Lithium Bis(trimethylsilyl) Phosphate as a Novel Bifunctional Additive for High-Voltage LiNi1.5Mn0.5O4/Graphite Lithium-Ion Batteries.

The beneficial role of lithium bis(trimethylsilyl) phosphate (LiTMSP), which may act as a novel bifunctional additive for high-voltage LiNi1.5Mn0.5O4 (LNMO)/graphite cells, has been investigated. LiTMSP is synthesized by heating tris(trimethylsilyl) phosphate with lithium tert-butoxide. The cycle performance of LNMO/graphite cells at 45 °C significantly improved upon incorporation of LiTMSP (0.5 wt %). Nuclear magnetic resonance analysis suggests that the trimethylsilyl (TMS) group in LiTMSP can react with hydrogen fluoride (HF), which is generated through the hydrolysis of lithium hexafluorophosphate (LiPF6) by residual water in an electrolyte solution or water generated via oxidative electrolyte decomposition reactions to form TMS fluoride. Inhibition of HF leads to a decrease in the concentration of transition-metal ion-dissolution (Ni and Mn) from the LNMO electrode, as determined by inductively coupled plasma mass spectrometry. In addition, the generation of the superior passivating surface film derived by LiTMSP on the graphite electrode, suppressing further electrolyte reductive decomposition as well as deterioration/reformation caused by migrated transition metal ions, is supported by a combination of chronoamperometry, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy. Furthermore, a LiTMSP-derived surface film has better lithium ion conductivity with a decrease in resistance of the graphite electrode, as confirmed by electrochemical impedance spectroscopy, leading to improvement in the rate performance of LNMO/graphite cells. The HF-scavenging and film-forming effects of LiTMPS are responsible for the less polarization of LNMO/graphite cells enabling improved cycle performance at 45 °C.

Event boundaries do not cause the immediate extinction deficit after Pavlovian fear conditioning in rats.

Recent work reveals that the extinction of conditioned fear depends upon the interval between conditioning and extinction. Extinction training that takes place within minutes to hours after fear conditioning fails to produce a long-term extinction memory, a phenomenon known as the immediate extinction deficit (IED). Neurobiological evidence suggests that the IED results from stress-induced dysregulation of prefrontal cortical circuits involved in extinction learning. However, a recent study in humans suggests that an "event boundary" between fear conditioning and extinction protects the conditioning memory from interference by the extinction memory, resulting in high levels of fear during a retrieval test. Here, we contrast these hypotheses in rats by arranging extinction trials to follow conditioning trials with or without an event boundary; in both cases, extinction trials are delivered in proximity to shock-elicited stress. After fear conditioning, rats either received extinction trials 60-sec after the last conditioning trial (continuous, no event boundary) or 15-minutes after conditioning (segmented, a standard "immediate" extinction procedure associated with an event boundary). Both groups of animals showed decreases in conditional freezing to the auditory conditioned stimulus (CS) during extinction and exhibited an equivalent IED relative to non-extinguished controls when tested 48 hours later. Thus, eliminating the event boundary between conditioning and extinction with the continuous extinction procedure did not prevent the IED. These data suggest that the IED is the result of shock-induced stress, rather than boundary-induced reductions in memory interference.

Prefrontal projections to the thalamic nucleus reuniens mediate fear extinction.

The thalamic nucleus reuniens (RE) receives dense projections from the medial prefrontal cortex (mPFC), interconnects the mPFC and hippocampus, and may serve a pivotal role in regulating emotional learning and memory. Here we show that the RE and its mPFC afferents are critical for the extinction of Pavlovian fear memories in rats. Pharmacological inactivation of the RE during extinction learning or retrieval increases freezing to an extinguished conditioned stimulus (CS); renewal of fear outside the extinction context was unaffected. Suppression of fear in the extinction context is associated with an increase in c-fos expression and spike firing in RE neurons to the extinguished CS. The role for the RE in suppressing extinguished fear requires the mPFC, insofar as pharmacogenetically silencing mPFC to RE projections impairs the expression of extinction memory. These results reveal that mPFC-RE circuits inhibit the expression of fear, a function that is essential for adaptive emotional regulation.

Use of cone beam CT in children and young people in three United Kingdom dental hospitals.

