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PubMed2004

[Screening serum response special antibodies of U251 cell line from surface display phage antibody library].

U251 cell is a sensitive cell line to serum, which stops at G0 phase of cell cycle in no-serum medium, and recovers growth when the serum is added into no-serum medium. The cell can express corresponding proteins in different phase of cell cycle. Therefore it is very signification for the study of cell cycle regulation mechanism that explores these proteins. In this paper, the mouse antibody phage display library was added into the bottle in which the serum starvation U251 cells had been cultured, and the special antibody phages were absorbed. Then the absorbed antibody phages were amplified by adding E. coli TG1 and helper phage M13K07. Amplified antibody phages were added into bottle in which the serum cultured cell after serum starvation (follow named as serum recovered cells) were incubated, so that the cell absorbed the no-special antibody phages for the serum starvation cell and the special antibody phages were in supernatant. The remaining no-special antibody phages in the supernatant were discarded by repeating above program 3-4 times. The pure special antibody phages were gotten, and amplified by adding the host cell E. coli TG1 and helper phage M13K07. Then the host bacterium infected special antibody phage was spread on the plate medium with ampicillin, and the monoclonal antibody phages were gotten. Using same as above program, the monoclonal antibody phages absorbed specially for serum recovered U251 cells were obtained when the serum recovered cells instead of serum starvation cells and serum starvation cells instead of serum recovered cells. In this study, ninety-six positive monoclonal antibody phages that absorbed specially the serum starvation cells and eighty-two positive monoclonal antibody phages that absorbed specially the serum recovered cells were obtained. By using cell immunochemistry assay, two special signification antibodies were obtained. one (No.11) was the strong response in serum starvation cells, the other (No.2) was the strong response in serum recovered cells. The antibody No.2 had the distinctive response to the serum recovered cells in different incubation time (15min, 30min, 1h, 2h, 4h, 8h, 12h and 48h) after serum starvation. The results showed that No.2 antibody would be useful to research the factors of cell cycle regulation and apply to tumor diagnosis.

Antibodies, Neoplasm↗
PubMed1997

Affirmative action and other special consideration admissions at the University of California, Davis, School of Medicine.

CONTEXT: The use of race as a criterion for admission to medical schools and other professional schools has become increasingly controversial. This study documents the experience of students at one medical school, admitted through a special admissions process that included race as one consideration. OBJECTIVE: To examine the medical school, postgraduate training, and career experiences of students admitted by a special consideration admission program that included traditional affirmative action admissions. DESIGN: Twenty-year, retrospective, matched-cohort study. SETTING: A public medical school. STUDY POPULATION: All affirmative action and other special consideration admissions between 1968 and 1987 (20 years). MAIN OUTCOME MEASURES: Academic progress, national board examination scores, graduation, residency evaluations, and practice characteristics. RESULTS: During the study period, 20% of students were special consideration admissions (range, 10%-45% per year). Of special consideration admissions, 53.5% were minority students, while 19% of regular admissions were minority students. When only underrepresented minority groups are analyzed, 42.7% of special consideration admissions and 4.0% of regular admissions were minorities. Of special consideration admissions, 94% graduated vs 97% of regular admissions. Regular admission students were more likely to receive honors or an A grade on core basic and clinical science courses. There was no difference in failure rates of core courses. Regular admission students had higher scores on Parts I and II of the National Board of Medical Examiners examination, and special consideration students were more likely to repeat the examination to receive a passing grade. Following graduation, the experience of the special consideration admission students was very similar to that of regular admission students. There was no difference in completion of residency training or evaluation of performance by residency directors. Both populations selected primary care disciplines at the same rate. The practice characteristics of the 2 populations were remarkably similar. CONCLUSIONS: Criteria other than undergraduate grade point average and Medical College Admission Test scores can be used in predicting success in medical school. An admissions process that allows for ethnicity and other special characteristics to be used heavily in admission decisions yields powerful effects on the diversity of the student population and shows no evidence of diluting the quality of the graduates.

California↗
PubMed1998

Do specialists do it better? The impact of specialization on the processes and outcomes of care for cancer patients.

