bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal dynamic policies for product and process innovation
Authors: Bayus Barry L. 
Published: May 2003

AbstractRelatively few studies have analytically examined incremental product and process R & D activities after a product is in the marketplace. In this paper, new product demand is modeled as a dynamic function of price and incremental product innovation, while process improvements influence costs. Optimal price, and product and process R & D expenditure patterns are studied analytically and with numerical methods. Results are partially consistent with existing hypotheses in the literature and, at the same time, some new insights are obtained. The main conclusion is that the rates of incremental product and process innovation over the product life cycle are a function of the interdependence between product and process improvements. Importantly, empirical innovation patterns matching each of the derived patterns have been reported by other researchers.
Current production targets and strategic decisions by corporate managers
Authors: Hughes John S. , Thevaranjan Alex 
Published: May 2003

AbstractThis article considers the potential role of current production targets in providing corporate managers with incentives for allocating their efforts toward operational and strategic decisions. Operational decisions relate to current production, while strategic decisions affect both current production and future profitability. A moral hazard exists to the extent that manager effort allocations are not observable. Of interest is the design of compensation contracts which efficiently resolve that hazard. Attention is mainly focused on distortions in current production away from targets which would be optimal if manager effort allocations were observable. The principal insight is that an increase in current production targets may, paradoxically, be motivated by a desire to induce a greater allocation of effort to strategic decisions.
Risk aversion, generalized correlation and investment in manufacturing capacities
Authors: Callen Jeffrey L. , Sarath Bharat 
Published: May 2003

AbstractThis study analyzes the relationship between product demand correlation and risk on the investment in dedicated and flexible manufacturing capacities. It is proved that for a risk averse (or risk neutral) decision‐maker, increased generalized correlation between output demands reduces the values of both dedicated and flexible manufacturing investments for all multivariate distributions. It is shown that no such monotonic relationship generally exists for the capacities themselves because of an economic tradeoff between risk and return. It is also proved that increased generalized correlation reduces the value of flexible capacity relative to dedicated capacity for the risk‐neutral decision maker. However, contrary to the extant literature, flexible capacity is still shown to be potentially valuable even if product demands are perfectly positively correlated. Finally, it is shown that increases in the risk of product demand, holding correlation (of product demand) constant, reduces the value of the investment in manufacturing capacities when output demands are either jointly normal or independent.
Institutional research productivity in production and operations management
Authors: Malhotra Manoj K. , Kher Hemant V. 
Published: May 2003

AbstractThis study investigates the research contributions of academic and other institutions in the area of Productions and Operations Management (POM) over the past 15 years. Similar studies have also been previously conducted in other functional areas of business such as Finance, Marketing, MIS and Management. Institutional productivity is assessed by counting the number of articles and number of standardized pages published in five major POM research journals during a 15 year period from 1980 to 1994. The journals selected include Management Science, Decision Sciences, Journal of Operations Management, IIE Transactions and International Journal of Production Research. A previous study had ranked these as the top 5 journals publishing high quality POM research. Results indicate that among the 50 institutions that emerged from our study as the top ranked ones, no single institution dominated the rankings across all the journals. The diversity of institutions reflected in these rankings shows that the field of POM is maturing and growing. Even though the overall research productivity has increased tremendously over the course of the past 15 years, the longitudinal analysis reveals that often there are periods of high and low productivity in the life of individual research institutions. The results of this study can be used by industrial researchers, doctoral students, and faculty members to assess the primary sources of contribution to each journal, to better guide their publication strategies, and even to help plan their careers.
Expression of parathyroid hormone‐related peptide and insulin‐like growth factor I during rat fracture healing
Authors: Okazaki Ken , Jingushi Seiya , Ikenoue Takashi , Urabe Ken , Sakai Hiroaki , Iwamoto Yukihide 
Published: May 2003

AbstractParathyroid hormone‐related peptide (PTHrP) and insulin‐like growth factor I (IGF‐I) are both involved in the regulation of bone and cartilage metabolisms and their interaction has been reported in osteoblasts. To investigate the interaction of PTHrP and IGF‐I during fracture healing, the expression of mRNA for PTHrP and IGF‐I, and receptors for PTH/PTHrP and IGF were examined during rat femoral fracture healing using an in situ hybridization method and an immunohistochemistry method, respectively. During intramembranous ossification, PTHrP mRNA, IGF‐I mRNA and IGF receptors were detected in preosteoblasts, differentiated osteoblasts and osteocytes in the newly formed trabecular bone. PTH/PTHrP receptors were markedly detected in osteoblasts and osteocytes, but only barely so in preosteoblasts. During cartilaginous callus formation, PTHrP mRNA was expressed by mesenchymal cells and proliferating chondrocytes. PTH/PTHrP receptors were detected in proliferating chondrocytes and early hypertrophic chondrocytes. IGF‐I mRNA and IGF receptor were co‐expressed by mesenchymal cells, proliferating chondrocytes, and early hypertrophic chondrocytes. At the endochondral ossification front, osteoblasts were positive for PTHrP and IGF‐I mRNA as well as their receptors. These results suggest that IGF‐I is involved in cell proliferation or differentiation in mesenchymal cells, periosteal cells, osteoblasts and chondrocytes in an autocrine and/or paracrine fashion. Furthermore, PTHrP may be involved in primary callus formation presumably co‐operating with IGF‐I in osteoblasts and osteocytes, and by regulating chondrocyte differentiation in endochondral ossification.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
In vivo load sharing among the quadriceps components
Authors: Zhang Li‐Qun , Wang Guangzhi , Nuber Gordon W. , Press Joel M. , Koh Jason L. 
Published: May 2003

