bluuebunny/crossref_metadata_2025 huggingface dataset:
Parenthood experiences during the child's first year: literature review
Authors: Nyström Kerstin , Öhrling Kerstin
Published: April 2004

Background.  Raising a child is probably the most challenging responsibility faced by a new parent. The first year is the basis of the child's development and is significant for growth and development. Knowledge and understanding of parents’ experiences are especially important for child health nurses, whose role is to support parents in their parenthood.

Aim.  The aim of this review was to describe mothers’ and fathers’ experiences of parenthood during the child's first year.

Method.  A literature search covering 1992–2002 was carried out using the terms parenthood, parenting, first year, infancy and experience. Of the 88 articles retrieved, 33 articles (both qualitative and quantitative) met the inclusion criteria and corresponded to the aim of this review. The data were analysed by thematic content analysis.

Findings.  Being a parent during the child's first year was experienced as overwhelming. The findings were described from two perspectives, namely mothers’ and fathers’ perspectives, since all the included studies considered mothers’ and fathers’ experiences separately. The following categories were identified concerning mothers: being satisfied and confident as a mother, being primarily responsible for the child is overwhelming and causes strain, struggling with the limited time available for oneself, and being fatigued and drained. The following categories were found for fathers: being confident as a father and as a partner, living up to the new demands causes strain, being prevented from achieving closeness to the child is hurtful, and being the protector and the provider of the family. The unifying theme for these categories was ‘living in a new and overwhelming world’.

Conclusion.  There is a need for nurse interventions aimed at minimizing parents’ experiences of strain. A suggested intervention is to find a method whereby child health nurses’ support would lead to parents becoming empowered in their parenthood.
Professional codes in a changing nursing context: literature review
Authors: Meulenbergs Tom , Verpeet Ellen , Schotsmans Paul , Gastmans Chris
Published: April 2004

Background.  Professional codes played a definitive role during a specific period of time, when the professional context of nursing was characterized by an increasing professionalization. Today, however, this professional context has changed.

Aim.  This paper reports on a study which aimed to explore the meaning of professional codes in the current context of the nursing profession.

Method.  A literature review on professional codes and the nursing profession was carried out. The literature was systematically investigated using the electronic databases PubMed and The Philosopher's Index, and the keywords nursing codes, professional codes in nursing, ethics codes/ethical codes, professional ethics.

Conclusion.  Due to the nursing profession's growing multidisciplinary nature, the increasing dominance of economic discourse, and the intensified legal framework in which health care professionals need to operate, the context of nursing is changing. In this changed professional context, nursing professional codes have to accommodate to the increasing ethical demands placed upon the profession. Therefore, an ethicization of these codes is desirable, and their moral objectives need to be revalued.
Using an electronic voting system in logic lectures: one practitioner's application
Authors: Stuart S. A. J. , Brown M. I. , Draper S. W.
Published: April 2004

This paper reports the introduction of electronic handsets, like those used on the television show ‘Who Wants To Be A Millionaire?’ into the teaching of philosophical logic. Logic lectures can provide quite a formidable challenge for many students, occasionally to the point of making them ill. Our rationale for introducing handsets was threefold: (i) to get the students thinking and talking about the subject in a public environment; (ii) to make them feel secure enough to answer questions in the lectures because the system enabled them to do this anonymously; and (iii) to build their confidence about their learning by their being able to see how they were progressing in relation to the rest of the students in the class. We have achieved all of these and more. Our experience has revealed that the use of handsets encourages a more dynamic form of student interaction in an environment – the lecture – that can, in the wrong hands, be utterly enervating, but they also provide an opportunity for the lecturer to respond to students' difficulties at the time when they really matter. In this paper, we discuss our case of rapid adoption, our grounds for judging it a success, and what that success seems to have depended on.
Fifty years of muscle and the sliding filament hypothesis
Authors: Huxley Hugh E.
Published: April 2004

This review describes the early beginnings of X‐ray diffraction work on muscle structure and the contraction mechanism in the MRC Unit in the Cavendish Laboratory, Cambridge, and later work in the MRC Molecular Biology Laboratory in Hills Road, Cambridge, where the author worked for many years, and elsewhere. The work has depended heavily on instrumentation development, for which the MRC laboratory had made excellent provision. The search for ever higher X‐ray intensity for time‐resolved studies led to the development of synchrotron radiation as an exceptionally powerful X‐ray source. This led to the first direct evidence for cross‐bridge tilting during force generation in muscle. Further improvements in technology have made it possible to study the fine structure of some of the X‐ray reflections from contracting muscle during mechanical transients, and these are currently providing remarkable insights into the detailed mechanism of force development by myosin cross‐bridges.
Phaiodactylipin, a glycosylated heterodimeric phospholipase A2 from the venom of the scorpion Anuroctonus phaiodactylus
Authors: Valdez‐Cruz Norma A. , Batista Cesar V. F. , Possani Lourival D.
Published: April 2004

