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1.
Enantiomers (R(+) and S(-)),RS-racemate (double compound) and (R+S)-conglomerate (mechanical mixture of enantiomers) of malic acid C 4 H 6 O 5 have been investigated by means of X-ray diffractometry and high temperature X-ray diffraction method.The RS-racemate was found to be able to form three polymorphic modifications,which we denominated as M1 (monoclinic,space group P2 1 /c),M2 (monoclinic,space group Cc),and Tc (triclinic,space group P-1),the latter modification having been unknown before.Modification Tc was also described,and its Xray diffraction characteristics,including interplanar spacings d,hkl indices,unit cell parameters,were defined.In addition,X-ray diffraction characteristics for both reported earlier M1 and M2 monoclinic polymorphic modifications were measured with higher accuracy.The ability of RS-racemate to form one of the above three modifications (M1,M2,and Tc) or their mixtures containing various proportions and combinations of the components (M1+M2,M1+Tc,or M2 +Tc) was found to depend on the type of crystallization medium (a melt,aqueous medium,ethanol or acetone solution),crystallization rate (from 2-3 minutes to 4 months),and crystallization temperature.Heating S-enantiomer and M1 RS-racemate up to their respective melting points (100 ℃ and 124 ℃,correspondingly) only made them undergo thermal deformations,while heating (R+S)-conglomerate in the temperature range of 96-110 ℃ resulted in its homogenization to form M2 RS-racemate,which,near the melting point (118 ℃),namely,in the range of 112-116 ℃,was transformed into M1 RS-racemate.  相似文献   

2.
The metabolic activity of organisms can be measured by recording the heat output using microcalorimetry. In this paper, the total alkaloids in the traditional Chinese medicine Radix Aconiti Lateralis were extracted and applied to Escherichia coli and Staphylococcus aureus. The effect of alkaloids on bacteria growth was studied by microcalorimetry. The power-time curves were plotted with a thermal activity monitor (TAM) air isothermal microcalorimeter and parameters such as growth rate constant (μ), peak-time (Tm), inhibitory ratio (I), and enhancement ratio (E) were calculated. The relationships between the concentration of Aconitum alkaloids and μ of E. coli or S. aureus were discussed. The results showed that Aconitum alkaloids had little effect on E. coli and had a potentially inhibitory effect on the growth of S. aureus.  相似文献   

3.
To our knowledge, few reports on Demodex studied at the molecular level are available at present. In this study our group, for the first time, cloned, sequenced and analyzed the chitin synthase (CHS) gene fragments of Demodex folliculorum, Demodex brevis, and Demodex canis (three isolates from each species) from Xi’an China, by designing specific primers based on the only partial sequence of the CHS gene of D. canis from Japan, retrieved from GenBank. Results show that amplification was successful only in three D. canis isolates and one D. brevis isolate out of the nine Demodex isolates. The obtained fragments were sequenced to be 339 bp for D. canis and 338 bp for D. brevis. The CHS gene sequence similarities between the three Xi’an D. canis isolates and one Japanese D. canis isolate ranged from 99.7% to 100.0%, and those between four D. canis isolates and one D. brevis isolate were 99.1%–99.4%. Phylogenetic trees based on maximum parsimony (MP) and maximum likelihood (ML) methods shared the same clusters, according with the traditional classification. Two open reading frames (ORFs) were identified in each CHS gene sequenced, and their corresponding amino acid sequences were located at the catalytic domain. The relatively conserved sequences could be deduced to be a CHS class A gene, which is associated with chitin synthesis in the integument of Demodex mites.  相似文献   

4.
Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first morphological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM.  相似文献   

