Product development of a programmable robotic toy to stimulate interest in the fields of science and technology amongst young girls

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 45).Statistically speaking, science, technology, and engineering are male dominated fields. Peluchi is a second-generation prototype of a programmable robotic toy targeted towards young girls in hope of promoting more interest in these areas. Peluchi is an educational toy designed to both appeal to girls aesthetically and stimulate them creatively and intellectually. The toy began as a group project for a class called SP. 779: Advance Toy Product Design in the fall of 2009. It existed as a much simpler prototype with a limited set of programmable actions. Since then, the group has continued to develop beta prototype within the course of a semester under the class 2.752: Design of Mechanical Products. Additional work has been done to add complexity and allow more user customization. This is achieved through the addition of modular accessories disguising different servos and sensors that can be plugged into the base unit. The prototype itself was also refined to be more seamless and robust. Analysis and extensive design work were concentrated on the custom ports for the accessories. Finally, manufacturability and marketing strategies were then explored and future plans were considered for the toy.by My Vu.S.B

Exceptional Points of Degeneracy Induced by Linear Time-Periodic Variation

We present a general theory of exceptional points of degeneracy (EPD) in periodically time-variant systems. We show that even a single resonator with a time-periodic component is able to develop EPDs, contrary to parity-time- (PT) symmetric systems that require two coupled resonators. An EPD is a special point in a system parameter space at which two or more eigenmodes coalesce in both their eigenvalues and eigenvectors into a single degenerate eigenmode. We demonstrate the conditions for EPDs to exist when they are directly induced by time-periodic variation of a system without loss and gain elements. We also show that a single resonator system with zero time-average loss-gain exhibits EPDs with purely real resonance frequencies, yet the resonator energy grows algebraically in time since energy is injected into the system from the time-variation mechanism. Although the introduced concept and formalism are general for any time-periodic system, here, we focus on the occurrence of EPDs in a single LC resonator with time-periodic modulation. These findings have significant importance in various electromagnetic and photonic systems and pave the way for many applications, such as sensors, amplifiers, and modulators. We show a potential application of this time-varying EPD as a highly sensitive sensor

Stimulated Raman scattering in an optical parametric oscillator based on periodically poled MgO-doped stoichiometric LiTaO3

The evolution versus pump power of the spectrum of a singly resonant optical parametric oscillator based on an MgO-doped periodically poled stoichiometric lithium tantalate crystal is observed. The onset of cascade Raman lasing due to stimulated Raman scattering in the nonlinear crystal is analyzed. Spurious frequency doubling and sum-frequency generation phenomena are observed and understood. A strong reduction of the intracavity Raman scattering is obtained by a careful adjustment of the cavity losses.Comment: 6 figure

The relation of cytokines of IL-17/IL-23 axis to Th1/Th2 cytokines and disease activity in systemic lupus erythematosus

INTRODUCTION: Interleukin (IL)-17 is recently linked to the pathogenesis of systemic lupus erythematosus (SLE) but its relation to disease activity has not been well characterised. The objectives of this study were to examine the relation of serum cytokine levels from the IL-17/IL-23 axis (IL-17, IL-23) to Th1 (IL-12, IFN-γ), Th2 (IL-10, IL-6, IL-4) cytokines and disease activity in SLE patients. METHODS: Serum cytokines were measured by enzyme-linked immunosorbent assays. Disease activity was determined by SLE disease activity index (SLEDAI), anti-dsDNA antibody, C3 and C4 levels. RESULTS: Serum levels of IL-17, IL-10 and IFN-γ were higher in SLE patients (n=70) compared to age- and sexmatched controls (n=14) [P<0.001]. Higher serum IL-23 level was found in active lupus patients who had cutaneous manifestation (P=0.003) and serositis (P=0.03) compared to those who had not. Serum IL-17 was not different between patients who had active lupus nephritis (n=23), non-renal active lupus (n=13) and inactive disease (n=34) [P=0.23]. However, an inverse correlation between serum IL-17 with proteinuria was found among all SLE patients (r= –0.27, P=0.03). Serum IL-17 level was, otherwise, not related to SLEDAI, glomerular filtration rate, activity or chronicity score and ISN/RPS class among patients with active lupus nephritis and was not found to correlate with serum IFN-γ or IL-10. CONCLUSIONS: Elevated serum IL-23 was found in patients with inflammatory manifestations including cutaneous involvement and serositis. Serum IL-17 level was not shown to correlate with disease activity but demonstrated an inverse correlation with proteinuria suggesting urinary loss of IL-17 and its involvement in lupus renal pathology.published_or_final_versionThe 15th Medical Research Conference (15th MRC), Department of Medicine, University of Hong Kong, Hong Kong, 16 January 2010. In Hong Kong Medical Journal, 2010, v. 16 n. 1, suppl. 1, p. 45, abstract no. 7