BACKGROUND: There is limited evidence about the use of cone-beam computed tomography (CBCT) in paediatric dentistry. Appropriate use of CBCT is particularly important because of greater radiation risks in this age group. AIM: To survey the use of CBCT in children and young people in three Dental Hospitals in the United Kingdom (UK), with special attention paid to aspects of justification and optimisation. DESIGN: Retrospective analysis of patient records over a 24-month period, looking at CBCT examinations performed on subjects under 18 years of age. Clinical indications, region of interest, scan field of view (FoV), incidental findings and exposure factors used were recorded. RESULTS: There were 294 CBCT examinations performed in this age group, representing 13.7% of all scanned patients. CBCT was used more frequently in the >13 year age group. The most common use was for localisation of unerupted teeth in the anterior maxilla and the detection of root resorption. Optimisation of X-ray exposures did not appear to be consistent. CONCLUSIONS: When planning a CBCT service for children and young people, a limited FoV machine would be the appropriate choice for the majority of clinical requirements. It would facilitate clinical evaluation of scans, would limit the number of incidental findings and contribute to optimisation of radiation doses.

Clinical pressure pain threshold testing in neck pain: comparing protocols, responsiveness, and association with psychological variables.

BACKGROUND: Quantitative sensory testing, including pressure pain threshold (PPT), is seeing increased use in clinical practice. In order to facilitate clinical utility, knowledge of the properties of the tool and interpretation of results are required. OBJECTIVES: This observational study used a clinical sample of people with mechanical neck pain to determine: (1) the influence of number of testing repetitions on measurement properties, (2) reliability and minimum clinically important difference, and (3) associations between PPT and key psychological constructs. DESIGN: This study was observational with both cross-sectional and prospective elements. METHODS: Experienced clinicians measured PPT in patients with mechanical neck pain following a standardized protocol. Subcohorts also provided repeated measures and completed scales of key psychological constructs. RESULTS: The total sample was 206 participants, but not all participants provided data for all analyses. Interrater and 1-week test-retest reliability were excellent (intraclass correlation coefficients [2,1]=.75-.95). Potentially important differences in reliability and PPT scores were found when using only 1 or 2 repeated measures compared with all 3. The PPT over a distal location (tibialis anterior muscle) was not adequately responsive in this sample, but the local site (upper trapezius muscle) was responsive and may be useful as part of a protocol to evaluate clinical change. Sensitivity values (range=0.08-0.50) and specificity values (range=0.82-0.97) for a range of change scores are presented. Depression, catastrophizing, and kinesiophobia were able to explain small but statistically significant variance in local PPT (3.9%-5.9%), but only catastrophizing and kinesiophobia explained significant variance in the distal PPT (3.6% and 2.9%, respectively). LIMITATIONS: Limitations of the study include multiple raters, unknown recruitment rates, and unknown measurement properties at sites other than those tested here. CONCLUSIONS: The results suggest that PPT is adequately reliable and that 3 measurements should be taken to maximize measurement properties. The variance explained by the psychological variables was small but significant for 3 constructs related to catastrophizing, depression, and fear of movement. Clinical implications for application and interpretation of PPT are discussed.

Leukaemic infiltration of the mandible in a young girl.

BACKGROUND: This report presents a case of leukaemic infiltration of the mandible in a 10-year-old female of Sudanese extraction. CASE REPORT: The patient was in remission from acute lymphoblastic leukaemia when she presented with pain localized to the alveolar ridge overlying the unerupted lower right second permanent molar. Two days later, she developed right inferior alveolar nerve paraesthesia. Radiographic imaging demonstrated cortical line absence around the developing lower right second and third permanent molars, and distal displacement of the lower right third molar. In addition, the cortical outline of the right inferior dental canal lacked clarity. Biopsy confirmed leukaemia recurrence demonstrating the Philadelphia chromosome. Tailored chemotherapy was commenced, and a bone marrow transplant was carried out 12 weeks later. At 6-month dental review, the patient remained exceptionally well with no bone pain and normal sensation in the right lower lip. CONCLUSION: The importance of regular and long-term dental examination of patients with leukaemia is discussed.

Results of selfmonitoring on glucometer systems Advance and Optium in daily routine.

