Corrosion Behavior of 316LN and 316 Stainless Steels During Long-term Exposure to Aerated 0.5 M NaCl Using Electrochemical Noise Technique

In the present work 316LN as well as 316 stainless steel (SS) coupons each of dimensions (0.025 × 0.018 × 0.006 m³) in well-polished condition were used as two nominal electrodes which were immersed in the aerated solution of 0.5 M NaCl. Correlated current and potential electrochemical noise (EN) signals were collected at 1 Hz sampling frequency for 1 h daily over a period of 30 days. The detrended EN data were used to calculate the noise resistance (R _N) as well as the spectral noise resistance at zero frequency (R _SN^o) values and other statistical parameters. To study the nature of pits and distribution of their diameters as well as depths, extensive observations of the pitted and the blank specimens were carried out using Confocal Laser Scanning Microscopy (CLSM). The current and the potential records of the two alloys showed distinct differences in their corrosion behavior. It was observed that within less than 4 h of immersion, 316SS showed signals indicative of unstable pitting and onset of stable pitting was noticed after 48 h of exposure. However, until about 24 h, 316LN showed just the random signals and unstable pitting was observed after 28 h. The signals clearly indicated continuous growth of the stable pits in 316SS as against the repassivation of the unstable pits in 316LN after 7 days exposure. It was observed that R _N values showed a continuous decrease in the case of 316SS, but were quite stable in the case of 316LN over the exposure period. Concurrent to these observations it was observed that 316SS specimen was extensively pitted. The frequency distributions of pit diameters as well pit depths were observed to be highest at 10-20 μm and 5-10 μm, respectively. However, pits with as large as 70-80 μm diameter and as deep as 20-25 μm too were observed. No pits were observed in case of 316LN even after 30 days of exposure, an observation that corroborates well with the stable R _N values. Thus, in the present investigation, the long-term tests using EN technique coupled with CLSM studies conclusively prove that many unstable pits initiated in 316SS turn into stable ones resulting in insidious localized corrosion attack whereas the unstable pits initiated in 316LN get passivated in the simulated coastal environment.     

Characterization and sequence of the Escherichia coli panBCD gene cluster

A 4589 bp DNA segment containing the Escherichia coli panBCD gene cluster was sequenced, and found to contain 6 complete open reading frames. panB, panC, and panD were identified by subcloning and insertional mutagenesis. The orientation of panD was also confirmed by orientation-specific expression of asparate-1-decarboxylase. panB and panC lie adjacent to one another, but are separated from panD by orf3, which is oriented in the opposite direction. Interruptions in the remaining open reading frames did not affect growth on glucose-minimal medium. No significant similarity to sequences in databases was found for orf1 and orf2. Orf3 contained extensive similarity to reading frames defined by E. coli yjiP, yjiQ, yhgA, and yafD. The function of these amino acid sequences is as yet undefined.     

Studies on the structural and ionic transport properties at elevated temperatures of La1−xMnO3±δ synthesized by a wet chemical method

Structural transformation and ionic transport properties are investigated on wet-chemically synthesized La_1−xMnO₃ (x=0.0–0.18) compositions. Powders annealed in oxygen/air at 1000–1080 K exhibit cubic symmetry and transform to rhombohedral on annealing at 1173–1573 K in air/oxygen. Annealing above 1773 K in air or in argon/helium at 1473 K stabilized distorted rhombohedral or orthorhombic symmetry. Structural transformations are confirmed from XRD and TEM studies. The total conductivity of sintered disks, measured by four-probe technique, ranges from 5 S cm⁻¹ at 298 K to 105 S cm⁻¹ at 1273 K. The ionic conductivity measured by blocking electrode technique ranges from 1.0×10⁻⁶ S cm⁻¹ at 700 K to 2.0×10⁻³ S cm⁻¹ at 1273 K. The ionic transference number of these compositions ranges from 3.0×10⁻⁵ to 5.0×10⁻⁵ at 1273 K. The activation energy deduced from experimental data for ionic conduction and ionic migration is 1.03–1.10 and 0.80–1.00 eV, respectively. The activation energy of formation, association and migration of vacancies ranges from 1.07 to 1.44 eV.     

Interleukin-1 beta-converting enzyme mediates cisplatin-induced apoptosis in malignant glioma cells

Increasing the susceptibility of tumor cells to apoptotic cell death following chemotherapy is of importance to the outcome of cancer treatment. Although the tumor suppressor gene p53 is required for efficient induction of apoptosis by chemotherapeutic agents, it is not the only apoptosis mediator gene. The molecular mechanisms mediating apoptosis following chemotherapy via p53-dependent or p53-independent pathways remain unclear. We show here that cis-diamminedichloroplatinum (cisplatin) induces the expression of interleukin-1 beta-converting enzyme (ICE), a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, in murine and human malignant glioma cells during apoptosis regardless of their p53 status. Furthermore, overexpression of the murine ICE gene induces apoptosis in these tumor cells. The apoptosis induced by cisplatin treatment or murine ICE overexpression can be suppressed by the tetrapeptide ICE inhibitor Ac-YVAD-CMK or the apoptosis inhibitors bcl-2 or bcl-2-related bcl-XL gene. These findings suggest that ICE may mediate apoptosis induced by chemotherapy, and its induction could represent a novel approach for the effective treatment of malignant glioma.     

Placebo-controlled immunotherapy with Cocos nucifera pollen extract

The effectiveness of Cocos nucifera pollen extract immunotherapy (CPE-IT) was studied in 96 patients allergic to C. nucifera pollen. A placebo-controlled study was performed at random for a period of 6-12 months. The clinical status of the patients measured by the symptom-medication scores demonstrated that C. nucifera pollen-allergic patients had significant (p < 0.005) clinical improvement after CPE-IT in comparison to placebo treatment. Serological study resulted a significant reduction (p < 0.001) of specific IgE and significant elevation (p < 0.01) of specific IgG in post-therapeutic patients' sera which were correlated significantly (r = 0.45, p < 0.001); the changes of the above immunoglobulin levels in the placebo-treated patients were nonsignificant. However, there was no correlation between symptom-medication scores and changes in specific serum IgE or IgG levels.     

