Identification of large variation in the photosynthetic induction response among 37 soybean [Glycine max (L.) Merr.] genotypes that is not correlated with steady-state photosynthetic capacity.

Irradiance continuously fluctuates during the day in the field. The speed of the induction response of photosynthesis in high light affects the cumulative carbon gain of the plant and could impact growth and yield. The photosynthetic induction response and its relationship with the photosynthetic capacity under steady-state conditions (P max) were evaluated in 37 diverse soybean [Glycine max (L.) Merr.] genotypes. The induction response of leaf photosynthesis showed large variation among the soybean genotypes. After 5 min illumination with strong light, genotype NAM23 had the highest leaf photosynthetic rate of 33.8 µmol CO2 m-2 s-1, while genotype NAM12 showed the lowest rate at 4.7 µmol CO2 m-2 s-1. Cumulative CO2 fixation (CCF) during the first 5 min of high light exposure ranged from 5.5 mmol CO2 m-2 for NAM23 to 0.81 mmol CO2 m-2 for NAM12. The difference in the induction response among genotypes was consistent throughout the growth season. However, there was no significant correlation between CCF and P max among genotypes suggesting that different mechanisms regulate P max and the induction response. The observed variation in the induction response was mainly attributed to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activation, but soybean lines differing in the induction response did not differ in the leaf content of Rubisco activase α- and ß-proteins. Future studies will be focused on identifying molecular determinants of the photosynthetic induction response and determining whether this trait could be an important breeding target to achieve improved growth of soybeans in the field.

Low-temperature synthesis of single-walled carbon nanotubes by alcohol gas source growth in high vacuum.

Carbon nanotube (CNT) growth was carried out on SiO2/Si substrates with a Co catalyst using an alcohol gas source method in an ultra-high vacuum chamber. The resulting CNTs were characterized by scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM). Reducing the ethanol pressure decreased the optimum growth temperature for maximum yield, enabling single-walled carbon nanotube (SWNT) growth at 400 degrees C. By employing an Al2Ox buffer layer, SWNT yield increased several times, even at 400 degrees C. Under TEM observation, the Co particle size on the Al2Ox layers did not show a significant dependence on the growth temperature between 400 and 700 degrees C. Raman and TEM results confirmed activation of Co particles with larger diameter (>1 nm) by the Al2Ox buffer layer.

Factors associated with vaginal birth after cesarean in a maternity hospital of Rio de Janeiro.

OBJECTIVES: Identifying characteristics associated with vaginal birth after cesarean. STUDY DESIGN: Case-control study based on medical records. STUDY POPULATION: women with previous cesarean, who had delivered in a public Rio de Janeiro maternity hospital between 1992 and 1996. SAMPLE: 141 cases (vaginal births after cesarean) and 304 controls (a new cesarean after other(s)). Multivariate analysis with logistic regression was carried out. RESULTS: The following characteristics were associated with greater probability of vaginal birth (IC=95%): only one previous cesarean (OR=19.05; IC=6.88-52.76); cervical dilatation at admission above 3 cm (OR=8.86; IC=4.93-15.94); gestational age below 37 weeks (OR=3.01; IC=1.40-6.46); history of at least one previous vaginal birth (OR=2.12; IC=1.18-3.82); level of education below high school (OR=1.94; IC=1.02-3.69). Chronic hypertension reduced the chances of vaginal birth (OR=0.44; IC=0.22-0.88). CONCLUSIONS: Among the factors that can be modified to reduce the number of repeated cesareans are: trial of labor promotion, reducing admission of women at early stages of labor and adequate hypertension management during pregnancy. CONDENSATION: Among the factors that can be modified to reduce the number of repeated cesareans are: the trial of labor promotion for women who present previous cesarean, reducing admission of women at early stages of labor and adequate hypertension management during pregnancy.

Studies on the association of 2-thiazolidinecarboxylic acid and antimony potassium tartrate: chiral recognition and prediction of absolute configuration by electrospray ionization mass spectrometry.

