Molecular regulation of secondary gorwth: searching for SHORT-ROOT function in cork formation

The analysis of molecular regulators involved in controlling the maintenance and function of plant meristems has been the subject of many studies. Some master regulators of these processes have been identified in Arabidopsis benefiting from the array of tools available for genetic and molecular analysis in this model plant. However, aspects such as secondary growth that are more extensively observed in woody plants, have been less studied. Secondary growth is responsible for the enlargement of the plant stems and roots and results from the activity of the lateral (secondary) meristems, vascular cambium and cork cambium (phellogen), which produce two important renewable natural resources, wood and cork, respectively.(...)

Risky behavior regarding drug use and HIV infection: an Internet questionnaire coupled with short education texts for Portuguese speakers

Surveys of risky behavior relating to HIV/AIDS are generally made for groups at risk of infection, for which HIV/AIDS prevalence is usually expected to be higher than in the general population. Therefore, an educational homepage in Portuguese was created on the Internet to inform/ask internauts regarding knowledge and behavior. The internauts were classified as adolescents (13 to 25 years) and adults (>25 years). The number of STDs was reported as 1. 8 ± 2. 6 infections (range: 1 to 20 infections); 43% used condoms during sexual intercourse. Alcohol consumption was reported by 63% and illicit drug use by 32% (marijuana 24% and inhalants 15%). Among the adolescents, 31% did not classified alcohol as a drug. The adults more frequently reported homosexuality, anal intercourse and STDs, although the adolescents also presented high rates of risky behavior. These results show the need to reach out to internauts through better control strategies. Different types of strategies must be encouraged, in order to reach people that use this means of communication and entertainment.

Measuring the impact of short and lending practices using the DGTW benchmarks

Mutual fund managers increasingly lend their holdings and/or use short sales to generate higher returns for their funds. This project presents a first look into the impact these practices on performance using the performance measures: i) Characteristic Selectivity (CS), the ability of the fund's managers to choose stocks that outperform their benchmarks; ii) Characteristic Timing (CT), the ability of the manager to time the market; iii) and Average Style (AS), the returns from funds systematically holding stocks with certain characteristics. These returns are computed through the DGTW benchmarks. The effect of other variables that have also been shown to impact fund’s returns – total net assets under management, investment styles, turnover and expense ratios – will also be analyzed. I find that managers who use short-sales do not exhibit better stock picking abilities than those who do not, while mutual funds that lend do present higher CS returns. In addition, while lending is not significant for the total performance of a fund, the employment of short-sales and of both short-sales and lending has a negative impact on the fund’s performance.

Essays in health economics: Volume-Outcome Effect, upcoding behaviour and the evaluation of a short-term intervention program

Evidence in the literature suggests a negative relationship between volume of medical procedures and mortality rates in the health care sector. In general, high-volume hospitals appear to achieve lower mortality rates, although considerable variation exists. However, most studies focus on US hospitals, which face different incentives than hospitals in a National Health Service (NHS). In order to add to the literature, this study aims to understand what happens in a NHS. Results reveal a statistically significant correlation between volume of procedures and better outcomes for the following medical procedures: cerebral infarction, respiratory infections, circulatory disorders with AMI, bowel procedures, cirrhosis, and hip and femur procedures. The effect is explained with the practice-makes-perfect hypothesis through static effects of scale with little evidence of learning-by-doing. The centralization of those medical procedures is recommended given that this policy would save a considerable number of lives (reduction of 12% in deaths for cerebral infarction).

