bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-Stage Fracturing Stimulations Improve Well Performance in Tight Oil Reservoirs of the Changqing Oilfield
Authors: Li Xianwen , Wei Hongmei , Chen Baochun , Liu Xinghui , Wang Wangcheng , Zhao Xinzhi
Published: November 2008

The oil reservoirs in the Changqing Oilfield consist of stacked sand/shale deposits, and the majority of the target zones have a permeability of 0.05–0.3mD. All oil wells completed in tight reservoirs from the Changqing Oilfield require fracture stimulation to achieve commercial production and to improve well productivity. Fracture stimulation is also very common for water injection wells to enhance injectivity. Multiple payzones in the region were either stimulated with standalone treatments that were isolated and pumped separately or with single-stage treatments to simultaneously treat several intervals using a kind of limited-entry technique. However, with the continuing development in these fields, larger pay intervals (gross pay thickness up to 75 meters) with poorer reservoir quality were encountered. Post-fracture production results indicated that the above stimulation techniques were not always effective in these tight reservoirs.

As a result, a new staging technique was evolved and employed to stimulate these tighter reservoirs with better economic effectiveness. With this technique, two or three pay intervals were first perforated and dual-stage fracture treatments were then performed: one stage at a time without using any mechanical isolation. The idea was two-fold:using the stress increase around the fracture created by the first injection to divert the subsequent treatment to un-stimulated interval(s), andusing the proppant banks created from the first propped treatment to minimize the proppant settling to the bottom portion of the fracture created by the second propped treatment.

Three-month average post-treatment production data indicated that the dual-stage treatments outperformed conventional single-stage treatments in some reservoir environments. Candidate selection was a key to the success of this technique, and reservoir conditions that favor these types of treatments are as follows: multiple pays, lower permeability, lower net pressure, and less stress contrast between different payzones. Radioactive tracer logging and microseismic fracture mapping were conducted to evaluate fracture height growth. This paper presents a case history of fracture performance evaluations. Reservoir data, fracture modeling and post-fracture production data were compiled and employed to demonstrate the benefits of this fracture treatment technique in some tight oil reservoirs.
Long-term seizure outcome after corpus callosotomy: a retrospective analysis of 95 patients
Authors: Tanriverdi Taner , Olivier André , Poulin Nicole , Andermann Frederick , Dubeau François
Published: November 2008

Object

The authors report long-term follow-up seizure outcome in patients who underwent corpus callosotomy during the period 1981–2001 at the Montreal Neurological Institute.

Methods

The records of 95 patients with a minimum follow-up of 5 years (mean 17.2 years) were retrospectively evaluated with respect to seizure, medication outcomes, and prognostic factors on seizure outcome.

Results

All patients had more than one type of seizure, most frequently drop attacks and generalized tonicclonic seizures. The most disabling seizure type was drop attacks, followed by generalized tonic-clonic seizures. Improvement was noted in several seizure types and was most likely for generalized tonic-clonic seizures (77.3%) and drop attacks (77.2%). Simple partial, generalized tonic, and myoclonic seizures also benefited from anterior callosotomy. The extent of the callosal section was correlated with favorable seizure outcome. The complications were mild and transient and no death was seen.

Conclusions

This study confirms that anterior callosotomy is an effective treatment in intractable generalized seizures that are not amenable to focal resection. When considering this procedure, the treating physician must thoroughly assess the expected benefits, limitations, likelihood of residual seizures, and the risks, and explain them to the patient, his or her family, and other caregivers.
Molecular markers relating to malignant progression in Grade II astrocytoma
Authors: Yue Wei-Ying , Yu Su-Huan , Zhao Shi-Guang , Chen Zhong-Ping
Published: November 2008

Object

Astrocytoma may progress rapidly or remain stable for many years. To clarify whether molecular characteristics could be prognostic factors, several cell cycling–associated molecular alterations in the diffuse astrocytoma have been investigated.

Methods

Thirty-three patients in whom WHO Grade II astrocytoma had been initially diagnosed were assigned to 1 of 3 groups. Group 1 consisted of 10 patients with malignant progression; the tumor had recurred within 5 years and histological analysis had confirmed that the tumor progressed to Grade III or IV. Group 2 consisted of 10 patients in whom there was no malignant progression; the tumor recurred within 5 years, but histological analysis confirmed that the tumor remained at Grade II. Group 3 consisted of 13 patients who did not experience recurrence within 5 years. Expression of Ki 67, TP53, p27, and p21 was examined using immunohistochemical analysis for the tumor samples obtained during the first and second (in recurrent cases) surgeries. Exons 5, 7, and 8 of TP53 were scanned by DNA sequencing.

Results

The Ki 67 labeling index expression was significantly higher in Group 1 (even though it was similar between initial and recurrent tumors) than that of Group 3 (p < 0.05). However, there was no difference between Group 2 (both initial and recurrent tumors) and Group 3. The TP53 protein accumulation was also higher in Group 1 than in Group 2 or 3 (p < 0.05); a difference in TP53 expression was not found between Groups 2 and 3. The p27 and p21 was expressed in all cases, but no predictive values were found. The p53 mutation was found only in 6 cases in Group 1.

Conclusions

Overexpression of TP53, TP53 mutation, and Ki 67 labeling index could be molecular markers in astrocytomas predicting malignant progression.
Long-term outcome after temporal lobe epilepsy surgery in 434 consecutive adult patients
Authors: Elsharkawy Alaa Eldin , Alabbasi Abdel Hamid , Pannek Heinz , Oppel Falk , Schulz Reinhard , Hoppe Mathias , Hamad Ana Paula , Nayel Mohamed , Issa Ahmed , Ebner Alois
Published: November 2008

Object

The aim of this study was to evaluate the long-term efficacy of temporal lobe epilepsy (TLE) surgery and potential risk factors for seizure recurrence after surgery.