OBJECTIVE: To assess the impact of specialization on processes and outcomes of care for cancer patients. DATA SOURCE: Papers published in English between 1980 and 1995 and identified through MEDLINE and Embase (MeSH terms: NEOPLASM (exploded), and PHYSICIAN PRACTICE PATTERNS (or DECISION MAKING, ATTITUDE OF HEALTH PERSONNEL, QUALITY OF HEALTH CARE, DELIVERY OF HEALTH CARE, HEALTH EDUCATION or OUTCOME ASSESSMENT HEALTH CARE), or through the reference lists of review articles. STUDY SELECTION: Studies providing information on the association between quality of care indicators for cancer patients and clinician/centre degree of specialization. A total of 47 papers concerning 46 empirical studies were considered. DATA EXTRACTION: For studies using process of care indicators, the proportion of specific procedures performed by specialists and non-specialists was abstracted. For studies using outcome indicators (e.g., mortality), the effect of specialization was quantified in terms of odds ratio (OR) expressing relative reduction in risk of death. The quality of individual studies using process or outcome indicators was assessed according to study design, avoidance of selection bias in patient identification and data analysis, degree of adjustment of the comparison between clinicians/centres with different levels of specialization. DATA SYNTHESIS: Specialized centres/clinicians fared better both when process and outcome indicators were used. While the former varied widely in different studies and their clinical relevance was often questionable, mortality was consistently lower when care was provided by specialized centres/clinicians, with the effect size being greater in smaller studies. For breast cancer, where all the studies were of sufficiently good quality, a pooled estimate of the effect of specialization was performed which showed that specialized cancer care was associated with an 18% (95% CI: 12%-23%) reduction in mortality. CONCLUSIONS: Despite the fact that care provided by specialized centres/clinicians appeared to be better both when assessed in relation to process indicators and to mortality, this evidence should be considered far from conclusive because of major methodological flaws in these studies. Relative to current efforts to promote evidence-based policy-making, this review underscores the limited capability of scientific information to provide reliable guidelines for structuring better health care systems.

Confidence Intervals↗
PubMed2006

The effect of poverty and caregiver education on perceived need and access to health services among children with special health care needs.

OBJECTIVES: We examined the association between several variables and the use of specialist physician services, developmental therapies, and prescription medications among children with special health care needs (N=38866). METHODS: We used a bivariate probit model to estimate whether a given child needed specialized services and whether that child accessed those services; we controlled for activity limitations and severity of special needs. Variables included family income, mother's (or other caregiver's) educational level, health insurance coverage, and perceived need for specialized services. We used data from the 2001 National Survey of Children with Special Health Care Needs. RESULTS: Lower-income and less-educated parents were less likely than higher-income and more-educated parents to say their special needs children needed specialized health services. The probability of accessing specialized health services-when needed-increased with both higher family income and insurance coverage. CONCLUSIONS: Children with special health care needs have less access to health services because their parents do not recognize the need for those services. An intervention in the form of information at the family level may be an appropriate policy response.

Adolescent↗
PubMed1992

[Division and specialization of the Western European physiology].

The 19th century has been thought to be the turning point that the experimental method began to take strong root as the core to solve many physiological subjects, and the discipline of physiology got firmly fixed as the specialized one in the western Europe. Authors found the following characteristics in the process of the division and specialization of the 19th century western physiology. 1) It was the process of its separation from the discipline of anatomy that was necessary in the development of physiology as the independent, specialized division. Newly grown ideas, that there were working functions specialized study, were the important background and basis of the development of physiology as the specialized discipline. 2) It was not until the force and influence of the metaphysical concept on the living things (vitalism) grew weak that physiology could become the specialized discipline. The new materialistic concept about living things made it possible for the researchers of that time to apply the physico-chemical method in the study of physiological problems. 3) Institutionalization of the physiological research and education accelerated its development and specialization. The followings appeared in the mid-19th century: specialized professorship, division as the separated subject in the undergraduated medical school curriculum, laboratory settings for the purpose of physiological study, establishment of independent academic societies and publication of their own journals. Two main factors, namely, both the settlement of the new physiological thought and method of the very scientific nature and the institutionalization within the academic and medical societies, exerted influences on each other in the ground of the 19th century western Europe. Through that process, the discipline of physiology took root deep as the independent specialized division in the societies of science and medicine.

