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The homogeneous chemical modification of cellulose with succinic anhydride was investigated in a solvent system containing 1-butyl-3-methylimidazolium chloride ionic liquid and dimethylsulfoxide using N-bromosuccinimide (NBS) as a catalyst. The results showed that the degree of substitution of the succinylated cellulosic samples, in the range of 0.24-2.31, noticeably increased as compared with the products without any catalysts, indicating that NBS was a novel efficient catalyst for cellulose succinoylation in ionic liquids. Fourier transform infrared and solid-state cross-polarization/magic angle spinning (13)C NMR spectroscopies also provided evidence of succinoylation reaction. The results indicated that the reaction of hydroxyl groups at C-6, C-2, and C-3 positions in cellulose occurred. The thermal stability of the succinylated cellulose was found to decrease upon chemical modification.

Objective: To study the histopathologic changes of primary brain stem injury and to investigate their significance in the diagnosis of primary brain stem injury., Methods: Sixty-five autopsy cases died of primary brain stem injury and other diseases were enrolled into this study. The cases were subdivided into brain stem injury group (n = 25) and control group (including 20 cases died of cardiovascular disease and 20 cases died of non-cardiovascular diseases). The brain stem tissue sections were stained with hematoxylin-eosin and silver impregnation techniques. Immunohisto chemical study for glial fibrillary acidic protein, neurofilament, amyloid-beta and myelin basic protein was carried out. The widest cross diameters of 10 axons highlighted by immunostaining were measured in each low power field (x 100) through light miscroscopy in all the cases studied., Results: In comparing with that of the control group, there were differences in the degree of contusion lesion, reactive astrocytosis, edema and pathologic changes of neuronal cells present in the brain stem injury group and was statistically significant (P < 0.05). The axons locating in the brain stem injury group showed a distinctive histology by the appearance of significantly larger diameters (P < 0.05)., Conclusions: Primary brain stem injury demonstrates certain distinctive histopathologic changes and measurement of axonal diameters provides an additional quantitative index useful in autopsy diagnosis.

Wheat straw hemicelluloses were converted to novel bifunctional hemicellulosic derivatives by etherification using acrylamide as reactant and sodium hydroxide as catalyst. The degree of substitution can be monitored by altering the molar ratio of acrylamide to xylose unit in hemicelluloses in the range of 1.0-10.0 and the molar ratio of sodium hydroxide to xylose unit in hemicelluloses in the range of 0.5-1.6, without changing the structure of the hemicelluloses. Comparison of the reaction in different media is discussed in detail. The optimized product with a high DS value of 0.58 was obtained by varying the condition parameters. Novel hemicellulosic derivatives containing carbamoylethyl and carboxyethyl groups could be confirmed by FT-IR, (1)H NMR, and (13)C NMR spectroscopies. The behavior of hemicellulosic derivatives was monitored by means of thermogravimetry (TG) and differential thermal analysis (TGA). It was found that the product with a high DS had a lower thermal stability than the native hemicelluloses.

A total of 207 schools (N = 33,693 students) participated in the Secondary 1 Program of Project P.A.T.H.S. in the Full Implementation Phase (2006-07). Participants responded to a Subjective Outcome Evaluation Form (Form A) to assess their views of the program, instructors, and perceived effectiveness after program completion. Utilizing the consolidated reports submitted to the funding body, the Research Team aggregated the consolidated data to form an overall profile of the perceptions of the program participants. Results showed that a high proportion of the respondents had positive perceptions of the program and the instructors, and roughly four-fifths regarded the program as helpful to them. The present study provides additional support for the effectiveness of the Tier 1 Program of Project P.A.T.H.S. in Hong Kong.

Hemicellulose-based hydrophobic biomaterials with degrees of substitution ranging from 0.46 to 1.54 were synthesized under mild conditions in homogeneous media (N,N-dimethylformamide-lithium chloride) by reacting the native wheat straw hemicellulosic polymers with lauroyl chloride using 4-dimethylaminopyridine as a catalyst. Other catalysts such as N-bromosuccinimide, N-methyl pyrrolidine, N-methyl pyrrolidinone, and pyridine were also investigated. Under optimum reaction conditions (2 equiv of lauroyl chloride and triethylamine per hydroxyl group, 5% 4-dimethylaminopyridine, 40 degrees C, 35 min), a high DS value of 1.54 was obtained. The biomaterials were characterized by FT-IR spectroscopy and (13)C NMR spectroscopy as well as by thermal analysis. The results showed that the lauroylation occurred preferably at the C-3 hydroxyl group of beta-D-Xylp units in the hemicelluloses, and the thermal stability of the hydrophobic polymers increased by esterification.

A series of novel water-soluble hemicellulosic derivatives, containing carbamoylethyl and carboxyethyl groups, were heterogeneously synthesized from wheat-straw hemicelluloses with acrylamide (AA) under alkaline conditions. The factors such as reaction temperature, reaction time, molar ratio of catalysis to xylose unit in hemicelluloses and molar ratio of acrylamide to xylose unit in hemicelluloses, were investigated. The average degree of substitution (DS) was calculated by (1)H NMR spectroscopy. DS values up to 0.23 in a one-step synthesis of hemicelluloses derivatives were obtained. Under optimum conditions (60°C, NaOH to xylose unit in hemicelluloses molar ratio of 0.8, AA to xylose unit in hemicelluloses molar ratio of 8.0, reaction time of 1h) an expected ratio of carbamoylethyl group to carboxyethyl group of 4.8 in the hemicellulosic derivatives was obtained. The structural features of the hemicellulosic derivatives were characterized by FTIR, NMR spectroscopy, and by elemental analysis. The current work provides a facile method for the synthesis of hemicellulose derivatives with bifunctional groups, which could be used as wet-end additives in the papermaking industry.

