Control system for actuation and sensing in digital microfluidics devices

Digital Microfluidics (DMF) is a second generation technique, derived from the conventional microfluidics that instead of using continuous liquid fluxes, it uses only individual droplets driven by external electric signals. In this thesis a new DMF control/sensing system for visualization, droplet control (movement, dispensing, merging and splitting) and real time impedance measurement have been developed. The software for the proposed system was implemented in MATLAB with a graphical user interface. An Arduino was used as control board and dedicated circuits for voltage switching and contacts were designed and implemented in printed circuit boards. A high resolution camera was integrated for visualization. In our new approach, the DMF chips are driven by a dual-tone signal where the sum of two independent ac signals (one for droplet operations and the other for impedance sensing) is applied to the electrodes, and afterwards independently evaluated by a lock-in amplifier. With this new approach we were able to choose the appropriated amplitudes and frequencies for the different proposes (actuation and sensing). The measurements made were used to evaluate the real time droplet impedance enabling the knowledge of its position and velocity. This new approach opens new possibilities for impedance sensing and feedback control in DMF devices.

Distribution of hepatitis C virus genotypes among different exposure categories in the State of Pará, Brazilian Amazon

INTRODUCTION: Epidemiological studies concerning HCV genotypic distribution in the Brazilian Amazon are scarce. Thus, this study determined the patterns of distribution of HCV genotypes among different exposure categories in the State of Pará, Brazilian Amazon. METHODS: A cross-sectional study was conducted on 312 HCV-infected individuals belonging to different categories of exposure, who were attended at the HEMOPA, CENPREN and a private hemodialysis clinic in Belém. They were tested for HCV antibodies using an immunoenzymatic test, RNA-HCV, using real-time PCR and HCV genotyping through phylogenetic analysis of the 5' UTR. The population groups were epidemiologically characterized according to data collected in a brief interview or medical consultation. RESULTS: Genotype 1 predominated in all the different categories of HCV exposure. HCV genotypic distribution among blood donors comprised genotypes 1 (94%) and 3 (6%). All patients with chronic hematologic diseases had HCV genotype 1. The genotypic distribution in illicit-drug users comprised genotypes 1 (59.6%) and 3 (40.4%). In patients under hemodialysis, genotypes 1 (90.1%), 2 (3.3%), and 3 (6.6%) were detected. Finally, the frequency of genotypes 1 and 3 was significantly different between the groups: BD and DU, PUH and DU, PUH and PCHD and PCHD and DU. CONCLUSIONS: The genotypic frequency and distribution of HCV in different categories of exposure in the State of Pará showed a predominance of genotype 1, regardless of the possible risk of infection.

Autoimmune diseases and pregnancy: analysis of a series of cases

BACKGROUND: An autoimmune disease is characterized by tissue damage, caused by self-reactivity of different effector mechanisms of the immune system, namely antibodies and T cells. All autoimmune diseases, to some extent, have implications for fertility and obstetrics. Currently, due to available treatments and specialised care for pregnant women with autoimmune disease, the prognosis for both mother and child has improved significantly. However these pregnancies are always high risk. The purpose of this study is to analyse the fertility/pregnancy process of women with systemic and organ-specific autoimmune diseases and assess pathological and treatment implications. METHODS: The authors performed an analysis of the clinical records and relevant obstetric history of five patients representing five distinct autoimmune pathological scenarios, selected from Autoimmune Disease Consultation at the Hospital of Braga, and reviewed the literature. RESULTS: The five clinical cases are the following: Case 1-28 years old with systemic lupus erythematosus, and clinical remission of the disease, under medication with hydroxychloroquine, prednisolone and acetylsalicylic acid, with incomplete miscarriage at 7 weeks of gestation without signs of thrombosis. Case 2-44 years old with history of two late miscarriages, a single preterm delivery (33 weeks) and multiple thrombotic events over the years, was diagnosed with antiphospholipid syndrome after acute myocardial infarction. Case 3-31 years old with polymyositis, treated with azathioprine for 3 years with complete remission of the disease, took the informed decision to get pregnant after medical consultation and full weaning from azathioprine, and gave birth to a healthy term new-born. Case 4-38 years old pregnant woman developed Behcet's syndrome during the final 15 weeks of gestation and with disease exacerbation after delivery. Case 5-36 years old with autoimmune thyroiditis diagnosed during her first pregnancy, with difficult control over the thyroid function over the years and first trimester miscarriage, suffered a second miscarriage despite clinical stability and antibody regression. CONCLUSIONS: As described in literature, the authors found a strong association between autoimmune disease and obstetric complications, especially with systemic lupus erythematosus, antiphospholipid syndrome and autoimmune thyroiditis.