Optically active 2-thiazolidinecarboxylic acid (2-THC), a substrate for D-amino acid oxidase in animal kidney, is known to undergo racemization quickly in solution. The association of (+)- and (-)-2-THC with antimony potassium tartrate K(2)[Sb(2)(L or D-tart)(2)] was studied by electrospray ionization mass spectrometry (ESI-MS). We observed that relative intensities of associated ions in acetonitrile/water solution were changing as the racemization progressed. For [Sb(2)(L-tart)(2)](2-), the intensities of the associated ions increased as (+)-2-THC underwent racemization to a (-)-isomer; on the other hand, the intensity of the associated ion decreased as (-)-2-THC underwent racemization to a (+)-isomer. In the case of [Sb(2)(D-tart)(2)](2-), an opposite effect on the intensities of the associated ions was observed. The change in the intensities of associated ions can be used for chiral recognition of (+)-2-THC and (-)-2THC. Stereochemical models of the association of the optical isomers with [Sb(2)(L- or D-tart)(2)](2-) were constructed from the consideration of both hydrogen bonding of NH-O functions and HSAB (hard and soft acids and bases) interaction of S and Sb atoms. Comparison of the stereochemical models with the ESI-MS results enabled us to predict the absolute configurations of the 2-THC isomers.

Geko, a novel gene involved in olfaction in Drosophila melanogaster.

To characterize genes involved in olfactory responses to chemical attractants, we screened 3000 P-element-tagged lines for their attraction to ethanol. Ten lines showed reduced levels of response, and revertants of these lines were obtained by excising the inserted P-element. The olfactory response of one line reverted to wild-type behavior compared to the original mutant line. The gene affected by this P-lacW insertion was named geko (gk). A 1.3-kb transcript was found to emanate from close to the P-insertion site, and the 5' upstream region was interrupted by the P-element. The amount of mRNA of gk gene in the P-lacW inserted line was about half that of the control strain. The response to ethanol of the gk(1) mutant was restored by transforming the genomic region containing this transcription unit. lacZ expression (stemming from this reporter-gene's presence in the transposon) was observed in the antenna and the antennal-maxillary complex (the olfactory organ of adults and larvae, respectively). gk mRNA was detected at the antenna and from other parts of the body. The deduced gk product showed no overall similarity to any reported amino-acid sequences.

Synthesis of four stereoisomers of 1,4-thiazane-3-carboxylic acid 1-oxide via the asymmetric transformation (combined isomerization-preferential crystallization) of 1,4-thiazane-3-carboxylic acid.

In order to synthesize four stereoisomers of 1,4-thiazane-3-carboxylic acid 1-oxide (TCA SO), (S)-1,4thiazane-3-carboxylic acid [(S)-TCA], which is one of the precursors, was prepared by the asymmetric transformation (combined isomerization-preferential crystallization) of (RS)-TCA. This asymmetric transformation was used (2R, 3R)-tartaric acid [(R)-TA] as a resolving agent and salicylaldehyde as the epimerization catalyst in propanoic acid at 110 degrees C to afford a salt of (S)-TCA with (R)-TA in 100% de with a yield of over 90%. Optically pure (S)-TCA was obtained by treating the salt with triethylamine in methanol in a yield of over 80%, based on (RS)-TCA as the starting material. In addition, asymmetric transformation of (R)-TCA gave (S)-TCA in a yield of 60-70%. (S)-TCA was oxidized by hydrogen peroxide in dilute hydrochloric acid to selectively crystallize (1S, 3S)-TCA.SO. (1R, 3S)-TCA SO of 70% de from the filtrate was allowed to form a salt with (R)-TA after a treatment with triethylamine to give (1R, 3S)-TCA SO as a single diastereoisomer. (1R, 3R)- and (1S, 3R)-TCA.SO were also prepared by starting from (R)-TCA that had been synthesized from L-cysteine.