AbstractKnee extension is always performed with coordinated contractions of multiple quadriceps muscle components: however, how the load is shared among them under normal and pathological conditions is unclear. We hypothesized that: the absolute moment generated by each quadriceps component increases with the total knee extension moment; the relative contribution and its dependence on the total knee extension moment are different for different quadriceps components; and the centrally located large vastus intermedius (VI) is favored by the central nervous system at low levels of activation. Electrical stimulation was used to activate each quadriceps component selectively in six human subjects. The relationship between the knee extension moment generated by an individual quadriceps component and the corresponding compound muscular action potential (M‐wave) over various contraction levels was established for each quadriceps component. This relationship was used to calibrate the corresponding EMG signal and determine load sharing among quadriceps components during submaximal isometric voluntary knee extension. The VI contributed the most (51.8–39.6%) and vastus medialis the least (9.5–12.2%) to knee extension moment (P < 0.05). As the knee extension moment increased, the relative contribution of the VI decreased (P = 0.017) while the relation contribution of the vastus lateralis and medialis increased (P ≤ 0.012). The absolute moment generated by each quadriceps component always increased with the total knee extension moment (P < 0.002). Our in vivo approach determined subject‐ and condition‐specific load sharing among individual muscles and showed that the central nervous system utilized the centrally located, uniarticular VI in submaximal isometric knee extension.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Healing of segmental bone defects with granular porous hydroxyapatite augmented with recombinant human osteogenic protein‐I or autologous bone marrow
Authors: den Boer Frank C. , Wippermann Burkhard W. , Blokhuis Taco J. , Patka Peter , Bakker Fred C. , Haarman Henk J. Th. M. 
Published: May 2003

AbstractHydroxyapatite is a synthetic bone graft, which is used for the treatment of bone defects and nonunions. However, it is a rather inert material with no or little intrinsic osteoinductive activity. Recombinant human osteogenic protein‐1 (rhOP‐1) is a very potent biological agent, that enhances osteogenesis during bone repair. Bone marrow contains mesenchymal stem cells, which are capable of new bone formation. Biosynthetic bone grafts were created by the addition of rhOP‐1 or bone marrow to granular porous hydroxyapatite. The performance of these grafts was tested in a sheep model and compared to the results of autograft, which is clinically the standard treatment of bone defects and nonunions. A 3 cm segmental bone defect was made in the tibia and fixed with an interlocking intramedullary nail. There were five treatment groups: no implant (n = 6), autograft (n = 8), hydroxyapatite alone (n = 8), hydroxyapatite loaded with rhOP‐1 (n = 8), and hydroxyapatite loaded with autologous bone marrow (n = 8). At 12 weeks, healing of the defect was evaluated with radiographs, a torsional test to failure, and histological examination of longitudinal sections through the defect. Torsional strength and stiffness of the healing tibiae were about two to three times higher for autograft and hydroxyapatite plus rhOP‐1 or bone marrow compared to hydroxyapatite alone and empty defects. The mean values of both combination groups were comparable to those of autograft. There were more unions in defects with hydroxyapatite plus rhOP‐1 than in defects with hydroxyapatite alone. Although the differences were not significant, histological examination revealed that there was more often bony bridging of the defect in both combination groups and the autograft group than in the group with hydroxyapatite alone. Healing of bone defects, treated with porous hydroxyapatite, can be enhanced by the addition of rhOP‐1 or autologous bone marrow. The results of these composite biosynthetic grafts are equivalent to those of autograft.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Cambium cell stimulation from surgical release of the periosteum
Authors: Simon Timothy M. , Van Sickle David C. , Kunishima Dennis H. , Jackson Douglas W. 
Published: May 2003