Methods

This retrospective study included 434 consecutive adult patients who underwent TLE surgery at Bethel Epilepsy Centre between 1991 and 2002.

Results

Hippocampal sclerosis was found in 62% of patients, gliosis in 17.3%, tumors in 20%, and focal cortical dysplasia (FCD) in 6.9%. Based on a Kaplan-Meier analysis, the probability of Engel Class I outcome for the patients overall was 76.2% (95% CI 71–81%) at 6 months, 72.3% (95% CI 68–76%) at 2 years, 71.1% (95% CI 67–75%) at 5 years, 70.8% (95% CI 65–75%) at 10 years, and 69.4% (95% CI 64–74%) at 16 years postoperatively. The likelihood of remaining seizure free after 2 years of freedom from seizures was 90% (95% CI 82–98%) for 16 years. Seizure relapse occurred in all subgroups. Patients with FCD had the highest risk of recurrence (hazard ratio 2.15, 95% CI 0.849–5.545). Predictors of remission were the presence of hippocampal atrophy on preoperative MR imaging and a family history of epilepsy. Predictors of relapse were the presence of bilateral interictal sharp waves and versive seizures. Six-month follow-up electroencephalography predicted relapse in patients with FCD. Short epilepsy duration was predictive of seizure remission in patients with tumors and gliosis; 28.1% of patients were able to discontinue antiepileptic medications without an increased risk of seizure recurrence (hazard ratio 1.05, 95% CI 0.933–1.20).

Conclusions

These findings highlight the role of etiology in prediction of long-term outcome after TLE surgery.
A Novel Co-polymer Based on Hydroxypropyl α-Cyclodextrin Conjugated to Low Molecular Weight Polyethylenimine as an in Vitro Gene Delivery Vector
Authors: Huang Hongliang , Yu Hai , Li Da , Liu Yang , Shen Fenping , Zhou Jun , Wang Qingqing , Tang Guping
Published: November 2008

A novel co-polymer based on 2-hydroxypropyl-α-cyclodextrin cross-linked by low molecular weight polyethylenimine was synthesized as a gene delivery vector. The copolymer could bind and condense DNA tightly. It showed lower cytotoxicity than PEI 25kDa in SK-BR-3 cells. Transfection efficiency was increased over 5.5-fold higher than PEI 25 kDa in SK-BR-3 cells in complete serum medium. It is a potential candidate vector for gene therapy.
Rescue of Fertility in Homozygous Mice for the Urokinase Plasminogen Activator Transgene by the Transplantation of Mouse Hepatocytes
Authors: Brezillon Nicolas M. , Dasilva Lucie , L'hôte David , Bernex Florence , Piquet Julie , Binart Nadine , Morosan Serban , Kremsdorf Dina
Published: November 2008

Development of the urokinase plasminogen activator/SCID (uPA/SCID) transgenic mouse model has opened new perspectives for the study of different biological mechanisms such as liver regeneration, stem cell differentiation, and human hepatic pathogens. We observed that homozygous uPA/SCID mice (uPA+/+/SCID) had a small offspring, indicating a fertility defect. The goal of this study was thus to rescue the fertility of homozygous uPA mice. A deregulation of ovarian function with an absence of corpus luteum was observed in female uPA+/+/SCID mice. In male uPA+/+/SCID mice, a decrease of the weight of the testes, epididymis, seminal vesicle, and prostate was measured. This was associated with an absence of seminal and prostatic secretions and a reduction in testicular sperm production. We hypothesized that the infertility of mice was the consequence of uPA-induced liver injury. Thus, in order to rescue liver function, hepatocytes from mice negative for the uPA transgene were transplanted into uPA+/+/SCID mice. Thirty days after cell transplantation, the livers of transplanted uPA+/+/SCID mice were totally repopulated and presented a normal morphology. Furthermore, transplantation restored normal body weight, life span, and reproductive organ function. In conclusion, we demonstrated that the transplantation of uPA+/+/SCID mice with healthy hepatocytes was sufficient to rescue the reproductive capacity of female and male uPA homozygous animals, highlighting the importance of normal liver function to reproductive capability.
Preliminary Survival Studies on Autologous Cultured Skin Fibroblasts Transplantation by Injection
Authors: Zhao Yuming , Wang Jiaqi , Yan Xiaoqing , Li Dan , Xu Jun
Published: November 2008

In the correction of aesthetic impairments on the face, dermal, and superficial subcutaneous defects, adequately safe implant material is required. Cultured autologous skin fibroblasts, as a protein repair system, create a living injectable system that has been utilized effectively to treat rhytids, depressed scars, subcutaneous atrophy, acne irregularities, and laser wounds. To evaluate the new method, we have investigated the survival and collagen secretion of autologous transplanted fibroblasts. In this study, rabbit fibroblasts were cultured and expanded. Cells (8 × 107/ml) were injected into the superficial and deep dermal junction of the dorsal ears. Two rabbits were injected independently with labeled [3H]TdR fibroblasts; similarly, eight rabbits were given unlabeled transplanted cells in the right ear and vehicle in the left. Each site was injected three times with the same amount of cells every 2 weeks. The grafts were evaluated for 5 months. After explantation, the samples were collected from the injected sites and stained with autoradiography, H&E, and sirius red, respectively. According to the histological observations, the [3H]TdR-labeled cells survived and large amounts of embryo fibroblasts were found in the experimental subgroup of the labeled cell group. The depth of dermis was significantly different between the experimental subgroup (701.3 ± 31.5 μm) and the control subgroup (638.3 ± 23.9 μm) of the unlabeled group (p < 0.01). There was also a significant difference of collagen III between the experimental subgroup (2.63 ± 1.41 cm2) and the control subgroup (1.05 ± 0.90 cm2) (p < 0.05). There was no significant difference of collagen I between the experimental subgroup (56.25 ± 14.41 cm2) and the control subgroup (55.41 ± 16.59 cm2) (p > 0.05). The results obtained demonstrate that the distinction of the depth of dermis should be interpreted by the increase of collagen III, instead of collagen I, which is produced by the transplanted fibroblasts. The investigation indicated that transplanted autologous skin fibroblasts could provide a potential and effective approach to treat minor facial tissue deficiencies.
Implicit dual control based on particle filtering and forward dynamic programming
Authors: Bayard David S. , Schumitzky Alan
Published: November 2008