Cross-case analyses of factors that influence the process and implementation quality of the Tier 1 Program of the Project P.A.T.H.S. based on seven cases were carried out. Systematic and integrative analyses revealed several conclusions. First, several factors related to policy, people, program, process, and place (5 "P"s) were conducive to the successful implementation of the Tier 1 Program in the schools. Second, there were obstacles and difficulties with reference to the 5 "P"s that impeded the quality of implementation. Third, policy support and people (especially commitment and passion of the principals, senior school administrators, and program implementers) are two main groups of factors that influence the quality of program implementation. Fourth, although there were different arrangements for program implementation, incorporation of the Tier 1 Program into the formal curriculum was a sound and viable strategy. Fifth, implementation of the Tier 1 Program in schools that admitted students with high or low academic achievement was viable. Sixth, the program was generally perceived positively by the program participants and implementers. Finally, the program implementers perceived the program to be beneficial to the program participants.

This case study was based on a school where the Tier 1 Program of the Project P.A.T.H.S. was integrated into the formal curriculum. In this case study, an interview with the school principal, vice-principal, and social worker was conducted in order to understand their perceptions of administrative arrangements and issues in the school, implementation characteristics, program effectiveness, program success, and overall impression. Results showed that several positive school and classroom attributes were conducive to program success, including positive school culture and belief in students' potentials, an inviting school environment, an encouraging classroom environment, high involvement of school administrative personnel, and systematic program arrangement.

In this paper, a case study is presented based on one school, conducted to examine the factors that influenced the process and quality of implementation of the Tier 1 Program of the Project P.A.T.H.S. Through interviews with the school contact person and focus group interviews with the instructors, an integration of the findings showed that several factors related to the program, people, process, policy, and place (5 "P"s) facilitated the implementation process of the Tier 1 Program in the school. Obstacles and difficulties with reference to the 5 "P"s that affected the quality of implementation were also identified. Overall, the quality of program implementation in the school was good, and the program was well received by the program implementers. Implications of the present findings for future program implementation with reference to school administrative arrangements and implementation issues are discussed.

To reduce the cost of biodiesel production, the feasibility of Zanthoxylum bungeanum Maxim seed oil (ZBMSO) was studied to produce biodiesel. A methyl ester biodiesel was produced from ZBMSO using methanol, sulfuric acid, and potassium hydroxide in a two-stage process. The main variables that affect the process were investigated. The high level of free fatty acids in ZBMSO was reduced to < 1% by an acid-catalyzed (2% H2SO4) esterification with methanol to oil molar ratios of 20-25:1 for 1 h. A maximum yield of 96% of methyl esters in ZBMSO biodiesel was achieved using a 6.5:1 molar ratio of methanol to oil, 0.9% KOH (percent oil), and reaction time of 0.5 h at 55 degrees C. Further investigation has also been devoted to the assessment of some important fuel properties of ZBMSO biodiesel produced under the optimized conditions according to specifications for biodiesel as fuel in diesel engines. The fuel properties of the ZBMSO biodiesel obtained are similar to those of no. 0 petroleum diesel fuel, and most of the parameters comply with the limits established by specifications for biodiesel.

Esterification of wheat straw hemicelluloses with acetyl chloride, propionyl chloride, n-octanoyl chloride, lauroyl chloride, palmitoyl chloride, stearoyl chloride, and oleoyl chloride, respectively, using N-bromosuccinimide (NBS) as a catalyst was achieved in DMF/LICl medium by microwave irradiation. The effects of various acyl chlorides and the molar ratios of xylose units in hemicelluloses/acyl chloride on the degree of substitution (DS) were investigated and DS reached up to 1.34 by a few minutes. (13)C NMR studies showed that the esterification occurred preferentially at the C-3 and C-2 positions. On the other hand, microwave irradiation brought a partial degradation of the polymer, and therefore resulted in a slight decrease in thermal stability of the hemicellulosic derivatives in comparison with conventional heating technique., (Copyright © 2008 Elsevier Ltd. All rights reserved.)

The Tier 2 Program of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes), designed and implemented primarily by school social workers, attempts to help adolescents with greater psychosocial needs. After completion of the Tier 2 Program in the Full Implementation Phase (2006/07 school year), 10,255 Secondary 1 students in 207 schools responded to the Subjective Outcome Evaluation Form (Form C) to assess their views of the program, instructors, and perceived effectiveness of the program. Results showed that high proportions of the respondents had positive perceptions of the program and the instructors, and roughly four-fifths of the respondents regarded the program as helpful to them. Pearson correlation analyses showed that perceptions of the program and instructors were significantly correlated with perceived effectiveness of the program. Participants who joined volunteer training activities generally had higher global subjective outcome evaluation scores than did participants who attended programs without volunteer training activities.

A total of 49 schools (N = 8,167 students) participated in the Secondary 2 Program of the Experimental Implementation Phase of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes). After completion of the Tier 1 Program, 270 instructors completed the Subjective Outcome Evaluation Form (Form B) to assess their views of the program, their own performance, and perceived effectiveness of the program. Based on the consolidated reports submitted by the schools to the funding body, the research team aggregated the consolidated data to form a "reconstructed" overall profile on the perceptions of the program implementers. Results showed that high proportions of the instructors had positive perceptions of the program and their own performance, and over 90% of the instructors regarded the program as helpful to the program participants. These findings are consistent with the subjective outcome evaluation findings based on the perspective of the program participants.

A total of 49 schools participated in the Secondary 2 Program of the Experimental Implementation Phase of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes). After completion of the program, 7,406 students completed a Subjective Outcome Evaluation Form (Form A) designed by the research team to reveal their comments about the program, instructors, and perceived effectiveness of the program. Based on the consolidated reports submitted by the schools, the research team aggregated the data to form a "reconstructed" overall profile on the perceptions of the program participants. Results showed that high proportions of the respondents had positive perceptions of the program and the instructors. About 80% of the respondents were satisfied with the program and regarded it as helpful to their overall development. The present findings provide support to the effectiveness of Secondary 2 Program of Project P.A.T.H.S. from the perspective of the program participants.

