Random distributed feedback fiber laser

Researchers conducted investigations to demonstrate the advantages of random distributed feedback fiber laser. Random lasers had advantages, such as simple technology that did not require a precise microcavity and low production cost. The properties of their output radiation were special in comparison to those of conventional lasers and they were characterized by complex features in the spatial, spectral, and time domains. The researchers demonstrated a new type of one-dimensional laser with random distributed feedback based on Rayleigh scattering (RS) that was presented in any transparent glass medium due to natural inhomogeneities of refractive index. The cylindrical fiber waveguide geometry provided transverse confinement, while the cavity was open in the longitudinal direction and did not include any regular point-action reflectors.

Risk factors of coronary heart disease and correlates of type 2 diabetes among Cuban Americans

Cuban Americans, a minority Hispanic subgroup, have a high prevalence of type 2 diabetes. Persons with diabetes experience a higher rate of coronary heart disease (CHD) compared to those without diabetes. The objectives of the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) are to investigate the risk factors of CHD and the etiology of diabetes among diabetics of minority ethnic populations. No information is available on the etiology of CHD risks for Cuban Americans. ^ This cross-sectional study compared Cuban Americans with (N = 79) and without (N = 80) type 2 diabetes residing in South Florida. Data on risk factors of CHD and type 2 diabetes were collected using sociodemographics, smoking habit, Rose Angina, Modifiable Activity, and Willet's food frequency questionnaires. Anthropometrics and blood pressure (BP) were recorded. Glucose, glycated hemoglobin, lipid profile, homocysteine, and C-reactive protein were assessed in fasting blood. ^ Diabetics reported a significantly higher rate of angina symptoms than non-diabetics (P = 0.008). After adjusting for age and gender, diabetics had significantly (P < 0.001) larger waist circumference and higher systolic BP than non-diabetics. There was no significant difference in major nutrient intakes between the groups. One quarter of subjects, both diabetics and non-diabetics, exceeded the intake of percent calories from total fat and almost 60% had cholesterol intake >200 mg/d and more than 60% had fiber intake <20 gm/d. The pattern of physical activity did not differ between groups though, it was much below the recommended level. After adjusting for age and gender, diabetics had significantly (P < 0.001) higher levels of blood glucose, glycated hemoglobin, triglycerides, and homocysteine than non-diabetics. In contrast, diabetics had significantly (P < 0.01) lower levels of high-density lipoprotein cholesterol (HDL-C). ^ Multivariate logistic regression analyses showed that increasing age, male gender, large waist circumference, lack of acculturation, and high levels of triglycerides were independent risk factors of type 2 diabetes. In contrast, moderate alcohol consumption conferred protection against diabetes. ^ The study identified several risk factors of CHD and diabetes among Cuban Americans. Health care providers are encouraged to practice ethno-specific preventive measures to lower the burden of CHD and diabetes in Cuban Americans. ^

Risk factors for type 2 diabetes mellitus and cardiovascular diseases in Hispanic adolescents

This cross-sectional study evaluated risk factors (RF) for type 2 diabetes (T2DM) and cardiovascular diseases (CVD) in 100 Hispanic adolescents(50 overweight, 50 non-overweight) aged 12-16 years, and their associations with body mass index (BMI), diet, physical activity (PA), gender, and birth weight (BW). The RF studied were fasting plasma glucose (FPG), insulin sensitivity (IS), total cholesterol (TC), triacylglycerols (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), acanthosis nigricans (AN), and blood pressure (BP). Dietary intakes were assessed using the Block Kids Questionnaire, fat-related intake behavior (FB) using the Fat-Related Diet Habits Questionnaire, and PA using the Modifiable Activity Questionnaire for Adolescents. Blood was collected after an overnight fast of 12 hours. All statistical analyses used SPSS 14.0. Overweight adolescents had presence of AN, higher BP, TC, TG, and LDL, and lower IS, ps < .001, as compared to non-overweight adolescents. Overweight adolescents were more likely to have 1 and 2 RF for T2DM and CVD as compared to having 0, ps < .001, and 2 RF as compared to having 1, p =.033. Adolescents with kilocalorie (Kcal) intake above requirements for age gender, and PA level were 4.6 times more likely to be overweight, p = .005. Overweight adolescents had worse FB, p = .011, and lower PA, p < .001. Adolescents with worse FB had higher BP, p = .016. Fiber below recommendations (14g/1,000 Kcal) was associated with being overweight, p = .012, and lower IS, p = .040. Adolescents with higher BW had higher FPG, p = .013. Our findings point to an association between being overweight and RF for T2DM and CVD, suggesting that overweight during adolescence may have serious health consequences for Hispanic adolescents. Also, our results indicate that Hispanic overweight adolescents eat more Kcal and less fiber than required, have worst FB, and less PA levels than their non-overweight counterparts. In addition, high BW and dietary habits of Hispanic adolescents, such as low fiber and FB, increase their risk for T2DM and CVD. We conclude that BMI can serve as a useful tool to identify Hispanic adolescents at risk for T2DM and CVD.