Optical Resolution by the Replacing Crystallization of DL-Threonine with L-Alanine as an Optically Active Cosolute.

DL-Threonine (DL-Thr) was optically resolved by replacing crystallization with L-alanine (L-Ala) as an optically active cosolute. D-Thr was preferentially crystallized from a supersaturated aqueous solution of DL-Thr in the presence of L-Ala. Optical resolution was successfully achieved to afford D-Thr with an optical purity of 96-98% and L-Thr of 91-95%. The partially resolved D- and L-Thr were recrystallized from water, taking account of the solubility of DL-Thr, to efficiently yield both enantiomers in an optically pure form.

Synthesis of Optically Active 1,4-Thiazane-3-carboxylic Acid via Optical Resolution by Preferential Crystallization of (RS)-2-Amino-3-[(2-chloroethyl)sulfanyl]propanoic Acid Hydrochloride.

Optically active 1,4-thiazane-3-carboxylic acid [TCA] was synthesized from cysteine via optical resolution by preferential crystallization. The intermediate (RS)-2-amino-3-[(2-chloroethyl)sulfanyl]propanoic acid hydrochlo-ride [(RS)-ACS•HCl] was found to exist as a conglomerate based on its melting point, solubility and IR spectrum. (RS)-ACS•HCl was optically resolved by preferential crystallization to yield (R)- and (S)-ACS•HCl. (R)- and (S)-ACS•HCl thus obtained were recrystallized from a mixture of hydrochloric acid and 2-propanol, taking account of the solubility of (RS)-ACS•HCl, efficiently yielding both enantiomers in optically pure forms. (R)- and (S)-TCA were then respectively synthesized by the cyclization of (R)- and (S)-ACS•HCl in ethanol in the presence of triethylamine.

Optical Resolution by Preferential Crystallization of (RS)-2-Amino-3-(2-carboxyethylthio)propanoic Acid.

Electrophilic additions of DL- and L-Cys to propenoic acid afforded (RS)- and (R)-2-amino-3-(2-carboxyethylthio)propanoic acids [(RS)- and (R)-ACE], respectively. (RS)-ACE was found to exist as a conglomerate based on its melting point, solubility, and infrared spectrum. (RS)-ACE was optically resolved by preferential crystallization to yield (R)- and (S)-ACE. The obtained (R)- and (S)-ACE were efficiently recrystallized from water, taking account of the solubility of (RS)-ACE, to give them in optically pure form.

[A survey of demand for medical care in three public health clinics in Rio de Janeiro, Brazil]. / Demanda ambulatorial em três serviços da rede pública do município do Rio de Janeiro, Brasil.

A sample survey was conducted in three public ambulatory medical care units in Rio de Janeiro in order to show the demographic and nosological aspects of the clientele as well as to evaluate the quality of clinic records. The sample included 2,029 patients registered in the health clinics and 3,980 consultants from October 1, 1990 to September 30, 1991. The diagnoses were coded according to the 9th revision of the International Classification of Dieases. Females accounted for about 60% of the sample, and more than a half were between 15 and 49 years of age. Children under 10 years old made up 28% of the total. About 38% of the patients came from the poor areas of the city: the "favelas". The case files were poorly filled out, frequently lacking useful information. The most frequent cause was classified in the XVIo chapter of the ICD - ill-defined causes, followed by respiratory, infectious, genitourinary and circulatory diseases. External causes predominated in one of the health clinics, which is an emergency service. There was a great demand for preventive measures, such as prenatal care and child care, even at the clinic that was traditionally devoted only to curative medicine. The most frequent specific diagnoses were upper respiratory tract infection, hypertension, gynecological problems, prenatal care, and skin diseases. There were no records for referrals to other health services. The poor quality of the medical records causes problems in terms of quality of health care. Use of such record-keeping systems, even while criticizing them, is essential to improve them.