AbstractAn autograft of periosteal tissue containing cambium cells has potential to become chondrogenic or osteogenic depending on the regeneration repair strategies. The potential number of harvestable cambium cells diminishes with age. Other factors may be associated with a reduction in the number or variable yields of cambium cells including harvest technique, harvest site location, and the time interval from harvest to implantation. Attempts to increase the number of cambium cells have included improvements in harvesting and handling technique, and expansion of the cells in tissue culture. An „in situ”︁ stimulation and proliferation technique would offer the potential for increasing the number of cambium cells in a cost‐effective manner for transplantation without the need for expansion in tissue culture.The hypothesis tested was that surgical release of the periosteum and its deep inner underlying cambium layer by sharply incising through the superficial periosteal fibrous layer down to and scoring the cortical bone surface would increase the number of cambium cells that could be harvested at a later time period. Two techniques for periosteal release were used to stimulate a proliferation of the underlying cambium layer and increase the cambium cells for harvest in skeletally mature goats: (1) sharply scoring all four‐sides of the tissue test site perimeter, and (2) sharply scoring only two sides of the tissue test site.The two‐sided and four‐sided release scoring of the periosteum induced stimulatory responses in the number of cambium cells. In addition, a marked increase in mRNA expression for BMP‐2 (p < 0.001) was observed within 24 h and remained elevated over baseline values for up to 96 h after this stimulation to the cambium layer.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The relationship between agoraphobia symptoms and panic disorder in a non-clinical sample of adolescents
Authors: HAYWARD C. , KILLEN J. D. , TAYLOR C. B. 
Published: May 2003

Background. The purpose of this study was to evaluate the clinical correlates of agoraphobic fear and avoidance and panic disorder in a non-clinical sample of adolescents.Method. In a sample of 2365 high school students, combined data from a questionnaire and a structured clinical interview were used to classify subjects with agoraphobic fear and avoidance. Panic symptoms, major depression, childhood separation anxiety disorder, anxiety sensitivity and negative affectivity were also assessed.Results. Fifteen subjects met study criteria for agoraphobic fear and avoidance in the past year. Only three (20%) of those with agoraphobia symptoms reported histories of panic attacks and there was no overlap between those with agoraphobic fear and avoidance and the 12 subjects who met DSM-III-R criteria for panic disorder. However, subjects with agoraphobia symptoms and those with panic disorder reported similar levels of anxiety sensitivity and negative affectivity. Childhood separation anxiety disorder was more common among those with agoraphobic fear and avoidance compared to those without.Conclusion. Agoraphobic avoidance is rare in non-clinical samples of adolescents and usually not associated with panic attacks. However, adolescents with agoraphobia symptoms and those with panic disorder have similar clinical correlates consistent with a panic/agoraphobia spectrum model.
Growth hormone responses to low-dose physostigmine administration: functional sex differences (sexual diergism) between major depressives and matched controls
Authors: RUBIN R. T. , ABBASI S. A. , RHODES M. E. , CZAMBEL R. K. 
Published: May 2003

Background. Considerable endocrine and non-endocrine evidence supports the hypothesis of increased cholinergic activity relative to noradrenergic activity in major depression. We previously reported functional sex differences (sexual diergism) in hypothalamo–pituitary–adrenal cortical (HPA) hormone responses to the administration of low-dose physostigmine (PHYSO), a cholinesterase inhibitor, in 12 female and eight male unipolar major depressives and 12 female and eight male individually matched control subjects. Because growth hormone (GH) secretion also is influenced by cholinergic mechanisms, we measured GH in the samples from this study.Method. Subjects underwent four test sessions 5–7 days apart: PHYSO (8 μg/kg i.v.), arginine vasopressin (AVP) (0·08 U/kg i.m.), PHYSO+AVP and saline control. The AVP was administered as a second stimulus to HPA axis hormone secretion. PHYSO and AVP produced no side-effects in about half the subjects and predominantly mild side-effects in the other half, with no significant patient–control differences. Point biserial correlations between side-effects (absent or present) after PHYSO and the corresponding GH responses were non-significant in all groups.Results. Afternoon baseline GH was significantly higher in the women than in the men, but it was not significantly different between the female or the male patients and their respective matched controls. AVP administration had no effect on GH. PHYSO administration acutely stimulated GH secretion, to a similar degree in the women and men. The depressed patients as a group had a significantly greater average post-PHYSO GH response than did their controls, with a trend toward a significant sex×diagnosis interaction: The female depressives had a significantly greater GH response than their female controls, whereas the male depressives had a similar GH response as their male controls.Conclusions. These findings suggest sexual diergism (functional sex differences) in baseline and cholinergically stimulated plasma GH measures between major depressives and matched normal controls.
Association between psychotic disorder and urban place of birth is not mediated by obstetric complications or childhood socio-economic position: a cohort study
Authors: HARRISON G. , FOUSKAKIS D. , RASMUSSEN F. , TYNELIUS P. , SIPOS A. , GUNNELL D. 
Published: May 2003