This paper develops a sampling‐based approach to implicit dual control. Implicit dual control methods synthesize stochastic control policies by systematically approximating the stochastic dynamic programming equations of Bellman, in contrast to explicit dual control methods that artificially induce probing into the control law by modifying the cost function to include a term that rewards learning. The proposed implicit dual control approach is novel in that it combines a particle filter with a policy‐iteration method for forward dynamic programming. The integration of the two methods provides a complete sampling‐based approach to the problem. Implementation of the approach is simplified by making use of a specific architecture denoted as a H‐block. Practical suggestions are given for reducing computational loads within the H‐block for real‐time applications. As an example, the method is applied to the control of a stochastic pendulum model having unknown mass, length, initial position and velocity, and unknown sign of its dc gain. Simulation results indicate that active controllers based on the described method can systematically improve closed‐loop performance with respect to other more common stochastic control approaches. Copyright © 2008 John Wiley & Sons, Ltd.
Iridium‐Catalyzed Enantioselective Allylic Alkylation using Chiral Phosphoramidite Ligand Bearing an Amide Moiety
Authors: Onodera Gen , Watabe Keijiro , Matsubara Masaki , Oda Kazuhiro , Kezuka Satoko , Takeuchi Ryo
Published: November 2008

New chiral phosphoramidites with an amide moiety were used for iridium‐catalyzed asymmetric allylic alkylation reactions. The best results were obtained with a ligand bearing an oxazolidinone moiety. The reaction of cinnamyl acetate with diethyl sodiomalonate without the use of lithium chloride gave the branched product with 94% ee.
Fullerene‐Promoted Singlet‐Oxygen Photochemical Oxygenations in Glass‐Polymer Microstructured Reactors
Authors: Carofiglio Tommaso , Donnola Paola , Maggini Michele , Rossetto Massimiliano , Rossi Emiliano
Published: November 2008

In this paper we report the fabrication of thiolene‐based microstructured reactors (MRs) that have been specifically designed to include solid‐supported reagents within the microchannels network. We propose a convenient solution to realize reversible press‐fit, leak‐proof interconnects that greatly simplify the MR coupling to the external environment such as capillary tubing, sample reservoirs and pumps. The MRs have been used to carry out the oxidation of α‐terpinene and methionine using [60]fullerene, covalently linked to Tentagel® and silica gel matrices, as a singlet oxygen sensitizer. High conversions have been observed for both substrates although, in the case of α‐terpinene, a partial photodegradation of the endo‐peroxide product was detected. Interestingly, in the case of methionine, a quantitative conversion to the corresponding sulfoxides was achieved in about 40 seconds, using low‐power, white LED illumination. The reaction time is considerably shorter when compared to the batch procedure that requires, for the same process, about one hour illumination and the use of a 300‐W tungsten halogen lamp.
Enantioselective Hydrogenation of Enones with a Hydroformylation Catalyst
Authors: Scheuermann née Taylor Caroline J. , Jaekel Christoph
Published: November 2008

Use of a typical rhodium precatalyst for hydroformylation results in the enantioselective hydrogenation of cyclic enones with up to 90% ee. Extensive screening of chiral ligands reveals the simple ligand Chiraphos as the best ligand, so far. The hydrogenation shows high chemoselectivity. Exclusive formation of saturated, chiral β‐branched ketones is observed. It is proposed that the catalyst follows a frustrated hydroformylation pathway (“monohydride‐based mechanism”) and differs by that from the classical cationic Schrock–Osborn type rhodium precatalysts (“dihydride‐based mechanism”) for enantioselective hydrogenation. The catalyst operates under neat conditions and is easily recyclable by simply distilling off the reaction mixture and treatment with syn gas prior to hydrogenation.
Are apes inequity averse? New data on the token‐exchange paradigm
Authors: Bräuer Juliane , Call Josep , Tomasello Michael
Published: November 2008

Recent studies have produced mixed evidence about inequity aversion in nonhuman primates. Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253–258, 2005] found inequity aversion in chimpanzees and argued that effort is crucial, if subjects are to evaluate how they are rewarded in comparison to a competitor for an identical performance. In this study we investigated inequity aversion with chimpanzees, bonobos and orangutans, using the method of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253–258, 2005] after introducing some methodological improvements. Subjects always received a less‐preferred food in exchange for a token, whereas the competitor received either the same type of food for their token (equity) or a more favored food for it (inequity). Apes did not refuse more of the less‐preferred food when a competitor had received the more favored food. Thus, with an improved methodology we failed to reproduce the findings of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253–258, 2005] that apes show inequity aversion. Am. J. Primatol. 71:175–181, 2009. © 2008 Wiley‐Liss, Inc.
The synthesis of PHA‐g‐(PTHF‐b‐PMMA) multiblock/graft copolymers by combination of cationic and radical polymerization
Authors: Macit Hülya , Hazer Baki , Arslan Hülya , Noda Isao
Published: November 2008