Europe↗
PubMed1975

The Sertoli cell junctional specializations and their relationship to the germinal epithelium as observed after efferent ductule ligation.

Seminiferous tubules from testes of normal and efferent ductule ligated mice were examined with the electron microscope. The tubules in the ligated animals were markedly distended and at most stages of the seminiferous cycle the epithelium exhibited a series of circumferentially-oriented ridges. Cross-sectional profiles of these ridges were studied with particular emphasis on the Sertoli cell junctional specializations and their relationship to the germinal cells. In the ligated specimen the basal cytoplasm of the Sertoli cells is highly attenuated, often appearing as a thin process resting on the basement lamina. Where the cytoplasm of one Sertoli cell ends, it meets in apposition with the cytoplasm of an adjoining Sertoli cell, and at these sites, junctional specializations are present. The ridges are comprised of a stalk of apical Sertoli cell cytoplasm, often appearing like an inverted cone, with young spermatids aligned along the lateral surfaces and the more mature spermatid population embedded within the apical cytoplasm. Junctional specializations were observed along these lateral Sertoli cell surfaces. In some instances, they formed a free surface, but usually early spermatids were in contact with the junctional specializations. With respect to the more mature spermatids, the acrosomal component was typically found in relation to a junctional specialization. Germ cells at the spermatocyte stage were also noted in relation to the Sertoli cell junctional specializations. The findings suggest that spermatocytes cross the Sertoli cell barrier and gain access to the adluminal compartment of the seminiferous tubule through the disengagement of the inter-Sertoli cell junctional complex. It is proposed that when the inter-Sertoli cell junctional specializations separate, the spermatocytes come in apposition with the newly freed junctional surfaces and remain in relation with them through the ensuing divisions. It appears that at some point, firm adhesion between germ cells and the junctional specializations occurs; the spermatid progeny may thus maintain contact with the original inter-Sertoli cell junctional specializations until their release into the tubule lumen.

Animals↗
PubMed1999

Undertaking specialization in the desert leaf-cutter ant Acromyrmex versicolor.

We investigated undertaking behaviour in the desert leaf-cutter ant to determine whether colonies show undertaking specialization, how task specialization is regulated and the consequences of specialization on colony performance. Task specialization has been hypothesized to be a result of internal physiological or genetic factors that govern worker behaviour. On the other hand, it has been suggested that task specialization could be a result of spatial structuring of workers allowing only a subset to have the opportunity to perform certain tasks. To test between these two hypotheses, we experimentally introduced dead ants into laboratory colonies with individually marked workers, and recorded all encounters and undertaking behaviours. Workers demonstrated individual specialization, in that some workers removed the dead ant more frequently than expected from encounter rate. Although individual workers differed in their opportunity to perform undertaking, this did not account for the specialization. These results suggest that undertaking specialization is governed by internal differences among workers. In addition, undertaking specialists removed corpses more successfully, and in the largest colony, more quickly, than nonspecialist workers, indicating that internally governed specialization is an important part of overall colony efficiency. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Excited-state electronic asymmetry of the special pair in photosynthetic reaction center mutants: absorption and Stark spectroscopy.