Phaiodactylipin was purified from the venom of the scorpion Anuroctonus phaiodactylus. It is the first protein to be purified from a scorpion of the family Iuridae and has a molecular mass of 19 172 atomic mass units. The mature protein is composed of two subunits, the large one consisting of 108 amino acid residues, whereas the small subunit has only 18 residues, and the structure is stabilized by five disulfide bridges. The heterodimer is expressed from a single message containing 769 base pairs and a signal peptide with 16 and/or 25 amino acid residues. During maturation an internal hexapeptide is excised. There are three putative sites of N‐glycosylation, one of which is situated in the small subunit region. The carbohydrate composition of this site was determined by mass spectrometry analysis and was found to contain three hexoses, two N‐acetyl‐hexoses and two deoxyhexoses. The protein has a calcium dependent phospholipase A2 type of activity. It is lethal to arthropods (insects and isopods), but not toxic to mammals, using doses up to 20 µg per 20 g mouse body weight. For crickets, a dose of 5 µg per animal is lethal; however, when injected into mice it is capable of causing only muscular inflammation, without rupture of the basal membrane of cells. It has a direct hemolytic effect in human erythrocytes and retards the coagulation time of blood. It is an unusual phospholipase A2, with only 36% and 50% amino acid sequence identities to the closest known phospholipases, imperatoxin I and phospholipin, respectively. Identities with bee and Heloderma venom phospholipase are only in the order of 28%.
Elements of the C‐terminal t peptide of acetylcholinesterase that determine amphiphilicity, homomeric and heteromeric associations, secretion and degradation
Authors: Belbeoc'h Stéphanie , Falasca Cinzia , Leroy Jacqueline , Ayon Annick , Massoulié Jean , Bon Suzanne
Published: April 2004

The C‐terminal t peptide (40 residues) of vertebrate acetylcholinesterase (AChE) T subunits possesses a series of seven conserved aromatic residues and forms an amphiphilic α‐helix; it allows the formation of homo‐oligomers (monomers, dimers and tetramers) and heteromeric associations with the anchoring proteins, ColQ and PRiMA, which contain a proline‐rich motif (PRAD). We analyzed the influence of mutations in the t peptide of Torpedo AChET on oligomerization and secretion. Charged residues influenced the distribution of homo‐oligomers but had little effect on the heteromeric association with QN, a PRAD‐containing N‐terminal fragment of ColQ. The formation of homo‐tetramers and QN‐linked tetramers required a central core of four aromatic residues and a peptide segment extending to residue 31; the last nine residues (32–40) were not necessary, although the formation of disulfide bonds by cysteine C37 stabilized T4 and T4–QN tetramers. The last two residues of the t peptide (EL) induced a partial intracellular retention; replacement of the C‐terminal CAEL tetrapeptide by KDEL did not prevent tetramerization and heteromeric association with QN, indicating that these associations take place in the endoplasmic reticulum. Mutations that disorganize the α‐helical structure of the t peptide were found to enhance degradation. Co‐expression with QN generally increased secretion, mostly as T4–QN complexes, but reduced it for some mutants. Thus, mutations in this small, autonomous interaction domain bring information on the features that determine oligomeric associations of AChET subunits and the choice between secretion and degradation.
HIV‐1 gp41 and gp160 are hyperthermostable proteins in a mesophilic environment
Authors: Krell Tino , Greco Frédéric , Engel Olivier , Dubayle Jean , Dubayle Joseline , Kennel Audrey , Charloteaux Benoit , Brasseur Robert , Chevalier Michel , Sodoyer Regis , El Habib Raphaëlle
Published: April 2004

HIV gp41(24–157) unfolds cooperatively over the pH range of 1.0–4.0 with Tm values of > 100 °C. At pH 2.8, protein unfolding was 80% reversible and the ΔHvH/ΔHcal ratio of 3.7 is indicative of gp41 being trimeric. No evidence for a monomer–trimer equilibrium in the concentration range of 0.3–36 µm was obtained by DSC and tryptophan fluorescence. Glycosylation of gp41 was found to have only a marginal impact on the thermal stability. Reduction of the disulfide bond or mutation of both cysteine residues had only a marginal impact on protein stability. There was no cooperative unfolding event in the DSC thermogram of gp160 in NaCl/Pi, pH 7.4, over a temperature range of 8–129 °C. When the pH was lowered to 5.5–3.4, a single unfolding event at around 120 °C was noted, and three unfolding events at 93.3, 106.4 and 111.8 °C were observed at pH 2.8. Differences between gp41 and gp160, and hyperthermostable proteins from thermophile organisms are discussed. A series of gp41 mutants containing single, double, triple or quadruple point mutations were analysed by DSC and CD. The impact of mutations on the protein structure, in the context of generating a gp41 based vaccine antigen that resembles a fusion intermediate state, is discussed. A gp41 mutant, in which three hydrophobic amino acids in the gp41 loop were replaced with charged residues, showed an increased solubility at neutral pH.
Spatial pattern of dry rainforest colonizing unburnt Eucalyptus savanna
Authors: Fensham R. J. , Butler D. W.
Published: April 2004

