bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemoselective Reduction of α,β-Unsaturated Aldehydes, Ketones, Carboxylic Acids, and Esters with Nickel Boride in Methanol–Water
Authors: Khurana Jitender Mohan , Sharma Purnima
Published: March 2004

A facile procedure for the conjugate reduction of α,β-unsaturated aldehydes, ketones, carboxylic acids, and esters is reported with nickel boride generated in situ from NiCl2·6H2O/NaBH4 in methanol–water at ambient temperature.
An Efficient Synthesis of 2,4-Disubstituted Quinolines by Electrophile-Mediated Cyclization Reactions of 2-Isocyanostyrene Derivatives
Authors: Kobayashi Kazuhiro , Takagoshi Kenichi , Kondo Shizuka , Morikawa Osamu , Konishi Hisatoshi
Published: March 2004

A novel quinoline synthesis starting with 2-isocyanostyrene derivatives is described. The treatment of 2-isocyanostyrene derivatives with aldehydes (or acetone) in the presence of a catalytic amount of diethyl ether–boron trifluoride afforded quinoline derivatives carrying a 1-hydroxyalkyl substituent at the 2-position. The use of acetaldehyde diethyl acetal or phenyloxirane as an electrophile under the same conditions gave the corresponding quinoline derivatives, carrying the 1-ethoxyethyl or 2-hydroxy-2-phenylethyl substituent at the 2-position, respectively. 2-Isocyanostyrene derivatives reacted with N,N-dimethyliminium salts without any catalyst to give 2-(1-dimethylaminoalkyl)quinolines.
Chiral 2,2′-Binaphthyldiimine–Nickel(II) Complexes as Lewis Acid Catalysts for Enantioselective Diels–Alder Reactions
Authors: Suga Hiroyuki , Kakehi Akikazu , Mitsuda Masashi
Published: March 2004

The preparation and application of a novel class of chiral Lewis acid catalysts based on chiral 2,2′-binaphthyldiimine ligands are described. Among the binaphthyldiimine–metal complexes tested, N,N′-bis(2-quinolylmethylene)-1,1′-binaphthyl-2,2′-diamine–Ni(II) complex was found to be an efficient chiral Lewis acid catalyst for asymmetric Diels–Alder reactions (endo: up to 96% ee) between cyclopentadiene and 3-alkenoyl-2-oxazolidinones. This catalyst is easy to prepare and is efficient; that is, 1 mol% of the Ni(II) catalyst promoted a Diels–Alder reaction between cyclopentadiene and 3-acryloyl-2-oxazolidinone smoothly with high enantioselectivity (endo: 90% ee).
Flavin Receptors. Effects of Melamine Derivatives Bearing Thiourea and Thiouronium Ion on the Binding and Reactivity of Flavin Mimics in Chloroform
Authors: Watanabe Shigeki , Kosaka Naoki , Kondo Shin-ichi , Yano Yumihiko
Published: March 2004

Melamine derivatives bearing thiourea and thiouronium ion were prepared as flavin receptors. The binding modes of the receptors for flavin mimics were evaluated from the binding constants and 1H NMR data in chloroform. The effects of the receptors on the oxidation of N-benzyl-1,4-dihydronicotinamide (BNAH) and benzenethiol by flavin mimics were kinetically investigated in chloroform.
Radical Cyclization of O-Pentafluorobenzoyloximes Having a (Cyclohexadiene)Fe(CO)3 Moiety
Authors: Tanaka Kenichi , Yukimura Noriaki , Narasaka Koichi
Published: March 2004

In the presence of atmospheric oxygen, O-pentafluorobenzoyloximes having a (2,4-cyclohexadienyl)Fe(CO)3 moiety at the α-position cyclize smoothly to give trans-fused [(4,5,6,7-η)-3a,7a-dihydro-3H-indole]Fe(CO)3 complexes. The cyclization proceeds via radical chain mechanism initiated by molecular oxygen, in which pentafluorobenzoyloxyl radical plays a role as a chain carrier. Thus obtained trans-fused dihydroindole iron complexes readily isomerize to the cis-fused isomers on acidic silica gel or under basic conditions. Such isomers are converted to 3a,7a-dihydroindole or indole derivatives by the oxidative removal of the Fe(CO)3 group.
Silica-Based Mesostructured Materials Induced by Surfactant Assemblies in the Two-Dimensionally Limited Space of a Layered Polysilicate Kanemite
Authors: Kimura Tatsuo , Itoh Daigo , Shigeno Tetsuro , Kuroda Kazuyuki
Published: March 2004

Silica-based mesostructured materials derived from a layered polysilicate kanemite were prepared by reactions with gemini-type diammonium (C16–3–16, C16–5–16, C16–3–1) surfactants. The surfactants were assembled in the two-dimensionally limited space between the silicate layers of kanemite, leading to the formation of lamellar, 2-d hexagonal, and disordered mesophases. Lamellar phases were formed by using C16–3–16 and C16–5–16 surfactants. An acid treatment of the lamellar C16–5–16–silicate complex induced the transformation into a 2-d hexagonal phase, whereas the C16–3–16–silicate complex retained its lamellar structure after the treatment. A disordered phase was obtained through the reaction of kanemite with C16–3–1 surfactants whose assembly shows a larger surface curvature. The formation of layered surfactant–silicate intermediates under various conditions and the transformation to other mesophases lead to the conclusion that the formation of ordered and disordered mesostructured materials derived from kanemite simply depends on the surfactant assemblies in the two-dimensionally limited space.
Thermal Dehydration of a Poly(vinyl alcohol) Film Promoted by Diphenyliodonium Trifluoromethanesulfonate: Absorption Spectra and Elemental Analysis Results
Authors: Yamamoto Yukio , Tagawa Seiichi
Published: March 2004