The use of external, noninvasive pacing for the termination of supraventricular tachycardia in the emergency department setting

STUDY OBJECTIVE: To determine the potential feasibility of external cardiac pacing for the termination of sustained supraventricular tachycardia in the emergency department setting. TYPE OF PARTICIPANTS: Three men and two women (mean age, 34 years) who presented to the ED with a narrow-complex, hemodynamically stable tachycardia that was later proven to be supraventricular in origin. INTERVENTION: Each patient underwent external overdrive pacing using a modified external pacemaker at a pulse amplitude of 120 mA and a rate between 240 and 280 pulses per minute. RESULTS: In four patients, external cardiac pacing was able to successfully terminate the tachycardia without complication. In one patient, the pacemaker was not able to terminate the tachycardia. CONCLUSION: We conclude that external, noninvasive pacing is a feasible means of terminating supraventricular tachycardia in the ED setting.     

Infant affect and affect regulation during the still-face paradigm with mothers and fathers: the role of infant characteristics and parental sensitivity

This laboratory study examined mothers' and fathers' sensitivity during face-to-face interactions with their infants as well as infants' affective and regulatory responses during mother-infant versus father-infant still face (SF). The degree to which infant gender and temperament as well as parental sensitivity predicted SF responses was also examined. Participants included 94 healthy, primarily White, middle-class 4-month-olds and their parents. Results indicated that mothers and fathers were equally sensitive toward their infants. Infants' affect and regulatory behaviors were also significantly stable across mother- and father-infant SF situations, although several differences in mean levels of regulation emerged. Finally, the extent to which exogenous and endogenous variables predicted infant SF responses differed as a function of which affect or regulatory variable was being examined and with which parent the infant was experiencing SF.     

Fifteen years experience with finger arterial pressure monitoring: assessment of the technology

We review the Finapres technology, embodied in several TNO-prototypes and in the Ohmeda 2300 and 2300e Finapres NIBP. Finapres is an acronym for FINger Arterial PRESsure, the device delivers a continuous finger arterial pressure waveform. Many papers report on the accuracy of the device in comparison with intra-arterial or with noninvasive but intermittent blood pressure measurements. We compiled the results of 43 such papers and found systolic, diastolic and mean accuracies, in this order, ranging from -48 to 30 mmHg, from -20 to 18 mmHg, and from -13 to 25 mmHg. Weighted for the number of subjects included pooled accuracies were -0.8 (SD 11.9), -1.6 (8.3) and -1.6 (7.6) mmHg respectively. Subdividing the pooled group according to criteria such as reference blood pressure, place of application, and prototype or commercial device we found no significant differences in mean differences or SD. Measurement at the finger allows uninterrupted recordings of long duration. The transmission of the pressure pulse along the arm arteries, however, causes distortion of the pulse waveform and depression of the mean blood pressure level. These effects can be reduced by appropriate filtering, and upper arm 'return-to-flow' calibration to bring accuracy and precision within AAMI limits. For the assessment of beat-to-beat changes in blood pressure and assessment of blood pressure variability Finapres proved a reliable alternative for invasive measurements when mean and diastolic pressures are concerned. Differences in systolic pressure are larger and reach statistical significance but are not of clinical relevance. Finger arteries are affected by contraction and dilatation in relation to psychological and physical (heat, cold, blood loss, orthostasis) stress. Effects of these phenomena are reduced by the built-in Physiocal algorithm. However, full smooth muscle contraction should be avoided in the awake patient by comforting the patient, and covering the hand. Arterial state can be monitored by observing the behaviour of the Physiocal algorithm. We conclude that Finapres accuracy and precision usually suffice for reliable tracking of changes in blood pressure. Diagnostic accuracy may be achieved with future application of corrective measures.     

Long-term evaluation of the ventricular defibrillation energy requirement

INTRODUCTION: Defibrillation energy requirements in patients with nonthoracotomy defibrillators may increase within several months after implantation. However, the stability of the defibrillation energy requirement beyond 1 year has not been reported. The purpose of this study was to characterize the defibrillation energy requirement during 2 years of clinical follow-up. METHODS AND RESULTS: Thirty-one consecutive patients with a biphasic nonthoracotomy defibrillation system underwent defibrillation energy requirement testing using a step-down technique (20, 15, 12, 10, 8, 6, 5, 4, 3, 2, and 1 J) during defibrillator implantation, and then 24 hours, 2 months, 1 year, and 2 years after implantation. The mean defibrillation energy requirement during these evaluations was 10.9+/-5.5 J, 12.3+/-7.3 J, 11.7+/-5.6 J, 10.2+/-4.0 J, and 11.7+/-7.4 J, respectively (P = 0.4). The defibrillation energy requirement was noted to have increased by 10 J or more after 2 years of follow-up in five patients. In one of these patients, the defibrillation energy requirement was no longer associated with an adequate safety margin, necessitating revision of the defibrillation system. There were no identifiable clinical characteristics that distinguished patients who did and did not develop a 10-J or more increase in the defibrillation energy requirement. CONCLUSION: The mean defibrillation energy requirement does not change significantly after 2 years of biphasic nonthoracotomy defibrillator system implantation. However, approximately 15% of patients develop a 10-J or greater elevation in the defibrillation energy requirement, and 3% may require a defibrillation system revision. Therefore, a yearly evaluation of the defibrillation energy requirement may be appropriate.