Abstract  The spatial pattern of dry rainforest and savanna tree species was analysed in a 1.56‐ha plot within an unburnt eucalypt savanna woodland in north Queensland, Australia. Rainforest colonization constituted only 1.3% of the basal area and mostly consisted of individuals less than 3 m high. The distribution of rainforest trees was highly clumped around the large savanna eucalypt trees. Ecological mechanisms generating the clumped distribution are discussed in light of evidence from this study and the literature. Herbaceous biomass was not reduced under trees, suggesting that relief from grass competition has not favoured rainforest colonization under tree crowns. Edaphic facilitation through nutrient enrichment under savanna tree crowns appears to be only minor on the moderate fertility soils of the area. The highly clumped pattern of colonizing dry rainforest may be a consequence of seeds dropped from birds roosting in savanna trees.
Do introduced honeybees (Apis mellifera, Hymenoptera) provide full pollination service to bird‐adapted Australian plants with small flowers? An experimental study of Brachyloma ericoides (Epacridaceae)
Authors: Celebrezze Thomas , Paton David C.
Published: April 2004

Abstract  In many previous studies of the effects of introduced honeybees on Australian ecosystems, it has been assumed that floral morphology is a primary factor determining whether introduced honeybees will be effective in pollinating endemic plants. Although both honeybees and birds contacted stigmas and anthers of the small‐flowered Brachyloma ericoides (Epacridaceae), the exclusion of birds but not honeybees resulted in a significantly lower proportion of flowers producing capsules (12.3 ± 2 vs 21.0 ± 2%). This suggests that native birds contributed significantly to fruit set even though honeybees were much more frequent visitors to flowers (5–6 vs 0.7–2.5 times per day) and moved more frequently between plants (25 vs 12.2% of movements). Fruit set following exposure to birds and honeybees was very low compared with shrub species in general and may have been limited by the pre‐emptive removal of pollen by the 10% of honeybees that actively collected pollen.
Do temperature and social environment interact to affect call rate in frogs (Crinia signifera)?
Authors: Wong Bob B. M. , Cowling A. N. N. , Cunningham Ross B. , Donnelly Christine F. , Paul D. Cooper
Published: April 2004

Abstract  Acoustic displays are pervasive and conspicuous forms of sexual advertisement used by animals to attract mates. Evidence suggests that individuals may use environmental cues and/or the presence of other displaying animals to select the best times for display to optimize the chances of mating. Less well‐known is how the physical and social environment might interact to affect the actual content of the display itself. We examined the effects of social environment and temperature on calling rate in a frog Crinia signifera. We found that both variables interacted to affect call rate but only among continuous callers. Call rate increased with temperature in individuals calling continuously on their own but no relationship was found in frogs calling continuously in the presence of others, either in a duet or in a group calling situation. We suggest that the temperature sensitivity of calling rate in frogs could depend on the social environment of the caller. As such, we suggest caution in generalizing about the way temperature affects calling rates in frogs and encourage greater consideration of how physical and social environments might interact to influence the signal content of acoustic displays.
Successful antimicrobial therapy and implant retention for streptococcal infection of prosthetic joints
Authors: Everts Richard J. , Chambers Stephen T. , Murdoch David R. , Rothwell Alastair G. , McKie John
Published: April 2004

Background:  Streptococci cause up to 20% of prosthetic joint infections but this has received little attention in the published literature.

Methods:  We reviewed retrospectively our experience with treatment of streptococcal prosthetic joint infections. Patients were followed up for up to 15 years after discontinuation of antimicrobial therapy and up to 8.5 years while on continuous antimicrobial therapy.

Results:  Eighteen cases were diagnosed between 1984 and 1995. These included one group A, seven group B, one group D, seven group G and one viridans‐group streptococcal infection as well as one group B and D streptococcal co‐infection. All were late‐onset infections and most (11 of 18, 61%) were acute. Hip and knee joints were equally affected. Six of seven group G streptococcal infections were associated with skin or soft tissue infections. Sixteen patients were treated primarily with antimicrobial agents including 5 days to 6 weeks given intravenously and 2 weeks to 8.5 years given orally. At latest follow up, 10 patients had been off antimicrobial therapy for at least 18 months without relapse, one patient had been off antimicrobial therapy for 7 months without relapse and four infections were successfully controlled with long‐term suppressive antimicrobial therapy. One infection was unable to be controlled with antimicrobial therapy.