5.
To examine students’ causal judgements of positive mood in relation to self-regulation, 128 participants from two different schools representing two distinct educational environments (Technical/Vocational School (TSO/BSO): N = 63; General Secondary School (ASO): N = 65) were asked to judge 45 statements containing three possible relationships (A → B; A ← B; A <> B) for all iterations of 5 constructs associated with positive mood, namely Hope, Optimism, Resilience, Confidence, Persistence, 4 constructs associated with self-regulation, namely Motivation, Social support, Problem-solvingLearning goals, and 1 construct representing Academic performance. Based on a Pareto analysis, mental models were constructed for each school. An analysis of the mental models indicates that all students believe positive mood constructs to be causally related to self-regulation constructs with Academic performance identified as the main driver and Learning goals as the primary outcome for both schools. It is concluded that an appreciation of participants’ causal attributions of positive mood states in relation to self-regulation can present a clearer picture of the conditions under which participants’ causal understanding of positive mood and self-regulation constructs can be activated and used as an interpretive and evaluative framework in learning encounters.  相似文献   

6.
Mutations of fms-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1) exon 12 genes are the most common abnormalities in adult acute myeloid leukemia (AML) with normal cytogenetics. To assess the prognostic impact of the two gene mutations in Chinese AML patients, we used multiplex polymerase chain reaction (PCR) and capillary electrophoresis to screen 76 AML patients with normal cytogenetics for mutations in FLT3 internal tandem duplication (FLT3/ITD) and exon 12 of the NPM1 gene. FLT3/ITD mutation was detected in 15 (19.7%) of 76 subjects, and NPM1 mutation in 20 (26.3%) subjects. Seven (9.2%) cases were positive for both FLT3/ITD and NPM1 mutations. Significantly more FLT3/ITD aberration was detected in subjects with French-American-British (FAB) M1 (42.8%). NPM1 mutation was frequently detected in subjects with M5 (47.1%) and infrequently in subjects with M2 (11.1%). FLT3 and NPM1 mutations were significantly associated with a higher white blood cell count in peripheral blood and a lower CD34 antigen expression, but not age, sex, or platelet count. Statistical analysis revealed that the FLT3/ITDpositive group had a lower complete remission (CR) rate (53.3% vs. 83.6%). Survival analysis showed that the FLT3/ITD-positive/NPM1 mutation-negative group had worse overall survival (OS) and relapse-free survival (RFS). The FLT3/ITD-positive/NPM1 mutation-positive group showed a trend towards favorable survival compared with the FLT3/ITD-positive/NPM1 mutation-negative group (P=0.069). Our results indicate that the FLT3/ITD mutation might be a prognostic factor for an unfavorable outcome in Chinese AML subjects with normal cytogenetics, while NPM1 mutation may be a favorable prognostic factor for OS and RFS in the presence of FLT3/ITD.  相似文献   

7.
Santalum album Linn. is an evergreen and hemi-parasitic tree, the heartwood-sandalwood of which was used during a long history in traditional Chinese medicine. Kuhnia rosmarinifolia Vent. is a good host for 1- or 2-year-old growing S. album. The interaction between S. album and K. rosmarinifolia is still little known. Many studies have been carried out on a number of plants for identification and diversity of endophytes. In this study, in total 25 taxa of endophytic fungi were isolated from the roots of S. album and the roots of K. rosmarinifolia. The most frequently isolated genera were Penicillium sp. 1 and Fusarium sp. 1 in the roots of S. album and K. rosmarinifolia, respectively. S. album is a root parasite of K. rosmarinifolia. The interesting result is that they apparently do not share the same endophytic fungi isolates. This study for the first time explored the content of endophytic fungi from S. album and K. rosmarinifolia, which provides important information for further studies.  相似文献   

8.
PiggyBac is a transposable DNA element originally discovered in the cabbage looper moth ( Trichoplusia ni). The T. ni piggyBac transposon can introduce exogenous fragments into a genome, constructing a transgenic organism. Nevertheless, the comprehensive analysis of endogenous piggyBac-like elements ( PLEs) is important before using piggyBac, because they may influence the genetic stability of transgenic lines . Herein, we conducted a genome-wide analysis of PLEs in the brown planthopper (BPH) Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), and identified a total of 28 PLE sequences. All N. lugens piggyBac-like elements ( NlPLEs) were present as multiple copies in the genome of BPH. Among the identified NlPLEs, NlPLE25 had the highest copy number and it was distributed on five chromosomes. The full length of NlPLE25 consisted of terminal inverted repeats and sub-terminal inverted repeats at both terminals, as well as a single open reading frame transposase encoding 546 amino acids. Furthermore, NlPLE25 transposase caused precise excision and transposition in cultured insect cells and also restored the original TTAA target sequence after excision. A cross-recognition between the NlPLE25 transposon and the piggyBac transposon was also revealed in this study. These findings provide useful information for the construction of transgenic insect lines.  相似文献   