Quality of life and application of the transtheoretical model to diabetes self -management behaviors in older adults with type 2 diabetes

One in five adults 65 years and older has diabetes. Coping with diabetes is a lifelong task, and much of the responsibility for managing the disease falls upon the individual. Reports of non-adherence to recommended treatments are high. Understanding the additive impact of diabetes on quality of life issues is important. The purpose of this study was to investigate the quality of life and diabetes self-management behaviors in ethnically diverse older adults with type 2 diabetes. The SF-12v2 was used to measure physical and mental health quality of life. Scores were compared to general, age sub-groups, and diabetes-specific norms. The Transtheoretical Model (TTM) was applied to assess perceived versus actual behavior for three diabetes self-management tasks: dietary management, medication management, and blood glucose self-monitoring. Dietary intake and hemoglobin A1c values were measured as outcome variables. Utilizing a cross-sectional research design, participants were recruited from Elderly Nutrition Program congregate meal sites (n = 148, mean age 75). ^ Results showed that mean scores of the SF-12v2 were significantly lower in the study sample than the general norms for physical health (p < .001), mental health (p < .01), age sub-group norms (p < .05), and diabetes-specific norms for physical health (p < .001). A multiple regression analysis found that adherence to an exercise plan was significantly associated with better physical health (p < .001). Transtheoretical Model multiple regression analyses explained 68% of the variance for % Kcal from fat, 41% for fiber, 70% for % Kcal from carbohydrate, and 7% for hemoglobin A 1c values. Significant associations were found between TTM stage of change and dietary fiber intake (p < .01). Other significant associations related to diet included gender (p < .01), ethnicity (p < .05), employment (p < .05), type of insurance (p < .05), adherence to an exercise plan (p < .05), number of doctor visits/year ( p < .01), and physical health (p < .05). Significant associations were found between hemoglobin A1c values and age ( p < .05), being non-Hispanic Black (p < .01), income (p < .01), and eye problems (p < .05). ^ The study highlights the importance of the beneficial effects of exercise on quality of life issues. Furthermore, application of the Transtheoretical Model in conjunction with an assessment of dietary intake may be valuable in helping individuals make lifestyle changes. ^

Cardiac Neural Crest Cells and Their Role in Murine Purkinje Fiber Development

The heart beat is regulated by the cardiac conduction system (CCS), a specialized group of cells that transmit electrical impulses around the heart chambers. During development, ventricular CCS cells originate from embryonic cardiomyocytes and not from the neural crest. Nonetheless, discoveries in chick implied that the cardiac neural crest (CNC) cells contribute to proper development of the ventricular CCS. In this report, the Splotch mouse mutant (Pax3sp), in which the CNC cells do not migrate to the heart, was used to investigate whether these cells also affect proper CCS development in mammals. Homozygote mutants (Pax3Sp!Sp) are lethal on 111 Embryonic Day 13 (E13), and can be phenotyped by spina bifida and exencephaly. Pax3Spi+ mice were crossed to obtain wild type, Pax3 Spi+ and Pax3 Sp!Sp embryos. Comparison of hematoxylin and eosin stained histological sections showed less trabeculation in El2.5 cardiac ventricles of Pax3Sp!Sp. Furthermore, immunofluorescence analysis with the Purkinje fiber marker Cx40 showed a qualitative difference between wild type and mutant hearts. Quantitative analysis indicated that Pax3 Sp!Sp ventricles had fewer Cx40 expressing cells, as well as less Cx40 being expressed per cell when compared to wild type ventricles. Immunofluorescence with the H3 histome mitosis antibody showed fewer proliferating cells in the ventricles of mutant embryos when compared to controls. These results suggest that CNCC affect the morphogenesis of cardiac ventricles and the development of the ventricular CCS by contributing cellular proliferation.