Conclusions:  Our results, and those of others, show that prosthetic joint infections caused by streptococci have a relatively good outcome with primary antimicrobial therapy and, when necessary, drainage, lavage or debridement. Provided the prosthesis is stable and the patient can tolerate long‐term antimicrobial therapy, this may be an effective alternative to excision arthroplasty.
Sexual function after rectal excision
Authors: Keating John P.
Published: April 2004

Background:  Rectal excision is associated with a risk of autonomic nerve damage and associated sexual dysfunction (SD). The evolution of our understanding of the anatomy and physiology of sexual function together with continual refinement of surgery for both benign and malignant disease has led to a decrease in the incidence of SD after rectal surgery. A knowledge of the degree of risk of postoperative SD is important both for the patient and as a benchmark for audit of individual colorectal practice.

Methods:  The available literature on the anatomy, physiology and surgical aspects of this topic has been researched through the Medline database. The more recently available data are reviewed in the context of the historical evolution of surgery for benign and malignant rectal disease.

Results and conclusions:  In the best hands, permanent impotence occurs in less than 2% of patients following restorative proctocolectomy and at a similarly low rate after proctocolectomy and ileostomy. Isolated ejaculatory dysfunction is also numerically a minor problem post operation for benign disease. Patient age is the most important predictor of SD after surgery for rectal cancer. The incidence of permanent impotence remains high (>40%) after abdomino‐perineal excision of the rectum (APE) but the continued decline in the use of this operation in favour of low anterior resection (LAR), which carries about half the risk of impotence compared to sphincter ablating surgery, is likely to have resulted in a fall in the absolute number of patients rendered impotent as a result of rectal cancer surgery. Anatomical dissection of the pelvis with preservation of the named autonomic fibres results in a low and predictable rate of sexual morbidity. Surgeons could profitably spend more time with their patients discussing the possible effects of surgery on sexual function. Further research is required to determine the effects of adjuvant therapy for rectal cancer on sexual function.
Impact of laparoscopic cholecystectomy on hospital utilization
Authors: Hobbs Michael S. , Mai Qun , Fletcher David R. , Ridout Steve C. , Knuiman Mathew W.
Published: April 2004

Objective:  The objective of the present study was to assess the impact of laparoscopic cholecystectomy (LC) and associated endoscopic retrograde pancreatography (ERCP) on hospital utilization.

Background:  Laparoscopic cholecystectomy (LC) has resulted in marked reductions in average length of hospital stay; but population‐based studies of hospital utilization have generally not taken into account increased cholecystectomy rates or associated increases in pre and postoperative admissions.

Methods:  We conducted a population‐based study of all residents of Western Australia who underwent cholecystectomy in the period 1980−2000. Record linkage was used to identify pre and postoperative admissions, and to estimate aggregate length of stay per case based on all relevant admissions. We estimated trends in cholecystectomy rates, proportions of cases with related pre and postoperative hospital admissions, average aggregate length of stay per case and total bed utilization per unit of population.

Results:  The introduction of LC was associated with a sustained increase in rates of cholecystectomy of 25%. Similar increases occurred in the percentage of cases with related preoperative and postoperative admissions. Average length of stay for index admissions declined by nearly 60% compared with 50% for all related admissions. Per capita hospital utilization for index admissions decreased by 45% compared with 38% for index and associated admissions combined, and 32% for all admissions for biliary disease.

Conclusions:  Reduced hospital utilization associated with LC was partly offset by increases in pre and postoperative admissions and a sustained increase in cholecystectomy rates. Record linkage is required to assess the true impact of new technologies on hospital utilization.
Fluid sinks within the earth's crust
Authors: Stober I. , Bucher K.
Published: April 2004

The Urach 3 research borehole in south‐west (SW) Germany has been drilled through the sedimentary cover, and the gneisses of the Variscian crystalline basement at 1600 m below the surface (Black Forest basement) has been reached. An additional 2800 m has been drilled through the fractured crystalline rocks, and the borehole has been used for a number of hydraulic tests in the context of a ‘hot‐dry rock’ (HDR) project exploring for geothermal energy. The fracture system of the basement is saturated with a NaCl brine with about 70 g L−1 dissolved solids. Water table measurements in the borehole cover a period of 13 years of observation, during which the water table continuously dropped and did not reach a steady‐state level. This unique set of data shows that the hydraulic potential decreases with depth, causing a continuous flow of fluid to the deeper parts of the upper continental crust. The potential decrease and the associated downward migration of fluid is an evidence for the progress of water (H2O)‐consuming reactions in the crystalline rocks. Computed stability relations among relevant phases at the pressure temperature (PT) conditions in the fracture system and documented fossil fracture coatings in granites and gneisses suggest that the prime candidate for the H2O‐consuming reaction is the zeolitization of feldspar. The potential of the gneisses to chemically bind H2O matches the estimated amount of migrating H2O.
Environmental Justice Grantmaking: Elites and Activists Collaborate to Transform Philanthropy
Authors: McCarthy Deborah
Published: April 2004

