2,377 research outputs found
New Isozyme Systems for Maize (Zea mays L.): Aconitate Hydratase, Adenylate Kinase, NADH Dehydrogenase, and Shikimate Dehydrogenase
Electrophoretic variation and inheritance of four novel enzyme systems were studied in maize (Zea mays L.). A minimum of 10 genetic loci collectively encodes isozymes of aconitate hydratase (ACO; EC 4.2.1.3.), adenylate kinase (ADK; EC 2.7.4.3), NADH dehydrogenase (DIA; EC 1.6.99.-), and shikimate dehydrogenase (SAD; EC 1.1.1.25). At least four loci are responsible for the genetic control of ACO. Genetic data for two of the encoding loci, Aco1 and Aco4, demonstrated that at least two maize ACOs are active as monomers. Analysis of organellar preparations suggests that ACO1 and ACO4 are localized in the cytosolic and mitochondrial subcellular fractions, respectively. Maize ADK is encoded by a single nuclear locus, Adk1, governing monomeric enzymes that are located in the chloroplasts. Two cytosolic and two mitochondrial forms of DIA were electrophoretically resolved. Segregation analyses demonstrated that the two cytosolic isozymes are controlled by separate loci, Dia1 and Dia2, coding for products that are functional as monomers (DIA1) and dimers (DIA2). The major isozyme of SAD is apparently cytosolic, although an additional faintly staining plastid form may be present. Alleles at Sad1 are each associated with two bands that cosegregate in controlled crosses. Linkage analyses and crosses with B-A translocation stocks were effective in determining the map locations of six loci, including the previously described but unmapped locus Acp4. Several of these loci were localized to sparsely mapped regions of the genome. Dia2 and Acp4 were placed on the distal portion of the long arm of chromosome 1, 12.6 map units apart. Dia1 was localized to chromosome 2, 22.2 centimorgans (cM) from B1. Aco1 was mapped to chromosome 4, 6.2 cM from su1. Adk1 was placed on the poorly marked short arm of chromosome 6, 8.1 map units from rgd1. Less than 1% recombination was observed between Glu1 (on chromosome 10) and Sad1. In contrast to many other maize isozyme systems, there was little evidence of gene duplication or of parallel linkage relationships for these allozyme loci
A multiple catheter technique for studies or hepatic metabolism and blood flow in dogs with portacaval transposition
A technique is described for in vivo hepatic metabolic studies, employing a multiple catheterization technique in dogs with chronic portacaval transposition. The animals are studied in the unanesthetized state immediately after the insertion of catheters through peripheral cut-downs. The gradient of metabolites entering and leaving the liver can be measured concomitantly with hepatic plasma flow. Additional simultaneous gradients can be obtained across the splanchnic capillary bed, or the hindquarters. Drugs can be introduced into the circulation by a systemic route or by primary injection into the hepatic circulation. The advantages of this approach compared to other methods of evaluating moment to moment hepatic function are discussed. © 1962
Prognostic factors for musculoskeletal sickness absence and return to work among welders and metal workers
OBJECTIVES: To analyse factors that determine the occurrence of sickness
absence due to musculoskeletal problems and the time it takes to return to
work. METHODS: A longitudinal study with two year follow up was conducted
among 283 male welders and metal workers. The survey started with a
standardised interview on the occurrence of musculoskeletal complaints. 61
(22%) workers were lost to follow up. Data on sickness absence among 222
workers during the follow up were collected from absence records and self
reports. Regression analysis based on proportional hazards models was
applied to identify risk factors for the occurrence and duration of
sickness absence due to various musculoskeletal complaints. RESULTS:
During the follow up 51% of the workers attributed at least one period of
sickness absence to musculoskeletal complaints which accounted for 44% of
all work days lost. A history of back pain was not associated with
sickness absence for back pain, partly because subjects with back pain
were more likely to be lost to follow up. Neck or shoulder pain and pain
of the upper extremities contributed significantly to neck or shoulder
absence (relative risk (RR) 3.35; 95% confidence interval (95% CI) 1.73 to
6.47) and to upper extremities absence (RR 2.29; 95% CI 1.17 to 4.46),
respectively. Company and job title were also significant predictors for
sickness absence due to these musculoskeletal complaints. Absence with
musculoskeletal complaints was not associated with age, height, body mass
index, smoking, and duration of employment. Return to work after neck or
shoulder absence was worse among metal workers than welders (RR 2.12; 95%
CI 1.08 to 4.17). Return to work after lower extremities absence was
strongly influenced by visiting a physician (RR 11.31; 95% CI 2.94 to
43.46) and by musculoskeletal comorbidity (RR 2.81; 95% CI 1.18 to 6.73).