The aim of this prospective clinical study was to compare the results of B-glucose estimations performed simultaneously on glucometer Advance (with Micro-draw strips) and Optium (G3 strips) by lay healthy volunteers under non-standardized conditions of everyday life, to assess the difficulties dealing with lay-handling of these systems and to demonstrate the possibilities of the software Glucobalance (Hypoguard) and PC-Link (Medisense/Abbott) for the analysis of selfmonitoring. In the course of 5 days, a total of 721 pairs of measurements were carried out on 10 pairs of glucometer Advance and Optium by 10 healthy volunteers aged 16-40 years. The data transfer of all values into computer from glucometer Advance using the Glucobalance software and from glucometer Optium using the PC-Link was carried out to determine the results. The correlation of B-glucose measured on the glucometer Advance and Optium was strong (r = 0.73). Glucometer Advance brings values about 0.21 +/- 0.06 mmol/l lower than glucometer Optium. The average difference found within each pairs of glucometers Advance - Optium varied. Nevertheless, these differences are acceptable for routine selfmonitoring. The handling of glucometer Advance is not difficult for lay persons. The Glucobalance software simplifies the result evaluation by each tested person. Even though there are some advantages in comparison with the PC-Link, it should be further developed.

Quantitative structure-activity relationships for predicting skin and respiratory sensitization.

Quantitative structure-activity relationships (QSARs) for predicting skin and respiratory sensitization are reviewed. Overall, progress has been hampered by the sparseness of good quality experimental data, a fact that makes it difficult, at this time, to recommend one or two QSARs for predicting skin and respiratory sensitization. Creation of appropriate data sets for uninvestigated classes of chemicals by experimentation should facilitate the development of more robust QSARs for predicting skin and respiratory sensitization. Such QSARs will be valuable in the evaluation of identifiable toxic hazards where dose responses are relevant, as is the case for skin and respiratory sensitization.

Comparison of models for the estimation of biological partition coefficients.

Several models have been published for calculating blood-air, tissue-air, or tissue-blood partition coefficients of volatile organic chemicals in human or rat tissues, from functions of their octanol-water partition coefficients or solubilities in vegetable oil and water. In this work, the relative accuracy, strengths, and limitations of the various models are examined. Comparison of predicted human tissue-air and tissue-blood partition coefficients with experimental values has been made for 12 chemicals, covering a wide range of lipophilicity (acetone, isopropanol, diethylether, methylene dichloride, benzene, toluene, trichloroethylene, trichloroethane, n-pentane, cyclohexane, n-hexane, and n-heptane). Seven published models for human tissue-air and 10 models for tissue-blood partition coefficients have been compared. Fewer models are available for predicting rat tissue-air and rat tissue-blood partition coefficients, but a similar comparison has been made. The ratio of predicted to experimental partition coefficients and their mean, R(mean), and the mean magnitude of the difference between predicted and experimental values of log(10) P, E, were used to assess the accuracy of each model. For the test set the most accurate for human blood-air partition coefficients were the empirical equations of Meulenberg and Vijverberg (R(mean) = 1.1 +/- 0.46, E = 0.156) and the empirical solvation equation of Abraham and Weathersby (1994) (R(mean) = 0.93 +/- 0.38, E = 0.166). For rat blood, predictions are much less accurate due to difficulties in modeling the effects of protein binding, which are much larger. Overall, for rat blood-air partition coefficients the equation of Meulenberg and Vijverberg (1999) (R(mean) = 0.74 +/- 0.50, E = 0.236) was the most accurate. The tissue-composition-based equations of Poulin and Krishnan, using solubilities in vegetable oil, performed well for human liver-air partition coefficients (R(mean) = 1.21 +/- 0.28, E = 0.079) for log(octanol-water partition coefficients) > 0.7 and for fat-air partition coefficients, but overestimated solubilities in human kidney and brain tissues (e.g., for kidney tissue, R = 1.88 +/- 0.58, E = 0.255). The equations of Meulenberg and Vijverberg (2000a), Abraham and Weathersby (1994), and Paterson and Mackay (1989) also performed moderately well for human tissue-air partition coefficients. For rat muscle-air, liver-air, and fat-air partition coefficients the model of Poulin and Krishnan (1996a) gave the most accurate predictions. For tissue-blood partition coefficients, generally good agreement with experimental values is obtained by the empirical model of Balaz and Lukacova (1999) (e.g., for human kidney, R(mean) = 1.15 +/- 0.38, E = 0.085) and, if solubility in fat is known, by the equations of Fiserova-Bergerova and Diaz (1986) (e.g., for human muscle, R(mean) = 1.10 +/- 0.39, E = 0.107). The equations of DeJongh et al. (1997) gave the most accurate predictions for rat muscle-blood, liver-blood and fat-blood partition coefficients (e.g., for rat muscle R(mean) = 1.03 +/- 0.39, E = 0.149), but predictions were less accurate than for human tissue-blood partition coefficients, attributable to difficulties in modeling the effect of protein binding. The choice of equation for use in physiologically based pharmacokinetic (PBPK) models depends on the species, tissue, and chemical lipophilicity.