Reactive Ion Etching of Polymer Films

The need for nanometer-sized features in integrated circuits calls for the use of dry-etching techniques using glow-discharge plasmas. The reactive ion etching (RIE) mode in which there is a large difference in potential between the gas phase and the solid surface yields particularly desirable, straight-walled etched structures. The design of processes and materials for RIE requires a knowledge of the effects of operating variables on various parameters. In the present work, the parameter emphasized is the etch rate. A novel aspect of the apparatus used incorporates a laser interferometer for in situ measurements of etch rate. Some observations on operating variables are: i. Chamber pressure is more critical when a fluoride-oxygen plasma is used than when oxygen alone is used. This is due to polymer deposition that occurs with the former along with etching. 2. The etch rate in the oxygen/RIE mode is almost the arithmetic sum of the oxygen/plasma mode together with the nitrogen/RIE mode except at low incident power levels where etch rate with oxygen/RIE is much greater than the sum of the other two. 3. Aromatic polymers etch more slowly than aliphatic polymers. 4. The oxygen/RIE rate of polyvinylchloride, PVC, decreases on addition of a compatible organotin compound. A 1:1 mixture of PVC with a tin compound etches at i/10 the rate of PVC alone.

Steady State Condition in the Measurement of VO<inf>2</inf>and VCO<inf>2</inf>by Indirect Calorimetry

Resting Metabolic Rate (RMR) is computed using VO<inf>2</inf>and VCO<inf>2</inf>short time 15-minute window measurement with Indirect Calorimetry (IC) instruments designed with mixing chamber. Steady state condition using a 10% variation coefficient criteria is the main objective to achieve metabolic long time prediction reliability. This study address how susceptible is the steady state VO<inf>2</inf>, VCO<inf>2</inf>measurement condition to the clino-orthostatic physiological maneuver. 30 young healthy subjects were analyzed. Only 18 passed the 10% variation coefficient inclusive criteria. They were exposed to 10 minutes clino-stage and 10 minutes orthostage. The hypothesis tests show not statistical significance (p< 0.1) in the average and variance analysis. It is concluded that the steady state is not influenced by the patient position IC test, probably because IC mixing chamber instruments are insensitive to detect a mayor physiological dynamics changes that can modify the steady state definition.

Inheritance of random amplified polymorphic DNA markers in cassava (Manihot esculenta Crantz)

The informativeness and inheritance of randomly amplified polymorphic DNA (RAPD) markers were investigated in an intraspecific F1 progeny derived from two heterozygous parents. The analysis confirmed the utility of RAPD markers for comparing candidate parents for the development of a molecular genetic map, and provided numerous markers for linkage analysis in a crop with a very limited history of classical or molecular genetic studies. Six potential parental lines (themselves F1 hybrid clones) showed between 1.82 and 0.62 segregating bands per primer in three hybrid families. Forty-three percent (309) of 722 primers produced polymorphic products in the most informative of these three crosses, revealing 328 single-dose (SD) markers segregating 1:1 for presence/absence in a progeny of 90 individuals. A second class of informative markers were those present in both parents but segregating in the progeny. Fifty-seven or 67% of the monomorphic but segregating markers exhibited the 3:1 ratio expected for SD dominant markers in a cross between heterozygotes. Linkage groups were constructed from the segregation of SD RAPD markers originating in the female (TMS 30572) and the male (CM2177-2) parent. Key words : RAPDs, molecular markers, genetic segregation, Manihot, single-dose markers.

Consumption of diets with different type of fat influences triacylglycerols-rich lipoproteins particle number and size during the postprandial state

BACKGROUND AND AIMS

Previous evidence suggests that dietary fat could influence the composition and size of triacylglycerols-rich lipoproteins (TRL). In a controlled intervention study on healthy subjects, we evaluated the influence of 3 dietary interventions, with different types of fat on postprandial TRL particle size and number.

METHODS AND RESULTS

Volunteers followed three different diets for four weeks each, according to a randomized crossover design. Western diet: 15% protein, 47% carbohydrates (CHO), 38% fat (22% saturated fatty acid (SFA)); Mediterranean diet: 15% protein, 47% CHO, 38% fat (24% monounsaturated fatty acid (MUFA)); high CHO enriched with ALNA diet: 15% protein, 55% CHO, <30% fat (8% polyunsaturated fatty acid (PUFA)). After a 12-h fast, volunteers consumed a breakfast with 1g fat and 7 mg cholesterol per kg body weight and a fat composition similar to that consumed in each of the diets: Butter meal: 35% SFA; Olive oil meal: 36% MUFA; Walnut meal: 16% PUFA, 4% α-linolenic acid. Tryglicerides (TG) in TRL (large and small TRL) were determined by ultracentrifugation and size and number of lipoprotein particles were measured with Nuclear Magnetic Resonance Spectroscopy at different time points. The olive oil meal reduced the number of total TRL postprandial particles compared with the other meals (P=0.002). Moreover, the olive oil meal also increased the TRL particle size compared with the walnut meal (P=0.001).