The thermal dehydration of poly(vinyl alcohol) (PVA) films containing diphenyliodonium trifluoromethanesulfonate (Ph2I+Tf−) was investigated in the temperature range of 150 to 190 °C by absorption spectroscopy and elemental analysis. The dehydration was greatly promoted in the presence of Ph2I+Tf−, which is known to be a thermally stable photoacid generator. The oxidation of thermally generated PVA radicals, α-hydroxyalkyl type radicals, by Ph2I+Tf− is considered to lead to the dehydration by cationic reactions. The dehydration yield, calculated from the elemental analysis results, became highest at 170 °C. A lowering of the dehydration yields at the higher temperatures, 180 and 190 °C, has been attributed to an elimination of the volatile H+Tf− from the films, resulting in the disappearance of the cationic intermediates participating in the dehydration.
Comparison of UV–Vis Changes Observed in Deprotonation of 2-Heptylbenzimidazole, 2-Heptyl-4,7-diphenylbenzimidazole, and Poly(2-heptylbenzimidazole-4,7-diyl)
Authors: Tanimoto Akitoshi , Shiraishi Kouichi , Yamamoto Takakazu
Published: March 2004

Shifts of the UV–vis peak caused by deprotonation of 2-heptylbenzimidazole and sterically strained 2-heptyl-4,7-diphenyl-benzimidazole and poly(2-heptylbenzimidazole-4,7-diyl) (P[4,7-Bim(Hep)]) are discussed. The π–π* absorption band of the strained molecules showed a large shift to a longer wavelength on deprotonation with NaOH. P[4,7-Bim(Hep)] showed a new absorption peak at about 400 nm.
The fate of augments to treat type-2 bone defects in revision knee arthroplasty
Authors: Patel J. V. , Masonis J. L. , Guerin J. , Bourne R. B. , Rorabeck C. H.
Published: March 2004

We report the five- to-ten year results of Anderson Orthopaedic Research Institute type-2 bone defects treated with modular metal augments in revision knee surgery.

A total of 102 revision knee arthroplasties in patients with type-2 defects treated with augments and stems were prospectively studied. Seven patients (seven knees) had incomplete follow-up and 15 patients (16 knees) died with the arthroplasty in situ. The mean follow-up of the 79 remaining knees was 7 ± 2 years (5 to 11). The presence of non-progressive radiolucent lines around the augment in 14% of knees was not associated with poorer knee scores, the range of movement, survival of the component or the type of insert which was used (p > 0.05). The survival of the components was 92 ± 0.03% at 11 years (95% CI, 10.3 to 11.2).

We recommend the use of modular augmentation devices to treat type-2 defects in revision knee surgery.
The management of chronic osteomyelitis using the Lautenbach method
Authors: Hashmi M. A. , Norman P. , Saleh M.
Published: March 2004

We describe our medium-term results for the management of chronic osteomyelitis in long bones using the Lautenbach procedure. Seventeen consecutive patients (18 segments) were treated prospectively. Osteomyelitis had been present for a mean of 12.5 years (1 to 31). A discharging sinus was present in all cases. Nine of the associated fractures had failed to unite and a further two needed correction of malunion. The Lautenbach procedure involves debridement, intramedullary reaming and the insertion of double-lumen tubes to establish both a local antibiotic delivery system and cavity analysis for volume and culture. The end-point of treatment is when the irrigate produces three consecutive clear cultures with improvement in the blood indices and obliteration of the cavity volume.

The mean length of treatment was 27 days (14 to 48). One patient required a second procedure and another local debridement for recurrence of the infection. Two patients had Papineau grafting because of cortical defects. All the patients have subsequently remained free from infection. After treatment 11 had internal or external fixation for treatment of non- or malunion or a joint replacement, including two successful limb-lengthening procedures. Two further patients, while cured of infection, underwent amputation for other reasons. The mean length of follow-up was 75 months.

This procedure allows precise control over the osteomyelitis until objective assessment suggests that infection has been cleared and the cavity obliterated.

We recommend this procedure for long-standing complex cases in which basic techniques using debridement and antibiotics have failed.
Hybrid alumina total hip arthroplasty using a press-fit metal-backed socket in patients younger than 55 years
Authors: Bizot P. , Hannouche D. , Nizard R. , Witvoet J. , Sedel L.
Published: March 2004

Between 1990 and 1992, we implanted 71 hybrid alumina-on-alumina hip arthroplasties in 62 consecutive patients under the age of 55 years, with a mean age of 46 years at surgery. There were 56 primary and 15 secondary procedures. The prostheses involved a cemented titanium alloy stem, a 32 mm alumina head, and a press-fit metal-backed socket with an alumina insert. Three patients (four hips) died from unrelated causes. Four hips had revision surgery for either deep infection, unexplained persistent pain, fracture of the alumina head, or aseptic loosening of the socket. The nine-year survival rate was 93.7% with revision for any cause as the end-point and 98.4% with revision for aseptic loosening as the end-point.