Background. Although urban place of birth has been identified as a risk factor for schizophrenia, the extent to which this association is mediated by socially patterned risk factors such as obstetric complications and childhood socio-economic position is unclear. The diagnostic specificity of the association within the clinical psychotic syndromes is also unclear.Method. A population cohort of 696025 males and females, born in Sweden between 1973 and 1980 and with linked birth and socio-economic data was followed up from age 16 for up to 9·8 years. Hospitalized cases of schizophrenia and other non-affective psychosis were identified from the Swedish Inpatient Discharge Register. We examined associations of these disorders with a three-level measure of urbanicity of birthplace before and after controlling for measures of foetal nutrition, obstetric complications and level of maternal education.Results. Urban compared to rural birthplace was associated both with increased risk of adult onset schizophrenia (hazard ratio 1·34, CI 0·91–1·96) and other non-affective psychoses (hazard ratio 1·63, CI 1·18–2·26). None of these associations was greatly affected by adjustment for obstetric complications or maternal educational level. In the group of other non-affective psychoses urban–rural differences in disease risk were strongest among those born in the winter months.Conclusion. Urbanization of birthplace is associated with increased risk of non-affective psychosis but this is not confined to narrowly defined cases. The magnitude of the association in Sweden is lower than that reported in other studies. Causal factors underlying this association appear to operate independently of risks associated with obstetric complications and parental educational status.
Social phobia in the Australian National Survey of Mental Health and Well-Being (NSMHWB)
Authors: LAMPE L. , SLADE T. , ISSAKIDIS C. , ANDREWS G. 
Published: May 2003

Background. This article reports data on social phobia from the first large scale Australian epidemiological study. Prevalence rates, demographic correlates and co-morbidity in the sample that met criteria for social phobia are reported and gender differences examined.Method. Data were obtained from a stratified sample of 10641 participants as part of the Australian National Survey of Mental Health and Well-Being (NSMHWB). A modified version of the Composite International Diagnostic Interview (CIDI) was used to determine the presence of social phobia, as well as other DSM-IV anxiety, affective and substance use disorders. The interview also screened for the presence of nine ICD-10 personality disorders, including anxious personality disorder, the equivalent of DSM-IV avoidant personality disorder (APD).Results. The estimated 12 month prevalence of social phobia was 2·3%, lower than rates reported in several recent nationally representative epidemiological surveys and closer to those reported in the Epidemiological Catchment Area study (ECA) and other DSM-III studies. Considerable co-morbidity was identified. Data indicated that the co-morbidity with depression and alcohol abuse and dependence were generally subsequent to onset of social phobia and that the additional diagnosis of APD was associated with a greater burden of affective disorder. Social phobia most often preceded major depression, alcohol abuse and generalized anxiety disorder.Conclusions. Social phobia is a highly prevalent, highly co-morbid disorder in the Australian community. Individuals with social phobia who also screen positively for APD appear to be at greater risk of co-morbidity with all surveyed disorders except alcohol abuse or dependence.
Dermatofibrosarcoma protuberans of the vulva and groin: detection of COL1A1‐PDGFB fusion transcripts by RT‐PCR
Authors: Gökden Neriman , Dehner Louis P. , Zhu Xiaopei , Pfeifer John D. 
Published: May 2003

Background:  Dermatofibrosarcoma protuberans (DFSP) is an uncommon infiltrative tumor of the dermis with characteristic cytogenetic features, specifically the translocation t(17;22)(q22;q13) which often manifests as a supernumerary ring chromosome r(17;22). The translocation results in the fusion of two genes, collagen type I alpha 1(COL1A1) and platelet‐derived growth factor B‐chain (PDGFB). The trunk and extremities are the anatomic sites of predilection for DFSP, whereas the vulva and groin are quite uncommon sites of involvement.Methods:  This investigation evaluated seven DFSPs (four vulvar and three groin) for the presence of COL1A1‐PDGFB fusion transcripts by reverse transcriptase‐polymerase chain reaction (RT‐PCR), using archival formalin‐fixed, paraffin‐embedded tissue.Results:  Six of seven cases (three vulvar, three groin) contained a COL1A1‐PDGFB fusion transcript. Sequence analysis of the PCR products revealed that the break‐point of the COL1A1 gene was located after exon 40 in two patients, after exon 42 in one patient, after exon 44 in one patient, and after exon 47 in two patients; the break‐point in the PDGFB gene was before exon 2 in all cases. No fusion transcript could be amplified in one case.Conclusions:  As in DFSP at other sites, COL1A1‐ PDGFB chimeric fusion transcripts are present in vulvar and groin DFSP. The transcripts can be detected in formalin‐fixed, paraffin‐embedded tumor tissues, and have the same general pattern of exon boundaries as in DFSP at other sites.