The chemical modification of sugarcane bagasse with succinic anhydride using pyridine as solvent after ultrasound irradiation was studied. The optimized parameters included ultrasound irradiating time 0-50 min, reaction time 30-120 min, succinic anhydride concentration by the ratio of dried sugarcane bagasse to succinic anhydride from 1:0.25 to 1:1.50, and reaction temperature 75-115 degrees C are required in the process. The extent of succinoylation was measured by the weight percent gain (WPG), which increased with increments of reaction time, succinic anhydride concentration, and reaction temperature. The ultrasound irradiation has a positive effect on bagasse succinoylation process. On the other hand, the ultrasonic pre-treatment application broke down the cell wall polymers, resulting in, therefore, a negative effect on the WPG. Evidences of succinoylation were also provided by FT-IR and CP MAS (13)C NMR and the results showed that the succinoylation at C-2 and C-3 occurred. The thermal stability of the succinylated bagasse decreased upon chemical modification.

Lauroylation of wheat straw hemicelluloses in the N, N-dimethylformamide/lithium chloride system under microwave irradiation was studied. The parameters optimized included lauroyl chloride concentration as the molar ratio of xylose unit in hemicelluloses/lauroyl chloride (1:1-1:4), 4-dimethylaminopyridine concentration (2-10%), reaction time (1-8 min), molar ratio of xylose unit in hemicelluloses/triethylamine (1:2), and reaction temperature (78 degrees C). The reaction efficiency was measured by the yield and degree of substitution (DS). Under an optimum reaction condition (molar ratio of xylose unit in hemicelluloses/lauroyl chloride 1:3, molar ratio of xylose unit in hemicelluloses/triethylamine 1:2, 5% 4-dimethylaminopyridine, 78 degrees C, 5 min), a DS of 1.63 was obtained. Changes in the structure of hemicelluloses were verified by FT-IR and 1H and 13C NMR spectroscopy. The results showed that the lauroylation occurred preferentially at the C-3 position of the xylose unit in hemicelluloses. The behavior of the lauroylated hemicelluloses was monitored by means of thermogravimetric (TG) and differential thermogravimetric (DTG) analysis. It was found that the product with low DS had a lower thermal stability than the native hemicelluloses, whereas the lauroylated polymers with high DS showed a higher thermal stability than the unmodified hemicelluloses.

Four schools participating in the experimental implementation phase of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes) (Secondary 1 level) were randomly selected and invited to join this research study. After completion of the Tier 1 Program, Secondary 1 students in the participating schools were invited to write a reflective journal in the form of a weekly diary in order to reveal their perceptions and feelings regarding the Tier 1 Program and the related benefits. Results of the qualitative data analyses showed that most of the respondents (a) had positive views on the program, (b) had positive views on the instructors, and (c) stated that they had acquired competencies at societal, familial, interpersonal, and personal levels after joining the program. The present qualitative findings based on students' weekly diaries provide additional support for the effectiveness of the Tier 1 Program of P.A.T.H.S. in Hong Kong.

The Tier 2 Program of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes) targets adolescents with greater psychosocial needs, and the related programs were designed and implemented by school social workers. After completion of the Tier 2 Program, 2,173 students in 52 schools responded to the Subjective Outcome Evaluation Form (Form C), assessing their views of the program, instructors, and perceived effectiveness of the program. Based on the consolidated reports submitted by the agencies to the funding body, the research team aggregated the consolidated data to form a "reconstructed" overall profile of the perceptions of the program participants. Four major types of program were identified, including programs based on the adventure-based counseling approach (N = 8), programs concentrated on volunteer training and services (N = 7), programs incorporating both adventure-based counseling and volunteer training elements (N = 30), and other programs with different foci (N = 7). Results showed that high proportions of the respondents had positive perceptions of the programs and the instructors, and roughly four-fifths of the respondents regarded the program as helpful to them. The present study provides support for the effectiveness of the Tier 2 Program of P.A.T.H.S. in Hong Kong for the experimental implementation phase.

To understand the implementation quality of the Tier 1 Program (Secondary 1 Curriculum) of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes), observers carried out process evaluation in the form of systematic observations of 22 units in 14 randomly selected schools. Results showed that the overall level of program adherence was generally high (range: 45-100%, with an average of 86.3%). High implementation quality of the program in the areas of student interest, student participation and involvement, classroom control, use of interactive delivery method, use of strategies to enhance student motivation, use of positive and supportive feedbacks, instructors' familiarity with the students, degree of achievement of the objectives, time management, lesson preparation, overall implementation quality, and success of implementation was also found. The present findings are consistent with those observations based on the experimental implementation phase, suggesting that the implementation quality of the Tier 1 Program (Secondary 1 Curriculum) was generally high.

An interim evaluation was conducted to understand the implementation quality of the Tier 1 Program (Secondary 2 Curriculum) of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programs) in the Experimental Implementation Phase. Twenty-five schools were randomly selected to participate in personal and/or telephone interviews to provide information on the implementation details of the program and perceived attributes of the worker-support scheme ("Co-Walker Scheme"). Results showed that a majority of the workers perceived that the students had positive responses to the program and the program was helpful to the students. They also identified several good aspects in the program and the Co-Walker Scheme, albeit expressing some negative comments on the program design and difficulties in the implementation process. In conjunction with other findings reported previously, the present findings suggest that the Tier 1 Program is well received by different stakeholders and it promotes the positive development of secondary school students in Hong Kong.

This study aimed to understand the implementation quality of the Tier 1 Program (Secondary 2 Curriculum) delivered in the Experimental Implementation Phase of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes). Observers carried out process evaluation in the form of systematic observations of curriculum units in four randomly selected schools. Results showed that the overall level of program adherence was generally high, ranging from 70 to 95%, with an average of 83.6%. The mean ratings of the program implementation quality were high, and the inter-rater reliability on these ratings across the observers was highly reliable. Despite limitations, the findings of this study suggest that the implementation quality of the Secondary 2 Program (Tier 1 Program) of the Experimental Implementation Phase was favorable, and provide supporting evidence to account for the successful and encouraging outcomes of a major positive youth development program in Hong Kong.