The rise of environmental justice activism since the 1980s provides an exceptional opportunity to study the relations between a grassroots movement and philanthropic foundations. I utilize archival documents and interviews with activists and funders to pose two guiding questions. One, to what degree has the environmental justice movement gained access to foundations? Two, to what degree does this movement maintain self‐determination in its relations with foundations? This paper shows that the movement successfully established connections with a few key foundations. I also show how environmental justice grantee organizations maneuvered around some of the foundation‐related constraints that might otherwise present very real threats to their self‐determination. This analysis builds on, but also goes beyond, the channeling and co‐optation literatures that emphasize the potentially negative influence of foundation funding on grantees. It also contributes to the newly developing social relations perspective which conceptualizes social movement philanthropy as a relationship that is mediated by many factors (for instance, the political orientation of the funder and grantee, among others).
Parent–Youth Conflict and School Delinquency/Cigarette Use: The Moderating Effects of Gender and Associations with Achievement‐Oriented Peers
Authors: Liu Ruth X.
Published: April 2004

Hypothesized gender‐specific relationships between parent–youth conflict and youth's school delinquency and cigarette use, and the moderating effect of associations with achievement‐oriented peers are estimated using information provided by a national sample of high school students (National Education Longitudinal Study [NELS] 1988–1990, N=13,348). Multiple regression analyses yielded results as follows: Conflict with fathers is more related to adolescent sons’ school delinquency and cigarette use than adolescent daughters’ while conflict with mothers is only predictive of daughters’ school delinquency and cigarette use. Further, associations with highly achievement‐oriented peers tend to mitigate adverse effect of conflict with the same‐sex parent on school delinquency and cigarette use. These results are observed while controlling for putative common antecedent variables.
The Efficacy of an Early Literacy Tutoring Program Implemented by College Students
Authors: Allor Jill , McCathren Rebecca
Published: April 2004

Absctract.  This article describes a two‐year study addressing the effectiveness of a highly structured, systematic tutoring intervention implemented by minimally trained college students with two cohorts of at‐risk first‐grade readers. Participants were 61 first‐grade children in Cohort 1 and 76 first‐grade children in Cohort 2. Tutors participated in three one‐hour training sessions and received occasional on‐site assistance. Individual tutoring sessions were scheduled for three to four times each week for one school year, with each cohort receiving approximately 10–14 hours of instruction across 44 sessions. The curriculum included a game to teach phonemic awareness and letter‐sound correspondence, structured word‐study activities, reading of leveled books, and simple comprehension strategies. Significant differences were found on measures of phonemic awareness and nonsense word reading for both cohorts. For Cohort 1, but not Cohort 2, significant differences were also detected for real‐word identification. Our results support using tutors to provide additional assistance and instruction in early reading, even when tutors are not professionally trained teachers.
A sheep cadaver model for demonstration and training periodontal surgical methods
Authors: Al‐Qareer Athbi H. A. , Afsah Mohammed R. , Müller Hans‐Peter
Published: April 2004

There is lack of data on the suitability of animal cadaver models for teaching purposes in dentistry. Here, we describe a model suitable for training for several periodontal surgical methods. Mandibles of freshly slaughtered Australian adult sheep and lambs were examined. Periodontal probing depths (PPDs) were measured at six sites of every tooth present. The following surgical techniques were critically analyzed: access flap with interrupted, continuous sutures; apically repositioned flap with periosteal sutures; coronally advanced flap with sling suture; gingivectomy; and distal wedge procedure. Probing depths were highest in the buccal furcation area of 1st and 2nd molars, where deep intrabony lesions were present in certain samples from adult sheep. Another area of increased probing depth was lingual to canines and incisors. Here, a pronounced lower dental pad of fibrous tissue was present. In this area, gingivectomy could always be accomplished. Fibrous tissue was also found distal to the most posterior molar, where the distal wedge procedure could be exercised. Access flaps and apically repositioned flaps could be performed particularly at premolars. Here, interrupted or continuous sutures were possible. Because of tight interdental contact areas, needle insertion was difficult at molars. After periosteal dissection, labial flaps at anterior teeth could easily be advanced coronally and sutured with sling sutures. Because of the teeth's dimensions and tight contact areas, simulation of more advanced techniques such as papilla preservation flaps was not possible. The sheep mandible seems to be a feasible training model for the demonstration and exercise of various periodontal surgical techniques for the treatment of periodontitis.
Rethinking the OSCE as a Tool for National Competency Evaluation
Authors: Boyd M. A. , Gerrow J.D. , Duquette P.
Published: April 2004

The relatively recent curriculum change to Problem‐Based Learning/Case‐Based Education has stimulated the development of new evaluation tools for student assessment. The Objective Structured Clinical Examination (OSCE) has become a popular method for such assessment.

The National Dental Examining Board of Canada (NDEB) began using an OSCE format as part of the national certification testing process for licensure of beginning dentists in Canada in 1996. The OSCE has been well received by provincial licensing authorities, dental schools and students. ‘Hands on’ clinical competency is trusted to the dental programs and verified through NDEB participation in the Accreditation process.