Clinical use of growth hormone and glutamine in short bowel syndrome

Growth hormone (GH) and glutamine (GLN) are considered bowel trophic factors and are used experimentally after bowel resection. Their clinical uses in short bowel syndrome (SBS) are still not standardized. It is of interest to verify metabolic, nutritional and side effects of the association of GH and GLN in SBS. Three patients, 39 (A), 33 (B), and 01 years old (C) underwent bowel resection with jejunum anastomosis 15 cm (A) and 60 cm (B) distant from the Treitz angle, and 40 cm (C) preserving the ileo cecal valve. GH Saizen (Serono - A), Genotropin (Pharmacia - B), and Norditropin (Novonordisk C) were administered in doses of 0.14 mg /kg/day. GLN (0.4 g/kg/day) was given orally for 10 days (A), 30 days (B) and 60 days to patient C (0.28 g/kg/day). Central TPN and adequate oral diet was administered according to the bowel adaptation phase. On the first day after beginning treatment patient A exhibited symptoms of hypoglycemia. There were no other side effects. After treatment, body weight was higher and analysis by bioelectrical impedance showed more lean mass and less fat mass compared to pre-treatment measurements. Nitrogen retention was progressively higher with treatment. Simultaneous treatment with GH and GLN does not cause significant side effects, and is associated with a favorable distribution of the body compartments and nitrogen retention in patients with the short bowel syndrome.

Nutritional follow-up of critically ill infants receiving short term parenteral nutrition

Few studies have tried to characterize the efficacy of parenteral support of critically ill infants during short period of intensive care. We studied seventeen infants during five days of total parenteral hyperalimentation. Subsequently, according to the clinical conditions, the patients received nutritional support by parenteral, enteral route or both up to the 10th day. Evaluations were performed on the 1st, 5th, and 10th days. These included: clinical data (food intake and anthropometric measurements), haematological data (lymphocyte count), biochemical tests (albumin, transferrin, fibronectin, prealbumin, retinol-binding protein) and hormone assays (cortisol, insulin, glucagon). Anthropometric measurements revealed no significant difference between the first and second evaluations. Serum albumin and transferrin did not change significantly, but mean values of fibronectin (8.9 to 16 mg/dL), prealbumin (7.7 to 18 mg/dL), and retinol-binding protein (2.4 to 3.7 mg/dL) increased significantly (p < 0.05) from the 1st to the 10th day. The hormonal study showed no difference for insulin, glucagon, and cortisol when the three evaluations were compared. The mean value of the glucose/insulin ratio was of 25.7 in the 1st day and 15.5 in the 5th day, revealing a transitory supression of this hormone. Cortisol showed values above normal in the beginning of the study. We conclude that the anthropometric parameters were not useful due to the short time of the study; serum proteins, fibronectin, prealbumin, and retinol-binding protein were very sensitive indicators of nutritional status, and an elevated glucose/insulin ratio, associated with a slight tendency for increased cortisol levels suggest hypercatabolic state. The critically ill patient can benefit from an early metabolic support.

Low efficacy of an ultra-short term, once-daily dose triple therapy with omeprazole, azithromycin, and secnidazole for Helicobacter pylori eradication in peptic ulcer

PURPOSE: To determine the eradication rate of an ultra-short treatment schedule for Helicobacter pylori infection in a population with peptic ulcers, using omeprazole, secnidazole, and azithromycin in a once-daily dose for 3 days. METHODS: Thirty patients with peptic ulcer diagnosed by upper endoscopy and for Helicobacter pylori infection by rapid urease test and histologic examination received omeprazole 40 mg, secnidazole 1000 mg, and azithromycin 500 mg, administered once daily for 3 days. A follow-up exam was performed 12 weeks after the end of the treatment. Patients who were negative for Helicobacter pylori infection by rapid urease test and histologic examination were considered cured. RESULTS: Patients were predominantly female, and the mean age was 50 years. Duodenal peptic ulcer was found in 73% of the patients. Eradication was achieved in 9 of the 28 (32%) patients as determined from the follow-up endoscopic exam. The eradication rate by intention to treat was 30%. Side effects were present in 3% of the patients, and compliance to treatment was total. CONCLUSIONS: In spite of the low rate of side effects and good compliance, the eradication index was low. A possible drawback of this therapy is that it reduces the efficacy of macrolide and nitroimidazole compounds in subsequent treatments.