To understand the implementation quality of the Tier 1 Program (Secondary 1 Curriculum) of the Project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes) in the full implementation phase, 100 schools were randomly selected to participate in personal and/or telephone interviews regarding the quality of the implementation process of the Tier 1 Program. In the interviews, the participants described the responses of the students to the program, the perceived benefits of the program, the perceived good aspects of the program, and the areas requiring improvement, difficulties encountered in the implementation process, and perceived attributes of the worker-support scheme ("Co-Walker Scheme"). Results showed that most workers perceived that the students had positive responses to the program and the program was beneficial to the students. They also identified several good aspects in the program, although negative comments on the program design and difficulties in the implementation process were also recorded. Roughly half of the respondents had positive comments on the "Co-Walker Scheme". In sum, the respondents generally regarded the program as beneficial to the students and they were satisfied with the Tier 1 Program (Secondary 1 Curriculum) in the full implementation phase, although some implementation difficulties were also expressed.

A total of 52 schools participated in the experimental implementation phase of the project P.A.T.H.S. (Positive Adolescent Training through Holistic Social Programmes). After completion of the Tier 1 Program (Secondary 1 level), 344 teachers and social workers responded to the Subjective Outcome Evaluation Form (Form B), assessing their views of the program and their own performance. Qualitative data analyses based on the schools' evaluation reports showed that the program implementers had enhanced knowledge and skills, learned to establish instructor-student relationships and cooperate with colleagues, and fostered self-development. The workers also appreciated the program philosophy and values, program design and resources, process of implementation, interaction between instructors and students, and program effectiveness. The findings also revealed that the workers encountered difficulties in the program implementation and they also made suggestions on how the program design, program arrangement, manpower deployment, and support for the program implementation could be improved.

A total of 52 schools participated in the Experimental Implementation Phase of the Project P.A.T.H.S. After completion of the Tier 1 Program, 8,057 students responded to a Subjective Outcome Evaluation Form (Form A) to assess their views of the program, instructors, and perceived effectiveness of the program. Based on the schools' evaluation reports, results of secondary data analyses on four open-ended questions showed that: (a) students felt that they had learned things at the personal, interpersonal, familial, and societal levels; (b) they appreciated the program design, instructors' performance, learning process, and program effectiveness; (c) they generally had positive comments on instructors' attitude and teaching process; and (d) they made some suggestions on how the program and its implementation could be improved. The present study, based on qualitative data of subjective outcome evaluation, provides additional support for the effectiveness of the Tier 1 Program of the Project P.A.T.H.S. in Hong Kong.

The homogeneous chemical modification of sugarcane bagasse cellulose with succinic anhydride using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as a reaction medium was studied. Parameters investigated included the molar ratio of succinic anhydride/anhydroglucose units in cellulose in a range from 2:1 to 14:1, reaction time (from 30 to 160min), and reaction temperature (between 60 and 110 degrees C). The succinylated cellulosic derivatives were prepared with a low degree of substitution (DS) ranging from 0.071 to 0.22. The results showed that the increase of reaction temperature, molar ratio of SA/AGU in cellulose, and reaction time led to an increase in DS of cellulose samples. The products were characterized by FT-IR and solid-state CP/MAS (13)C NMR spectroscopy, and thermal analysis. It was found that the crystallinity of the cellulose was completely disrupted in the ionic liquid system under the conditions given. The data also demonstrated that homogeneous modification of cellulose with succinic anhydride in AmimCl resulted in the production of cellulosic monoester. The thermal stability of the succinylated cellulose decreased upon chemical modification.

Homogeneous modification of cellulose, isolated with 10% KOH from delignified sugarcane bagasse, was performed in room-temperature ionic liquid 1-allyl-3-methylinidazolium chloride with phthalic anhydride in the absence of catalyst. The results showed the degree of substitution of phthalated cellulosic derivatives, ranging from 0.10 to 0.73, increased with the increment of reaction temperature, reaction time, and the molar ratio of phthalic anhydride/anhydroglucose units in cellulose under the conditions given. The products were characterized by FT-IR and solid-state CP/MAS 13C NMR spectroscopy as well as thermal analysis, and the results revealed that the phthalation reaction at C-6, C-2, and C-3 positions of the cellulose all occurred. The thermal stability of the phthalated cellulose was found to decrease upon chemical modification. However, this thermal stability of the phthalated cellulose over 200 degrees C is rather satisfactory.

In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 degrees C with 18% NaOH and 18% KOH for 2h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of 'cellulose' residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS (13)C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4-38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0-38.6%) than that from wood-based fibres (60-70%) and had much shorter fibres (0.35-0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.

To understand the implementation quality of the Tier 1 Program of the Project P.A.T.H.S., 25 schools and three school social service units were randomly selected to participate in telephone interviews regarding the quality of the implementation process of the Tier 1 Program of the P.A.T.H.S. Project. In the telephone interviews, the participants described the responses of the students and the workers to the program, the perceived benefits of the program, their assessment of the positive and negative features of the program, as well as difficulties involved in the implementation process. Results showed that most workers perceived that the students had positive responses to the program and half of the workers had positive experiences about the program, although negative comments on the program design and difficulties in the implementation were also recorded. Nearly all workers (97.1%) regarded the program to be beneficial to the students and most of them (78.6%) had positive global evaluation of the project. In short, while the program implementers expressed concerns about the program design and the implementation process, they generally regarded the program as helpful to the students and they had positive global evaluation of the program.

