Recurrent ~24 h Periods in RXTE ASM Data

Analysis of data from the Rossi X-ray Timing Explorer satellite's All Sky Monitor instrument for several X-ray binary sources has identified a recurrent \~24 h period. This period is sometimes highly significant, giving rise to the possibility of it being identified as an orbital or super-orbital period. Further analysis has revealed the same period in a number of other X-ray sources. As a result this period has been discounted as spurious, described variously as arising from daily variations in background levels and beating between the sampling period and long-term secular trends in the light curves. We present here an analysis of the spurious periods and show that the dominant mechanism is in fact spectral leakage of low-frequency power present in the light curves.Comment: 9 Pages, 10 figures, 1 table, submitted to PASA 20th December 2004. Added 1 page of text and 3 figures to clarify results and discussion. Resubmitted 16th May 2005. Accepted 25th June 200

Comparison of anesthetic efficacy of 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:80,000 epinephrine for inferior alveolar nerve block in patients with irreversible pulpitis

Objectives: This study was done to compare the anesthetic efficacy of 4% articaine with 1:100,000 epinephrine with that of 2% lidocaine with 1:80,000 epinephrine during pulpectomy in patients with irreversible pulpitis for inferior alveolar nerve block in mandibular posterior teeth. Material and Methods: Patients with irreversible pulpitis referred to the Department of Conservative Dentistry and Endodontics, K.D. Dental College, randomly received a conventional inferior alveolar nerve block containing 1.8 mL of either 4% articaine with 1:100,000 epinephrine or 2% lidocaine with 1:80,000 epinephrine. After the patient's subjective assessment of lip anesthesia, the absence/presence of pulpal anesthesia through electric pulp stimulation was recorded and the absence/presence of pain was recorded through visual analogue scale. Results: The pulpal anesthesia success for articaine (76%) was slightly more than with lidocaine (58%) as measured with pulp tester as well as for the pain reported during the procedure the success rate of articaine (88%) was slightly more than that of lidocaine (82%) although the difference between the two solutions was not statistically significant. Conclusions: Both the local anesthetic solutions had similar effects on patients with irreversible pulpitis when used for inferior alveolar nerve block

Laser Irradiation of Tumors for the Treatment of Cancer: An Analysis of Blood Flow, Temperature and Oxygen Transport

It has been shown that hypoxic tumor cells are resistant to radiation and that increasing tumor oxygen levels via laser-mediated hyperthermia treatment increases tumor cell radiosensitivity. Hence, studies of the effects of laser irradiation on tumor oxygen levels are of great interest, as they allow for the optimization of hyperthermia treatment. Accordingly, the main purpose of this experiment was to develop a finite element model to simulate the heat transfer due to laser irradiation of tumor tissue, the blood flow through a tumor capillary, and the effect of changing temperature on blood flow rates and oxygen delivery to tumor tissue. This was achieved by using finite element models in COMSOL Multiphysics. We employed two geometries based on those used in a simliar study by He et al. [1]: a tumor-containing breast model to simulate laser heating of the tissue and a capillary and tumor tissue model to simulate the effect of heating on blood flow and tissue oxygen concentration. By plotting partial pressure of oxygen as a function of radius at three different points in the tissue, we observed that the oxygen concentration was greatest near the inlet and lowest near the outlet (as expected), and that at all points in the tissue, heating increased the tissue oxygen partial pressure to about the same extent (0.75 ? 1 mm Hg). Furthermore, sensitivity analyses suggested ambient air cooling at the breast surface to be ideal and a laser intensity of 18000 W/m2 to be optimal for hyperthermia treatment. The model we developed was validated by comparison to a similar model and has potential for use in future studies on optimization of hyperthermia treatment

Long-term Periodicities in the Flux from Low Mass X-ray Binaries

Using data from the All Sky Monitor (ASM) on the Rossi X-ray Timing Explorer (RXTE) we have searched for long term periodicities in the X-ray flux of GX 1+4, Sco X-2 (GX 349+2), and GX 339-4. For GX 1+4 we also used data from BATSE and Galactic Centre scans performed by RXTE. We find no evidence for X-ray modulations at the suggested ~304 d orbital period of GX 1+4. However, we find tentative evidence for a periodicity at 420 d to 460 d. An upper limit of 15% peak-to-peak is set on any sinusoidal modulation in the 1.5 - 3.0 keV flux of Sco X-2 for periods in the 30 to 100 d range. For GX 339-4 we confirm the Low State modulation and report the detection of significant low-frequency modulations in both the High State and Very High State. We fail to detect this modulation in the Off State. We show that if the reported orbital period of GX 339-4 lies in the range 0.5 - 1.7 d, then it is not present in the RXTE ASM light curve.Comment: 7 pages, 8 figures. Accepted for publication in Advanced in Space Research, 16th of March 200