9.
The motion of a projectile in a constant gravitational field is an age-old problem. If there is no resistive force, the problem is simple. However, with the intoduction of resistive forces, the complexity of the problem increases. Recently, there has been a growing interest in the problem of projectile motion under a resistive force proportional to the square of velocity. The problem for resistive force proportional to vv cannot be solved in closed analytical form. A series solution of the equation leads to divergent series for x (t) and y (t) for reasonable values of the initial speed and angle of projection. However, we demonstrate that by inverting the series for x (t), i.e., expressing t in terms of x, and substituting this in y (t) one can express y in terms of x which is a highly convergent series and one can obtain the path of projectile with a few terms of the series. We further demonstrate that one can obtain the path even with a few terms of the divergent series for x (t) and y (t) by using extrapolation methods.  相似文献   

10.
Penicillium digitatum is the most important pathogen of postharvest citrus. Gene targeting can be done in P. digitatum using homologous recombination via Agrobacterium tumefaciens mediated transformation (ATMT), but the frequencies are often very low. In the present study, we replaced the Ku80 homolog (a gene of the non-homologous end-joining (NHEJ) pathway) with the hygromycin resistance cassette (hph) by ATMT. No significant change in vegetative growth, conidiation, or pathogenicity was observed in Ku80-deficient strain (ΔPdKu80) of P. digitatum. However, using ΔPdKu80 as a targeting strain, the gene-targeting frequencies for both genes PdbrlA and PdmpkA were significantly increased. These results suggest that Ku80 plays an important role in homologous integration and the created ΔPdKu80 strain would be a good candidate for rapid gene function analysis in P. digitatum.  相似文献   

11.

Objective

A study in a Caucasian population has identified two single-nucleotide polymorphisms (SNPs) in ZNF533, one in DOCK4, and two in IMMP2L, which were all significantly associated with autism. They are located in AUTS1 and AUTS5, which have been identified as autism susceptibility loci in several genome-wide screens. The present study aimed to investigate whether ZNF533, DOCK4, and IMMP2L genes are also associated with autism in a northeastern Chinese Han population.

Methods

We performed a similar association study using families with three individuals (one autistic child and two unaffected parents). A family-based transmission disequilibrium test (TDT) was used to analyze the results.

Results

There were significant associations between autism and the two SNPs of ZNF533 gene (rs11885327: χ 2=4.5200, P=0.0335; rs1964081: χ 2=4.2610, P=0.0390) and the SNP of DOCK4 gene (rs2217262: χ 2=5.3430, P=0.0208).

Conclusions

Our data suggest that ZNF533 and DOCK4 genes are linked to a predisposition to autism in the northeastern Chinese Han population.  相似文献   

12.

Objective

Helicobacter pylori maintains long-term persistence in the host and combats oxidative stress via many antioxidant proteins, which are expected to be relevant to bacterial-associated gastric diseases. We aimed to investigate the expression of three essential antioxidants in H. pylori strains isolated from patients with different clinical outcomes. Methods: Forty H. pylori strains were isolated from endoscopic biopsy specimens of gastric mucosa from 13 patients with gastric cancer, 13 with peptic ulcer, and 14 with gastritis. The expression of thioredoxin 1 (Trx1), arginase (RocF), and alkyl hydroperoxide reductase (AhpC) in H. pylori was measured by real-time PCR. Comparisons among multiple sample sets were analyzed using a one-way ANOVA test. Pearson’s correlation test was used to assess relationships among multiple continuous variables.