Sequential three-stage treatments with 80% EtOH containing 0.2% NaOH, 2.5% H2O2-0.2% EDTA containing 1.5% NaOH and 2.5% H2O2-0.2% TAED containing 1.0% NaOH at 75 degrees C for 3h released 8.0% and 10.4%, 79.1% and 77.0% and 12.9% and 12.5% of the original hemicelluloses from perennial grass and cocksfoot grass, respectively. It was found that the four alkaline peroxide-soluble hemicellulosic fractions contained higher amounts of xylose (33.4-38.2%), uronic acids (9.3-15.3%) and rhamnose (3.0-3.9%), but were lower in glucose (25.1-28.3%), galactose (13.3-15.3%) and mannose (0.4-1.5%) than those of the two alkaline EtOH-soluble hemicellulosic fractions in which glucose (32.9-36.0%), xylose (20.1-22.6%), arabinose (14.1-21.4%), galactose (16.6-19.9%), mannose (4.1-9.9%) and uronic acids (3.4-7.4%) were the major sugar components. 13C NMR spectroscopy confirmed that all the six hemicellulosic fractions were composed of galactoarabinoxylans, 4-O-methylglucuronoarabinoxylans and beta-glucan. In addition, the studies showed that the four alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic and had larger molecular weights (Mw, 28,400-38,650 g mol(-1)) than those of the two alkaline EtOH-soluble hemicellulosic fractions (Mw, 16,460-17,420 g mol(-1)).

Cell walls of sugarcane bagasse were first delignified with chlorite followed by ultrasonic irradiation and then by two-step sequential extractions at 23 degrees C with 15 and 18% KOH for 2 h, 15 and 18% NaOH for 2 h, 8 and 10% KOH for 12 h, and 8 and 10% NaOH for 12 h and by a single one-stage isolation with 10% KOH for 16 h and with 10% NaOH for 16 h, which released 79.4, 81.8, 83.6, 85.7, 61.5, and 65.6% of the original hemicelluloses, and subsequently yielded 50.7, 49.5, 48.6, 47.8, 57.2, and 55.4% of the cellulose, respectively. The six cellulosic preparations were free of bound lignin and had a purity of 77.1-90.1% with the intrinsic viscosity (eta), viscosity average degree of polymerization, and molecular weight (M(w)) ranging from 534.1 to 631.6 mL g(-1), from 1858.1 to 2238.2 mL g(-1), and from 301000 to 362600 g mol(-1), respectively. The structural features of the isolated six cellulosic samples were comparatively examined by Fourier transform infrared and cross-polarization/magic angle spinning (13)C NMR spectroscopy and X-ray diffraction, and their thermal stability was investigated by using thermogravimetric analysis. It was found that all of the cellulosic preparations have the typical cellulose I structure but the crystallinity of the SCB cellulose was lower than that of flax, cotton, and kenaf.

Objective: To compare the beneficial effects of Atenolol and Metoprolol on cardiomyocyte apoptosis and related gene expressions after acute myocardial infarction (AMI) in rats., Methods: AMI model was established with the ligation of anterior descending coronary artery in 251 randomly selected female SD rats. Twenty-four hours after operation, the 124 survivors were randomly assigned to AMI control group (MI group, n = 43), Atenolol group (group A, 10 mg x kg(-1) d(-1), n = 39), and Metoprolol group (group B, 20 mg x kg(-1) x d(-1), n = 42). Sham operation group (group S, n = 27) was also established. Two subgroup (48 h subgroup and 4 weeks subgroup) was randomly divided in each group according to the time points. Drugs were given to each treatment group by gastric gavage 24 h after ligation. Cardiomyocyte apoptosis was detected with terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) and DNA ladder. Bcl-2, bax and caspase-3 genes were detected with immunohistochemistry and Western blot analysis., Results: Compared with AMI control group, myocyte apoptosis rate (MAR) significantly decreased only in infarction area (P < 0.01) in group B. Bcl-2 expression was found to increase in myocytes of infarction, border and non-infarcted areas except for non-infarcted area of group A. Changes of the expressions of bax and caspase-3 was not significant. Four weeks after AMI, MAR was found to decrease significantly in scar, border and non-infarcted areas (P < 0.05, P < 0.01) in both group A and group B. No significant changes of bcl-2, bax and caspase-3 expressions was found except for a significant decrease of bax expression in non-infarcted area of group A. As indicated by Western blot, no significant change of the expressions of caspase-3, bcl-2 and bax were found in myocytes of group A and group B compared with AMI control group; however, bcl-2/bax ratio significantly increased to the same level of sham-operated group (P < 0.05)., Conclusion: Both Atenolol and Metoprolol treatment can reduce cardiomyocyte apoptosis in infarction/scar, border and non-infarcted areas after AMI, mainly through the increase of bcl-2 expression and bcl-2/bax ratio.

This paper outlines the conceptual bases of 'beliefs in the future' as a positive youth development construct and the implications for curriculum development. Based on the concepts of hope and optimism, 'beliefs in the future' comprises (i) valued and attainable goals; (ii) the ability to plan goal-directed pathways and alternative ones in times of difficulties; (iii) positive appraisal of one's capabilities and efforts and (iv) positive and realistic expectancies of the future. With reference to the adolescents' cognitive advancement and developmental needs, as well as gender and cultural issues, ten units that promote beliefs in the future for Secondary 1-3 students in Hong Kong are designed in the Project P.A.T.H.S., supported by the Hong Kong Jockey Club Charities Trust. In the Secondary 1 curriculum, the goal of the units is to guide students to develop realistic and optimistic future orientation. In the Secondary 2 and 3 curricula, the goals of the units are to enhance students' optimistic future orientation as well as hopeful goal-directed thoughts and motivation in the aspects of academic achievement and future careers.

This paper outlines the conceptual bases of "cognitive competence" as a positive youth development construct and the implications for curriculum development. Cognitive competence refers to the cognitive processes that comprise (i) creative thinking, which includes various creative thinking styles, such as legislative, global, and local thinking styles; and (ii) critical thinking, which includes reasoning, making inferences, self-reflection, and coordination of multiple views. Based on the adolescent development progression on cognitive competence, and with reference to Hong Kong Chinese context, six units are designed to promote creative and critical thinking for Secondary 1-3 students in the Project P.A.T.H.S., supported by the Hong Kong Jockey Club Charities Trust. In the Secondary 1 curriculum, the goals of the units are to enable students to recognize different but inter-related thinking styles and to apply these thinking skills to deal with daily life issues. The goal in the Secondary 2 curriculum is to enhance students' creative thinking skills to solve problems, whereas the goal in the Secondary 3 curriculum is to enhance students' critical thinking skills to accept beliefs and make decisions.