Comparison of ambulatory blood pressure monitoring and self-blood pressure monitoring for diagnosing white coat hypertension amongst pregnant women

Background: White coat hypertension (WCH) is a common and well recognized phenomenon. It is also very prevalent amongst pregnant women and is often diagnosed as chronic/ gestational hypertension leading to unnecessary medications during pregnancy. ABPM is the gold standard for diagnosis of WCH. SBPM is an easy effective and reliable method to measure blood pressure but its efficacy needs to be tested and compared with ABPM in cases of WCH. It is important to compare the two methods in assessing WCH so SBPM can be utilized in cases of WCH, if found useful and efficacious.Methods: All pregnant women who presented to the ANC were screened for hypertension. Those who were diagnosed to be hypertensive in antenatal clinic and these patients were then admitted for ambulatory blood pressure monitoring (ABPM) for 24 hours and SBPM on 6 hourly bases for 5 days.Results: The ABPM and SBPB readings were noted, tabulated and compared. It was found that the prevalence of ‘WCH’ in this study using ABPM and SBPM were 47.368% (27/54) and 45.614% (26/54) respectively.Conclusions: The results in diagnosing WCH using ABPM and SBPM were comparable

Prevalence of white coat hypertension amongst pregnant women admitted with high BP recordings in ante-natal clinic

Background: White coat hypertension (WCH) is a common and well recognized phenomenon with significant prevalence amongst all age groups. This is also quite prevalent in the pregnant women with an intermediate long term prognosis between hypertensive and normo-tensive individuals. It is important to assess the true prevalence WCH in pregnant women and to prevent unnecessary medications to them during pregnancy but at the same time to keep a timely follow up and a watchful eye on these patients to identify complications at the earliest. Study was conducted at a peripheral secondary level hospital with a small obstetrics and gynecology OPD and ward. 54 patients were diagnosed to be hypertensive in Antenatal Clinic.Methods: All pregnant women who presented to the ANC were screened for hypertension. Those who were diagnosed to be hypertensive in antenatal clinic and these patients were then admitted for Ambulatory Blood Pressure Monitoring (ABPM) for 24 hours.Results: The ABPM tracings were checked and tabulated to arrive at the final diagnosis after 24 hrs. The prevalence of ‘WCH’ in this study was 48.15% as 26/54 patients were found to have their average BP < 140/90 mmHg after measurement by ABPM over 24 hours so they were diagnosed as ‘White Coat Hypertension’ patients.Conclusions: Many women who come to ANC in the early pregnancy are diagnosed to have hypertension. WCH is a well known phenomenon in pregnancy. WCH must be ruled out prior to starting these patients on anti-hypertensive medications

Quenching of the radio jet during the X-ray high state of GX 339-4

We have observed the black hole candidate X-ray binary GX 339-4 at radio wavelengths before, during and after the 1998 high/soft X-ray state transition. We find that the radio emission from the system is strongly correlated with the hard X-ray emission and is reduced by a factor > 25 during the high/soft state compared to the more usual low/hard state. At the points of state transition we note brief periods of unusually optically-thin radio emission which may correspond to discrete ejection events. We propose that in the low/hard state black hole X-ray binaries produce a quasi-continuous outflow, in the high/soft state this outflow is suppressed, and that state transitions often result in one or more discrete ejection events. Future models for low/hard states, such as ADAF/ADIOS solutions, need to take into account strong outflow of relativistic electrons from the system. We propose that the inferred Comptonising corona and the base of the jet-like outflow are the same thing, based upon the strong correlation between radio and hard X-ray emission in GX 339-4 and other X-ray binaries, and the similarity in inferred location and composition of these two components.Comment: Accepted for publication in ApJ Letter

MACHINE LEARNING ASSISTED QUICK EYESCAN (MLAQE) FOR SIGNAL INTEGRITY CHECK

Presented herein is a quick scan method for signal integrity checks through sampling of four points under certain thermal condition. The techniques presented herein use a machine learning trained model to ensure signal integrity check fidelity