Medical care and deaths due to coronary artery disease in Brazil, 1980-1999

OBJECTIVE: To estimate the frequency of medical care preceding deaths due to coronary artery diseases (CAD) in different Brazilian regions and capitals and to describe trends in medical care from 1980 to 1999. METHODS: Information on medical care preceding deaths due to coronary artery diseases/acute myocardial infarction in adults > 20 years from 1980 to 1999 was collected in the DATASUS, the databank of the Brazilian Health Ministry. Sex, states, and capitals selected for 1999 were analyzed in the study. Medical care was stratified as follows: with, without, and ignored medical care. The descriptive analysis comprised frequencies, ratios of frequency, test for proportions, and increments or reductions in frequencies. RESULTS: Acute myocardial infarction (AMI) represented 75 to 85% of the CAD in the period; the frequency of deaths with medical care ranged from 48.9 to 63%, and that of ignored medical care ranged from 27.2 to 41.5%. The frequency of other CAD with medical care ranged from 56 to 76%. The frequency of deaths preceded by medical care decreased by 17.8%, and that with ignored medical care increased by 36.5% (RF=2). The values for the other CAD were -20.2% and +64.6% (RF=44.4). Deaths preceded by medical care were more frequent in females at all ages and in all Brazilian regions. CONCLUSION: The results show a high frequency of sudden death and suggest errors in diagnosis or codification and overestimation of the statistics about mortality. Validation of the death certificate diagnosis and frequent surveillance are required.

The influence of patient's consciousness regarding high blood pressure and patient's attitude in face of disease controlling medicine intake

OBJECTIVE: To assess the relation between blood pressure control and the following: the Morisky-Green test, the patient's consciousness regarding high blood pressure, the patient's attitude in face of medicine intake, the patient's attendance at medical consultations, and the subjective physician's judgment. METHODS: We studied 130 hypertensive patients with the following characteristics: 73% females, 60±11 years, 58% married, 70% white, 45% retired, 45% with incomplete elementary schooling, 64% had a familial income of 1 to 3 minimum wages, body mass index of 30±7 kg/m², consciousness regarding the disease for a mean period of 11±9.5 years, and mean treatment duration of 8 ±7 years. RESULTS: Only 35% of the hypertensive individuals had blood pressure under control and a longer duration of treatment (10±7 vs 7±6.5 years; P<0.05). The retiree predominated. The result of the Morisky-Green test did not relate to blood pressure control. In evaluating the attitude in face of medicine intake, the controlled patients achieved significantly higher scores than did the noncontrolled patients (8±1.9 vs 7 ±2, P<0.05). The hypertensive patients had higher levels of consciousness regarding their disease and its treatment, and most (70%) patients attended 3 or 4 medical consultations, which did not influence blood pressure control. The physicians attributed significantly higher scores regarding adherence to treatment to controlled patients (6±0.8 vs 5±1.2; P<0.05). CONCLUSION: Consciousness regarding the disease, the Morisky-Green test, and attendance to medical consultations did not influence blood pressure control.

Training medical students to conduct motivational interviewing: a randomized controlled trial.