The development of a positive youth development program for Secondary 1 to 3 students in Hong Kong is outlined here. The Full Program consists of 40 units per grade, 20 of which belong to the Core Program. Each unit takes 30 minutes of class time to complete. The major features of the program are as follows: (i) strong theoretical underpinnings, (ii) comprehensive and holistic coverage of youth development, (iii) an expected effective developmental outcome of the participating students, (iv) a happy and stimulating developmental process of the students, (v) flexible teaching schedules and combinations of program units, (vi) professional training for participating teachers and social workers, and (vii) rigorous quality assurance of the program product. The whole project will contribute significantly to the fields of youth development, whole-person education, and life and moral education.

This study tested a model of suicidal ideation with family cohesion, expressiveness, conflicts, teacher support, teacher-student relationships and peer support as antecedents, and self-esteem and depression as mediators. Data was collected from survey questionnaires with 433 Hong Kong Chinese adolescents. The results showed that only family cohesion, conflicts, teacher support and peer support significantly predicted self-esteem and depression, with depression being a strong mediator of suicidal ideation. Implications of the findings for future research were discussed.

Two-stage treatments of sugarcane bagasse with mild alkali and acidic 1,4-dioxane were performed. Pretreatment with 1M NaOH aqueous solution at 20, 25, 30, 35, and 40 degrees C for 18 h released 55.5%, 57.3%, 59.1%, 60.9%, and 62.1% of the original hemicelluloses, respectively. Post-treatment of the corresponding alkali-treated residue with 1,4-dioxane-2M HCl (9:1, v/v) at 87 degrees C for 2h, respectively, degraded 11.6%, 11.9%, 11.4%, 10.9%, and 10.6% of hemicelluloses (% dry starting material). It was found that the five alkali-soluble hemicellulosic preparations contained a much higher amounts of xylose (78.0-82.2%) and slightly higher uronic acids (4.8-5.8%), mainly 4-O-methyl-alpha-d-glucopyranosyluronic acid, but were lower in arabinose (9.3-11.7%) and glucose (2.2-4.1%) than those of the corresponding five acidic dioxane-degraded hemicellulosic fractions in which xylose (44.9-46.8%), arabinose (35.9-38.1%), and glucose (13.0-13.7%) were the major sugar constituents. The studies revealed that the five alkali-soluble hemicellulosic preparations were more linear and acidic, and had a large molecular weight (35,200-37,430 g mol(-1)) than those of the hemicellulosic fractions (12,080-13,320 g mol(-1)) degraded during the acidic dioxane post-treatment. This demonstrated that the post-treatment with acidic dioxane under the condition used resulted in substantial degradation of the hemicellulosic polymers. The 10 hemicellulosic samples were further characterized by FT-IR and 1H and 13C NMR spectroscopy, GPC and thermal analysis, and the results are reported.

Seven residual hemicellulosic preparations (19.6-45.0% of the original hemicelluloses) were extracted from wheat straw pre-treated with various organic solvents using 1.8% H2O2-0.18% cyanamide at 50 degrees C and pH 10.0 for 4 h. Their chemical compositions and physicochemical properties were determined using GC, HPLC, GPC, FT-IR and 13NMR spectroscopy. The results indicated that all the residual hemicellulosic preparations were heteropolysaccharides containing xylose, glucose, arabinose, galactose, mannose, rhamnose and 4-O-methyl-alpha-D-glucopyranosyluronic acid. The predominant monosaccharide was xylose, ranging between 67.7% and 81.9% of the total neutral sugars, composed mainly of L-arabino-(4-O-methyl-D-glucurono)-D-xylan. The content of contaminant lignin in the isolated residual hemicelluloses was 2.89-5.31%. The Mw values of the two residual hemicellulosic preparations H6 and H7 (42,710 and 44,080 g mol-1, respectively) obtained from the aqueous-alcohol pre-treated straw were much higher than those of H1-H5 (12,980-15,950 g mol-1) extracted from the organic acid pre-treated straw.

The isolation of cellulose from wheat straw was studied using a two-stage process based on steam explosion pre-treatment followed by alkaline peroxide post-treatment. Straw was steamed at 200 degrees C, 15 bar for 10 and 33 min, and 220 degrees C, 22 bar for 3, 5 and 8 min with a solid to liquid ratio of 2:1 (w/w) and 220 degrees C, 22 bar for 5 min with a solid to liquid ratio of 10:1, respectively. The steamed straw was washed with hot water to yield a solution rich in hemicelluloses-derived mono- and oligosaccharides and gave 61.3%, 60.2%, 66.2%, 63.1%, 60.3% and 61.3% of the straw residue, respectively. The washed fibre was delignified and bleached by 2% H2O2 at 50 degrees C for 5 h under pH 11.5, which yielded 34.9%, 32.6%, 40.0%, 36.9%, 30.9% and 36.1% (% dry wheat straw) of the cellulose preparation, respectively. The optimum cellulose yield (40.0%) was obtained when the steam explosion pre-treatment was performed at 220 degrees C, 22 bar for 3 min with a solid to liquid ratio of 2:1, in which the cellulose fraction obtained had a viscosity average degree of polymerisation of 587 and contained 14.6% hemicelluloses and 1.2% klason lignin. The steam explosion pre-treatment led to a significant loss in hemicelluloses and alkaline peroxide post-treatment resulted in substantial dissolution of lignin and an increase in cellulose crystallinity. The six isolated cellulose samples were further characterised by FT-IR and 13C-CP/MAS NMR spectroscopy and thermal analysis.