The electronic absorption line shape and Stark spectrum of the lowest energy Q(y)() transition of the special pair in bacterial reaction centers contain a wealth of information on mixing with charge transfer states and electronic asymmetry. Both vary greatly in mutants that perturb the chemical composition of the special pair, such as the heterodimer mutants, and in mutants that alter interactions between the special pair and the surrounding reaction center protein, such as those that add or remove hydrogen bonds. The conventional and higher-order Stark spectra of a series of mutants are presented with the aim of developing a systematic description of the electronic structure of the excited state of the special pair that initiates photosynthetic charge separation. The mutants L168HF, M197FH, L131LH and L131LH/M160LH/M197FH are known to have different hydrogen-bonding patterns to the special pair; however, they exhibit Stark effects that are very similar to wild type. By contrast, the addition of a hydrogen bond to the M-side keto carbonyl group of the special pair in M160LH greatly affects both the absorption and Stark spectra. The heterodimer special pairs, L173HL and M202HL, exhibit much larger Stark effects than wild type, with the greatest effect in the M-side mutant. Double mutants that combine the M-side heterodimer and a hydrogen-bond addition to the L-side of the special pair decrease the magnitude of the Stark effect. These results suggest that the electronic asymmetry of the dimer can be perturbed either by the formation of a heterodimer or by adding or deleting a hydrogen bond to a keto carbonyl group. From the pattern observed, it is concluded that the charge transfer state P(L)(+)P(M)(-) has a larger influence on the excited state of the dimer in wild type than the P(L)(-)P(M)(+)charge transfer state. Furthermore, asymmetry can be varied continuously, from extreme cases in which the heterodimer and hydrogen-bond effects work together, to cases in which hydrogen bonding offsets the effects of the heterodimer, to cases in which the homodimer is perturbed by hydrogen bonds. This leads to a unified model for understanding the effects of perturbations on the electronic symmetry of the special pair, and this can be connected with perturbations on the properties of many other systems such as donor-acceptor-substituted polyenes.

Dimerization↗
PubMed2003

Accuracy of magnifying endoscopy with methylene blue in the diagnosis of specialized intestinal metaplasia and short-segment Barrett's esophagus in Japanese patients without Helicobacter pylori infection.

BACKGROUND: The use of methylene blue chromoendoscopy in the diagnosis of specialized intestinal metaplasia in short-segment Barrett's esophagus is controversial. This study evaluated the use of magnifying endoscopy with methylene blue for this purpose. METHODS: A total of 30 patients (21 men, 9 women; median age 61 years, range 32-79 years) with short lengths of columnar-lined esophagus were enrolled in a prospective trial of magnifying endoscopy with methylene blue in which the appearance after methylene blue staining was used to target biopsy specimens. Patients were screened for Helicobacter pylori infection, and only those without infection were enrolled (because many Japanese patients have pan-gastritis caused by H pylori infection, and intestinal metaplasia distal to the squamocolumnar junction may be secondary to H pylori-induced gastritis). All biopsy specimens were stained with H and E; MUC2 immunostaining was used to identify specialized intestinal metaplasia. RESULTS: Thirty patients with short-segment columnar-lined esophagus underwent magnifying endoscopy with methylene blue. Ninety-three biopsy specimens were obtained, 33 from methylene blue-stained areas and 60 from unstained areas, each about 7 mm from the marginal edge of stained areas. Specialized intestinal metaplasia was confirmed in biopsy specimens from 28 of the 33 stained areas (sensitivity 84.8%); in biopsy specimens from 55 of the 60 unstained areas, specialized intestinal metaplasia was not found (specificity 91.7%). In magnified views of methylene blue-positive areas, a tubular, cavernous, or elliptical pattern was seen. Sixteen of 21 men (76.2%) and 3 of 9 women had specialized intestinal metaplasia, and short-segment Barrett's esophagus was diagnosed in these patients. Even in patients with less than 1 cm of columnar-lined esophagus, 8 of 10 stained areas contained specialized intestinal metaplasia (sensitivity 80%) and 23 of 24 unstained areas did not (specificity 95.8%). Six of 12 patients (50%) with less than 1 cm of columnar-lined esophagus had specialized intestinal metaplasia. In total, 19 of 30 patients had specialized intestinal metaplasia. CONCLUSIONS: Magnifying endoscopy with methylene blue selectively detects specialized intestinal metaplasia within short-segment columnar-lined esophagus.

Adult↗
PubMed2002

Transition rates between specialization and generalization in phytophagous insects.

Although most species of animals exhibit specialized patterns of resource use, it is unclear whether specialization evolves at a faster rate than generalization. To test this hypothesis, transition rates toward specialization and toward generalization were estimated using phylogenies from 15 groups of phytophagous insects. Among the groups studied, maximum-likelihood analyses showed that the forward transition rate from generalization to specialization was significantly higher than the reverse transition rate from specialization to generalization (mean ratio of forward to reverse transition rate = 1.47 using uniform branch lengths and 1.76 using Grafen branch lengths). Although phylogenetic conservatism of host-plant use is common, the results suggest that the evolution of specialization is a highly dynamic process. For example, higher transitions rates both toward and away from specialization as well as equal transition rates were inferred. Collectively, the results reveal a tendency for directional evolution toward increased specialization but also indicate that specialization does not always represent an evolutionary dead-end that strongly limits further evolution.