The desire to refine the OCSE has resulted in the development of a new format. Previously OSCE stations consisted of case‐based materials and related multiple‐choice questions. The new format has case‐based material with an extended match presentation. Candidates ‘select one or more correct answers’ from a group of up to15 options. The blueprint is referenced to the national competencies for beginning practitioners in Canada.

This new format will be available to students on the NDEB website for information and study purposes. Question stems and options will remain constant. Case histories and case materials will change each year.

This new OSCE will be easier to administer and be less expensive in terms of test development.

Reliability and validity is enhanced by involving content experts from all faculties in test development, by having the OSCE verified by general practitioners and by making the format available to candidates. The new OSCE will be pilot tested in September 2004. Examples will be provided for information and discussion.
Establishment of an atopic dermatitis‐like skin model in a hairless mouse by repeated elicitation of contact hypersensitivity that enables to conduct functional analyses of the stratum corneum with various non‐invasive biophysical instruments
Authors: Matsumoto Katsuo , Mizukoshi Koji , Oyobikawa Midori , Ohshima Hiroshi , Tagami Hachiro
Published: April 2004

Background/aims: Pathogenesis of atopic dermatitis (AD) has been studied in animal models such as the NC/Nga mouse strain or Balb/C mice that are repeatedly treated with 2,4,6‐trinitro‐1‐chrolobenzene (TNCB). These mice exhibit features of chronic contact dermatitis, including an intensified early type skin reaction, increased number of mast cells and elevated serum IgE levels with a shift of cutaneous cytokine expression from a type 1 to type 2 profile. However, it is difficult to investigate the unique skin changes of AD such as dry skin, barrier dysfunction, and increased turnover of the stratum corneum (SC) in these animals with biophysical instruments because of the presence of their fur coats. In this study, we succeeded in establishing a mouse model of AD in hairless mice that are suitable for various functional analyses of the SC as well as for examining the immunological characteristics of human AD by treating TNCB‐contact sensitized hairless mice with 1% TNCB every other day for 36 days.

Methods: In hairless animals treated with TNCB every 2 days for 36 days, we measured time courses of skin swelling induced by contact hypersensitivity reaction on days 0, 6, 20 and 36. During the time course, non‐invasive measurements for skin surface condition with biophysical instruments were conducted, and the area size and the rear surface villi of corneocytes obtained were measured. Also skin samples and blood samples were taken at each time point for histology and measurement of serum IgE level.

Results: A gradual intensification of an early type contact hypersensitivity reaction was observed over the treatment period. These mice exhibited reduced SC hydration, heightened trans‐epidermal water loss, and increased skin thickness. These mice also showed a decrease in the surface area size of each corneocytes and marked villus formation on their rear surface. Histologically, there was an increase in the number of CD4 and CD8 positive T cells in the epidermis. Also observed was a marked increase in the number of dermal mast cells and eosinophils, which correlated with elevated serum IgE levels induced by TNCB treatments.

Conclusions: From the results obtained we conclude that repeated treatments of TNCB‐sensitized hairless mice with TNCB provides a useful means by which to study the pathological characteristics of AD skin lesions as well as their immunological characteristics.
Analysis of the absorbance spectra of skin lesions as a helpful tool for detection of major pathophysiological changes
Authors: Takiwaki Hirotsugu , Miyaoka Yuki , Arase Seiji
Published: April 2004

Background/aims: Although reflectance spectrophotometry is often applied to measurement of skin color, raw data of reflectance spectra of normal and lesional skin are difficult to analyze. The purpose of this pilot study was to determine whether measurement of spectral difference in absorbance (SDA) between various skin lesions and normal skin adjacent to them could yield useful information for clinics in dermatology.

Methods: We studied spectral reflectance of a total of 173 various skin lesions. After converting obtained reflectance into apparent absorbance A (=log10(1/reflectance)), we examined the profile of SDA, that is, Alesion−Anormal skin in the range of 400–700 nm, and compared them with the absorbance spectra of melanin and hemoglobin.

Results: SDA of epidermal pigmentary disorders was similar to the absorption spectrum of melanin in vitro, but the cases with intradermal melanin deposition showed a different pattern, reflecting the scattering effect of the dermis. SDA of erythematous lesions was similar to the spectra of either oxygenated or reduced hemoglobin, and varied according to the oxygenated level of cutaneous blood. SDA of lesions with a combination of factors appeared as a simple summation of spectra corresponding to each of the factors.