Sugarcane bagasse was esterified with acetic anhydride using N-bromosuccinimide as a catalyst under mild conditions in a solvent free system. The extent of acetylation was measured by weight percent gain, which varied from 2.1% to 24.7% by changing the reaction temperature (25-130 degrees C) and duration (0.5-6.0 h). N-Bromosuccinimide was found to be a novel and highly effective catalyst for acetylation of hydroxyl groups in bagasse. At a concentration of 1% of the catalyst in acetic anhydride, a weight percent gain of 24.7% was achieved at 120 degrees C for 1 h, compared with 5.1% for the un-catalyst reaction under the same reaction condition. FT-IR and CP-MAS 13C-NMR studies produced evidence for acetylation. The thermal stability of the products decreased slightly upon chemical modification, but no significant decrease in thermal stability was observed for WPG > or = 24.7%. More importantly, the acetylation significantly increased hydrophobic properties of the bagasse. The oil sorption capacity of the acetylated bagasse obtained at 80 degrees C for 6 h, was 1.9 times higher than the commercial synthetic oil sorbents such as polypropylene fibres. Therefore, these oil sorption-active materials can be used to substitute non-biodegradable materials in oil spill cleanup.

A sequential totally chlorine-free procedure for isolation of cellulose from wheat straw was proposed in this study. The dewaxed straw was pretreated with 0.5 M NaOH in 60% methanol at 60 degrees C for 2.5 h under ultrasonic irradiation for 0-35 min and sequentially posttreated with 2% H(2)O(2)-0.2% TAED at pH 11.8 for 12 h at 48 degrees C, which together solubilized 85.3-86.1% of the original hemicelluloses and 91.7-93.2% of the original lignin, respectively. The yield of crude cellulose ranged between 46.2 and 49.2% on a dry weight basis related to wheat straw, which contained 11.2-12.2% residual hemicelluloses and 2.5-2.9% remaining lignin. Further treatment of the corresponding crude cellulosic preparations with 80% acetic acid-70% nitric acid under the condition given yielded 36.8-37.7% of the purified cellulose, which contained minor amounts of bound hemicelluloses (2.5-2.8%) and was relatively free of associated lignin (0.1-0.2%). The isolated crude and purified cellulose samples were comparatively studied by FT-IR and CP/MAS (13)C NMR spectroscopy, and the relative crystallinity was also estimated. The final stage treatment with 80% acetic acid-70% nitric acid decreased the hemicelluloses and lignin associated in the crude cellulose but led to 3.1-5.4% degradation of the original cellulose; in addition, the purity of the obtained cellulose was high. However, it was found that the final stage treatment is not severe enough to cause decrystallization of cellulose. The thermal stability of the purified cellulose is higher than that of the corresponding crude cellulose.

Sequential treatments of dewaxed bagasse with distilled water, 0.5 M NaOH, 0.5, 1.0, 1.5, 2.0, and 3.0% H(2)O(2) at pH 11.5, and 2 M NaOH at 55 degrees C for 2 h solubilized 2.8, 52.5, 14.9, 3.3, 5.5, 5.0, 2.8, and 2.2% of the original lignin, respectively. The eight isolated lignin fractions were subjected to a comprehensive structural characterization by UV, FT-IR, and (1)H and (13)C NMR spectroscopies and thermal analysis. The nitrobenzene oxidation method was also applied to the in situ lignins. The seven lignin fractions, isolated successively with alkali and alkaline peroxide, were all SGH-type lignins, with a small amount of esterified p-coumaric acid and mainly etherified ferulic acid. No significant differences were found in the weight-average molecular weights (1680-2220 g/mol) of the seven alkali and alkaline peroxide dissolved lignins. However, the first four lignin fractions, isolated with 0.5 M NaOH and 0.5, 1.0, and 1.5% H(2)O(2) at pH 11.5, were rich in syringyl units and contained large amounts of noncondensed ether structures, whereas the last three lignin fractions, isolated sequentially with 2.0 and 3.0% H(2)O(2) at pH 11.5 and 2 M NaOH at 55 degrees C for 2 h, had a higher degree on condensation and were rich in guaiacyl lignins.

Treatment of wheat straw with hot water at 80-95 degrees C for 0.5 h at pH 6.0-8.0 released 41.0-53.0% of the original lipophilic extractives. The chemical compositions of six lipophilic extractives were determined by GC on a medium-length high-temperature capillary column without derivatization, thus giving a method for direct determination of individual components of free fatty and resin acids, sterols, waxes, sterol esters, and triglycerides. The extracts contained 68.7-75.8% lipophilic substances, comprising mainly free fatty acids (25.8-48.4%), waxes (9.4-27.0%), sterols (4.1-8.0%), triglycerides (3.3-11.0%), and sterol esters (2.6-5.1%). Minor amounts of diglycerides (0.3-0.5%), resin acid (0.5-3.1%), and phenolic compounds (0.9-3.6%) were also quantitatively determined in the extractives.

The cell wall material of Chinese shrubs Haloxylon ammodendron and Elaeagnus angustifolia was fractionated by successive extractions with ethanol/H(2)O (60:40, v/v) under acidic conditions (0.2 N HCl) at 70 degrees C for 4 h, and 2% H(2)O(2) at pH 11.5 for 16 h, respectively. The sequential two-step treatment resulted in the dissolution of 83.9% and 87.6% of the original hemicelluloses from dewaxed H. ammodendron and E. angustifolia, respectively. Xylose, glucose, and galactose were the major sugar constituents in the two acidic organosolv-soluble hemicellulosic preparations. The two alkaline peroxide-soluble hemicellulosic fractions were shown to be composed primarily of xylose, comprising over 80% of the total sugars. The results also showed that the two alkaline peroxide-soluble hemicellulosic fractions were more linear and acidic, and had higher molecular mass and thermal stability than the two acidic organosolv-soluble hemicellulosic preparations. The 2% H(2)O(2) posttreatment did not result in any significant changes in the macromolecular structure of the isolated hemicelluloses. It is probable that lignin protects hemicelluloses and cellulose from being attacked by peroxide.