The outcome in the surviving patients (50 patients, 57 hips) with a minimum five-year follow-up (mean eight years) was excellent in 47 hips (82.5%), very good in eight (14%), good in one and fair in one. A thin, partial, lucent line, mainly in zone III was present in 38% of the sockets and one socket had a complete lucency less than 1 mm thick. One stem had isolated femoral osteolysis. There was no detectable component migration nor acetabular osteolysis.

This hybrid arthroplasty gave satisfactory medium-term results in active patients. The press-fit metal-backed socket appeared to have reliable fixation in alumina-on-alumina hip arthroplasty. The excellent results using cemented fixation of the stem may be related to the low production of wear debris.
AIDS-related ankle arthropathy: mycobacterium avium-intracellulare infection
Authors: Redfern D. J. , Coleridge S. D. , Bendall S. P.
Published: March 2004

We present a case of Mycobacterium avium-intracellulare (MAI) infection of the ankle joint in a patient with HIV infection. The patient presented with a painful, destructive arthropathy of the ankle. Initial microbiological studies were negative but infection with MAI was later identified from biopsies taken during hindfoot fusion. Antibiotic triple therapy was given and the patient remains pain-free without evidence of active infection. To our knowledge, this is the first case of MAI infection of the ankle reported in the literature. A high index of suspicion of (atypical) Mycobacterial infection should be maintained in patients with HIV infection presenting with an indolent but destructive arthropathy of the ankle joint.
Dhaga syndrome: a previously undescribed entity
Authors: Arora A. , Agarwal A.
Published: March 2004

Three children between the ages of 18 months and four years presented with a discharging sinus or sinuses at the wrist due to a ‘sacred’ thread (the Moli Dhaga) which had been tied around it. This thread had been forgotten by the parents and had become embedded in the soft tissues of the wrist. Plain radiographs showed a circumferential constriction in the soft tissue shadow in all three. In two, there was a periosteal reaction in the distal radius or ulna with an indentation which we have called the constriction sign. Surgical removal of the buried thread was successful in all cases.
Reoperation after autologous chondrocyte implantation
Authors: Henderson I. , Tuy B. , Oakes B.
Published: March 2004

We have reviewed 22 patients from a total of 135 treated by autologous chondrocyte implantation (ACI) who had undergone further surgery for pain in the knee and mechanical symptoms after a mean of 10.5 months. There were 31 grafted lesions. At operation the findings included lifting (24/31) and detachment (3/31) of periosteal patches for which arthroscopic shaving was performed. Chondroplasty was undertaken on two new lesions, another required an ACI and a further patient required trimming of a meniscus.

The mechanical symptoms resolved within two weeks. At the last review, two to 14 months from reoperation; 68% had improved, and 86% had normal or nearly normal IKDC scores. Of the 31 lesions, 30 (97%) had normal or nearly normal visual repair scores.

Biopsy showed good integration with subchondral bone and the marginal interface in all specimens, most of which showed hyaline or hyaline-like cartilage (70%). Troublesome mechanical symptoms required surgery in 13% of ACI-treated patients and were attributed to periosteal extrusion. Simple arthroscopic debridement was curative.
Preservation of the bone mineral density of the femur after surface replacement of the hip
Authors: Kishida Y. , Sugano N. , Nishii T. , Miki H. , Yamaguchi K. , Yoshikawa H.
Published: March 2004

We investigated the effect of the Birmingham hip resurfacing (BHR) arthroplasty on the bone mineral density (BMD) of the femur. A comparative study was carried out on 26 hips in 25 patients. Group A consisted of 13 patients (13 hips) who had undergone resurfacing hip arthroplasty with the BHR system and group B of 12 patients (13 hips) who had had cementless total hip arthroplasty with a proximal circumferential plasma-spray titanium-coated anatomic Ti6A14V stem. Patients were matched for gender, state of disease and age at the time of surgery. The periprosthetic BMD of the femur was measured using dual-energy x-ray absorptiomentry of the Gruen zones at two years in patients in groups A and B.

The median values of the BMD in zones 1 and 7 were 99% and 111%, respectively. The post-operative loss of the BMD in the proximal femur was significantly greater in group B than in group A. These findings show that the BHR system preserves the bone stock of the proximal femur after surgery.
Union of defects in the pars interarticularis of the lumbar spine in children and adolescents
Authors: Fujii K. , Katoh S. , Sairyo K. , Ikata T. , Yasui N.
Published: March 2004

Lumbar spondylolysis can heal with conservative treatment, but few attempts have been made to identify factors which may affect union of the defects in the pars. We have evaluated, retrospectively, the effects of prognostic variables on bony union of pars defects in 134 young patients less than 18 years of age with 239 defects of the pars who had been treated conservatively. All patients were evaluated by CT scans when first seen and more than six months later at follow-up.

The results showed that the spinal level and the stage of the defects were the predominant factors. The site of the defects in the pars, the presence or development of spondylolisthesis, the condition of the contralateral pars, the degree of lumbar lordosis and the degree of lumbar inclination all significantly affected union.
Giant-cell tumour of bone
Authors: Zhen W. , Yaotian H. , Songjian L. , Ge L. , Qingliang W.
Published: March 2004

Giant-cell tumour of bone (GCT) is a locally benign aggressive tumour. The use of adjuvant agents, such as phenol or liquid nitrogen has been recommended to destroy the remaining tumour cells after curettage, and filling of the defect with methylmethacrylate cement has been advocated. Between 1957 and 1992 we treated 92 patients with a GCT with 50% aqueous zinc chloride solution and bone grafting. Their mean age at the time of surgery was 31 years (15 to 59) and the mean follow-up was 11 years (5 to 31).

