Techniques for improving landmine detection using ground penetrating radar

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (February 23, 2007)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Electrical engineering.Improving the probability of detection of landmines is a challenging task for many scientists all around the world. The goal of this research is to be a part of this challenging work to investigate techniques for landmine detection. Two techniques for detecting the landmines, one in depth domain and the other in frequency domain, have been studied and a few modifications are suggested, along with the results. The data collected from Ground Penetrating Radar (GPR) from various test sites is used to evaluate the performance of these detection techniques. The first technique is proposed for use with Handheld GPR systems, while the second technique is proposed for use with Vehicle mounted GPR systems. The techniques proved to be useful in improving the detection of low metal or plastic mines

Mechanisms linking hypertriglyceridemia to acute pancreatitis

Hypertriglyceridemia (HTG) is a metabolic disorder, defined when serum or plasma triglyceride concentration (seTG) is >1.7 mM. HTG can be categorized as mild to very severe groups based on the seTG value. The risk of acute pancreatitis (AP), a serious disease with high mortality and without specific therapy, increases with the degree of HTG. Furthermore, even mild or moderate HTG aggravates AP initiated by other important etiological factors, including alcohol or bile stone. This review briefly summarizes the pathophysiology of HTG, the epidemiology of HTG-induced AP and the clinically observed effects of HTG on the outcomes of AP. Our main focus is to discuss the pathophysiological mechanisms linking HTG to AP. HTG is accompanied by an increased serum fatty acid (FA) concentration, and experimental results have demonstrated that these FAs have the most prominent role in causing the consequences of HTG during AP. FAs inhibit mitochondrial complexes in pancreatic acinar cells, induce pathological elevation of intracellular Ca2+ concentration, cytokine release and tissue injury, and reduce the function of pancreatic ducts. Furthermore, high FA concentrations can induce respiratory, kidney, and cardiovascular failure in AP. All these effects may contribute to the observed increased AP severity and frequent organ failure in patients. Importantly, experimental results suggest that the reduction of FA production by lipase inhibitors can open up new therapeutic options of AP. Overall, investigating the pathophysiology of HTG-induced AP or AP in the presence of HTG and determining possible treatments are needed

Cavity Quantum Electrodynamics of a two-level atom with modulated fields

We studied the interaction of a two-level atom with a frequency modulated cavity mode in an ideal optical cavity. The system, described by a Jaynes-Cumming Hamiltonian, gave rise to a set of stiff nonlinear first order equations solved numerically using implicit and semi-implicit numerical algorithms. We explored the evolution of the atomic system using nonlinear dynamics tools, like time series, phase plane, power spectral density, and Poincar\'{e} sections plots, for monochromatic and bichromatic modulations of the cavity field. The system showed quasiperiodic and possibly chaotic behavior when the selected monochromatic frequencies, or ratio of the bichromatic frequencies were irrational (incommensurate) numbers. In addition, when the modulated frequencies were overtones of the Rabi frequency of the system, a single dominant frequency emerged for the system.Comment: REVTeX, 6 pages, 6 figure

Synthesis, Characterization and Phase Transition Studies on Some N-(4-Butyloxy Benzylidene)-4-Alkoxy Anilines, 4O.Om Compounds - A Dilatometric Study

Dilatometric studies are carried out on the synthesized N-(4-butyloxy benzylidene)-4-alkoxy anilines, 4O.Om compounds with the m = 3 to 7 and 9. Characterization of these compounds is done using the polarizing microscope attached with a hot stage. The differential scanning calorimeter is employed to find out the transition temperatures as well as the heats of transitions. All the compounds exhibit nematic phase with varying thermal ranges with the clearing temperatures are above 100 OC as unlike the case of the well known N-(4-butyloxy benzylidene)-4-alkyl anilines, 4O.m compounds which exhibit rich poymorphysim and the clearing temperatures are well below 100 OC. As expected the isotropic to nematic transition exhibited first order nature and the results are discussed with the body of the data available in literature

A comparative study of intrathecal ropivacaine with fentanyl and L-bupivacaine with fentanyl in lower abdominal and lower limb surgeries