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3‐hydroxy alkanoate)‐g‐(poly(tetrahydrofuran)‐b‐poly(methyl methacrylate)) (PHA‐g‐(PTHF‐b‐PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA‐g‐PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHx) in the presence of AgSbF6. Therefore, PHA‐g‐PTHF graft copolymers with hydroxyl ends were produced. In the presence of Ce+4 salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA‐g‐(PTHF‐b‐PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their γ‐values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using 1H‐NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of proccessible polyaniline derivatives for corrosion inhibition
Authors: Bhandari Hema , Sathiyanaranayan S. , Choudhary Veena , Dhawan S. K.
Published: November 2008

This article reports the synthesis and characterization of copolymers based on aniline and substituted anilines by using dodecylbenzene sulfonic acid as a dopant. The copolymers were soluble in organic solvents, such as methanol, ethanol, isopropanol, N‐methylpyrrolidinone, dimethylsulphoxide, and have conductivity of the order of 1.5 to 10−7 S/cm depending upon the monomer ratios and extent of dopant used. The effect of substituents like 2‐methyl, 2‐ethyl, and 2‐isopropyl groups on the electrochemical, conductivity, thermal stability, solubilization, and spectroscopic behavior of the copolymers has been evaluated. The composition of the copolymers was determined by 1H‐NMR spectroscopy. Corrosion inhibition behavior of the copolymers in 1.0N HCl has been evaluated using linear polarization resistance method and Tafel extrapolation method. The corrosion efficiency depends upon the copolymer composition and it increased with increasing amount of 2‐alkyl aniline in the feed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Social change, intercultural conflict, and marital dynamics in a chinese marriage in brief concurrent individual and couple therapy
Authors: Shi Qijia , Scharff Jill savege
Published: November 2008

“There is beginning and ending. There is cause and consequence in everything. Knowing what comes first and what comes later is close to Tao.” Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis of Dibenzochalcogenaborins and Systematic Comparisons of Their Optical Properties by Changing a Bridging Chalcogen Atom
Authors: Kobayashi Junji , Kato Keiko , Agou Tomohiro , Kawashima Takayuki
Published: November 2008

Novel hetero‐π‐conjugated compounds (dibenzochalcogenaborins) with the same molecular framework, bearing a boron atom as an acceptor and chalcogen atoms as a donor, were synthesized, and systematic comparisons among these molecules were performed. X‐ray crystallographic analysis of these molecules showed similar structures with high planarity. UV/Vis spectroscopy and theoretical calculations revealed that the absorption maxima and the HOMO–LUMO gap changed by systematically changing the bridging chalcogen atom. Dibenzooxaborin and dibenzothiaborin showed fluorescence emission both in solution and in the solid state with a small Stokes shift, indicating the high rigidity of these compounds. On the other hand, dibenzoselenaborin exhibited a very weak fluorescence as a result of the heavy atom effect.
Spatial variability of rainfall regions in West Africa during the 20th century
Authors: Yepdo Djomou Zéphirin , Monkam David , Lenouo André
Published: November 2008

Four regions spread in five areas are identified in West Africa for the base period 1901–1940. Trends have a magnitude of up to 1.5 K per century, with a decreasing of the precipitation since the year 1970. The application of a segment of 15 years with overlap going from 1901 to 1940 (P0), and 1961 to 1998 (P4) throughout the periods 1916–1955 (P1), 1931–1970 (P2) and 1946–1985 (P3), shows important spatiotemporal modifications of rainfall regions south of 15°N. From P0 to P4, the surface of semiarid land doubles while wetland is reduced to half. Copyright © 2008 Royal Meteorological Society
Caenorhabditis elegansas an undergraduate educational tool for teaching RNAi
Authors: Andersen Janet , Krichevsky Alexander , Leheste Joerg R. , Moloney Daniel J.
Published: November 2008

Discovery of RNA‐mediated interference (RNAi) is widely recognized as one of the most significant molecular biology breakthroughs in the past 10 years. There is a need for science educators to develop teaching tools and laboratory activities that demonstrate the power of this new technology and help students to better understand the RNAi process.C. elegansis an ideal model organism for the undergraduate laboratory because of the simplicity of worm maintenance, its well‐studied genetic background, and the fact that it can be employed as a model organism in laboratory environments where vertebrate research is restricted. Certain unique features ofC. elegansmake it a very suitable organism for RNAi studies. Specifically, nematode strains highly sensitive to RNAi are readily available from public sources, and RNAi induction by a feeding method is an uncomplicated procedure that lends itself readily as an educational tool. In this article, we provide a detailed depiction of the use ofC. elegansas an RNAi educational tool, describing two separate RNAi‐based experiments. One is a qualitative experiment where students can examine the effects of knocking down theunc‐22gene involved in the regulation of muscle contraction, which results in a “twitching” phenotype. The other experiment is a quantitative RNAi experiment, where students measure the effect of knocking down thelsy‐2gene involved in neuronal development. Although these experiments are designed for a college‐level study, nematode research projects can also be accomplished in secondary school facilities.
Student and community perceptions about organ donors, non‐donors and transplant recipients
Authors: Hyde Melissa K. , White Katherine M.
Published: November 2008