Twelve (13%) had a local recurrence and one had a wound infection. Two developed degenerative changes around the knee. Eighty-six (93%) achieved good or excellent function. Three had moderate function, and three needed amputation. Our findings indicate that treatment with an aqueous solution of zinc chloride and reconstructive bone grafting after curettage gives good results.
Metal-on-metal resurfacing of the hip in patients under the age of 55 years with osteoarthritis
Authors: Daniel J. , Pynsent P. B. , McMinn D. J. W.
Published: March 2004

The results of conventional hip replacement in young patients with osteoarthritis have not been encouraging even with improvements in the techniques of fixation and in the bearing surfaces. Modern metal-on-metal hip resurfacing was introduced as a less invasive method of joint reconstruction for this particular group.

This is a series of 446 hip resurfacings (384 patients) performed by one of the authors (DJWM) using cemented femoral components and hydroxyapatite-coated uncemented acetabular components with a maximum follow-up of 8.2 years (mean 3.3). Their survival rate, Oxford hip scores and activity levels are reviewed.

Six patients died due to unrelated causes. There was one revision (0.02%) out of 440 hips. The mean Oxford score of the surviving 439 hips is 13.5. None of the patients were told to change their activities at work or leisure; 31% of the men with unilateral resurfacings and 28% with bilateral resurfacings were involved in jobs that they considered heavy or moderately heavy; 92% of men with unilateral hip resurfacings and 87% of the whole group participate in leisure-time sporting activity.

The extremely low rate of failure in spite of the resumption of high level occupational and leisure activities provides early evidence of the suitability of this procedure for young and active patients with arthritis.
Conflicting values in contemporary Galicia
Authors: O’Rourke Bernadette
Published: March 2004

This article analyses and attempts to explain conflicting views about the value associated with Galician in contemporary Galicia. It does so by tracing the possible source of these conflicting values historically, from the effects of language contact with Spanish since the fourteenth
century, right through to attempts made to revive Galician in the late nineteenth century to the current sociolinguistic situation in the context of the twenty-first century. It explores the reasons why the number of Galician speakers continues to decline despite the seemingly more favourable
attitudes towards the language amongst the Galician population.
The transition(s) to democracy and discourses of memory
Authors: Solís Fernando León
Published: March 2004

This article examines the tension between two competing interpretations of the transition to democracy in the Spanish State. It will investigate the strategies used by the ‘official’ discourse, as expressed in El País, aiming to achieve a closure with the past
along the lines of an epic, and thus to legitimize the present status quo. It will also look into the ‘divergent’ interpretation of the Catalan daily Avui for which there are two different transitions to democracy: the one already completed by Catalonia even before the death of
Franco and the other carried out by the rest of Spain, which has not been completed as yet. Through its use of a ‘reality’ discourse Avui aims at (1) downplaying the ‘mythical’ passage to democracy of the official discourse; and (2) reinforcing the Catalan ‘historical
memory’ which demands a recognition of the role of Catalans in the process of democratization in Spain and their long-standing democratic credentials which other Spaniards are constructed as still lacking.
Fighting fascism
Authors: Goppel Anna
Published: March 2004

This article analyses German and Austrian women’s involvement in the Spanish Civil War. It discusses what motivated their decision to go to Spain, analyses their social and political background and examines their journey, arrival and involvement in Spain. Not only the nature of
the women’s involvement in Spain is of interest, but also the questions of how many supported the Republic, when they began to be involved, where they came from, and how they got to Spain.
Customer Portfolio Management: Toward a Dynamic Theory of Exchange Relationships
Authors: Johnson Michael D. , Selnes Fred
Published: March 2004

Management of an entire portfolio of customers who are at different relationship stages requires a dynamic theory of exchange relationships that captures the trade-offs between scale economies and lifetime customer value. This article contributes to the understanding of relationship management by developing a typology of exchange relationship mechanisms and a model of relationship dynamics and by simulating the model to provide guidelines for customer portfolio management. An important insight from the research is that a key to the creation of value through closer relationships lies in bringing weaker relationships into a portfolio in the first place. Another insight is that firms that position themselves toward offerings with low economies of scale, such as personal services, must build closer relationships to create value.
When is a Preannounced New Product Likely to be Delayed?
Authors: Wu Yuhong , Balasubramanian Sridhar , Mahajan Vijay
Published: March 2004

Consider that a firm announces a deadline for a new product introduction. Conditional on such a preannouncement, how must an external observer evaluate whether the product will be delayed beyond that deadline? Using data collected from managers in the computer hardware, software, and telecommunications industries, the authors present an analysis that demonstrates that delays in new product introductions beyond preannounced deadlines can be jointly explained by factors related to (1) the firm's motivations to delay the product, (2) the presence of constraints that prevent delay (or the availability of opportunities to delay the product), and (3) the firm's abilities pertaining to product development.
Market Orientation, Creativity, and New Product Performance in High-Technology Firms
Authors: Im Subin , Workman John P.
Published: March 2004