Results

Trx1 expression of H. pylori in gastric cancer and peptic ulcer tissues was higher than that in tissues with gastritis. RocF expression of H. pylori in gastric cancer tissues was higher than that in tissues exhibiting peptic ulcer and gastritis. However, we did not find any differences in AhpC expression in samples from patients with different clinical outcomes. The expression of Trx1 and RocF had a positive, linear correlation. The expression of Trx1 and AhpC had a positive correlation without a linear trend. We found no correlation between the expression of RocF and AhpC.

Conclusions

Our observations indicate that the expression of Trx1 and RocF in H. pylori might be related to gastric carcinogenesis. In H. pylori, the expression of members of the antioxidant system may be correlated and relevant to gastric cancer.  相似文献   

13.
Immediate Knowledge of Results (KR) feedback at the task level may motivate test takers by showing that their answers matter. Appealing feedback cues may help to prevent negative emotions in lower performers who receive a higher amount of negative feedback. In this experiment, we varied the presence of KR feedback and the feedback delivery mode in a 1 × 5 between-subjects design (i.e., no feedback vs. text, color, sound, or animation feedback) to investigate effects on learning outcomes and affective-motivational measures. Our sample included 661 fifth and sixth graders who solved two computer-based multiple-choice science tests. First, students worked on an 18-item treatment test (with experimental feedback manipulation). Students repeatedly rated their effort, enjoyment, pride, and boredom during the test, as well as their expectancy of success and attainment value after the test. Subsequently, they worked on a posttest (without feedback) that assessed recall and near-transfer learning. All KR feedback conditions significantly increased recall, but there was no evidence for near-transfer learning. Feedback had a significant, negative effect on attainment value, whereas significant interactions between the feedback conditions and students’ treatment performance revealed that feedback effects on several affective-motivational dimensions (i.e., expectancy of success, enjoyment, pride, and boredom) were performance-dependent. Feedback benefited higher performers’ motivation and affect but showed negative effects on some affective-motivational measures for lower performers. The pattern of results indicated that color/sound/animation feedback may have reduced the effect of performance on emotional feedback perception to some extent. However, none of the feedback conditions improved affective-motivational outcomes independent of students’ performance.  相似文献   

14.
BackgroundChild maltreatment has been associated with the development of various mental health problems, including the development of personality disorders.ObjectiveThis study investigated the association between child maltreatment and personality disorder symptoms in 125 women who transitioned out of residential care.MethodThe Child Trauma Questionnaire was used for the measurement of child maltreatment, and Personality disorder symptoms were measured using the Personality Diagnostic Questionnaire 4 + . The Psychological Distress Index was used to control for symptoms of distress.ResultsA Stepwise regression analysis showed that the majority of the associations were found between self-reported emotional abuse, neglect and personality disorder symptoms. Emotional abuse was significantly related to the Paranoid (β = .42, p<0.001), Schizoid (β = .18, p <0.05), Schizotypal (β = .18, p<0.05), Histrionic (β = .22, p<0.05), Avoidant (β = .31, p < .001), Dependent (β = 0.31, p < .001), Obsessive Compulsive (β = 0.29, p = .001), Passive Aggressive (β = 0.23, p<0.01) and the Depressive personality disorder (β = .38, p < .001). Emotional neglect was significantly associated to the Borderline Personality Disorder (β = .32, p<0.001) and the Paranoid Personality Disorder (β =-0.22, p<0.05).ConclusionsThe current study underlines the detrimental effects of childhood maltreatment, and in particular the effects of emotional abuse and neglect.  相似文献   

15.
In three experiments, transfer effects in appetitive serial feature-positive discrimination procedures (X→A+,A?) were examined with rat subjects. Nonreinforced presentations of the feature (X) alone had little or no effect on that cue’s ability to modulate responding to the target cue with which it had originally been trained (A) but enhanced its ability to modulate responding to another cue (B), which had been the target within another serial feature-positive discrimination (Y→B+,B?). These effects were observed when the nonreinforcedX presentations occurred either concurrently withX→A+,A? training or afterward. Regardless of whether or not nonreinforcedX presentations were administered,X did not modulate responding evoked by a cue that had not been trained within a serial feature-positive discrimination. These data help resolve conflicts in published reports of transfer or its absence in this conditioning situation, and shed light on the nature of the modulatory or occasion-setting powers of feature cues in serial feature-positive discrimination learning.  相似文献   