Short- and long-term outcomes of ileal pouch-anal anastomosis for ulcerative colitis

Ileal pouch-anal anastomosis was an important advancement in the treatment of ulcerative colitis. The aim of this study was to determine whether early complications of ileal pouch-anal anastomosis in patients with ulcerative colitis are associated with poor late functional results. PATIENTS AND METHODS: Eighty patients were operated on from 1986 to 2000, 62 patients with ileostomy and 18 without. The early and late complications were recorded. Specific emphasis has been placed on the incidence of pouchitis with prolonged follow-up. RESULTS: The ileostomy was closed an average of 9.2 months after the first operation. Fourteen patients were excluded from the long-term evaluation; 6 patients were lost to regular follow-up, 4 died, and 4 patients still have the ileostomy. Of the 4 patients that died, 1 died from surgical complications. Early complications after operation (41) occurred in 34 patients (42.5%). Late complications (29) occurred in 25 patients as follows: 16 had pouchitis, 3 associated with stenosis and 1 with sexual dysfunction; 5 had stenosis; and there was 1 case each of incisional hernia, ileoanal fistula, hepatic cancer, and endometriosis. Pouchitis occurred in 6 patients (9.8%) 1 year after ileal pouch-anal anastomosis, 9 (14.8%) after 3 years, 13 (21.3%) after 5 years, and 16 (26.2%) after more than 6 years. The mean daily stool frequency was 12 before and 5.8 after operation. One pouch was removed because of fistulas that appeared 2 years later. CONCLUSIONS: Ileal pouch-anal anastomosis is associated with a considerable number of early complications. There was no correlation between pouchitis and severe disease, operation with or without ileostomy, or early postoperative complications. The incidence of pouchitis was directly proportional to duration of time of follow-up.

Design formula for the flexural strengthening of RC beams using prestressed CFRP reinforcement

Applying a certain prestress level to the carbon fiber reinforced polymer (CFRP) reinforcement according to either externally bonded reinforcing (EBR) or near surface mounted (NSM) techniques can mobilize the strengthening potentialities of this high tensile strength composite material. For the prediction of the flexural behavior of reinforced concrete (RC) structures strengthened with prestressed EBR or NSM CFRPs, however, simplified analytical and design formulations still need to be developed as a guidance for engineers to design this type of strengthened structures by hand calculation without any programming help. Hence, the current work aims to briefly explain a developed simplified analytical approach, with a design framework, to predict the flexural behavior of RC beams flexurally strengthened with either prestressed EBR or NSM CFRP reinforcements. Moreover, an upper limit for the prestress level is proposed in order to optimize the ductility performance of the NSM prestressing technique. The good predictive performance of the analytical approaches was appraised by simulating the results of experimental programs composed of RC beams strengthened with prestressed NSM CFRP reinforcements.

Exploring the potentialities of a new type of CFRP laminate for the simultaneous flexural and shear strengthening of RC beams: numerical research

This study aims to develop an innovative carbon fibre reinforced polymer (CFRP) laminate with a U configuration to address strengthening interventions, where the increment of both flexural and shear capacity of reinforced concrete (RC) elements is required. This strengthening solution combines the near surface mounted (NSM) and embedded through section (ETS) techniques in the same application, since these techniques have already evidenced high performance on flexural and shear strengthening of RC beams using FRP systems, respectively. In fact, the proposed hybrid technique aims to mobilize the advantages provided by these two strengthening techniques by using an innovative CFRP laminate. The strengthening efficacy of this new hybrid NSM/ETS technique was numerically assessed and compared to the corresponding efficiency of NSM and ETS techniques applied separately for the flexural and shear strengthening of RC beams, respectively. The numerical models are described and the main relevant results are presented and discussed.