The ability to generate and market creative ideas in new products (NPs) and related marketing programs (MPs) in response to changing market needs is key to the success of a firm. This research examines the mediating role of NP and MP creativity between market orientation and NP success. The authors investigate (1) whether market orientation facilitates or inhibits creativity, (2) whether creativity influences NP performance, and (3) how to define and measure creativity in the NP development and launch contexts. They use a two-stage sampling frame to collect 312 sets of responses from managers and NP team leaders and thereby address the potential for common method bias in measures of creativity and NP performance. The findings indicate that NP and MP creativity mediates the relationship between market orientation and NP success. The authors also show that the meaningfulness dimension, rather than the novelty dimension, of creativity is of greater importance in explaining the link between market orientation and NP success. The empirical results provide significant theoretical and managerial implications for NP strategy.
Antecedents and Consequences of the Service Climate in Boundary-Spanning Self-Managing Service Teams
Authors: De Jong Ad , De Ruyter Ko , Lemmink Jos
Published: March 2004

In this article, the authors examine antecedents and consequences of the service climate in boundary-spanning self-managing teams (SMTs) that deliver financial services. Using data from members of 61 SMTs and their customers, the authors show a differential impact of the SMT service climate on various marketing performance measures. Furthermore, they obtain support for independent group-level effects of intrateam support and team member flexibility on employee perceptions of the SMT service climate. Both effects are persistent over time and demonstrate that collective perceptions in the SMT have incremental value in the explanation of the service climate.
Attention Capture and Transfer in Advertising: Brand, Pictorial, and Text-Size Effects
Authors: Pieters Rik , Wedel Michel
Published: March 2004

The three key ad elements (brand, pictorial, and text) each have unique superiority effects on attention to advertisements, which are on par with many commonly held ideas in marketing practice. This is the main conclusion of an analysis of 1363 print advertisements tested with infrared eye-tracking methodology on more than 3600 consumers. The pictorial is superior in capturing attention, independent of its size. The text element best captures attention in direct proportion to its surface size. The brand element most effectively transfers attention to the other elements. Only increments in the text element's surface size produce a net gain in attention to the advertisement as a whole. The authors discuss how their findings can be used to render more effective decisions in advertising.
The Roles of Channel-Category Associations and Geodemographics in Channel Patronage
Authors: Inman J. Jeffrey , Shankar Venkatesh , Ferraro Rosellina
Published: March 2004

Consumers purchase goods from various channels or retail formats, such as grocery stores, drugstores, mass merchandisers, club stores, and convenience stores. To identify the most appropriate channels and to allocate the distribution of products among channels efficiently, managers need a better understanding of consumer behavior with respect to these channels. The authors examine the moderating role of channel-category associations in consumer channel patronage by extending the literature on brand associations to the context of channels, and they estimate a model that links channel-category associations with consumer geodemographics and channel share of volume. The authors first identify the product categories associated with particular channels through a correspondence analysis of a field-intercept survey. They then use the channel-category associations and geodemographic factors to estimate their direct and interactive effects on channel share of volume. The channel-category associations have significant main effects and interaction effects with channel type and geodemographic factors on channel share of volume, and they account for the majority of the explained variance (72%) in channel share of volume. Overall, the findings provide several conceptual and managerial insights into consumer channel perceptions and patronage behavior.
“Listening In” to Find and Explore New Combinations of Customer Needs
Authors: Urban Glen L. , Hauser John R.
Published: March 2004

By “listening in” to ongoing dialogues between customers and Web-based virtual advisers (e.g., Kelley Blue Book's Auto Choice Advisor), the authors identify new product opportunities based on new combinations of customer needs. The data are available at little incremental cost and provide the scale necessary for complex products (e.g., 148 trucks and 129 customer needs in the authors’ application). The authors describe and evaluate the methodologies with formal analysis, Monte Carlo simulation (calibrated on real data), and a “proof-of-concept” application in the pickup-truck category (more than 1000 Web-based respondents). The application identified opportunities for new truck platforms worth approximately $2.4 billion–$3.2 billion and $1 billion–$2 billion, respectively.
Portfolios of Interfirm Agreements in Technology-Intensive Markets: Consequences for Innovation and Profitability
Authors: Wuyts Stefan , Dutta Shantanu , Stremersch Stefan
Published: March 2004

Despite the high relevance of firms’ portfolios of upstream interfirm agreements in technology-intensive markets, little is known about their impact on innovative success. The authors develop a conceptual framework that explains the consequences of different portfolio descriptors for radical innovation, incremental innovation, and profitability. An empirical test in the pharmaceutical industry shows strong support for the developed theory.
Further Suicidal Behavior Among Medically Serious Suicide Attempters
Authors: Beautrais Annette L.
Published: March 2004

Analysis of rates of further suicidal behavior among individuals making medically serious suicide attempts may help to predict suicide and suicide attempt from baseline characteristics of the individual and the index suicide attempt. Data are drawn from a 5‐year study of 302 individuals making medically serious suicide attempts with information collected by personal interview at baseline, 6, 18, 30, and 60 months after the index attempt. Within 5 years, 6.7% died by suicide; 37% made at least one nonfatal suicide attempt. Although baseline characteristics permitted a modest prediction of suicide attempt, only a very limited prediction of suicide was possible. Almost half of those who made serious suicide attempts made a further fatal or nonfatal attempt within 5 years. These findings imply the need for enhanced follow‐up, treatment, and surveillance of all patients making serious suicide attempts.
An Investigation of Differences Between Self‐Injurious Behavior and Suicide Attempts in a Sample of Adolescents
Authors: Muehlenkamp Jennifer J. , Gutierrez Peter M.
Published: March 2004