Background: Subarachnoid block (SAB) is the anesthesia of choice and is the gold standard for lower abdominal and lower limb surgeries. SAB, a popular and common anesthetic procedure practiced worldwide. Today heavy bupivacaine, 0.5% is most commonly used for spinal anesthesia. Levo-bupivacaine, new long-acting local anesthetic, has a pharmacological activity very similar to that of racemic bupivacaine. Due to lesser cardiovascular side-effects and central nervous system toxicity, use of levo-bupivacaine, a pure S (−) enantiomer of bupivacaine has progressively increased. Ropivacaine has a less systemic toxicity, especially cardio toxic profile than both racemic and levo-bupivacaine. Though less potent, even 50% higher dose is still less toxic than bupivacaine. So, intrathecal ropivacaine may prove useful than that of bupivacaine or levo-bupivacaine when anesthesia of a similar quality and shorter duration is desired.Methods: This study was conducted in 60 adult patients aged between 18 and 60 years, who underwent elective lower abdominal and lower limb surgeries under spinal anesthesia. They were distributed in two groups. Group R: 30 patients were given injection ropivacaine 3 ml (0.75%) + injection fentanyl 0.5 ml (25 µg). Group L: 30 patients were given injection L-bupivacaine 3 ml (0.5%) + injection fentanyl 0.5 ml (25 µg). Hemodynamic parameters such as pulse rate, blood pressure, and respiratory rate, sensory and motor blockade were assessed at 0, 5, 10, 15, 30, 45, 60, 90, and 120 mins following the block. Thereafter, observation was continued at 30 mins intervals until the motor block regressed completely as defined by modified Bromage score. Time of two segment regression, duration of complete and effective analgesia, and time to first analgesic dose, side effects, and complications were studied.Results: Statistical analysis was done using SPSS software 16.0. Data obtained is tabulated in the excel sheet and analyzed. Chi-square test for proportion and t-test for quantitative data were done. Block characteristics were compared using Mann–Whitney U-test. Both the groups were comparable with respect to age, sex, height, weight, body mass index, level of SAB, American Society of Anesthesiologist score (p>0.05). The mean time for onset of sensory block with p=0.49 which was clinically and statistically not significant for both groups. The mean time for onset of motor block (Bromage 3) with p=0.16 was clinically and statistically not significant. The time taken for two segment regression of sensory block was p=0.22 statistically not significant. There was no clinical or statistical significance in the incidence of side effects in both groups.Conclusion: This study revealed that the intrathecal ropivacaine with fentanyl provided adequate anesthesia for lower abdominal and lower limb surgeries. Ropivacaine achieved a shorter duration of sensory and motor blockade, and a lesser degree of motor blockade when compared to L-bupivacaine. Thus, ropivacaine was justified for short duration ambulatory surgeries of lower abdominal and lower limb surgeries. Furthermore, fentanyl as an adjuvant to both ropivacaine and L-bupivacaine enhanced the duration of the sensory block. Hence, ropivacaine with fentanyl in spinal anesthesia for lower abdominal and lower limb surgeries is a better alternative compared to L-bupivacaine with fentanyl favoring day care ambulatory surgeries

Glioblastoma treated with magnetic resonance imaging-guided laser interstitial thermal therapy: Safety, efficacy, and outcomes

BACKGROUND: Despite the multitude of available treatments, glioblastoma (GBM) remains an aggressive and uniformly fatal tumor. Laser interstitial thermal therapy (LITT) is a novel, minimally invasive treatment that holds promise for treating patients with GBM who are not candidates for traditional open craniotomy. However, due to the recent introduction of LITT into clinical practice, large series that evaluate safety and long-term outcomes after LITT are lacking. OBJECTIVE: To present our institution\u27s series of over 50 GBM patients treated with LITT, with regard to safety, efficacy, and outcomes. METHODS: We performed a retrospective descriptive study of patients with histologically proven GBM who underwent LITT. Data collected included demographics, tumor location and volume, tumor genetic markers, treatment volume, perioperative complications, and long-term follow-up data. RESULTS: We performed 58 LITT treatments for GBM in 54 patients over 5.5 yr. Forty-one were recurrent tumors while 17 were frontline treatments. Forty GBMs were lobar in location, while 18 were in deep structures (thalamus, insula, corpus callosum). Average tumor volume was 12.5 ± 13.4 cm3. Average percentage of tumor treated with the yellow thermal damage threshold (TDT) line (dose equivalent of 43°C for 2 min) was 93.3% ± 10.6%, and with the blue TDT line (dose equivalent of 43°C for 10 min) was 88.0% ± 14.2%. There were 7 perioperative complications (12%) and 2 mortalities (3.4%). Median overall survival after LITT for the total cohort was 11.5 mo, and median progression-free survival 6.6 mo. CONCLUSION: LITT appears to be a safe and effective treatment for GBM in properly selected patients

Clinical Outcomes and Predictors of Thirty-Day Readmissions of Hypertriglyceridemia-Induced Acute Pancreatitis

Background: Hypertriglyceridemia (HTG) is a well-established cause of acute pancreatitis often leading to significant morbidity, mortality, and healthcare burden. This study aimed to describe the rate, reasons, and predictors of HTG-induced acute pancreatitis (HTG-AP) in the USA. Methods: This retrospective study analyzed the Nationwide Readmissions Database (NRD) for 2018 to determine all adults (≥ 18 years) readmitted within 30 days of an index hospitalization of HTG-AP. Hospitalization characteristics and adverse outcomes for 30-day readmissions were highlighted and compared with index admissions of HTG-AP. Furthermore, independent predictors for 30-day readmissions of HTG-AP were also identified. P values ≤ 0.05 were considered statistically significant. Results: In 2018, the rate of 30-day readmission of HTG-AP was noted to be 13.5%. At the time of readmission, AP (45.2%) was identified as the most common principal diagnosis, followed by chronic pancreatitis (6.3%) and unspecified sepsis (4.8%). Compared to index admissions, 30-day readmissions of HTG-AP had a higher proportion of patients with Charlson Comorbidity Index (CCI) scores ≥ 3 (48.5% vs. 33.8%, P < 0.001). Furthermore, we noted higher rates of inpatient mortality (1.7% vs. 0.7%, odds ratio (OR): 2.55, 95% confidence interval (CI): 1.83 - 3.57, P < 0.001), mean length of stay (LOS) (5.6 vs. 4.1 days, OR: 1.5, 95% CI: 1.2 - 1.7, P < 0.001), and mean total healthcare charge (THC) ($56,799 vs.$36,078, OR: 18,702, 95% CI: 15,136 - 22,267, P < 0.001) for 30-day readmissions of HTG-AP compared to index admissions. Independent predictors for 30-day all-cause readmissions of HTG-AP included hypertension, protein energy malnutrition (PEM), CCI scores ≥ 3, chronic kidney disease and discharge against medical advice. Conclusions: AP was the principal diagnosis on presentation in only 45.2% patients for 30-day readmissions of HTG-AP. Compared to index admissions, 30-day readmissions of HTG-AP had a higher comorbidity burden, inpatient mortality, mean LOS and mean THC