CONCLUSION

Our data showed that short-term intake of the Mediterranean diet and the acute intake of an olive oil meal lead to the formation of a reduced number and higher-size TRL particle compared with other fat sources. These novel findings have implications for understanding the postprandial lipoprotein mechanisms, and could favour the lower cardiovascular risk in Mediterranean countries.

Controlled release properties and final macroporosity of a pectin microspheres-calcium phosphate composite bone cement

The use of calcium phosphate cements (CPC) is restricted by their lack of macroporosity and poor drug release properties. To overcome these two limitations, incorporating degradable polymer microparticles into CPC is an attractive option, as polymer microparticles could help to control drug release and induce macroporosity after degradation. Although few authors have yet tested synthetic polymers, the potentiality of polysaccharides' assuming this role has never been explored. Low-methoxy amidated pectins (LMAP) constitute valuable candidates because of their biocompatibility and ionic and pH sensitivity. In this study, the potentiality of a LMAP with a degree of esterification (DE) of 30 and a degree of amidation (DA) of 19 was explored. The aim of this study was to explore the influence of LMAP microspheres within the composite on the cement properties, drug release ability and final macroporosity after microspheres degradation. Three LMAP incorporation ratios, 2%, 4% and 6% w/w were tested, and ibuprofen was chosen as the model drug. In comparison with the CPC reference, the resulting composites presented reduced setting times and lowered the mechanical properties, which remained acceptable for an implantation in moderate-stress-bearing locations. Sustained release of ibuprofen was obtained on at least 45days, and release rates were found to be controlled by the LMAP ratio, which modulated drug diffusion. After 4months of degradation study, the resulting CPC appeared macroporous, with a maximum macroporosity of nearly 30% for the highest LMAP incorporation ratio, and interconnectivity between pores could be observed. In conclusion, LMAP appear as interesting candidates to generate macroporous bone cements with tailored release properties and macroporosity by adjusting the pectin content within the composites.

[Latin American survey on delirium in critical patients]

OBJECTIVES

This study has aimed to establish the intensivist physician's concepts and practices in this region regarding the diagnosis, management and prevention of delirium in intensive care units (ICU).

DESIGN

A survey was distributed among the FEPIMCTI member societies for distribution among its medical members.

RESULTS

Eight hundred fifty-four intensive care physicians from 12 Latin America countries, most of them from Argentina, Mexico, Chile and Colombia, responded to the survey. There was a majority of academic ICUs (70.5%). A total of 56.55% responded that they always evaluated the diagnosis of delirium and only 10.2% answered never. A general clinical assessment was made by 69.5%, only 19.6% used the CAM-ICU scale and 9% the checklist assessment of delirium. It was agreed or strongly agreed by 88.3% that delirium was an expected event in the ICU and by 90.1% that delirium was underdiagnosed in ICU. A total of 97% responded that it was a problem that requires intervention and which is preventable (66.5%). It was considered that excessive sedation is given in the ICU by 74.5% and 70.5% believed that opiates are associated with the onset of delirium, while 87.1% considered that some sedatives are associated with its development. Ventilator-associated pneumonia (VAP) was considered as a risk factor by 70.2% of the respondents and 87.8% considered that it made extubation difficult.

CONCLUSIONS

Although delirium is considered to be a common and preventable problem with serious implications for critically ill patients, the intensivist physicians surveyed do not use a tool for its evaluation in the ICU. Educational efforts are needed to disseminate the effectiveness and usefulness of the scales that allow for early and accurate diagnosis of delirium in the ICU.