Data from 390 high school students were collected to examine potential differences between adolescents who had attempted suicide and those who engaged in self‐injurious behavior on measures of depression, suicidal ideation, and attitudes toward life and death. Significant differences were found between controls and the self‐harm groups on all dependent variables. A significant difference on attitudes toward life was found between the self‐injury and suicide attempt groups. Post‐hoc regression analyses showed that measures of depression, suicide ideation, and attitudes towards life predicted participants' self‐harm categorization. These findings provide preliminary evidence that self‐injurious behavior is different from attempted suicide among a community sample of adolescents.
Completed Suicides Among Quebec Adolescents Involved With Juvenile Justice and Child Welfare Services
Authors: Farand Lambert , Chagnon François , Renaud Johanne , Rivard Michele
Published: March 2004

In the Province of Quebec (Canada), adolescents involved with the child welfare and juvenile justice systems committed at least one third of all completed suicides in their age group in 1995 and 1996. Their risk of suicide, standardized for age and sex, was five times that of the general adolescent population, and female juvenile delinquents had the highest relative risk of suicide (36.1). Cumulated risk factors may explain those results. Since 40% of those suicides did occur when subjects were still actively involved with the child welfare and juvenile justice systems, those agencies should revise their suicide prevention strategies.
Youth Suicide: Insights from 5 Years of Arizona Child Fatality Review Team Data
Authors: Azrael Deborah , Hemenway David , Miller Matthew , Barber Catherine W. , Schackner Robert
Published: March 2004

Data on 153 youth suicides in Arizona (1994–1999) were used to explore demographic, behavioral, and experiential factors that distinguish between firearm suicide and suicide by other means. In bivariate analyses, White youths were more likely than non‐White youths to use a firearm to commit suicide as were youths who had not experienced a life crisis or expressed suicidal thoughts in the past, relationships that hold in multivariate analyses at the p < 0.2 level. Targeted suicide prevention activities should supplement interventions focused on restricting access to highly lethal means of suicide such as firearms.
Suicidality and Its Relationship to Treatment Outcome in Depressed Adolescents
Authors: Barbe Rémy P. , Bridge Jeffrey , Birmaher Boris , Kolko David , Brent David A.
Published: March 2004

This study investigates the impact of suicidality on treatment outcome in 107 depressed adolescents who participated in a clinical trial, and received either cognitive‐behavioral (CBT), systemic‐behavioral‐family (SBFT), or non‐directive‐supportive therapy (NST). Suicidal depressed adolescents had a higher dropout rate and were more likely to be depressed at the end of treatment, in large part due to the particularly poor response of suicidal patients to NST. The relationship between suicidality and treatment response was mediated by severity of depression and hopelessness at intake. Hopelessness should be specifically targeted early in treatment. Suicidal depressed adolescents should not receive NST but a specific treatment like CBT.
Young Adults' Support Strategies when Peers Disclose Suicidal Intent
Authors: Dunham Katherine
Published: March 2004

In response to the growing suicide rate among adolescents and young adults, researchers have noted the importance of peer responses to suicidal disclosures in this population. The most adaptive response is to inform a responsible adult about the suicidal peer, but existing data indicate that most adolescents and young adults choose to talk to the peer on their own. The present study examined whether young adults' own history of suicidal ideation, gender, social history with suicide, and ambiguity of the disclosure would predict their response to a hypothetical suicidal peer. The data revealed significant effects of ambiguity and participants' suicidal ideation on the confidants' response strategy. The confidants' experience with others' attempted or completed suicides increased their likelihood of saying they would tell an authority, whereas their own history of ideation or attempts reduced the likelihood of that response. These effects were most pronounced when the hypothetical peer's suicidal intent was not completely clear, which may often be the case in disclosures by suicidal adolescents. Youth and young adults should be encouraged to inform adults about suicidal peers, particularly those who have been suicidal themselves previously, and who may resist that strategy. It is postulated that these particular peers may be more easily convinced to respond in this manner if they could be involved in the intervention with their suicidal peer.
Suicidal Behavior in Schizophrenia and Schizoaffective Disorder: Examining the Role of Depression
Authors: Harkavy‐Friedman Jill M. , Nelson Elizabeth A. , Venarde David F. , Mann J. John
Published: March 2004

Understanding the relationship between depression and suicidal behavior among individuals with schizophrenia and schizoaffective disorder can aid assessment and treatment. In this study, 86 individuals with schizophrenia and schizoaffective disorder were assessed for past and current suicidal behavior, depression, hopelessness, and reasons for living. Thirty‐four percent reported a history of suicide attempts. Suicidal behavior typically occurred 4.5 years after the onset of psychosis and 7.5 years after the onset of the first major depressive episode for those who had a history of major depression. Depression was frequent among both attempters and non‐attempters, but only half of the attempters reported a suicide attempt during an episode of major depression. And almost half of those with depression never made a suicide attempt despite a long history of illness. Although depression is a potential stressor for triggering suicidal behavior in a vulnerable subset of individuals with schizophrenia, schizophrenia research must identify other risk factors for suicidal behavior. Clinicians should remember that even without a depressive episode there is still a significant risk for suicidal behavior in schizophrenia.
Suicidality and Psychosis: Beyond Depression and Hopelessness
Authors: Warman Debbie M. , Forman Evan M. , Henriques Gregg R. , Brown Gregory K. , Beck Aaron T.
Published: March 2004

