Self-assembly of a one-dimensional iron(II) coordination polymer with p-phenylenebis(picolinaldimine).

catena-Poly[[[dichloridoiron(II)]-mu-N,N'-bis(2-pyridylmethylene)benzene-1,4-diamine] methanol disolvate], [FeCl(2)(C(18)H(14)N(4))].2CH(3)OH, forms a one-dimensional coordination polymer. The polymeric chains run parallel to the c axis. O-H...Cl-Fe and C-H...O hydrogen-bonding interactions with methanol solvent molecules stabilize the open supramolecular framework. Each Fe(II) atom adopts an octahedral geometry coordinated by four N atoms from two N,N'-bis(2-pyridylmethylene)benzene-1,4-diamine ligands and completed by two cis Cl atoms. The compound has C(2) (and C(i)) molecular symmetry, which is coincident with the crystallographic twofold symmetry at (0, y, 1/4). The one-dimensional structure is propagated via the crystallographic inversion center located at the benzene ring centroid (0, 1/2, 0).

Effects of breed and feed supplementation on the fertility of cows developed for milk production in Zimbabwe.

Forty-six indigenous Sanga-type (Nkone and Tuli breeds) cows and 46 crossbred (Nkone x Jersey and Tuli x Jersey) cows were randomly allocated to four treatment combinations in a 2 x 2 factorial arrangement with two breeds and two dietary levels, a control diet and a diet supplemented with dairy meal containing 14 per cent crude protein at the rate of 2 kg per cow per day. The progesterone concentration was measured in milk samples taken three times a week from 10 days postpartum for up to 200 days, and the cows' bodyweights and body condition scores were recorded fortnightly. The pregnancy rate in the crossbred cows was significantly higher (P<0.05) than in the indigenous cows, and the assumed pregnancy loss rate 30 days after conception was significantly higher (P<0.05) in the indigenous cows than in the crossbred cows. The supplemented crossbred cows had a lower pregnancy loss rate than the supplemented indigenous cows (P<0.05). All the supplemented indigenous cows that lost pregnancies were in their first parity, whereas all the crossbred cows that lost pregnancies were multiparous and were not supplemented. The indigenous cows weighed significantly more (P<0.05) than the crossbred cows irrespective of diet, and the supplemented cows of both breeds weighed more (P<0.05) than the control cows. The supplemented indigenous cows had significantly higher (P<0.05) body condition scores than the control cows. The mean dairy milk yield of all the breeds was generally low but significantly higher (P<0.05) in the crossbred than in the indigenous cows.

Regulation of estrous cycles in dairy cattle: A review.

Artificial insemination has allowed rapid genetic progress in dairy cattle through the use of semen from genetically superior sires. Detection of estrus and proper timing of insemination remain as major problems limiting reproductive efficiency in dairy herds. Numerous programs for regulating estrous cycles have been examined in this review. While several programs appear promising, results remain variable and the need for accurate detection of estrus has not been eliminated. Nulliparous heifers seem to respond more consistently than lactating cows. Further research is required to develop a successful program that will consistently produce a precise synchrony of estrus and ovulation with normal fertility and be cost effective.

The relationship of age and stage of gestation to the incidence of embryo death in dairy cattle.

Milk progesterone concentrations were measured thrice-weekly in approximately 200 autumn-calving cows of NIRD dairy herds in each of two successive years, about 100 being common to both years. From this, it was concluded that embryo death, later than the 14th day after artificial insemination occurred in about 10% of cows of each year. Most of the deaths occurred around the 35th day after AI, the time when the fetal membranes are becoming attached to the uterine wall. The incidence of embryo death around this time increases with age of cow.

Evaluation of tail paste as an oestrus detection aid using serial progesterone analysis.

Serial progesterone assay of 127 commercial dairy cows over several months identified 363 possible oestrous events. Of these, tail paste correctly identified 81.5 per cent, while the stockmen unaided recorded only 70.2 per cent (national average 55 to 60 per cent). The significance of such a degree of improvement, the factors restricting oestrus detection efficiency and the difficulties in creating the appropriate mental attitude to oestrus detection improvements are discussed.

Large cell lymphoma. II. Differential diagnosis of centroblastic and B-immunoblastic subtypes by morphometry on cytologic preparations.