The Effect of Carbohydrate Amount, Quality and Type on Arterial Pulse Pressure in Cuban-Americans with and Without Type 2 Diabetes

Background: Arterial pulse pressure, the difference between systolic and diastolic blood pressure, has been used as an indicator (surrogate measure) of arterial stiffness. High arterial pulse pressure (> 40) has been associated with increased cardiovascular disease and mortality. Several clinical trials have reported that the proportion of calories from carbohydrate has an effect on blood pressure. The primary objective of this study was to assess arterial pulse pressure and its association with carbohydrate quantity and quality (glycemic load) with diabetes status for a Cuban American population. Methods: A single point analysis included 367 participants. There was complete data for 365 (190 with and 175 without type 2 diabetes). The study was conducted in the investigator’s laboratory located in Miami, Florida. Demographic, dietary, anthropometric and laboratory data were collected. Arterial pulse pressure was calculated by the formula systolic minus the diastolic blood pressure. Glycemic load, fructose, sucrose, percent of average daily calories from carbohydrate, fat and protein, grams of fiber and micronutrient intakes were calculated from a validated food frequency questionnaire. Results: The mean arterial pulse pressure was significantly higher in participants with (52.9 ± 12.4) than without (48.6 ± 13.4) type 2 diabetes. The odds of persons with diabetes having high arterial pulse pressure (>40) was 1.85 (95% CI =1.09, 3.13); p=0.023. For persons with type 2 diabetes higher glycemic load was associated with lower arterial pulse pressure. Conclusions: Arterial pulse pressure and diet are modifiable risk factors of cardiovascular disease. Arterial pulse pressure may be associated with carbohydrate intake differently considering diabetes status. Results may be due to individuals with diabetes following dietary recommendations. The findings of this study suggest clinicians take into consideration how medical condition, ethnicity and diet are associated with arterial pulse pressure before developing a medical nutrition therapy plan in collaboration with the client.

Creep deflection of low-strength reinforced concrete flexural members strengthened with carbon fiber composite sheets

The low-strength concrete is defined as a concrete where the compressive cubic strength is less than 15 MPa. Since the beginning of the last century, many low-strength concrete buildings and bridges have been built all over the world. Being short of deeper study, composite sheets are prohibited in strengthening of low-strength reinforced concrete members (CECS 146; ACI 440). Moreover, there are few relevant information about the long-term behavior and durability of strengthened RC members. This fact undoubtedly limits the use of the composite materials in the strengthening applications, therefore, it is necessary to study the behaviours of low-strength concrete elements strengthened with composite materials (FRP) for the preservation of historic constructions and innovation in the strengthening technology. Deformability is one of criteria in the design of concrete structures, and this for functionality, durability and aesthetics reasons. Civil engineer possibly encounters more deflection problems in the structural design than any other type of problem. Many materials common in structural engineering such as wood, concrete and composite materials, suffer creep; if the creep phenomenon is taken into account, checks for serviceability limit state criteria can become onerous, because the creep deformation in these materials is in the same order of magnitude as the elastic deformation. The thesis presents the results of an experimental study on the long-term behavior of low-strength reinforced concrete beams strengthened with carbon fiber composite sheets (CFRP). The work has investigated the accuracy of the long-term deflection predictions made by some analytical procedures existing in literature, as well as by the most widely used design codes (Eurocode 2, ACI-318, ACI-435).

BEHAVIOR OF FIBER REINFORCED POLYMER COMPOSITE PILES WITH ELLIPTICAL CROSS SECTIONS IN INTEGRAL ABUTMENT BRIDGE FOUNDATIONS