Animals↗
PubMed2000

Parental employment and health insurance coverage among school-aged children with special health care needs.

OBJECTIVES: This study examined parental employment and health insurance coverage among children with and without special health care needs. Special needs were defined as conditions likely to require a high amount of parental care, potentially affecting parental employment. METHODS: Data from the 1994 National Health Interview Survey were analyzed for 21,415 children aged 5 to 17 years, including 1604 children with special needs. Logistic regression was used to estimate the effect of special needs on the odds of full-time parental employment and on the odds of a child's being uninsured, having Medicaid, or having employer-sponsored insurance. RESULTS: Parents of children with special needs had less full-time employment. Their children had lower odds of having employer-sponsored insurance (adjusted odds ratio [OR] = 0.7) than other children. Children with special needs had greater odds of Medicaid coverage (adjusted OR = 2.3-5.1, depending on family income). Children with and without special needs were equally likely to be uninsured. CONCLUSIONS: Lower full-time employment among parents of children with special needs contributes to the children's being less likely to have employer-sponsored health insurance. Medicaid covers many children with special needs, but many others remain uninsured.

Adolescent↗
PubMed1987

Extracellular matrix-cytoskeletal connections at the surface of the specialized contractile fibroblast (myofibroblast) in Dupuytren disease.

The cellular basis of contracture of the palmar fascia in patients who have Dupuytren disease involves the generation of intracellular force and the transmission of this force to the surrounding tissue. A specialized cell, the myofibroblast, supposedly generates this intracellular force. Recently published studies from our laboratory demonstrated that the cytoskeleton of the myofibroblast contains non-muscle myosin and not smooth-muscle myosin, suggesting that it utilizes a non-muscle contractile system. In addition, these studies identified the extracellular glycoprotein fibronectin, not the basal-lamina-specific glycoprotein laminin, at the surface of myofibroblasts, suggesting that the transmission of the intracellular force to the surrounding tissue also occurs by a non-muscle mechanism. Because of the lack of proteins that are specific to smooth muscle in the specialized cell in Dupuytren disease, we prefer the term specialized contractile fibroblast to describe this type of cell. To determine the mechanism by which the intracellular force may be transmitted to the surrounding tissue, we examined the ultrastructure of the connection of the cytoskeleton of the specialized contractile fibroblast to the surrounding extracellular matrix. By electron microscopy, extracellular filamentous material was identified at the surface of the specialized contractile fibroblast. These extracellular fibrils were found to be in close association with intracellular bundles of actin microfilaments, resulting in specialized transmembranous associations at the surface of the specialized contractile fibroblast. Bundles of filamentous extracellular material were found to extend from the surface of the specialized contractile fibroblast, connecting it with the surrounding matrix and also with adjacent specialized contractile fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed2004

Special education services and school performance in a regional cohort of low-birthweight infants at age nine.

Previous research has shown that low birthweight is a predictor of several adverse educational outcomes, including special educational placement, by middle school age. Most low-birthweight follow-up studies that have extended to school age have focused on very small infants-- < 1500 or < 1000 g; less is known of the school age outcomes for infants with only moderately low birthweight (1500-2000 g). This study examines the prevalence of special educational placement and the relationship of such placement to grade retention, verbal and performance scores on tests of general intelligence, reading and maths achievement scores and classroom hyperactivity among low-birthweight children. In a regional birth cohort of 1105 infants born between 1984 and 1987 and weighing 500-2000 g, 868 children were available for follow-up at age nine. Information on special education placement as well as grade retention, intelligence, academic achievement and classroom behaviour was available on 645 (74% completion rate). Nearly a third of the cohort was classified as needing special education. Special education placement followed a birthweight gradient, occurring among 29.3% of children with birthweights 1500-2000 g, among 32.5% in children 1000-1500 g and 49.4% in children < 1000 g. Among children in special education, a similar birthweight gradient was found for maths achievement and hyperactivity, but not for reading achievement or IQ scores. Among children not in special education, only maths achievement showed such a decline with birthweight. A substantial proportion of low-birthweight children, including those of moderate low birthweight, receive special education services, although the need is greatest among those with the lowest birthweights. Maths achievement declined with birthweight regardless of educational placement. The medical and social risk factors that accompany low birthweight and may account for these findings, require further study.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