Non-absorbable disaccharides versus placebo/no intervention and lactulose versus lactitol for the prevention and treatment of hepatic encephalopathy in people with cirrhosis

Background Non-absorbable disaccharides (lactulose and lactitol) are recommended as first-line treatment for hepatic encephalopathy. The previous (second) version of this review included 10 randomised clinical trials (RCTs) evaluating non-absorbable disaccharides versus placebo/no intervention and eight RCTs evaluating lactulose versus lactitol for people with cirrhosis and hepatic encephalopathy. The review found no evidence to either support or refute the use of the non-absorbable disaccharides and no differences between lactulose versus lactitol. Objectives To assess the beneficial and harmful effects of i) non-absorbable disaccharides versus placebo/no intervention and ii) lactulose versus lactitol in people with cirrhosis and hepatic encephalopathy. Search methods We carried out electronic searches of the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 10), MEDLINE, EMBASE, and Science Citation Index Expanded to 19 October 2015; manual searches of meetings and conference proceedings; checks of bibliographies; and correspondence with investigators and pharmaceutical companies. Selection criteria We included RCTs, irrespective of publication status, language, or blinding. Data collection and analysis Two review authors, working independently, retrieved data from published reports and correspondence with investigators. The primary outcomes were mortality, hepatic encephalopathy, and serious adverse events. We presented the results of meta-analyses as risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI). We assessed the quality of the evidence using 'Grading of Recommendations Assessment Development and Evaluation' (GRADE) and bias control using the Cochrane Hepato-Biliary Group domains. Our analyses included regression analyses of publication bias and other small study effects, Trial Sequential Analyses to detect type 1 and type 2 errors, and subgroup and sensitivity analyses. Main results We included 38 RCTs with a total of 1828 participants. Eight RCTs had a low risk of bias in the assessment of mortality. All trials had a high risk of bias in the assessment of the remaining outcomes. Random-effects meta-analysis showed a beneficial effect of non-absorbable disaccharides versus placebo/no intervention on mortality when including all RCTs with extractable data (RR 0.59, 95% CI 0.40 to 0.87; 1487 participants; 24 RCTs; I2 = 0%; moderate quality evidence) and in the eight RCTs with a low risk of bias (RR 0.63, 95% CI 0.41 to 0.97; 705 participants). The Trial Sequential Analysis with the relative risk reduction (RRR) reduced to 30% confirmed the findings when including all RCTs, but not when including only RCTs with a low risk of bias or when we reduced the RRR to 22%. Compared with placebo/no intervention, the non-absorbable disaccharides were associated with beneficial effects on hepatic encephalopathy (RR 0.58, 95% CI 0.50 to 0.69; 1415 participants; 22 RCTs; I2 = 32%; moderate quality evidence). Additional analyses showed that non-absorbable disaccharides can help to reduce serious adverse events associated with the underlying liver disease including liver failure, hepatorenal syndrome, and variceal bleeding (RR 0.47, 95% CI 0.36 to 0.60; 1487 participants; 24 RCTs; I2 = 0%; moderate quality evidence). We confirmed the results in Trial Sequential Analysis. Tests for subgroup differences showed no statistical differences between RCTs evaluating prevention, overt, or minimal hepatic encephalopathy. The evaluation of secondary outcomes showed a potential beneficial effect of the non-absorbable disaccharides on quality of life, but we were not able to include the data in an overall meta-analysis (very low quality evidence). Non-absorbable disaccharides were associated with non-serious (mainly gastrointestinal) adverse events (very low quality evidence). None of the RCTs comparing lactulose versus lactitol evaluated quality of life. The review found no differences between lactulose and lactitol for the remaining outcomes (very low quality evidence). Authors' conclusions This review includes a large number of RCTs evaluating the prevention or treatment of hepatic encephalopathy. The analyses found evidence that non-absorbable disaccharides may be associated with a beneficial effect on clinically relevant outcomes compared with placebo/no intervention. EnglishCroatianGerman Plain language summary Are non-absorbable disaccharides associated with beneficial or harmful effects in people with cirrhosis and hepatic encephalopathy? Background Cirrhosis is a chronic disorder of the liver. People with cirrhosis may develop hepatic encephalopathy, a condition that results in poor brain functioning. Hepatic encephalopathy may be clinically obvious (overt) with changes including poor concentration, tremor, and alterations in consciousness. Others have no obvious clinical changes (minimal) but, when tested, some aspects of brain function such as attention and the ability to perform complex tasks are impaired. The reason why people develop hepatic encephalopathy is complex. The accumulation of ammonia plays a key role. The non-absorbable disaccharides, lactulose and lactitol, are indigestible sugars that reduce the levels of ammonia in the blood. Review question We investigated the use of non-absorbable disaccharides for the prevention and treatment of hepatic encephalopathy in people with cirrhosis by reviewing randomised clinical trials (RCTs). Search date The search date was October 2015. Study funding sources Seven RCTs received financial support and 11 RCTs received lactitol or inactive placebo free of charge from a pharmaceutical company. Study characteristics We included 29 RCTs comparing non-absorbable disaccharides with inactive placebo or no intervention and nine RCTs comparing lactulose with lactitol. Seven of the included RCTs evaluated the prevention of hepatic encephalopathy and 31 evaluated the treatment of hepatic encephalopathy. Sixteen of the treatment RCTs included people with overt hepatic encephalopathy while 15 included people with minimal hepatic encephalopathy. The duration of treatment varied depending on the type of hepatic encephalopathy from five days to one year. Key results People who received non-absorbable disaccharides were less likely to die than people given a placebo or no treatment. They were also less likely to develop serious complications of their liver disease such as liver failure, bleeding, and infections. The non-absorbable disaccharides were also effective in preventing the development of hepatic encephalopathy and increased the number of participants who recovered from hepatic encephalopathy. There was some evidence from a small number of trials that lactulose has a beneficial effect on the quality of life, but we were unable to include the data in an overall analysis. The non-absorbable disaccharides were associated with adverse events including diarrhoea, nausea, bloating, and flatulence. None of the RCTs comparing lactulose versus lactitol reported quality of life. The analyses showed no differences between the two interventions for the remaining outcomes. Quality of the evidence In the comparison of non-absorbable disaccharides versus placebo/no intervention, we found moderate quality evidence of benefit for the outcomes of death, hepatic encephalopathy, and serious complications. The evidence for the remaining outcomes was of very low quality