Despite efforts to encourage organ donation, low organ donation rates in Australia and other Western nations do not meet the demand for transplantable organs. One influence on organ donation decision‐making yet to be fully explored is that of prototype perceptions about organ donors, non‐donors and transplant recipients. We conducted focus groups and interviews with 54 student and community participants to explore these perceptions of donors and non‐donors in a living and posthumous context, as well as transplant recipients. Using content and thematic analysis, transcripts were analysed for consistently emerging themes. Donors were generally perceived positively as altruistic and giving and as ordinary people; however, some participants questioned the motives of living anonymous donors. Non‐donors were commonly viewed negatively as self‐absorbed and unaware, with living‐related non‐donors particularly perceived as cold‐hearted and weak. Transplant recipients were generally viewed sympathetically (unfortunate and unwell); however, many participants also expressed negative views about transplant recipients as responsible for their predicament, depending upon the type of organ transplant needed. To encourage people's willingness to donate their organs, it is crucial to understand the extent to which these perceptions influence organ donation decisions. Copyright © 2008 John Wiley & Sons, Ltd.
Allosteric Regulation of Proteases
Authors: Hauske Patrick , Ottmann Christian , Meltzer Michael , Ehrmann Michael , Kaiser Markus
Published: November 2008

Allostery is a basic principle of control of enzymatic activities based on the interaction of a protein or small molecule at a site distinct from an enzyme's active center. Allosteric modulators represent an alternative approach to the design and synthesis of small‐molecule activators or inhibitors of proteases and are therefore of wide interest for medicinal chemistry. The structural bases of some proteinaceous and small‐molecule allosteric protease regulators have already been elucidated, indicating a general mechanism that might be exploitable for future rational design of small‐molecule effectors.
Iridium(III) Complexes with Sulfonyl and Fluorine Substituents: Synthesis, Stereochemistry and Effect of Functionalisation on their Photophysical Properties
Authors: Ragni Roberta , Orselli Enrico , Kottas Gregg S. , Omar Omar Hassan , Babudri Francesco , Pedone Adriana , Naso Francesco , Farinola Gianluca M. , De Cola Luisa
Published: November 2008

The synthesis and photophysical and electrochemical characterisation of new heteroleptic iridium complexes with electron‐withdrawing sulfonyl groups and fluorine atoms bound to phenylpyridine ligands are reported. The emission energy of these materials strongly depends on the position of the sulfonyl groups and on the number of fluorine substituents. A 90 nm wide tuning range of photoluminescence from the blue‐green (λem=468 nm) of iridium(III)bis[2‐(4′‐benzylsulfonyl)phenylpyridinato‐N,C2′][3‐(pentafluorophenyl)‐pyridin‐2‐yl‐1,2,4‐triazolate] to the orange (λem=558 nm) of iridium(III)bis[2‐(3′‐benzylsulfonyl)phenylpyridinato‐N,C2′](2,4‐decanedionate) has been achieved. Emission quantum yields ranging from 47 to 71 % have also been found for degassed solutions of the complexes, and a surprisingly high value of 16 % was recorded for iridium(III)bis[2‐(5′‐benzylsulfonyl‐3′,6′‐difluoro)phenylpyridinato‐N,C2′](2,4‐decanedionate) in air‐equilibrated dichloromethane. A unusual stereochemistry of the benzylsulfonyl‐substituted dimer and heteroleptic complexes has been detected by 1H NMR spectroscopy, and is characterised by the mutual cis disposition of the pyridyl nitrogen atoms of the phenylpyridine ligands, which differs from the most common trans arrangement reported in the literature.
A Synthetic, Structural, Spectroscopic and DFT study of ReI, CuI, RuII and IrIII Complexes Containing Functionalised Dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz)
Authors: Lundin Natasha J. , Walsh Penny J. , Howell Sarah L. , Blackman Allan G. , Gordon Keith C.
Published: November 2008

The ligands 11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine and 2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole have been coordinated to ReI, CuI, RuII and IrIII metal centres. Single‐crystal X‐ray analyses were performed on fac‐chlorotricarbonyl(11‐cyanodipyrido[3,2‐a:2′,3′‐c]phenazine)rhenium (C22H9ClN5O3Re, a=6.509(5), b=12.403(5), c=13.907(5) Å, α=96.88(5), β=92.41(5), γ=92.13(5)°, triclinic, P$\bar 1$, Z=2) and bis‐2,2′‐bipyridyl(2‐(11‐dipyrido[3,2‐a:2′,3′‐c]phenazine)‐5‐phenyl‐1,3,4‐oxadiazole)ruthenium triflate⋅2 CH3CN (C52H36F6N12O8RuS2, a=10.601(5), b=12.420(5), c=20.066(5) Å, α=92.846(5), β=96.493(5), γ=103.720(5)°, triclinic, P$\bar 1$, Z=2). The ground‐ and excited‐state properties of the ligands and complexes have been investigated with a range of techniques, including electrochemistry, absorption and emission spectroscopy, spectroelectrochemistry and excited‐state lifetime studies. Spectroscopic, time‐resolved and DFT studies reveal that the ligand‐centred (LC) transitions and their resultant excited states play an important role in the photophysical properties of the complexes. Evidence for the presence of lower‐lying metal‐to‐ligand charge‐transfer transitions is obtained from resonance Raman spectroscopy, but nanosecond transient Raman experiments suggest that once excited, the 3LC state is populated.
Stereoselective Alcohol Silylation by Dehydrogenative Si–O Coupling: Scope, Limitations, and Mechanism of the Cu–H‐Catalyzed Non‐Enzymatic Kinetic Resolution with Silicon‐Stereogenic Silanes
Authors: Rendler Sebastian , Plefka Oliver , Karatas Betül , Auer Gertrud , Fröhlich Roland , Mück‐Lichtenfeld Christian , Grimme Stefan , Oestreich Martin
Published: November 2008