Every year in the US and other cold-climate countries considerable amount of money is spent to restore structural damages in conventional bridges resulting from (or “caused by”) salt corrosion in bridge expansion joints. Frequent usage of deicing salt in conventional bridges with expansion joints results in corrosion and other damages to the expansion joints, steel girders, stiffeners, concrete rebar, and any structural steel members in the abutments. The best way to prevent these damages is to eliminate the expansion joints at the abutment and elsewhere and make the entire bridge abutment and deck a continuous monolithic structural system. This type of bridge is called Integral Abutment Bridge which is now widely used in the US and other cold-climate countries. In order to provide lateral flexibility, the entire abutment is constructed on piles. Piles used in integral abutments should have enough capacity in the perpendicular direction to support the vertical forces. In addition, piles should be able to withstand corrosive environments near the surface of the ground and maintain their performance during the lifespan of the bridge. Fiber Reinforced Polymer (FRP) piles are a new type of pile that can not only accommodate large displacements, but can also resist corrosion significantly better than traditional steel or concrete piles. The use of FRP piles extends the life of the pile which in turn extends the life of the bridge. This dissertation studies FRP piles with elliptical shapes. The elliptical shapes can simultaneously provide flexibility and stiffness in two perpendicular axes. The elliptical shapes can be made using the filament winding method which is a less expensive method of manufacturing compared to the pultrusion or other manufacturing methods. In this dissertation a new way is introduced to construct the desired elliptical shapes with the filament winding method. Pile specifications such as dimensions, number of layers, fiber orientation angles, material, and soil stiffness are defined as parameters and the effects of each parameter on the pile stresses and pile failure have been studied. The ANSYS software has been used to model the composite materials. More than 14,000 nonlinear finite element pile models have been created, each slightly different from the others. The outputs of analyses have been used to draw curves. Optimum values of the parameters have been defined using generated curves. The best approaches to find optimum shape, angle of fibers and types of composite material have been discussed.

A genetic variant of the CAPN10 gene in Mexican subjects with dyslipidemia is associated with increased HDL-cholesterol concentrations after the consumption of a soy protein and soluble fiber dietary portfolio

Dyslipidemia is a major public health problem, and therefore, it is important to develop dietary strategies to diminish the prevalence of this disorder. It was recently reported that diet may play an important role in triggering insulin resistance by interacting with genetic variants at the CAPN10 gene locus in patients with metabolic syndrome. Nonetheless, it remains unknown whether genetic variants of genes involved in the development of type 2 diabetes are associated with variations in high-density lipoprotein cholesterol (HDL-C). The study used a single-center, prospective, cohort design. Here, we assessed the effect of four variants of the CAPN10 gene on HDL-C levels in response to a soy protein and soluble fiber dietary portfolio in subjects with dyslipidemia. In 31 Mexican dyslipidemic individuals, we analyzed four CAPN10 gene variants (rs5030952, rs2975762, rs3792267, and rs2975760) associated with type 2 diabetes. Subjects with the GG genotype of the rs2975762 variant of the CAPN10 gene were better responders to dietary intervention, showing increased HDL-C concentrations from the first month of treatment. HDL-C concentrations in participants with the wild type genotype increased by 17.0%, whereas the HDL-C concentration in subjects with the variant genotypes increased by only 3.22% (p = 0.03); the low-density lipoprotein cholesterol levels of GG carriers tended to decrease (-12.6%). These results indicate that Mexican dyslipidemic carriers of the rs2975762-GG genotype are better responders to this dietary intervention.

Use of Fiber Reinforced Polymer Composite Cable for Post-tensioning Application

Corrosion of steel tendons is a major problem for post-tensioned concrete, especially because corrosion of the steel strands is often hard to detect inside grouted ducts. Non-metallic tendons can serve as an alternative material to steel for post-tensioning applications. Carbon fiber reinforced polymer (CFRP), given its higher strength and elastic modulus, as well as excellent durability and fatigue strength, is the most practical option for post-tensioning applications. The primary objective of this research project was to assess the feasibility of the use of innovative carbon fiber reinforced polymer (CFRP) tendons and to develop guidelines for CFRP in post-tensioned bridge applications, including segmental bridges and pier caps. An experimental investigation and a numerical simulation were conducted to compare the performance of a scaled segmental bridge model, post-tensioned with two types of carbon fiber strands and steel strands. The model was tested at different prestress levels and at different loading configurations. While the study confirms feasibility of both types of carbon fiber strands for segmental bridge applications, and their similar serviceability behavior, strands with higher elastic modulus could improve structural performance and minimize displacements beyond service loads. As the second component of the project, a side-by-side comparison of two types of carbon fiber strands against steel strands was conducted in a scaled pier cap model. Two different strand arrangements were used for post-tensioning, with eight and six strands, respectively representing an over-design and a slight under-design relative to the factored demand. The model was tested under service and factored loads. The investigation confirmed the feasibility of using carbon fiber strands in unbonded post-tensioning of pier caps. Considering both serviceability and overload conditions, the general performance of the pier cap model was deemed acceptable using either type of carbon fiber strands and quite comparable to that of steel strands. In another component of this research, creep stress tests were conducted with carbon fiber composite cable (CFCC). The anchorages for all the specimens were prepared using a commercially available expansive grout. Specimens withstood 95% of the guaranteed capacity provided by the manufacturer for a period of five months, without any sign of rupture.