OBJECTIVE: To examine the effectiveness of motivational interviewing (MI) training among medical students. METHODS: All students (n=131) (year 5) at Lausanne Medical School, Switzerland were randomized into an experimental or a control group. After a training in basic communication skills (control condition), an 8-h MI training was completed by 84.8% students in the exprimental group. One week later, students in both groups were invited to meet with two standardized patients. MI skills were coded by blinded research assistants using the Motivational Interviewing Treatment Integrity 3.0. RESULTS: Superior MI performance was shown for trained versus control students, as demonstrated by higher scores for "Empathy" [p<0.001] and "MI Spirit" [p<0.001]. Scores were similar between groups for "Direction", indicating that students in both groups invited the patient to talk about behavior change. Behavior counts assessment demonstrated better performance in MI in trained versus untrained students regarding occurences of MI-adherent behavior [p<0.001], MI non-adherent behavior [p<0.001], Closed questions [p<0.001], Open questions [p=0.001], simple reflections [p=0.03], and Complex reflections [p<0.001]. Occurrences were similar between groups regarding "Giving information". CONCLUSION: An 8-h training workshop was associated with improved MI performance. PRACTICE IMPLICATIONS: These findings lend support for the implementation of MI training in medical schools.

Periodontitis and gingivitis in inflammatory bowel disease: a case-control study.

BACKGROUND: The oral cavity is frequently affected in patients with inflammatory bowel disease (IBD), especially in patients with Crohn's disease (CD). Periodontitis is thought to influence systemic autoimmune or inflammatory diseases. We aimed to analyze the relationship of periodontitis and gingivitis markers with specific disease characteristics in patients with IBD and to compare these data with healthy controls. METHODS: In a prospective 8-month study, systematic oral examinations were performed in 113 patients with IBD, including 69 patients with CD and 44 patients with ulcerative colitis. For all patients, a structured personal history was taken. One hundred thirteen healthy volunteers served as a control group. Oral examination focussed on established oral health markers for periodontitis (bleeding on probing, loss of attachment, and periodontal pocket depth) and gingivitis (papilla bleeding index). Additionally, visible oral lesions were documented. RESULTS: Both gingivitis and periodontitis markers were higher in patients with IBD than in healthy control. In univariate analysis and logistic regression analysis, perianal disease was a risk factor for periodontitis. Nonsmoking decreased the risk of having periodontitis. No clear association was found between clinical activity and periodontitis in IBD. In only the CD subgroup, high clinical activity (Harvey-Bradshaw index > 10) was associated with 1 periodontitis marker, the loss of attachment at sites of maximal periodontal pocket depth. Oral lesions besides periodontitis and gingivitis were not common, but nevertheless observed in about 10% of patients with IBD. CONCLUSIONS: IBD, and especially perianal disease in CD, is associated with periodontitis. Optimal therapeutic strategies should probably focus on treating both local oral and systemic inflammation.

Prevalence and control of Babesiosis in the Americas

This review presents up-to-date information on the distribution and control measures of babesiosis in Latin America. Bovine babesiosis caused by Babesia bovis and B. bigemia will be emphasized. The disease is endemic is most countries and poses a serious economic burdenon livestock production in the region (U.S.$1365 million/year, FAO, 1989). Of the estimated 250 million cattle in Central and South America, approximately 175 million (70%) are in tick-infested regions. Humid, tropical and subtropical areas favor development of the main vector, the one-host tick Boophilus microplus. In many regions bovine babesiosis is enzootically stable as consequence of a balanced host-parasite relationship. However, Latin America offers a wide range of epidemiologica conditions that are influenced by variations from tropical to cool climates and by susceptible purebred cattle that are regularly imported to upgrade local stocks. The control measures employed in most countries for babesiosis esentially rely on chemotherapy, use of acaricides for B. microplus, and to a lesser degree, on immunization methods. In general, these measures are expensive, time consuming, and in many cases, provide limited success. Finally, the zoonotic potential ob babesiosis will be addressd, with special emphasis on the situation in the United States. Even though bovine babesiosis has long been eradicated from the U.S.A., human babesiosis in endemic in the northeastern region of the country.

Epidemiological features and control of schistosomiasis japonica in China

Achievements and successes have been obtained in schistosomiasis control in China. An epidemic survey was carried out and its results analyzed.