Ligand‐stabilized copper(I)–hydride catalyzes the dehydrogenative Si–O coupling of alcohols and silanes—a process that was found to proceed without racemization at the silicon atom if asymmetrically substituted. The present investigation starts from this pivotal observation since silicon‐stereogenic silanes are thereby suitable for the reagent‐controlled kinetic resolution of racemic alcohols, in which asymmetry at the silicon atom enables discrimination of enantiomeric alcohols. In this full account, we summarize our efforts to systematically examine this unusual strategy of diastereoselective alcohol silylation. Ligand (sufficient reactivity with moderately electron‐rich monophosphines), silane (reasonable diastereocontrol with cyclic silanes having a distinct substitution pattern) as well as substrate identification (chelating donor as a requirement) are introductorily described. With these basic data at hand, the substrate scope was defined employing enantiomerically enriched tert‐butyl‐substituted 1‐silatetraline and highly reactive 1‐silaindane. The synthetic part is complemented by the determination of the stereochemical course at the silicon atom in the Si–O coupling step followed by its quantum‐chemical analysis thus providing a solid mechanistic picture of this remarkable transformation.
[IrCl2Cp*(NHC)] Complexes as Highly Versatile Efficient Catalysts for the Cross‐Coupling of Alcohols and Amines
Authors: Prades Amparo , Corberán Rosa , Poyatos Macarena , Peris Eduardo
Published: November 2008

A comparative study on the catalytic activity of a series of [IrCl2Cp*(NHC)] complexes in several C–O and C–N coupling processes implying hydrogen‐borrowing mechanisms has been performed. The compound [IrCl2Cp*(InBu)] (Cp*=pentamethyl cyclopentadiene; InBu=1,3‐di‐n‐butylimidazolylidene) showed to be highly effective in the cross‐coupling reactions of amines and alcohols, providing high yields in the production of unsymmetrical ethers and N‐alkylated amines. A remarkable feature is that the processes were carried out in the absence of base, phosphine, or any other external additive. A comparative study with other known catalysts, such as Shvo's catalyst, is also reported.
Highly Dispersed Ruthenium Hydroxide Supported on Titanium Oxide Effective for Liquid‐Phase Hydrogen‐Transfer Reactions
Authors: Yamaguchi Kazuya , Koike Takeshi , Kim Jung Won , Ogasawara Yoshiyuki , Mizuno Noritaka
Published: November 2008

Supported ruthenium hydroxide catalysts (Ru(OH)x/support) were prepared with three different TiO2 supports (anatase TiO2 (TiO2(A), BET surface area: 316 m2 g−1), anatase TiO2 (TiO2(B), 73 m2 g−1), and rutile TiO2 (TiO2(C), 3.2 m2 g−1)), as well as an Al2O3 support (160 m2 g−1). Characterizations with X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and X‐ray absorption fine structure (XAFS) showed the presence of monomeric ruthenium(III) hydroxide and polymeric ruthenium(III) hydroxide species. Judging from the coordination numbers of the nearest‐neighbor Ru atoms and the intensities of the ESR signals, the amount of monomeric hydroxide species increased in the order of Ru(OH)x<Ru(OH)x/TiO2(C)<Ru(OH)x/Al2O3<Ru(OH)x/TiO2(B)<Ru(OH)x/TiO2(A). These supported ruthenium hydroxide catalysts, especially Ru(OH)x/TiO2(A), showed high catalytic activities and selectivities for liquid‐phase hydrogen‐transfer reactions, such as racemization of chiral secondary alcohols and the reduction of carbonyl compounds and allylic alcohols. The catalytic activities of Ru(OH)x/TiO2(A) for these hydrogen‐transfer reactions were at least one order of magnitude higher than those of previously reported heterogeneous catalysts, such as Ru(OH)x/Al2O3. These catalyses were truly heterogeneous, and the catalysts recovered after the reactions could be reused several times without loss of catalytic performance. The reaction rates monotonically increased with an increase in the amount of monomeric ruthenium hydroxide species, which suggests that the monomeric species are effective for these hydrogen‐transfer reactions.
A novel ankyrin‐repeat protein interacts with the regulatory proteins of inner arm dynein f (I1) of Chlamydomonas reinhardtii
Authors: Ikeda Kazuho , Yamamoto Ryosuke , Wirschell Maureen , Yagi Toshiki , Bower Raqual , Porter Mary E. , Sale Winfield S. , Kamiya Ritsu
Published: November 2008

How ciliary and flagellar motility is regulated is a challenging problem. The flagellar movement in Chlamydomonas reinhardtii is in part regulated by phosphorylation of a 138 kD intermediate chain (IC138) of inner arm dynein f (also called I1). In the present study, we found that the axoneme of mutants lacking dynein f lacks a novel protein having ankyrin repeat motifs, registered as FAP120 in the flagellar proteome database. FAP120 is also missing or decreased in the axonemes of bop5, a mutant that has a mutation in the structural gene of IC138 but assembles the dynein f complex. Intriguingly, the amounts of FAP120 in the axonemes of different alleles of bop5 and several dynein f‐lacking mutants roughly parallel their contents of IC138. These results suggest a weak but stoichiometric interaction between FAP120 and IC138. We propose that FAP120 functions in the regulatoryprocess as part of a protein complex involving IC138. Cell Motil. Cytoskeleton 2008. © 2008 Wiley‐Liss, Inc.
Peptides and Peptide Mimics as Modulators of Apoptotic Pathways
Authors: Orzáez Mar , Gortat Anna , Mondragón Laura , Pérez‐Payá Enrique
Published: November 2008