Conclusion: Our method may offer easy and quick detection of major pathophysiological changes in skin lesions.
Reconstructions in limited‐view thermoacoustic tomography
Authors: Xu Yuan , Wang Lihong V. , Ambartsoumian Gaik , Kuchment Peter
Published: April 2004

The limited‐view problem is studied for thermoacoustic tomography, which is also referred to as photoacoustic or optoacoustic tomography depending on the type of radiation for the induction of acoustic waves. We define a “detection region,” within which all points have sufficient detection views. It is explained analytically and shown numerically that the boundaries of any objects inside this region can be recovered stably. Otherwise some sharp details become blurred. One can identify in advance the parts of the boundaries that will be affected if the detection view is insufficient. If the detector scans along a circle in a two‐dimensional case, acquiring a sufficient view might require covering more than a π‐, or less than a π‐arc of the trajectory depending on the position of the object. Similar results hold in a three‐dimensional case. In order to support our theoretical conclusions, three types of reconstruction methods are utilized: a filtered backprojection (FBP) approximate inversion, which is shown to work well for limited‐view data, a local‐tomography‐type reconstruction that emphasizes sharp details (e.g., the boundaries of inclusions), and an iterative algebraic truncated conjugate gradient algorithm used in conjunction with FBP. Computations are conducted for both numerically simulated and experimental data. The reconstructions confirm our theoretical predictions.
Segmentation of IMRT plans for radical lung radiotherapy delivery with the step‐and‐shoot technique
Authors: Nioutsikou Elena , Bedford James L. , Christian Judith A. , Brada Michael , Webb Steve
Published: April 2004

The purpose of this work was to determine a segmentation protocol for the treatment of localized non‐small‐cell lung cancer (NSCLC) with intensity‐modulated radiotherapy (IMRT) that is as effective as possible while practically simple and hence robust to known practical inaccuracies. This study focused on the stratification of continuous profiles into a discrete number of intensity levels. The selection of the segmentation parameters for the delivery of the fluence profiles using multiple static fields has been considered. Five‐field equispaced IMRT treatment plans of five patients with NSCLC were selected. The study comprised nine treatment plans for each patient, starting from a conformal plan, optimizing it for IMRT and then segmenting it utilizing different numbers of segments in each case and optimizing for segment weights separately. A conformal plan, optimized for beam directions, collimator and wedge angles, was also used for comparison with the IMRT plans, so as to consider the best coplanar conformal case. A dose objective for the PTV and the organs‐at‐risk plus a constraint for the spinal cord were set for all inverse plans. All stages were compared with the aid of dose‐volume histograms, dose distributions at the plane of the isocenter, intensity maps for key beams and plots of PTV homogeneity and overall conformality versus complexity. The unsegmented IMRT plans gave the best results but cannot be realized in practice with an MLC. They were best approximated by plans that needed 106–167 segments to deliver, but did not deteriorate significantly when approximated by plans which required 26–40 segments in total. All segmented IMRT plans gave a better lung sparing than the conformal plans, indicating that the deterioration of IMRT plans following segmentation is not equivalent to that of unmodulated, conformal plans. However, optimized conformal plans have the potential to approach the lung sparing achieved by segmented IMRT plans. Among the IMRT situations examined, five‐field treatment plans for the lung, utilizing a maximum of 40 segments in total, have proven to give a good approximation of the IMRT plans with continuous modulation.
Absolute dosimetry in a fast neutron beam
Authors: Bourhis‐Martin E. , Brede H. J. , Greif K.‐D. , Baumhoer W. , Rassow J. , Sauerwein W.
Published: April 2004

Since 1978, the Universitätsklinikum in Essen operates a fast neutron beam for patient treatment. Dosimetric studies were performed in a rectangular neutron/photon field using a transportable water calorimeter, which had been developed at the Physikalisch‐Technische Bundesanstalt. The water calorimeter allowed small dosimeters to be directly calibrated in units of absorbed dose‐to‐water in a cylindrical phantom of 50 mm in diameter. Also, the twin detector method was applied in order to determine the photon and the neutron dose separately. By making use of a calibrated ionization chamber, the absorbed dose‐to‐water calibration in the cylindrical water phantom was transferred to a water phantom, a cube 300 mm on a side. Experiments and Monte Carlo calculations covering the neutron producing target, the collimator and the influence of the water calorimeter on the spectral neutron fluence at the measurement position allow the relative uncertainty of the absorbed dose‐to‐water determination to be reduced to 2.6% (1 SD). This direct absorbed dose‐to‐water determination by calorimetry has shown that the treatment planning system underestimates the physical dose to tissue by 9%. For clinical purposes, the statement of the prescribed dose had to be increased by 9% in order that the absolute absorbed dose remains constant and that the same biological endpoints are reached.
Influence of initial electron beam parameters on Monte Carlo calculated absorbed dose distributions for radiotherapy photon beams
Authors: Tzedakis Antonis , Damilakis John E. , Mazonakis Michael , Stratakis John , Varveris Haralambos , Gourtsoyiannis Nicholas
Published: April 2004