Relation between hospital specialization with primary percutaneous coronary intervention and clinical outcomes in ST-segment elevation myocardial infarction: National Registry of Myocardial Infarction-4 analysis.

BACKGROUND: Hospitals with primary percutaneous coronary intervention (PPCI) capability may choose to predominately offer PPCI to their patients with ST-segment elevation myocardial infarction (STEMI), or they may selectively offer PPCI or fibrinolytic therapy based on patient and hospital-level factors. Whether a greater level of hospital specialization with PPCI is associated with better quality of care is unknown. METHODS AND RESULTS: We analyzed data from the National Registry of Myocardial Infarction-4 to compare in-hospital mortality and times to treatment in STEMI across different levels of hospital specialization with PPCI. We divided 463 hospitals into quartiles of PPCI specialization based on the relative proportion of reperfusion-treated patients who underwent PPCI (< or =34.0%, >34.0 to 62.5%, >62.5 to 88.5%, >88.5%). Hierarchical multivariable regression assessed whether PPCI specialization was associated with better outcomes, after adjusting for patient and hospital characteristics, including PPCI volume. We found that greater PPCI specialization was associated with a lower relative risk of in-hospital mortality in patients treated with PPCI (adjusted relative risk comparing the highest and lowest quartiles, 0.64; P=0.006) but not in those treated with fibrinolytic therapy. Compared with patients at hospitals in the lowest quartile of PPCI specialization, adjusted door-to-balloon times in the highest quartile were significantly shorter (99.6 versus 118.3 minutes; P<0.001), and the likelihood of door-to-balloon times exceeding 90 minutes was significantly lower (relative risk, 0.78; P<0.001). Adjusting for PPCI specialization diminished the association between PPCI volume and clinical outcomes. CONCLUSIONS: Greater specialization with PPCI is associated with lower in-hospital mortality and shorter door-to-balloon times in STEMI patients treated with PPCI.

Angioplasty, Balloon↗
PubMedDate not supplied

Mathematics education and students with learning disabilities: introduction to the special series.

The prevalence of students with mathematics learning disabilities has triggered an interest among special education researchers and practitioners in developing an understanding of the needs of this group of students, and in identifying effective instructional programming to foster their mathematical performance during the school years and into adulthood. Research into the characteristics of students with mathematics learning disabilities is being approached from different perspectives, including developmental, neurological and neuropsychological, and educational. This diversity helps us develop a broader understanding of students' learning needs and difficulties. Special education assessment practices encompass a variety of approaches, including norm-referenced, criterion-referenced, and nonstandardized procedures, depending on the specific assessment questions professionals seek to answer. Students' mathematical knowledge and conceptual understanding must be examined to determine their strengths and weaknesses, curriculum-based progress, and use of cognitive strategies to arrive at mathematical solutions. Research findings have identified empirically validated interventions for teaching mathematics curricula to students with mathematics learning disabilities. Research studies have been grounded in behavioral theory and cognitive psychology, with an emergent interest in the constructivist approach. Although research studies have focused primarily on computational performance, more work is being conducted in the areas of story-problem solving and technology. These areas as well as other math curricular skills require further study. Additionally, the needs of adults with math LD have spurred educators to examine the elementary and secondary math curricula and determine ways to infuse them with life skills instruction accordingly. As the field of mathematics special education continues to evolve, special educators must remain cognizant of the developments in and influences on the field of mathematics education. Reform efforts have shaped the field significantly since the 1950s, contributing to the curriculum offered in mathematics textbooks and the pedagogical practices taught in higher education courses. Mathematics educators continue to search for a better understanding of how children learn mathematics; this process is shaped by the prevailing theoretical orientations and research methodologies. This special series in mathematics special education provides readers with information about the characteristics of students with mathematics learning disabilities, assessment procedures, mathematics programming, teacher preparation, and future directions for the field. The series originated as a result of discussions with Dr. Lee Wiederholt and Dr. Judith K. Voress, who saw a need for the compilation of recent research and best practices in mathematics special education. I thank them for their support of and thoughtful insights about the development of this series. I also appreciate the support of Dr. George Hynd and his editorial assistant, Kathryn Black, in finalizing the details for publication. Finally, I am most appreciative of the authors' contributions to this series; their work continues to significantly influence the development of the field of mathematics special education and programming for students with mathematics learning disabilities.