16.
This paper examines a New Zealand Pākehā (European) teacher's professional development experience working with Māori (indigenous people of New Zealand), and their protocols and practices. A Māori kaumatua (male leader) experienced in theatre direction, acting, and psychiatric nursing led Māori marginalised youth to disclose their personal stories, wrap them in tikanga (customs) and move forward to create theatre from their experiences. This paper discusses a participant observer process of living on a marae (Māori congregational place), working with Māori, experiencing Māori protocols and practices on a daily basis, and the recommendations for teachers dealing with cultural difference in the classroom.  相似文献   

17.
Newborn wild house mice (Mus musculus) were fostered upon maternal conspecifics, prairie deer mice (Peromyscus maniculatus bairdi) or laboratory rats (Rattus norvegicus). Male subjects were weaned into individual cages, in which they remained until testing commenced. At 35 days of age, subjects were given a four-choice test in which they had the opportunity to investigate tunnels scented with clean wood chips or with chips soiled by an adult male conspecific, deer mouse or rat. Compared to theMus-nursed andPeromyscus-nursed mice,Rattus-nursed mice were more active during the test and less reluctant to investigate theRattus-scented tunnel. These results were replicated in a two-choice test (Mus- vs.Rattus-scented tunnels) that included a group of mice fostered onto conspecifics, but withRattus scents present in the maternity cage throughout the nursing period. Early exposure to the scent ofRattus had no significant effects on the responses ofMus-nursed mice to the scent ofRattus.  相似文献   

18.
BackgroundChildhood maltreatment poses a risk factor for adult sexual aggression among men.ObjectiveEfforts were made to examine links between childhood sexual abuse (CSA) and sexual aggression after controlling variance associated with other forms of abuse.Participants and settingThis sample was comprised of men (n = 489) who completed a national survey regarding their history of possible abuse and/or sexual aggression.MethodsMaltreatment indices included CSA, parental and sibling physical abuse, exposure to domestic violence, peer bullying, and family emotional abuse. Self-report indicators of sexual frotteurism, coercion and rape were provided by the Sexual Experiences Survey–Short Form Perpetration.ResultsCSA links with the criterion indicators were relatively stronger (r = 0.36, d = 0.65, p < .001) than those found for non-sexual forms of abuse. CSA accounted for unshared variance in sexual aggression with these effects magnified by the addition of parental physical abuse (d = 2.1) or exposure to domestic violence (d = 2.2). The relative risks of prior acts of rape were elevated by CSA (RR = 4.39, p < .001), parental physical abuse (RR = 3.85, p < 0.001), exposure to domestic violence (RR = 3.81, p < .001), or sibling physical abuse (RR = 2.56, p = 0.007). These risks of completed rape were higher as well among respondents polyvictimized by two (RR = 4.92, p < .001) or more (RR = 8.94, p < 0.001) forms of abuse.ConclusionsMultiple forms of child maltreatment, particularly CSA, were strongly associated with adult sexual aggression in this sample of men from the general population.  相似文献   

19.
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20.
The current study identified affective profiles and examined their relations to behavioral engagement and disengagement as well as achievement among undergraduate students enrolled in a college anatomy course (N = 278). Cluster analysis was used to identify four affective profiles: Positive, Deactivated, Negative, and Moderate-Low. Students in the Positive and Deactivated profiles were more engaged, less disengaged, and earned higher grades on subsequent exams than those in Moderate-Low and Negative profiles, which did not differ from one another. Subsequent analyses indicated that the relation of affective profiles to achievement was mediated through engagement. Results provide support for the importance of examining students’ mixed affective experiences in terms of both valence and activation dimensions, adding important contributions to largely variable-oriented literature on academic affect and its relation to engagement and achievement.  相似文献   

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