The present study examined recent suicide attempters with and without psychotic disorders in order to understand factors that contribute to suicide ideation during and following the suicide attempt. Patients with psychotic disorders endorsed higher levels of suicide ideation than patients without psychotic disorders. Even when depression, hopelessness, substance abuse, and social problem solving were controlled for, there was a significant association between psychotic disorder and suicide ideation. During the follow‐up period, patients with psychotic disorders subsequently attempted suicide at a significantly higher rate than patients without psychotic disorders. The clinical relevance of these findings is discussed.
The Role of the Dorsal Hippocampus in the Acquisition and Retrieval of Context Memory Representations
Authors: Matus-Amat Patricia , Higgins Emily A. , Barrientos Ruth M. , Rudy Jerry W.
Published: March 2004

It is argued that the hippocampus contributes to contextual fear conditioning by supporting the acquisition of a conjunctive memory representation of context, which associates with shock. This function was examined by studying the context pre-exposure facilitation effect (CPFE). A rat that is shocked immediately after being placed into a context subsequently displays almost no fear of that context. However, if it is pre-exposed to the context the day before immediate shock, it displays significant freezing to that context. By using 5-aminomethyl-3-hydroxysoxazole to temporarily inactivate the dorsal hippocampus (DH) at three different phases of the procedure, which produces the CPFE, we show that the hippocampus is necessary for the following: (1) acquisition of the context memory, (2) retrieval of this memory at the time of immediate shock, and (3) retrieval of the context-shock memory at the time of testing. In contrast, inactivating the DH before a standard contextual shock experience had no effect on contextual fear conditioning. These results support the view that two processes can support contextual fear conditioning: (1) conditioning to the conjunctive representation, which depends on the hippocampus, and (2) conditioning to the features that make up the context, which does not.
Postsynaptic TrkB-Mediated Signaling Modulates Excitatory and Inhibitory Neurotransmitter Receptor Clustering at Hippocampal Synapses
Authors: Elmariah Sarina B. , Crumling Mark A. , Parsons Thomas D. , Balice-Gordon Rita J.
Published: March 2004

Tyrosine receptor kinase B (TrkB)-mediated signaling modulates synaptic structure and strength in hippocampal and other neurons, but the underlying mechanisms are poorly understood. Full-length and truncated TrkB are diffusely distributed throughout the dendrites and soma of rat hippocampal neurons grownin vitro. Manipulation of TrkB-mediated signaling resulted in dramatic changes in the number and synaptic localization of postsynaptic NMDA receptor (NMDAR) and GABAAreceptor (GABAAR) clusters. BDNF treatment resulted in an increase in the number of NMDAR and GABAAR clusters and increased the proportion of clusters apposed to presynaptic terminals. Downregulation of TrkB signaling resulted in a decrease in receptor cluster number and synaptic localization. Examination of the time course of the effects of BDNF on receptor clusters showed that the increase in GABAAR clusters preceded the increase in NMDAR clusters by at least 12 hr. Moreover, the TrkB-mediated effects on NMDAR clusters were dependent on GABAAR activation. Although TTX, APV, and CNQX treatment had no effect, blockade of GABAARs with bicuculline abolished the BDNF-mediated increase in NMDAR cluster number and synaptic localization. In contrast, application of exogenous GABA prevented the decrease in NMDAR clusters induced by BDNF scavenging. Together, these results suggest that TrkB-mediated signaling modulates the clustering of postsynaptic GABAARs and that receptor activity is required for a subsequent upregulation of NMDAR clusters. Therefore, TrkB-mediated effects on postsynaptic neurotransmitter clusters may be part of a mechanism that balances inhibitory and excitatory synaptic transmission in developing neural circuits.
The Functional Neuroanatomy of Temporal Discrimination
Authors: Pastor Maria A. , Day Brian L. , Macaluso Emiliano , Friston Karl J. , Frackowiak Richard S. J.
Published: March 2004

Two identical stimuli, such as a pair of electrical shocks to the skin, are readily perceived as two separate events in time provided the interval between them is sufficiently long. However, as they are presented progressively closer together, there comes a point when the two separate stimuli are perceived as a single stimulus. Damage to posterior parietal cortex, peri-supplementary motor area (peri-SMA), and basal ganglia can disturb this form of temporal discrimination. Our aim was to establish, in healthy subjects, the brain areas that are involved in this process. During functional magnetic resonance imaging scanning, paired electrical pulses, separated by variable inter-stimulus intervals (5-110 msec), were delivered to different sites on one forearm (8-64 mm from the midline). Subjects were required to simply detect the stimulus (control task) or to identify a stimulus property. For temporal discrimination (TD), subjects reported whether they felt one or two stimuli. For spatial discrimination, they reported whether the stimuli were located on the right or left side of the forearm. Subjects reported their choice by pressing a button with the opposite hand. Our results showed that discrimination, as opposed to simply detection, activated several brain areas. Most were common to both discrimination tasks. These included regions of prefrontal cortex, right postcentral gyrus and inferior parietal lobule, basal ganglia, and cerebellum. However, activation of pre-SMA and anterior cingulate was found to be specific to the TD task. This suggests that these two frontal regions may play a role in the temporal processing of somatosensory events.
Neuron-Specific Apolipoprotein E4 Proteolysis Is Associated with Increased Tau Phosphorylation in Brains of Transgenic Mice
Authors: Brecht Walter J. , Harris Faith M. , Chang Shengjun , Tesseur Ina , Yu Gui-Qiu , Xu Qin , Dee Fish Jo , Wyss-Coray Tony , Buttini Manuel , Mucke Lennart , Mahley Robert W. , Huang Yadong
Published: March 2004