282 NOVEL SEQUENTIAL MEDIA FOR THE PRODUCTION OF CENTRAL AMERICA'S FIRST IN VITRO-PRODUCED SENEHOL CALVES

Panama, like many countries in Central America, has a tropical climate with high temperature and humidity throughout the year. These conditions negatively affect the fertility and productivity of dairy cattle; therefore, it is necessary to develop and apply technologies to improve those parameters in heat-stressed cattle. One such technology is in vitro embryo production (IVP). The objectives of this study were to a) introduce, for the first time in Panama, IVP procedures for bovine embryos and b) evaluate the efficacy of novel sequential media (SM) on in vitro embryo development and pregnancy rates. Oocytes collected from slaughterhouse ovaries of Holstein cows were matured and fertilized (with Senepol semen) in vitro using standard procedures. The resultant zygotes were cultured in an atmosphere of 6% CO2, 5% O2, and 89% N2 at 38.5°C in either control medium plus BSA (3 mg mL-1; mSOF, Tanaka et al. 1996 JICA Manual) for 144 h post-insemination (hpi; n = 1,072) or a semi-defined medium for 96 hpi followed by a second semi-defined medium for 48 h additional culture (n = 1,081; see Table 1). The experiment was replicated 5 times between January 2007 and May 2009, and data were analyzed using chi-square. Zygotes cultured in SM resulted in more >4-cell embryos at 48 hpi than controls (93 v. 81%; P < 0.01), more >8-cell embryos at 96 hpi than controls (79 v. 65%; P < 0.01), and more blastocysts at 144 hpi than controls (45 v. 37%; P < 0.05). A subset of quality grade 1 blastocysts produced in SM (n = 35) or mSOF (n = 30) were transferred nonsurgically to synchronized recipients. Pregnancy rates at 60 days were similar between SM and mSOF embryos (62 v. 45%, respectively). From the first 14 embryo transfers, 7 calves have been born (4 from SM and 3 from mSOF). These results demonstrate that the SM used in this study, which contained antioxidants and growth factors, supported enhanced in vitro embryo development. Additional transfers are needed to determine if the use of SM will also result in a statistically higher pregnancy rate, which would be economically important from a commercial point of view. This represents the first report of IVP calves in Central America. Table 1.Composition of novel sequential media

Transmural strains in the ovine left ventricular lateral wall during diastolic filling

Rapid early diastolic left ventricular (LV) filling requires a highly compliant chamber immediately after systole, allowing inflow at low driving pressures. The transmural LV deformations associated with such filling are not completely understood. We sought to characterize regional transmural LV strains during diastole, with focus on early filling, in ovine hearts at 1 week and 8 weeks after myocardial marker implantation. In seven normal sheep hearts, 13 radiopaque markers were inserted to silhouette the LV chamber and a transmural beadset was implanted into the lateral equatorial LV wall to measure transmural strains. Four-dimensional marker dynamics were obtained 1 week and 8 weeks thereafter with biplane videofluoroscopy in closed-chest, anesthetized animals. LV transmural strains in both cardiac and fiber-sheet coordinates were studied from filling onset to the end of early filling (EOEF, 100 ms after filling onset) and at end diastole. At the 8 week study, subepicardial circumferential strain (ECC) had reached its final value already at EOEF, while longitudinal and radial strains were nearly zero at this time. Subepicardial ECC and fiber relengthening (Eff) at EOEF were reduced to 1 compared with 8 weeks after surgery (ECC:0.02+/-0.01 to 0.08+/-0.02 and Eff:0.00+/-0.01 to 0.03+/-0.01, respectively, both P<0.05). Subepicardial ECC during early LV filling was associated primarily with fiber-normal and sheet-normal shears at the 1 week study, but to all three fiber-sheet shears and fiber relengthening at the 8 week study. These changes in LV subepicardial mechanics provide a possible mechanistic basis for regional myocardial lusitropic function, and may add to our understanding of LV myocardial diastolic dysfunction.

2-Methoxyestradiol attenuates hypertension and coronary vascular remodeling in spontaneously hypertensive rats

OBJECTIVES

Accumulating data provide evidence that some metabolites of 17beta-estradiol are biologically active and mediate multiple effects on the cardiovascular and renal systems. We investigated the effect of 2-methoxyestradiol (an active metabolite of estradiol with non-feminizing activity) on the development of hypertension and myocardial vascular remodeling in male and female ovarectomized SHR.

METHODS

Rats were divided into five groups: intact females, ovarectomized (OVX), OVX+ 2-methoxyestradiol (2ME), control males, and male+2ME. Systolic blood pressure was determined from 10 to 18 weeks. Structural changes in coronary vessels were quantified by an image analyzer. Immunoblotting of phosphorylated ERK1/2 and NADPH oxidase activity were performed on mesenteric arteries.

RESULTS

Treatment with 2ME reduced the increase in systolic blood pressure in male and ovarectomized rats to values not different from those obtained in intact females. Myocardial arterioles and small arteries showed significant increases in wall-to-lumen ratio and perivascular fibrosis in male and ovarectomized rats when compared with intact females. NADPH oxidase activity was increased in mesenteric arteries from males and ovarectomized females as compared with intact females. Finally, the expression of phosphorilated ERK1/2 were significantly higher in mesenteric arteries from male and ovariectomized animals than in those from intact females. Those effects of ovarectomy and gender differences were totally or partially prevented by treatment with 2-methoxyestradiol.

CONCLUSIONS

These data demonstrate that 2-methoxyestradiol protects the vasculature from hypertension-induced myocardial arterial remodeling in male and ovarectomized SHR, and that might be in part related to decreased superoxide generation and ERK1/2 activation.