Fuel level sensor based on polymer optical fiber Bragg gratings for aircraft applications

Safety in civil aviation is increasingly important due to the increase in flight routes and their more challenging nature. Like other important systems in aircraft, fuel level monitoring is always a technical challenge. The most frequently used level sensors in aircraft fuel systems are based on capacitive, ultrasonic and electric techniques, however they suffer from intrinsic safety concerns in explosive environments combined with issues relating to reliability and maintainability. In the last few years, optical fiber liquid level sensors (OFLLSs) have been reported to be safe and reliable and present many advantages for aircraft fuel measurement. Different OFLLSs have been developed, such as the pressure type, float type, optical radar type, TIR type and side-leaking type. Amongst these, many types of OFLLSs based on fiber gratings have been demonstrated. However, these sensors have not been commercialized because they exhibit some drawbacks: low sensitivity, limited range, long-term instability, or limited resolution. In addition, any sensors that involve direct interaction of the optical field with the fuel (either by launching light into the fuel tank or via the evanescent field of a fiber-guided mode) must be able to cope with the potential build up of contamination-often bacterial-on the optical surface. In this paper, a fuel level sensor based on microstructured polymer optical fiber Bragg gratings (mPOFBGs), including poly (methyl methacrylate) (PMMA) and TOPAS fibers, embedded in diaphragms is investigated in detail. The mPOFBGs are embedded in two different types of diaphragms and their performance is investigated with aviation fuel for the first time, in contrast to our previous works, where water was used. Our new system exhibits a high performance when compared with other previously published in the literature, making it a potentially useful tool for aircraft fuel monitoring.

Effect of Fatty Acids Fiber Concentration in Broiler Ration to Cholesterol, HDL and LDL Blood Serum

Cholesterol, HDL (High Density Lipoprotein) and LDL (Low Density Lipoprotein) in blood serum of broiler could can be controlled by food manipulation using different fatty acids and fiber content in ration. This research was planned to study the influence of fat i.e. cis-trans fatty acids and raw fiber content on feed to cholesterol, HDL and LDL biosynthesizing broiler blood serum. The research model was experimental and the design used was Completely Randomized Design in factorial pattern 2 x 3. The first factor was type of fat (L) : L1= cis fatty acid and L2 = trans fatty acid. The second factor was fiber content in feed (S) i.e. S1 = 5% ; S2 = 7%, and S3 = 9%. Each treatment was repeated four times, it means 24 observation. Variables observed were : cholesterol, HDL, LDL concentration in blood serum of broiler. The result indicated that the use of 5 % palm kernel oil and 5 % tallow fat in feed containing 5 %, 7 % and 9 % fiber respectively have unsignificant result (P>0.01) to cholesterol and LDL blood serum of broiler, but have significant to HDL concentration (P<0.01). The average cholesterol of blood serum was between 76.46 mg/dl (L2S3) to 99.88 mg/dl (control), HDL concentration was 21.19 mg/dl (L2S1) to 38.85 mg/dl (control), and LDL concentration was 46.83 mg/dl (L2S2) to 61.14 mg/dl (control). It can be concluded that feeding with far in the form of cis (palm kernel oil) or trans (tallow) when combined with proporsional fiber addition can be used as feed because it does not increase the cholesterol and LDL in broiler blood. The reduction of cholesterol as much as 23.53 % in control feed was found in treatment with 5 % tallow addition in combination with 9 % raw fiber content, HDL concentration was higher in treatment with palm kernel oil compared to tallow addition. (Animal Production 7(1): 27-33 (2005) Key Words : Cholesterol, HDL, LDL, Cis Fatty Acid, Trans Fatty Acid