Determination and control of schistosomiasis

The subject of this conference reflects the scientific community's interest in seeking to understand the complex causal web whose various social, economic, and biological components interact in the production and reproduction of schistosomiasis and its control in relation to community participation. From the onset, the author stresses the impossibility of dealing separately with community participation, as if social components were just one more "weapon" in the arsenal for schistosomiasis control. This study begins with a brief historical review of the 71 years of control activities with this endemic disease, stressing the enormous efforts and huge expenditures in this field vis-à-vis the limited results, despite the extraordinary technological development of specific, classical control inputs such as new treatment drugs and molluscicides. The article then discusses the various strategies used in control programs, emphasizing ideological consistencies and contradictions. Interactions at the macro and micro levels are discussed, as are the determinants and risk factors involved in producing the disease's endemicity. Unequal occupation of space leaves the segregated portion of the population exposed to extremely favorable conditions for transmission of the disease. This raises the issue of how to control an endemic disease which is so closely linked to the way of life imposed on the population. The study challenges the classical control model and suggests an alternative model now undergoing medium-term investigation in the States of Espirito Santo, and Pernambuco, Brazil. The author concludes that we do not need new strategies, but a new control model, contrary to the prevailing classical model in both concept and practice. From the conceptual point of view, the new model mentioned above is different from others in that schistosomiasis control is seen from a social perspective stressing the population's accumulated knowledge in addition to the building of shared knowledge. The model's praxis has the following characteristics: (1) it is integrated with and financed by research agencies and health services; (2) it operates at the local health services level; (3) use of molluscicides has been eliminated; (4) emphasis is given to individual medical treatment and improvement of sanitary conditions.

A prospective randomised multi-centre controlled trial on tight glucose control by intensive insulin therapy in adult intensive care units: the Glucontrol study.

PURPOSE: An optimal target for glucose control in ICU patients remains unclear. This prospective randomized controlled trial compared the effects on ICU mortality of intensive insulin therapy (IIT) with an intermediate glucose control. METHODS: Adult patients admitted to the 21 participating medico-surgical ICUs were randomized to group 1 (target BG 7.8-10.0 mmol/L) or to group 2 (target BG 4.4-6.1 mmol/L). RESULTS: While the required sample size was 1,750 per group, the trial was stopped early due to a high rate of unintended protocol violations. From 1,101 admissions, the outcomes of 542 patients assigned to group 1 and 536 of group 2 were analysed. The groups were well balanced. BG levels averaged in group 1 8.0 mmol/L (IQR 7.1-9.0) (median of all values) and 7.7 mmol/L (IQR 6.7-8.8) (median of morning BG) versus 6.5 mmol/L (IQR 6.0-7.2) and 6.1 mmol/L (IQR 5.5-6.8) for group 2 (p < 0.0001 for both comparisons). The percentage of patients treated with insulin averaged 66.2 and 96.3%, respectively. Proportion of time spent in target BG was similar, averaging 39.5% and 45.1% (median (IQR) 34.3 (18.5-50.0) and 39.3 (26.2-53.6)%) in the groups 1 and 2, respectively. The rate of hypoglycaemia was higher in the group 2 (8.7%) than in group 1 (2.7%, p < 0.0001). ICU mortality was similar in the two groups (15.3 vs. 17.2%). CONCLUSIONS: In this prematurely stopped and therefore underpowered study, there was a lack of clinical benefit of intensive insulin therapy (target 4.4-6.1 mmol/L), associated with an increased incidence of hypoglycaemia, as compared to a 7.8-10.0 mmol/L target. (ClinicalTrials.gov # NCT00107601, EUDRA-CT Number: 200400391440).

Factors associated with clinical leptospirosis: a population-based case-control study in the Seychelles (Indian Ocean).