Prestress losses in reinforced concrete beams strengthened with NSM-CFRP laminates

Using prestressed near surface mounted fibre reinforced polymers (NSM-FRP) is nowadays regaining the attention from the scientific community for the strengthening of existing reinforced concrete (RC) structures. The application of prestressed internal FRP bars and externally bonded prestressed FRPs has already been deeply investigated and revealed considerable benefits when compared to the corresponding passive solutions. A certain amount of prestress provides benefits mainly associated to structural integrity and material durability. Immediately after prestress transference, it is possible to close some of the existing cracks, decreasing the susceptibility of the element to corrosion and, a certain amount of deflection can be recovered due to the creation of a negative curvature. However, very few studies have been carried out to properly assess the preservation of prestress over time. In this context, several reinforced concrete beams strengthened with prestressed NSM carbon FRP (CFRP) laminates were prestressed and monitored for about 40 days. The data obtained from these experimental programs is in this paper presented and analysed. The observed prestress losses were later modelled using finite elements analysis and, although this topic is not addressed in this paper, the obtained results revealed considerable precision. The largest strain losses in the CFRP laminate were found to be mainly located in the extremities of the bonded length, while in the central zone most of the applied pre-strain was retained over time. The highest CFRP strain losses were observed in the first 6 to 12 days after prestress transfer, suggesting that the application of prestressed NSM-FRP will be very effective over time.

Mechanical characterization of old chestnut beams

The main objective of this work is to evaluate, by non-destructive techniques, seven old Chestnut beams. For that, after the geometric assessment and the detailed visual inspection that allowed to strength grade the beams, a series of non-destructive tests was setup. In a first step, non-destructive bending tests, under the elastic limit, were performed to quantify the modulus of elasticity in bending (MoE) of the seven beams. Then, Resistograph® and Pilodyn® tests were done to assess the superficial decay and to have aclearer idea of the voids dimensions. Then, two beams were tested in bending until failure to evaluate the bending strength. In a second step, end parts were cut from the beams, one per end of the beams, to perform Resistograph®, Pilodyn® and ultrasound tests, to quantify the density of the beams and to extract meso-specimens to be used in tension parallel to the grain tests

Analytical approach for the flexural analysis of RC beams strengthened with prestressed CFRP

The objective of this paper is to propose a simplified analytical approach to predict the flexural behavior of simply supported reinforced-concrete (RC) beams flexurally strengthened with prestressed carbon fiber reinforced polymer (CFRP) reinforcements using either externally bonded reinforcing (EBR) or near surface mounted (NSM) techniques. This design methodology also considers the ultimate flexural capacity of NSM CFRP strengthened beams when concrete cover delamination is the governing failure mode. A moment–curvature (M–χ) relationship formed by three linear branches corresponding to the precracking, postcracking, and postyielding stages is established by considering the four critical M–χ points that characterize the flexural behavior of CFRP strengthened beams. Two additional M–χ points, namely, concrete decompression and steel decompression, are also defined to assess the initial effects of the prestress force applied by the FRP reinforcement. The mid-span deflection of the beams is predicted based on the curvature approach, assuming a linear curvature variation between the critical points along the beam length. The good predictive performance of the analytical model is appraised by simulating the force–deflection response registered in experimental programs composed of RC beams strengthened with prestressed NSM CFRP reinforcements.

Prestress losses in NSM-CFRP flexurally strengthened RC beams

The use of prestressed near surface mounted fibre reinforced polymers (NSM-FRP) has been long acknowledged to be a suitable approach to strengthen and retrofit existing reinforced concrete structures. The application of a certain amount of prestress to the FRP prior to its installation provides a number of benefits, mainly related to crack width and deflection requisites at serviceability limit state conditions. After transferring the prestress to a structural element, some of the existing cracks can be closed, decreasing the vulnerability of the element to corrosion and, a certain amount of deflection can be recovered due to the introduced negative curvature. However, these benefits can only be assured if the prestress is properly preserved over time. In this context, three series of reinforced concrete beams, in a total of 10 beams, were strengthened with a prestressed carbon FRP laminate (CFRP) and monitored for about 40 days. The data obtained from these tests is in this paper presented and analysed. The observed losses of strain in the CFRP laminate were found to be mainly located in the extremities of the bonded length, while in the central zone most of the initial strain was well-preserved over time. Additionally, the highest CFRP strain losses were observed in the first 6 to 12 days after prestress transfer, suggesting that the benefits of prestressed NSM-FRP will not be considerably lost over time.