新型笼状同多钒酸盐[Ni(1,10′-phen)_3]_2·[V_2~ⅣV_8~ⅤO_(26)]的水热合成和晶体结构

尽管多金属氧酸盐 (POMs)的研究已有180多年的历史,但大量的POMs结构在最近几十年才被陆续解析出来[1～4].其中 ,同多钒酸盐由于钒配位几何形状的多样性,结构最为丰富 ,例如:[V4 O12 ]4-[5],[V5O14 ]3-[6],[V10 O2 8]6-[7] ,[V15O4 2 ]9-[8],[V13 O3 4 ]3-[9].值得注意的是,在这些化合物中,钒的化合价均处于最高氧化态+5价.由于+4价钒不易在溶液中(尤其是水中)稳定存在,因此在以往的常压溶液合成中具有混合价态的同多钒酸盐报道很少.与饱和价态的同多钒酸盐相比,混价多钒酸盐具有更为新奇的电荷分布和拓扑学几何构型,并且在 POMs的理论研究和抗病毒药物、电存储材料以及磁性材料等应用领域有特殊的研究和开发价值[1,10,11].因此,制备具有混价的新型同多钒酸盐一直倍受关注.近年来,水热合成技术的引入使同多钒酸盐合成化学迅速发展.水热体系提供了一个特殊的反应环境 [12 ],使制备各种具有混合价态的同多钒酸盐成为可能.Müller等[13]对这一领域开...

ELECTROCHEMICAL STUDY OF ISOPOLYOXOMETALLATES AND HETEROPOLYOXOMETALLATES FILM MODIFIED MICROELECTRODES .1. PRETREATMENT AND MODIFICATION OF THE MO80-26(4-) MODIFIED CARBON-FIBER MICROELECTRODE

In this paper the preparation of isopoly- and heteropolyoxometallates (IPA and HPA) thin film modified carbon fiber (CF) microelectrodes and the factor that influences the modification of IPA and HPA films are described. IPA and HPA film modified CF microelectrodes can all be prepared by cyclic potential scan and simple dip coating. The modified electrodes prepared are very stable and reversible in acidic solution with monolayer characteristics. The electrochemical pretreatment of CF microelectrodes plays an important role in the modification of IPA and HPA film. The absorption of IPA and HPA film on electrode surfaces has been discussed on the basis of surface conditions of the CF microelectrode and the structure of IPA and HPA.

INTEGRAÇÃO lavoura-pecuária-floresta - programa 26.

2009

PRINCIPAIS INDICADORES: AGRÍCOLAS, v. 3, n. 26, 2010.

2010

PRINCIPAIS INDICADORES: LEITE E DERIVADOS, v. 3, n. 26, 2010.

2010

PRINCIPAIS INDICADORES: MACROECONÔMICOS, v. 3, n. 26, 2010.

2010

IDENTIFICAÇÃO e controle de pragas da mandioca - programa 26.

2009

World-wide evangelization the urgent business of the church; addresses delivered before the fourth international convention of the Student volunteer movement for foreign missions, Toronto, Canada, February 26-March 2, 1902.

http://www.archive.org/details/worldwideevangel00unknuoft

Laparoscopic Appendectomy in Italy: An Appraisal of 26,863 Cases

Objective: To evaluate the practice of laparoscopic appendectomy (LA) in Italy. Methods: On behalf of the Italian Society of Young Surgeons (SPIGC), an audit of LA was carried out through a written questionnaire sent to 800 institutions in Italy. The questions concerned the diffusion of laparoscopic surgery and LA over the period 1990 through 2001, surgery-related morbidity and mortality rates, indications for LA, the diagnostic algorithm adopted prior to surgery, and use of LA among young surgeons (<40 years). Results: A total of 182 institutions (22.7%) participated in the current audit, and accounted for a total number of 26863 LA. Laparoscopic surgery is performed in 173 (95%) institutions, with 144 (83.2%) routinely performing LA. The mean interval from introduction of laparoscopic surgery to inception of LA was 3.4 ± 2.5 years. There was an emergent basis for 8809 (32.8%) LA procedures (<6 hours of admission); 10314 (38.4%) procedures were performed on an urgent basis (<24 hours of admission); while 7740 (28.8%) procedures were elective. The conversion rate was 2.1% (561 cases) and was due to intraoperative complications in 197 cases (35.1%). Intraoperative complications ranged as high as 0.32%, while postoperative complications were reported in 1.2% of successfully completed LA. The mean hospital stay for successfully completed LA was 2.5 ± 1.05 days. The highest rate of intraoperative complications was reported as occurring during the learning curve phase of their experience (in their first 10 procedures) by 39.7% of the surgeons. LA was indicated for every case of suspected acute appendiceal disease by 51.8% of surgeons, and 44.8% order abdominal ultrasound (US) prior to surgery. A gynecologic counseling is deemed necessary only by 34.5% surgeons, while an abdominal CT scan is required only by 1.5%. The procedure is completed laparoscopically in the absence of gross appendiceal inflammation by 83%; 79.8% try to complete the procedure laparoscopically in the presence of concomitant disease; while 10.4% convert to open surgery in cases of suspected malignancy. Of responding surgeons aged under 40, 76.3% can perform LA, compared to 47.3% surgeons of all age categories. Conclusions: The low response rate of the present survey does not allow us to assess the diffusion of LA in Italy, but rather to appraise its practice in centers routinely performing laparoscopic surgery. In the hands of experienced surgeons, LA has morbidity rates comparable to those of international series. The higher diagnostic yield of laparoscopy makes it an invaluable tool in the management algorithm of women of childbearing age; its advantages in the presence of severe peritonitis are less clear-cut. Surgeons remain the main limiting factor preventing a wider diffusion of LA in our country, since only 47.3% of surgeons from the audited institutions can perform LA on a routine basis.

Imátgenes 25, 26, 27 y última imatgen

Su mirada recorrió los lomos del estante inferior y se detuvo en un título que le llamó la atención. Lo liberó de la hilera que lo aprisionaba y lo abrió al azar. Al menos eso era lo que pretendía, aunque el libro se abrió por una página señalada con un pliegue en la esquina superior. Quien lo practicó quería señalar un punto con una indicación perenne. Seguro que era cosa de su abuelo, fallecido hacía ya unos cuantos años. Fue precisamente el recuerdo de su muerte lo que le animó a entrar en la biblioteca. No sabía porqué, pero de repente le había venido a la mente la imagen del anciano leyendo ensimismado en aquel sillón antiguo, rodeado de incontables volúmenes, páginas, frases, palabras, letras.