Apolipoprotein E (apoE) is found in amyloid plaques and neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) brains, but its role in their pathogenesis is unclear. Previously, we found C-terminal-truncated fragments of apoE in AD brains and showed that such fragments can cause neurodegeneration and can induce NFT-like inclusions in cultured neuronal cells and in transgenic mice. Here, we analyzed apoE fragmentation in brain tissue homogenates from transgenic mice expressing apoE3 or apoE4 in neurons [neuron-specific enolase (NSE)-apoE] or astrocytes [glial fibrillary acidic protein (GFAP)-apoE] by Western blotting. The C-terminal-truncated fragments of apoE accumulated, in an age-dependent manner, in the brains of NSE-apoE4 and, to a significantly lesser extent, NSE-apoE3 mice; however, no fragments were detected in GFAP-apoE3 or GFAP-apoE4 mice. In NSE-apoE mice, the pattern of apoE fragmentation resembled that seen in AD brains, and the fragmentation was specific for certain brain regions, occurring in the neocortex and hippocampus, which are vulnerable to AD-related neurodegeneration, but not in the less vulnerable cerebellum. Excitotoxic challenge with kainic acid significantly increased apoE fragmentation in NSE-apoE4 but not NSE-apoE3 mice. Phosphorylated tau (p-tau) also accumulated in an age-dependent manner in NSE-apoE4 mice and, to a much lesser extent, in NSE-apoE3 mice but not in GFAP-apoE3 or GFAP-apoE4 mice. Intraneuronal p-tau inclusions in the hippocampus were prominent in 21-month-old NSE-apoE4 mice but barely detectable in NSE-apoE3 mice. Thus, the accumulation of potentially pathogenic C-terminal-truncated fragments of apoE depends on both the isoform and the cellular source of apoE. Neuron-specific proteolytic cleavage of apoE4 is associated with increased phosphorylation of tau and may play a key role in the development of AD-related neuronal deficits.
Abnormal Hippocampal Axon Bundling in EphB Receptor Mutant Mice
Authors: Chen Zhi-Yong , Sun Chunhua , Reuhl Kenneth , Bergemann Andrew , Henkemeyer Mark , Zhou Renping
Published: March 2004

Axons travel frequently in bundles to reach their target. After arriving at the target, axon terminals defasciculate, migrate to topographically defined positions, and form synapses with appropriate target neurons. Here we present evidence that the B-type receptors of the erythropoietin-producing hepatocellular (Eph) family and a ligand, ephrin-B3, influence hippocampal axon defasciculation. The EphB receptors are expressed in the hippocampus, and the ligand, ephrin-B3, is transcribed in the lateral septum, the major subcortical target of hippocampal neurons. Ephrin-B3 promotes adhesion of hippocampal neurons to the ligand-expressing substratesin vitro, and the loss of the receptor EphB2 abrogates the effects of ephrin-B3. In mice deficient in EphB2 and EphB3, many hippocampal axons remain in bundles. This phenotype was also observed in mice that were specifically deleted for the cytoplasmic domain of EphB2. These observations indicate that the EphB receptors and their ligand regulate hippocampal axon defasciculation at the septal target, possibly through a receptor-mediated forward signaling mechanism.
Prokineticin 2 Modulates the Excitability of Subfornical Organ Neurons
Authors: Cottrell G. Trevor , Zhou Qun-Yong , Ferguson Alastair V.
Published: March 2004

The recent discovery of prokineticin 2 (PK2) expression in the suprachiasmatic nucleus and its receptors in critical autonomic control centers of the brain, including the subfornical organ (SFO), suggests the intriguing possibility that PK2 regulates the excitability of SFO neurons and thus influences autonomic function. Using current-clamp techniques to record from dissociated SFO neurons, we examined the effects of PK2 on the excitability of these cells. PK2 (20 nm) induced depolarizations in 40% of SFO neurons (n= 45; mean, 7.5 ± 1.7 mV), an effect that was reversible, PK2-specific, and concentration dependent. The depolarization was accompanied by an increase in action potential frequency from 0.4 ± 0.1 to 1.4 ± 0.5 Hz in responding cells (n= 10). This excitatory effect appears to be, in part, attributable to a PK2-induced decrease in the delayed rectifier potassium current (IK). In 10 SFO neurons recorded using perforated patch voltage-clamp techniques, six demonstrated a reversible decrease inIK(mean decrease, 26.7 ± 6.4%) in response to 20 nmPK2, whereas artificial CSF alone was without an effect on these currents. These data are the first to show excitatory effects of PK2 on neurons and, in addition, demonstrate that this peptide modulates voltage-activated K+channels. The activation of SFO neurons by PK2 illustrates a mechanism through which this peptide may exert circadian control of autonomic functions.