The conserved B3 domain of VIVIPAROUS1 has a cooperative DNA binding activity

The biochemical activities that underlie the genetically defined activator and repressor functions of the VIVIPAROUS1 (VP1) protein have resisted in vitro analysis. Here, we show that a glutathione S-transferase (GST) fusion protein, including only the highly conserved B3 domain of VP1, has a highly cooperative, sequence-specific DNA binding activity. GST fusion proteins that include larger regions of the VP1 protein have very low activity, indicating that removal of the flanking protein sequences is necessary to elicit DNA binding in vitro. DNA competition and DNase I footprinting analyses show that B3 binds specifically to the Sph element involved in VP1 activation of the C1 gene, whereas binding to the G-box-type VP1-responsive element is of low affinity and is nonspecific. Footprint analysis of the C1 promoter revealed that sequences flanking the core TCCATGCAT motif of Sph also contribute to the recognition of the Sph element in its native context. The salient features of the in vitro GST-B3 DNA interaction are in good agreement with the protein and DNA sequence requirements defined by the functional analyses of VP1 and VP1-responsive elements in maize cells.     

实现软件与硬件的真正协同

设计师们正在对一些新的设计方法进行评估，以期加快设计周期，缓解因新产品上市时间日趋加快带来的前所未有的重压。其中所建议使用的加速SoC设计周期的方法之一是硬件/软件的协同设计。拥有一种功能强大的协同设计工具可使设计理念大幅提升到系统级，从而改善硬件和软件设计小组之间的信息交流。同时它的使用还能有效地保护在RTL设计实现流程方面的现有投资。一些厂家已宣布，采用硬件/软件协同设计技术已使其设计时间减少一半，生产效率大为提高。那么，什么是真正的硬件/软件协同设计，它对设计小组又有怎样的意义？为此，本文将对硬…     

Atmospheric Effects on Compressive Creep of SiC-Whisker-Reinforced Alumina

A SiC-whisker-reinforced alumina composite was crept in compression at 1200° to 1400°C in an air ambient and in nitrogen. The data were described by a power-law-type constitutive relation. The measured value of the stress exponent was n = 1 at 1200°C and n = 3 at 1300° and 1400°C in both ambients. TEM observations were correlated with the measured creep response to determine active deformation mechanisms. Values of n = 1 were associated with diffusional creep and unaccommodated grain-boundary sliding, while values of n = 3 were associated with increased microstructural damage in the form of cavities. Experiments conducted in circulated air resulted in higher creep rates than comparable experiments in nitrogen. The accelerated creep rates were caused by the thermal oxidation of SiC and the resultant formation of a vitreous phase along composite interfaces. The glassy phase facilitated cavitation, weakened interfaces, and enhanced boundary diffusion.     

Syntheses of 12-aminododecanoic and 11-aminoundecanoic acids from vernolic acid

12-Aminododecanoic acid and 11-aminoundecanoic acid, monomer precursors for nylon-12 and nylon-11, respectively, have been synthesized from vernolic (cis-12,13-epoxy-cis-9-octadecenoic) acid via a reaction sequence that includes the formation of 12-oxododecanoic acid oxime. Saponification of vernonia oil, followed by a low-temperature recrystallization at −20°C, gave 51% vernolic acid (97% purity, m.p. 23–25°C). Hydrogenation afforded cis-12,13-epoxystearic acid (m.p. 52–54°C, lit. m.p. 52–54°C), which upon oxidation with periodic acid in tertiary butyl alcohol gave 12-oxododecanoic acid with an isolated yield of 71.0%. Reaction of the oxoacid with hydroxylamine hydrochloride gave 12-oxododecanoic acid oxime, which was catalytically reduced to give 12-aminododecanoic acid with a yield greater than 85% and a melting point of 184–186°C (lit. m.p. 185–187°C). 11-Aminoundecanoic acid was prepared from the 12-oxododecanoic acid oxime via a three-step reaction sequence that involved a Beckmann rearrangement, Hofmann degradation, and hydrolysis. Thus, the aldoxime acid was hydrolyzed in the presence of nickel acetate tetrahydrate to give 11-carbamoylundecanoic acid (48% yield, m.p. 129–131°C, lit. m.p. 129–130°C). The amide was then treated with a solution of sodium methoxide and bromine at 70–80°C to give 11-(methoxycarbonylamino)undecanoic acid at 75% yield (m.p. 84–86°C; elemental analysis, calculated for C₁₃H₂₅NO₄: C, 60.19; H, 9.73; N, 5.40; O, 24.68%; found C, 60.02; H, 9.81; N, 5.26; O, 24.91%), which upon alkaline hydrolysis and subsequent neutralization gave 11-aminoundecanoic acid at 34% yield (m.p. 189–192°C, lit. m.p. 190°C). Mass spectrometric and ¹³C nuclear magnetic resonance data of the previously unreported 11-(methoxycarbonylamino)undecanoic acid is provided.     