Adolescent↗
PubMed1990

Case-mix specialization in the market for hospital services.

Historically, cost-based reimbursement encouraged hospitals to compete on the basis of quality, leading to duplication of services and other inefficient behavior. More recently, prospective payment, selective contracting, and other innovations in reimbursement have strengthened incentives for more efficient hospital operations. In principle, hospitals may be able to reduce their costs by limiting the array of services they provide, but there has been little empirical evidence that U.S. hospitals are moving toward greater specialization or that specialization leads to cost savings. This article explores recent changes in case-mix specialization and the relationship of these changes to hospital costs. It first describes an index of specialization derived from Information Theory and shows that this index provides intuitively reasonable results in characterizing patterns of specialization across hospitals. The analysis then demonstrates that specialization, as measured by this index, in fact increased from 1980 through 1985; that specialization can indeed lower hospital costs; and that increases in specialization have been largest in those hospitals with the greatest incentives to reduce costs.

Costs and Cost Analysis↗
PubMed2004

Hemispheric specialization for language.

Hemispheric specialization for language is one of the most robust findings of cognitive neuroscience. In this review, we first present the main hypotheses about the origins of this important aspect of brain organization. These theories are based in part on the main approaches to hemispheric specialization: studies of aphasia, anatomical asymmetries and, nowadays, neuroimaging. All these approaches uncovered a large inter-individual variability which became the bulk of research on hemispheric specialization. This is why, in a second part of the review, we present the main facts about inter-individual variability, trying to relate findings to the theories presented in the first part. This review focuses on neuroimaging as it has recently given important results, thanks to investigations of both anatomical and functional asymmetries in healthy subjects. Such investigations have confirmed that left-handers, especially "familial left-handers", are more likely to have an atypical pattern of hemispheric specialization for language. Differences between men and women seem less evident although a less marked hemispheric specialization for language was depicted in women. As for the supposed relationship between anatomical and functional asymmetries, it has been shown that the size of the left (not the right) planum temporale could explain part of the variability of left hemispheric specialization for language comprehension. Taken as a whole, findings seem to vary with language tasks and brain regions, therefore showing that hemispheric specialization for language is multi-dimensional. This is not accounted for in the existing models of hemispheric specialization.

Animals↗
PubMedDate not supplied

Construction and characterization of a specialized ribosome system for the overproduction of proteins in Escherichia coli.

A recombinant Escherichia coli system was constructed to overexpress proteins using the specialized ribosomes developed by Herman de Boer and co-workers at Genentech. Specialized ribosomes carry a mutation in the anti-Shine-Dalgarno region of 16 S ribosomal RNA, which is the site of messenger RNA binding. A complementary mutation in the ribosome binding site (the Shine-Dalgarno region) of a particular mRNA results in specific and efficient translation of this mRNA on the specialized ribosomes. Production of beta-galactosidase with this system was characterized with respect to transcription, translation, plasmid replication, and cell growth rate. Translation of specialized mRNA on specialized ribosomes gave 5 times more enzyme activity than did translation of wild-type mRNA on wild-type ribosomes under similar conditions. The system described here offers a number of advantages when compared to a similar system described recently: (1) two separate specialized systems were constructed; (ii) the genes for specialized mRNA and specialized rRNA are on separate plasmids, allowing for different combinations of mRNA and rRNA; and (iii) appropriate controls were constructed for each plasmid.

Base Sequence↗