Periodontal impact of surgically induced dental lesions in mandibular osteodistraction: an animal study.

AIM: The objective of the study was to evaluate the impact of dental lesions on the periodontium, in a canine model of mandibular osteodistraction. MATERIAL AND METHODS: In six adult male Beagle dogs, an osteotomy was made between the right second lateral incisor and canine, and a distraction device placed. The roots adjacent to the osteotomy were deliberately damaged by the reciprocating saw and chisel, with preservation of the attached gingiva. The osteodistraction protocol used was: latency of 7 days, rate of distraction 1mm per day, and rhythm once a day for 5 days. Vital staining was carried out with tetracycline, Xylenol Orange and Calcein Green. The dogs were sacrificed after 12 weeks of consolidation and the specimens were evaluated with light microscopy (native, polarized light, fluorescence, and after toluidin blue staining). RESULTS: The periodontal ligament (PDL) regeneration was observed in the 2500 slices examined. Cementum and dentine lesions were repaired by cellular cementum. Loose dentine and cementum-dentine fragments were embedded in regenerated PDL and their surface repaired by cementum. By means of light microscopic examination and within the limited observation time, no degenerative pulpal changes were found, when the pulp canal was not entered. Extensive pulp exposure and destruction resulted in ingrowth of the PDL and bone-like tissue. In that case, cellular cementum also lined the dentine surface of the pulp canal. CONCLUSION: Although there was an extensive reparative response to the para-pulpal lesions, none of the changes observed showed evidence of a loss of functional integrity of the periodontium at the distraction site. The fate of the tooth with exposed pulp canal remains uncertain