BACKGROUND: In Western countries, leptospirosis is uncommon and mainly occurs in farmers and individuals indulging in water-related activities. In tropical countries, leptospirosis can be up to 1000 times more frequent and risk factors for this often severe disease may differ. METHODS: We conducted a one-year population-based matched case-control study to investigate the frequency and associated factors of leptospirosis in the entire population of Seychelles. RESULTS: A total of 75 patients had definite acute leptospirosis based on microagglutination test (MAT) and polymerase chain reaction (PCR) assay (incidence: 101 per 100,000 per year; 95% confidence interval [CI]: 79-126). Among the controls, MAT was positive in 37% (past infection) and PCR assay in 9% (subclinical infection) of men aged 25-64 with manual occupation. Comparing cases and controls with negative MAT and PCR, leptospirosis was associated positively with walking barefoot around the home, washing in streams, gardening, activities in forests, alcohol consumption, rainfall, wet soil around the home, refuse around the home, rats visible around the home during day time, cats in the home, skin wounds and inversely with indoor occupation. The considered factors accounted for as much as 57% of the variance in predicting the disease. CONCLUSION: These data indicate a high incidence of leptospirosis in Seychelles. This suggests that leptospires are likely to be ubiquitous and that effective leptospirosis control in tropical countries needs a multifactorial approach including major behaviour change by large segments of the general public.

Simulium spp. control program in Rio Grande do Sul, Brazil

Insects of the Simuliidae family have been the object of control in Rio Grande do Sul since the 70s. Their constant attacks became a social-economical problem as well as a problem of Public Health, with serious consequences to men and to the economy of the areas in which the insects develop. At first, the control was done with a chemical larvicide Themephos ABATE 500 E, but an imperfect measuring of outflow to determine the quantity of the product made Simulium spp. resistant to it. From 1983 on, following a study of a new method for the outflow measuring, we started to use a biological larvicide Bacillus thuringiensis serovar israelensis based. The biological control uses the new method in 36.4% of the state area, assisting about 3,500,000 inhabitants.

Can You Home Again? Desertion and Control of Hometowns in Civil Wars

What allows an armed group in a civil war to prevent desertion? This paper addresses this question with a focus on control in the rearguard. Most past studies focus on motivations for desertion. They explain desertion in terms of where soldiers stand in relation to the macro themes of the war, or in terms of an inability to provide positive incentives to overcome the collective action problem. However, since individuals decide whether and how to participate in civil wars for multiple reasons, responding to a variety of local conditions in an environment of threat and violence, a focus only on macro-level motivations is incomplete. The opportunities side of the ledger deserves more attention. I therefore turn my attention to how control by an armed group eliminates soldiers’ opportunities to desert. In particular, I consider the control that an armed group maintains over soldiers’ hometowns, treating geographic terrain as an important exogenous indicator of the ease of control. Rough terrain at home affords soldiers and their families and friends advantages in ease of hiding, the difficulty of using force, and local knowledge. Based on an original dataset of soldiers from Santander Province in the Spanish Civil War, gathered from archival sources, I find statistical evidence that the rougher the terrain in a soldier’s home municipality, the more likely he is to desert. I find complementary qualitative evidence indicating that soldiers from rough-terrain communities took active advantage of their greater opportunities for evasion. This finding has important implications for the way observers interpret different soldiers’ decisions to desert or remain fighting, for the prospect that structural factors may shape the cohesion of armed groups, and for the possibility that local knowledge may be a double-edged sword, making soldiers simultaneously good at fighting and good at deserting.

Information and education in schistosomiasis control: an analysis of the situation in the State of Minas Gerais, Brazil

This paper presents the main ideas discussed in the round-table "Social and Educacional Aspects of Schistosomiasis Control", during the VII International Symposium of Schistosomiais. Considering the perspectives of schistosomiasis control in Brazil, it is described the example of the State of Minas Gerais , where the disease has been registered for more than seven decades. The importance of an extensive evaluation is now more important, considering the recent change in the Brazilian health system, since the Federal responsibility for the tropical diseases control programs have been replaced by the municipalities coordination. In this way, it is urgent to develop effective alternatives to assist the municipal staffs in the control task. In the specific case of health education, one observes a wide gap between the planned objectives and what is in fact carried out. Instant objectives and the utilization of traditional techniques prevail, which do not take into account the active participation of the population involved. Based on the authors' experience in the scientific and health education, the paper analyzes: (1) some data from a case study in the metropolitan region of Belo Horizonte, which presents the social representation and perception of schistosomiasis by the population; (2) an analysis of 35 different informative and educative materials used in Brazil since the sixties, and (3) some recommendations resulted from the studies that were carried out.