perfused cultures, but that productivity could be improved by implementing suitable feeding strategies. The antibody productivity of one cell line, MCL1, during exponential phase was not affected by media type or glucose level. The maximum productivity of two cell lines in continuous culture was found to occur at dilution rates below the maximum, from 0.019 to 0.030 hr-1.