Cells in the balance: Programmed cell death is an important and stringently controlled process. Aberrancies in its control mechanisms can lead to disease; overactive apoptosis can cause neurodegenerative disorders, whereas deficient apoptotic activity can lead to cancer. Therefore, controlling apoptotic pathways with peptides is showing increasing promise as a strategy in drug development.

magnified image

Programmed cell death or apoptosis is a noninvasive and strictly regulated cellular process required for organism development and tissue homeostasis. Deficiencies in apoptotic pathways are the source of many diseases such as cancer, neurodegenerative and autoimmune diseases, and disorders related to an inappropriate loss of cells such as heart failure, stroke, and liver injury. Validation of the various points of intervention as targets for drug development has been the subject of a vast number of studies. Peptides are essential tools for drug discovery, as well as preclinical and pharmaceutical drug development.
Asymmetric Synthesis and Biological Evaluation of Glycosidic Prodrugs for a Selective Cancer Therapy
Authors: Tietze Lutz F. , von Hof J. Marian , Krewer Birgit , Müller Michael , Major Felix , Schuster Heiko J. , Schuberth Ingrid , Alves Frauke
Published: November 2008

A severe limitation in cancer therapy is the often insufficient differentiation between malign and benign tissue using known chemotherapeutics. One approach to decrease side effects is antibody‐directed enzyme prodrug therapy (ADEPT). We have developed new glycosidic prodrugs such as (−)‐(1S)‐26 b based on the antibiotic (+)‐duocarmycin SA ((+)‐1) with a QIC50 value of 3500 (QIC50=IC50 of prodrug/IC50 of prodrug+enzyme) and an IC50 value for the corresponding drug (prodrug+enzyme) of 16 pM. The asymmetric synthesis of the precursor (−)‐(1S)‐19 was performed by arylation of the enantiomerically pure epoxide (+)‐(S)‐29 (≥98 % ee).
Photocatalytic Oxidation of CO on TiO2: Chemisorption of O2, CO, and H2
Authors: Dai Wenxin , Chen Xun , Zheng Xiangping , Ding Zhengxin , Wang Xuxu , Liu Ping , Fu Xianzhi
Published: November 2008

On the surface: Adsorption of O2 at the surface oxygen vacancy (SOV) sites of TiO2 reconstructs the lattice oxygen (healing SOVs), resulting in a decrease of the photocatalytic activity of oxidizing CO over vacuum‐pretreated TiO2 with increasing temperature (see scheme). Adsorption of H2 produces new SOVs at the TiO2 surface and stabilizes the photocatalytic activity.

magnified image

Photocatalytic oxidation of CO over vacuum‐pretreated TiO2 is performed in a series of systems with the introduction of O2, CO, and H2 in different orders. The photocatalytic oxidation of CO is dependent on the order of introduction of O2, CO, or H2, and introducing O2 prior to CO promotes the oxidation of CO. Moreover, an increase of reaction temperature suppresses the oxidation of CO, but the preintroduction of H2 reduces this suppression effect. The results of the chemisorption of O2, CO, and H2 at the TiO2 surface reveal that the adsorbed O2 heals the surface oxygen vacancy (SOV) sites of TiO2, while the adsorbed CO and H2 promote the formation of new SOVs. It is proposed that changes in the amounts of adsorbed O2 and SOVs are mainly responsible for the differences of CO conversion in different systems.
Secure fast WLAN handoff using time‐bound delegated authentication
Authors: Chien Hung‐Yu , Hsu Tzu‐Hang
Published: November 2008

To support multimedia applications with good quality of services for roaming wireless local area network users, it is imperative to reduce the long re‐authentication latency that users experience during handoff among access points (APs). Athough a great deal of research resources have been put into the reduction of the re‐authentication latency, these schemes developed so far seem to either suffer from heavy overhead problems or have weak security. In this paper, we propose a novel approach to reducing the re‐authentication latency. With the authentication server (AS) periodically delegating its authentication authority to the authenticated APs, the APs can authenticate the roaming users on behalf of the AS. As our performance analysis and simulation results demonstrate, our new approach is capable of greatly reducing the latency and overhead while achieving a high security level. Furthermore, it does not increase the complexity on the AP side because only the already existing four‐way handshake with new keying mechanism is required. Copyright © 2008 John Wiley & Sons, Ltd.
Low‐grade fibromyxoid sarcoma versus fibromatosis: A comparative study of clinicopathological and immunohistochemical features
Authors: Meng Guo‐Zhao , Zhang Hong‐Ying , Bu Hong , Geng Jian‐Guo
Published: November 2008

We have studied 11 cases of low‐grade fibromyxoid sarcoma (LGFMS) and 15 cases of fibromatosis with respect to clinicopathological features and immunohistochemical expression of Ki‐67, nm23, cyclinD1, and p53, in order to investigate the differential diagnosis between this two groups. Formalin‐fixed, paraffin‐embedded sections from 11 cases of LGFMS and 15 cases of fibromatosis were studied histologically and immunohistochemically. The immunostainings were semiquantitatively evaluated using the Allred score system. Microscopically, LGFMS was composed of bland spindle cells arranged in a whorled pattern showing alternating myxoid zones and fibrous stroma zones with prominent arcade curvilinear capillaries. Cytological atypia, mitotic figures, and tumor necrosis were absent in all 11 cases of LGFMS. In contrast, fibromatosis was less cellular and more fascicular, containing more collagen and showing no alternating fibrous and myxoid zones as compared with LGFMS. The immunostaining scores of nm23 in LGFMS were significantly lower than that in fibromatosis. The immunostaining scores of Ki‐67, p53, and cyclinD1 in LGFMS were significantly higher than that in fibromatosis. Thus, we consider that LGFMS can be distinguished from fibromatosis by clinicopathological features, and assessments of the immunohistochemical expression level of cyclinD1, p53, nm23, and Ki‐67 are helpful in the differential diagnosis. Diagn. Cytopathol. 2009. © 2008 Wiley‐Liss, Inc.
Alveolar soft part sarcoma presenting as a breast mass in a 13‐year‐old female
Authors: Van Buren Regina , Stewart Jimmie
Published: November 2008