CONCLUSIONS: Complaints of the neck or shoulder and upper extremities in
the 12 months before the study were associated with sickness absence for
these complaints during the follow up. Workers with absence due to pain
from back, neck or shoulder, upper extremities, or lower extremities were
at higher risk of subsequent sickness absence in the next year
KENYAMANAN TERMAL KLIMATOLOGIS KOTA-KOTA BESAR DI PULAU SULAWESI BERDASARKAN TEMPERATURE HUMIDITY INDEX (THI)
Meningkatnya urbanisasi dan berkurangnya ruang terbuka hijau di wilayah perkotaan menyebabkan permasalahan pemanasan perkotaan, yaitu fenomena Urban Heat Island (UHI) yang akan berimplikasi kepada tingkat kenyamanan termal yang dapat dirasakan penduduk urban di luar ruangan. Penelitian ini mengkaji tingkat kenyamanan termal secara klimatologis serta kecenderungannya di kota-kota besar di Pulau Sulawesi dengan menggunakan indeks THI. Dua variabel iklim digunakan untuk menghitung indeks THI, yaitu suhu udara rata-rata harian dan kelembapan relatif harian selama periode 1985-2012 di 6 titik pengamatan yang mewakili masing-masing kota. Formula THI yang digunakan adalah formula dengan batas kenyamanan yang telah dimodifikasi untuk iklim tropis. Analisis klimatologis menunjukkan Palu dan Mamuju merupakan kota dengan kandungan uap air yang relatif rendah dengan suhu yang relatif tinggi secara klimatologis jika dibandingkan dengan kota lainnya. Sehingga, kedua kota tersebut memiliki tingkat kenyamanan yang paling rendah dirasakan oleh populasi perkotaan secara berturut yaitu 10,2% dan 24,7%, sedangkan Manado dan Minahasa Utara merupakan kota yang paling nyaman dengan prosentase, yaitu 31,6 % dan 31,9%. Indeks THI tersebut cenderung mengalami peningkatan kecuali di Mamuju dengan laju terbesar dialami oleh Makassar sebesar 0,03⁰C per tahun atau 0,3⁰C per 10 tahun dengan koefisien determinasi sebesar 41,6%
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Self-assembly, nematic phase formation and organocatalytic behaviour of a proline-functionalized lipopeptide
The self-assembly of the amphiphilic lipopeptide PAEPKI-C16 (P = proline, A = alanine, E = glutamic acid, K = lysine, I = isoleucine, C16 = hexadecyl) was investigated using a combination of spectroscopic, microscopic and scattering methods and compared to C16-IKPEAP with the same (reversed) peptide sequence and the alkyl chain positioned N-terminally and which lacks a free N-terminal proline residue. The catalytic activity of these peptides were then compared using a model aldol reaction system. For PAEPKI-C16, Cryo-TEM images showed the formation of micrometer length fibers, which by Small-angle X-ray scattering (SAXS) were found to have a radius of 2.5 - 2.6 nm. Spectroscopic analysis shows these fibers are built from -sheets. This behaviour is in complete contrast to that of C16-IKPEAP which forms spherical micelles with peptides in a disordered conformation [Hutchinson, J. A. et al. J. Phys. Chem. B 2019, 123, 613]. For PAEPKI-C16, the spontaneous alignment of fibers was observed upon increasing pH, which was accompanied by observed birefringence and anisotropy of SAXS patterns. This shows the formation of a nematic liquids and unprecedented nematic hydrogel formation was also observed these lipopeptides at sufficiently high concentrations. SAXS shows retention of an ultrafine (1.7 nm core radius) fibrillar network within the hydrogel. PAEPKI-C16 with free N-terminal proline shows enhanced anti:syn diastereoselectivity and better conversion compared to C16-IKPEAP. The cytotoxicity of PAEPKI-C16 was also lower than C16-IKPEAP for both fibroblast and cancer cell lines. These results highlight the sensitivity of lipopeptide properties to the presence of a free proline residue. The spontaneous nematic phase formation by PAEPKI-C16 points to the highly anisotropy of its ultrafine fibrillar structure and the formation of such a phase at low concentration in aqueous solution may be valuable for future applications
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Maternal Syphilis: Variations in Prenatal Screening, Treatment, and Diagnosis of Congenital Syphilis
Syphilis is a sexually transmitted infection that, if left untreated, can impact fetal development. In this systematic review of syphilis in pregnancy, we attempt to better understand worldwide discrepancies regarding its diagnosis and management. OVID MEDLINE and PubMed databases were searched for keywords and 74 relevant articles were identified. Twenty-nine articles were ultimately included in our review. In the literature spanning from 1944—2014, we identified several variations in maternal syphilis screening and treatment, as well as a spectrum of gestational outcomes. Even following the publication of universal guidelines by the World Health Organization, the Centers for Disease Control and Prevention, and scientific investigators, practice patterns have continued to vary. Greater adherence to these guidelines could improve the quality of research in this area and promote earlier detection and thus prevention of maternal and congenital syphilis
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