Measurements were made, using semiautomatic electronic planimetry, of nuclear and nucleolar parameters of cytologic preparations from 18 cases of centroblastic and 9 cases of B-immunoblastic Non-Hodgkin's lymphomas, in order to determine whether these two subgroups of large cell lymphoma could be differentiated objectively by morphologic criteria. Statistically significant differences between centroblastic and B-immunoblastic lymphoma occurred in the mean and standard deviation of nucleolar area, the mean nuclear area, and the number of nucleoli per nucleus. The most useful discriminatory parameter was mean nucleolar area. The mean percentage of immunoblasts, defined as cells with nuclear area greater than 35 micron 2 and mean nucleolar area greater than 3 micron 2, was significantly different between the two groups of patients. The results suggest that although the groups of centroblastic and of immunoblastic lymphomas can be differentiated by measurable morphologic criteria, the individual cases form a spectrum from nodular centroblastic through diffuse centroblastic to immunoblastic, with polymorphic forms in between. A comparison with the results of a similar study on histologic sections from the same patients demonstrated that morphologic measurements on these two types of material are not interchangeable but, in general, the same conclusions were reached by morphometric study on histologic and cytologic specimens.

Adolescents' reported usage of selected foods in relation to their perceptions and social norms for those foods.

This paper reports a study of factors associated with the consumption of 22 diverse foods among 2082 students aged 12-15 years in Tasmania, Australia. Students provided data by completing a printed questionnaire. Multiple linear regression was used to assess how well self-reported usual (past) frequency of consumption of a food could be estimated from their perceptions of the qualities of the food (their liking for it, its healthfulness) and their descriptive social norms for the food (its usage by parents and its usage by friends). For all foods, multiple R was significant (p < 0.0001), with values ranging from 0.28-0.64 (median for the 22 foods being 0.49). Standardized regression coefficients for liking and parental usage were highly significant (p < 0.0001) for all foods. However, consistently lower coefficients were found for friends' usage (11 with p < 0.01, but only three with p < 0.0001) and healthfulness (five with p < 0.01, but only one with p < 0.0001). The absolute and relative magnitudes of the regression coefficients varied substantially between the foods. Liking was a stronger predictor than parental usage for 11 of the foods, and parental usage out-ranked liking for the remaining 11. Regression coefficients for friends' usage and healthfulness were smaller than those for liking and parental usage for all foods studied.

The Hobart Salt Study 1995: few meet national sodium intake target.

OBJECTIVE: To estimate 24-hour sodium and potassium excretion in an urban Australian population. DESIGN AND SETTING: Cross-sectional survey of an urban population in Hobart, Tasmania, in 1995. PARTICIPANTS: Systematic sample (87 men, 107 women) from the Commonwealth Electoral Roll of people aged 18-70 years on 30 June 1995 whose residential address was within 10 km of the Hobart General Post Office. MAIN OUTCOME MEASURE: Conformity with the national target for sodium intake for the year 2000 of < or = 100 mmol/day. RESULTS: The target was met by 6% of men and 36% of women. This difference between the sexes was significant (P < 0.001), while differences between age groups and socioeconomic levels were not significant. CONCLUSION: Our findings confirm the low level of conformity with the national sodium target reported by the handful of Australian studies over the past decade. Given the major community costs associated with hypertension, our results highlight the need for effective and properly monitored action to reduce sodium intakes.

Binuclear rhenium(I) complexes with bridging [2.2]paracyclophane-diimine ligands: probing electronic coupling through pi-pi interactions.

Two pseudo-para substituted bis-diimino[2.2]paracyclophane ligands (4,16-bis(picolinaldimine)-[2.2]paracyclophane (BPPc) and 4,16-bis(methyl-picolinaldimine)-[2.2]paracyclophane (BmPPc)) were prepared by the condensation reaction of the appropriate picolinaldimine with 4,16-diamino-[2.2]paracyclophane (2). An improved synthesis of 2 from [2.2]paracyclophane also is reported. BPPc (3a): monoclinic, P2(1)/c, a = 8.2238(11) A, b = 15.336(2) A, c = 8.4532(11) A, beta = 98.578(3) degrees, V = 1054.2(2) A(3), Z = 2. To investigate the binding properties of the bis-diimino[2.2]paracyclophane ligands, binuclear rhenium(I) tricarbonyl chloride complexes [Re(CO)(3)Cl](2)(micro-BPPc) (5a) and [Re(CO)(3)Cl](2)(micro-BmPPc) (5b) were prepared and fully characterized by infrared spectroscopy, (1)H NMR spectroscopy, elemental analysis, UV-visible absorption spectroscopy, and cyclic voltammetry. Two model complexes, Re(tolyl-pyCa)(CO)(3)Cl (4) (tolyl-pyCa = N-(p-tolyl)-2-pyridinecarboxaldimine) and [Re(CO)(3)Cl](2)(micro-PBP) (6) (PBP = p-phenylenebis(picolinaldimine)), also are reported. The dimeric compounds 5 and 6 each undergo two one-electron, predominantly diimine-centered reduction processes. Spectroscopic data and comproportionation constants (5a, 23 +/- 9; 5b, 23 +/- 9; 6, 2750 +/- 540) are consistent with relatively weak interactions between the diimine groups mediated by the paracyclophane bridging group, and these results are consistent with steric and electronic factors.