Adolescent patients with breast lesions represent a unique population of patients whose differential diagnoses differ from adults. We report a clinically unsuspected case of alveolar soft part sarcoma (ASPS) presenting in the breast of a 13‐year‐old female. ASPS is a rare neoplasm that is usually present in the head, neck, or lower extremities. This rare case presentation gives us the opportunity to review the differential diagnosis of adolescent breast lesions. We also will review diagnostic features of ASPS on fine‐needle aspiration. These are relatively rare disease processes about which many cytopathology professionals may be unfamiliar. Diagn. Cytopathol. 2009. © 2008 Wiley‐Liss, Inc.
Low‐grade papillary cystadenocarcinoma of the parotid gland: Presentation of a case with cytological, histopathological, and immunohistochemical features and pertinent literature review
Authors: Aloudah Noura M. , Raddaoui Emad , Aldhahri Saleh , Al‐Abbadi Mousa A.
Published: November 2008

Cystadenocarcinoma of the salivary glands is a very rare, slow growing, low‐grade malignant neoplasm. However, when it occurs, it poses a diagnostic challenge. They are usually well circumscribed and exhibit multicystic appearance. The cytological features of fine‐needle aspirates show bland appearing papillary and micropapillary neoplasm with variable cellularity and absence of cytological atypia. The cells are small to medium in size with abundant and occasionally vacuolated cytoplasm. The nuclei are eccentric, bland appearing, round, and at the most part uniform in size without anaplasia or mitotic activity. The background is commonly mucoid. Histologically, the neoplasm is usually well circumscribed and contains variably sized multicystic spaces with papillary structures. Foci of definite stromal invasion by tumor cells have to be present to justify the diagnosis of carcinoma. The remainders of the cytological features are similar to these seen on cytological smears. Typically, they are slow growing and conservative, but complete surgical excision is considered adequate. We present a case in a 57‐year‐old Saudi man that we believe the first from our region demonstrating the clinical and pathological features. Diagn. Cytopathol. 2009. © 2008 Wiley‐Liss, Inc.
Intermediate‐grade squamous intraepithelial lesion may be a valid diagnostic/interpretive category
Authors: Ravinsky Esther , Baker Patricia
Published: November 2008

We undertook this study to assess the characteristics of smears with features intermediate between high‐grade squamous intraepithelial lesion (HSIL) and low‐grade squamous intraepithelial lesion (ISIL). We also wanted to determine how these smears correlate with high risk biopsy diagnosis and to compare this with the biopsy correlation of LSIL and HSIL.

Seventy‐four squamous intraepithelial lesion (SIL) smears were identified as intermediate‐grade SIL smears taken at colposcopy in a 1 year period. They were correlated with concurrent colposcopically guided biopsies.

Thirty‐five percent of cases with intermediate‐grade SIL smears had a biopsy diagnosis of moderate dysplasia or higher as compared with 12% for LSIL 74% for HSIL.

This confirmed our hypothesis that intermediate‐grade SIL smears have a rate of biopsy diagnosis of moderate dysplasia or higher intermediate to that of LSIL and HSIL. Diagn. Cytopathol. 2009. © 2008 Wiley‐Liss, Inc.
Greater intrasex phenotype variability in males than in females is a fundamental aspect of the gender differences in humans
Authors: Lehre Anne‐Catherine , Lehre Knut P. , Laake Petter , Danbolt Niels C.
Published: November 2008

Human studies of intrasex variability have shown that males are intellectually more variable. Here we have performed retrospective statistical analysis of human intrasex variability in several different properties and performances that are unrelated or indirectly related to intelligence: (a) birth weights of nearly 48,000 babies (Medical Birth Registry of Norway); (b) adult weight, height, body mass index and blood parameters of more than 2,700 adults aged 18–90 (NORIP); (c) physical performance in the 60 meter dash event of 575 junior high school students; and (d) psychological performance reflected by the results of more than 222,000 undergraduate university examination grades (LIST). For all characteristics, the data were analyzed using cumulative distribution functions and the resultant intrasex variability for males was compared with that for females. The principal finding is that human intrasex variability is significantly higher in males, and consequently constitutes a fundamental sex difference. © 2008 Wiley Periodicals, Inc. Dev Psychobiol 51: 198–206, 2009
Preparation of Bis(m‐phenylene)‐32‐crown‐10‐Based Cryptand/Bisparaquat [3]Rotaxanes with High Efficiency
Authors: Li Shijun , Liu Ming , Zhang Jinqiang , Zheng Bo , Wen Xianhong , Li Ning , Huang Feihe
Published: November 2008

Two [3]rotaxanes were synthesized from two bis(m‐phenylene)‐32‐crown‐10‐based cryptands and a bisparaquat derivative by using a threading‐followed‐by‐stoppering method. As a result of strong association and positive cooperative complexation between the cryptands and the bisparaquat derivative, high yields and high selectivities were achieved. No [2]rotaxanes were found during the preparation.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)