Innovations in Large-Scale Supported Distance Teaching: Transformation for the Internet,Not Just Translation

This paper reports on large-scale trials of Internet-based university-level distance teaching. The use of technology, and more specifically the Internet, has been an important advance for distance education. However, simply translating material from familiar media into electronic form is rarely productive—and is certainly inadequate for supported distance education, which aims to engage the student in a “community of learning.” The value Internet technology brings to distance education lies not in direct translation from other media but in transformation of support mechanisms to exploit its potential range. The paper addresses how instruction and support functions can be served and potentially enhanced by an Internet-based structure. It considers which changes in culture help to preserve or improve teaching quality while adapting to screen-based and often asynchronous interactions. It discusses our trials of mechanisms for interactions among students and tutors; assignment marking using an electronic marking tool; electronic assignment handling; synchronous and asynchronous Internet-based problem sessions; and automatic student registration. The paper summarizes qualitative and quantitative findings of an extensive evaluation involving several hundred students over three courses and considering learning, student experience, assignment marking, problem sessions, scalability, and integration into existing administrative structures. It highlights both costs and gains of using the Internet to transform the distance learning environment for those associated with it: students, tutors, administrators, and institutions.     

Dietary fat and body composition

Vascular endothelial growth factor (VEGF) is a cytokine that induces angiogenesis. Angiogenesis is a prominent histologic component of the luteinization process. Luteinization is also characterized by granulosa cell progesterone secretion in response to the luteinizing hormone (LH) surge. Local VEGF production in human pre-ovulatory follicles, induced by LH, was postulated to be a luteinization mediator in women. To investigate this hypothesis, serum and fluid from the dominant follicle of 31 healthy regularly cycling multiparous women undergoing laparoscopic sterilization were obtained. VEGF was measured by enzyme-linked immunosorbent assay, and LH and progesterone were measured by radioimmunoassay. Follicle aspiration was performed at a median of 13 days from the last menstrual period (range 11-17 days). The median pre-ovulatory follicle diameter was 16 mm (range 11-23 mm). Follicle fluid VEGF concentrations (mean 6900 pg/ml, range 1200-17 100 pg/ml) were correlated positively with follicle fluid progesterone concentrations (mean 10 176 nmol/l, range 636-66780 nmol/l, r=0.62, P=0.002). This correlation was even tighter (r=0.87, P < 0.0001) when only samples from the 22 women in the earliest stages of follicle luteinization were considered. In these women serum LH concentrations were also correlated with follicle fluid VEGF concentrations (r=0.51, P=0.02). Our findings demonstrate the close dynamic relationship between VEGF production and early luteinization in human follicles during normal non-stimulated cycles.     

Promotion of hepatic lipid oxidation and gluconeogenesis as a strategy for appetite control

There is considerable evidence that hepatic vagal afferents monitor the availability of liver glycogen and glucose metabolites, and that this mechanism participates in appetite regulation. Thus, promotion of gluconeogenesis and liver glycogen storage may enhance satiety. Hepatic lipid oxidation drives gluconeogenesis by positive allosteric modulation of pyruvate carboxylase and fructodiphosphatase. The rate-limiting enzyme for hepatic lipid oxidation, carnitine acyltransferase I, is activated by exogenous carnitine, and inhibited by malonyl coA. The lipogenesis inhibitor (-)-hydroxycitrate--a natural fruit acid found in the Brindall berry--can decrease production of malonyl coA in hepatocytes by potent inhibition of citrate lyase; many studies demonstrate that (-)-hydroxycitrate can reduce body fat accumulation in growing rats, owing in large part to a reduction in appetite. Joint administration of (-)-hydroxycitrate and carnitine should therefore promote hepatic lipid oxidation, gluconeogenesis, and satiety. Thermogenic effects as well as a reduction of the respiratory quotient can also be predicted. If this technique proves clinically useful in weight management, it could be used in conjunction with chromium picolinate and soluble fiber supplements, which appear to aid hunger control at the level of the hypothalamus and terminal ileum, respectively.     

Mediators of the Relation Between Maternal Depressive Symptoms and Child Internalizing and Disruptive Behavior Disorders.

[Correction Notice: An erratum for this article was reported in Vol 18(1) of Journal of Family Psychology (see record 2007-16896-001). On page 551, in Table 2, two values are listed incorrectly. In row 17, Early Child Externalizing (K, Grade 2), the correlation coefficients in columns 4 and 5 should be transposed to read -.087 in column 4 (People in My Life Communication) and -.208 in column 5 (Inventory of Parent Experiences Community Support).] Drawing on a normative sample of 224 youth and their biological mothers, this study tested 4 family variables as potential mediators of the relationship between maternal depressive symptoms in early childhood and child psychological outcomes in preadolescence. The mediators examined included mother-child communication, the quality of the mother-child relationship, maternal social support, and stressful life events in the family. The most parsimonious structural equation model suggested that having a more problematic mother-child relationship mediated disruptive behavior-disordered outcomes for youths, whereas less maternal social support mediated the development of internalizing disorders. Gender and race were tested as moderators, but significant model differences did not emerge between boys and girls or between African American and Caucasian youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oropharyngeal candidiasis in patients with AIDS: randomized comparison of fluconazole versus nystatin oral suspensions

A total of 167 human immunodeficiency virus (HIV)-infected patients with oropharyngeal candidiasis were randomly assigned to receive 14 days of therapy with liquid suspension fluconazole (100 mg once daily) or liquid nystatin (500,000 U four times daily). At day 14, 87% of the fluconazole-treated patients were clinically cured, as opposed to 52% in the nystatin-treated group (P < .001). Fluconazole eradicated Candida organisms from the oral flora in 60%, vs. a 6% eradication rate with nystatin (P < .001). The fluconazole group had fewer relapses noted on day 28 (18%, vs. 44% in the nystatin group; P < .001). This relapse difference no longer existed by day 42. Fluconazole oral suspension as a systemic therapy was more effective than liquid nystatin as a topical therapy in the treatment of oral candidiasis in HIV-infected patients and provided a longer disease-free interval before relapse.