Effect of ultrasound on the yield and physiochemical properties of hemicelluloses from wheat straw using 0.5 M NaOH in 60% aqueous methanol has been comparatively studied. The results showed that applying sonication for 5, 10, 15, 20, 25, 30, and 35 min resulted in an increasing yield of hemicelluloses by 2.9%, 3.9%, 6.0%, 8.6%, 8.6%, 8.6%, and 9.2% of the original hemicelluloses, respectively, in comparison with the experiment performed without ultrasonic assistance. The hemicelluloses isolated by ultrasound-assisted extraction, showed a slightly lower molecular weight, associated lignin, and thermal stability during the first stage of decomposition, but slightly more linear as compared to the hemicelluloses obtained by classical method without ultrasonic irradiation. No substantial differences in the main structure features between the hemicellulosic preparations isolated by classical or ultrasound-assisted extractions were found.

A new method has been developed for the quantitative determination of hydroxycinnamic acids participating in ester or ether linkages to the cell wall polymers. The method is based on mild alkaline hydrolysis followed by acid hydrolysis or mild alkaline hydrolysis, which partially removed esterified phenolic acids, and high-temperature concentrated alkaline treatment, which cleaved both the ester and ether linkages. It was found that traditional mild alkaline hydrolysis and acid hydrolysis released only part of the ester- and ether-linked phenolic acids, respectively. Approximately half (44.0-47.9%) of the total ester-linked p-coumaric acid and 18.2-32.6% of the total esterified ferulic acid remained ester-linked to the mild alkali-soluble lignin polymers, and 55.0-72.0% of the total ether-linked p-coumaric acid and 37.5-53.8% of the total ether-linked ferulic acid remained ether-linked to the solubilized lignin molecules after the acid hydrolysis. To correct this, a second mild alkaline hydrolysis of the alkali-soluble lignin preparations and acid hydrolysis of the solubilized lignin fractions, obtained from the first acid hydrolysis of the cell wall materials, was investigated. On the basis of this new method, a majority of the cell wall p-coumaric acid (55.8-81.5%) was found to be ester-linked to cell wall components, mainly to lignin, and about half of the cell wall ferulic acid is etherified through its phenolic oxygen to the cell wall lignin component, whereas the remainder is esterified to the cell wall hemicelluloses and/or lignin in different plant materials.

A sequential treatment of dewaxed barley straw with sodium hydroxide, different concentrations of hydrogen peroxide, and potassium hydroxide/sodium borate degraded various proportions of the original lignin and solubilized different amounts of the original hemicelluloses. The isolated lignin fractions were subjected to comprehensive structural characterization by UV, FT-IR, and (13)C NMR spectroscopy, and their chemical compositions were analyzed by alkaline nitrobenzene oxidation. All of the lignin fractions were typical of grass lignins and had weight-average molecular weights between 1750 and 2190. It was found that the peroxide treatment at low concentrations (< or =2.0%) resulted in a slight increase in the amount of carboxyl groups, whereas the treatment at a relatively high concentration of alkaline peroxide, such as at 3.0% H(2)O(2), led to a noticeable oxidation of the lignins, as shown by an increase of carboxyl groups. Moreover, the results obtained indicated that the successive treatments with alkali and alkaline peroxide under the conditions used did not significantly affect the beta-O-4 structures of lignins. Substantial amounts of etherified ferulic acids were cleaved by the sequential treatments with alkaline peroxide, as shown in the (13)C NMR spectra. The results underscore the structural differences between alkali- and alkaline peroxide-soluble lignins from barley straw.

Objective: To compare the effects of carvedilol and metoprolol in preventing from left ventricular remodeling (LVRM) after acute myocardial infarction (AMI) in rats., Methods: Twenty-four hours after ligating left coronary artery, 105 surviving female SD rats were randomly assigned to AMI control, carvedilol 1 mg/(kg.d) and metoprolol 2 mg/(kg.d) groups. Sham-operated rats (n = 16) were selected randomly as non-infarction control. After four weeks of drugs therapy, hemodynamic studies and pathologic analysis were performed. Exclusive of MI size < 35% or > 55%, complete experimental variables were obtained in 46 rats, which were comprised of AMI (n = 11), carvedilol (n = 12), metoprolol (n = 11), and Sham-operated (n = 12) groups., Results: Compared with sham-operated group, left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV) and weight (LVW), were all significantly increased (P < 0.05-0.001), while maximal rate of rise and fall (+/- dp/dt) of LV pressure as well as their corrected values (+/- dp/dt/LVSP) were all significantly decreased (P < 0.01-0.001) in AMI group. In comparison with AMI group, the LVEDP and LVV were all significantly decreased (all P < 0.001), while +/- dp/dt and +/- dp/dt/LVSP were significantly increased (P < 0.05-0.001) in both carvedilol and metoprolol group, with LVW and RVW only decreased in carvedilol group (P < 0.05-0.01)., Conclusions: 1. Carvedilol can effectively attenuate LVRM, and improve hemodynamics and LV function after AMI in rats, 2. Metoprolol has equivalent beneficial effects as carvedilol on hemodynamics, LV dilatation and function, but not LV hypertrophy.

Water-treated maize stems were subjected to delignification with peroxymonosulfuric acid at 20 degrees C for 144 h, with peroxyformic acid at 80 degrees C for 6 h, with peracetic acid at 50 degrees C for 6 h, and with 2% hydrogen peroxide at 45 degrees C for 12 h at pH 1.5, 4.4, 9.5, 11.5, 12.0, and 12.6, respectively, which solubilized 47.1, 91.3, 33.3, 16.6, 15.9, 17.4, 86.2, 87.7, and 91. 3% of the original lignin, respectively. Substantial lignins were released during the treatment with peroxyformic acid and hydrogen peroxide at pH > or =11.5, whereas an insignificant effect on delignification was observed by using peroxymonosulfuric acid, peracetic acid, and hydrogen peroxide under acidic, natural, and weakly alkaline media conditions. The structures of the isolated lignin preparations were investigated by chemical analysis, gel permeation chromatography, and UV, FT-IR, and (13)C NMR spectroscopy.