Our aim in the present study was to investigate the effects of initial electron beam characteristics on Monte Carlo calculated absorbed dose distribution for a linac 6 MV photon beam. Moreover, the range of values of these parameters was derived, so that the resulted differences between measured and calculated doses were less than 1%. Mean energy, radial intensity distribution and energy spread of the initial electron beam, were studied. The method is based on absorbed dose comparisons of measured and calculated depth‐dose and dose‐profile curves. All comparisons were performed at 10.0 cm depth, in the umbral region for dose‐profile and for depths past maximum for depth‐dose curves. Depth‐dose and dose‐profile curves were considerably affected by the mean energy of electron beam, with dose profiles to be more sensitive on that parameter. The depth‐dose curves were unaffected by the radial intensity of electron beam. In contrast, dose‐profile curves were affected by the radial intensity of initial electron beam for a large field size. No influence was observed in dose‐profile or depth‐dose curves with respect to energy spread variations of electron beam. Conclusively, simulating the radiation source of a photon beam, two of the examined parameters (mean energy and radial intensity) of the electron beam should be tuned accurately, so that the resulting absorbed doses are within acceptable precision. The suggested method of evaluating these crucial but often poorly specified parameters may be of value in the Monte Carlo simulation of linear accelerator photon beams.
Contextually Evoked Object-Specific Responses in Human Visual Cortex
Authors: Cox David , Meyers Ethan , Sinha Pawan
Published: April 2004

Human visual recognition processes are remarkably robust and can function effectively even under highly degraded viewing conditions. Contextual information may play a critical role in such circumstances. Here, we provide neurophysiological evidence that contextual cues can elicit object-specific neural responses, which have hitherto been believed to be based on intrinsic cues alone. Specifically, we find that the “fusiform face area” (FFA) maintains its selectivity for faces without regard to whether the faces are defined intrinsically or contextually. This finding further elucidates the role of the FFA and reveals neural correlates of contextual processing in the service of robust object recognition.
Organization of
lin
Genes and IS
6100
among Different Strains of Hexachlorocyclohexane-Degrading
Sphingomonas paucimobilis
: Evidence for Horizontal Gene Transfer
Authors: Dogra Charu , Raina Vishakha , Pal Rinku , Suar Mrutyunjay , Lal Sukanya , Gartemann Karl-Heinz , Holliger Christof , van der Meer Jan Roelof , Lal Rup
Published: April 2004

The organization of
lin
genes and IS
6100
was studied in three strains of
Sphingomonas paucimobilis
(B90A, Sp+, and UT26) which degraded hexachlorocyclohexane (HCH) isomers but which had been isolated at different geographical locations. DNA-DNA hybridization data revealed that most of the
lin
genes in these strains were associated with IS
6100
, an insertion sequence classified in the IS
6
family and initially found in
Mycobacterium fortuitum.
Eleven, six, and five copies of IS
6100
were detected in B90A, Sp+, and UT26, respectively. IS
6100
elements in B90A were sequenced from five, one, and one regions of the genomes of B90A, Sp+, and UT26, respectively, and were found to be identical. DNA-DNA hybridization and DNA sequencing of cosmid clones also revealed that
S. paucimobilis
B90A contains three and two copies of
linX
and
linA
, respectively, compared to only one copy of these genes in strains Sp+ and UT26. Although the copy number and the sequence of the remaining genes of the HCH degradative pathway (
linB
,
linC
,
linD
, and
linE
) were nearly the same in all strains, there were striking differences in the organization of the
linA
genes as a result of replacement of portions of DNA sequences by IS
6100
, which gave them a strange mosaic configuration. Spontaneous deletion of
linD
and
linE
from B90A and of
linA
from Sp+ occurred and was associated either with deletion of a copy of IS
6100
or changes in IS
6100
profiles. The evidence gathered in this study, coupled with the observation that the G+C contents of the
linA
genes are lower than that of the remaining DNA sequence of
S. paucimobilis
, strongly suggests that all these strains acquired the
linA
gene through horizontal gene transfer mediated by IS
6100
. The association of IS
6100
with the rest of the
lin
genes further suggests that IS
6100
played a role in shaping the current
lin
gene organization.
Transcriptional Organization and Posttranscriptional Regulation of the
Bacillus subtilis
Branched-Chain Amino Acid Biosynthesis Genes
Authors: Mäder Ulrike , Hennig Susanne , Hecker Michael , Homuth Georg
Published: April 2004

In
Bacillus subtilis
, the genes of the branched-chain amino acids biosynthetic pathway are organized in three genetic loci: the
ilvBHC-leuABCD
(
ilv-leu
) operon,
ilvA
, and
ilvD
. These genes, as well as
ybgE
, encoding a branched-chain amino acid aminotransferase, were recently demonstrated to represent direct targets of the global transcriptional regulator CodY. In the present study, the transcriptional organization and posttranscriptional regulation of these genes were analyzed. Whereas
ybgE
and
ilvD
are transcribed monocistronically, the
ilvA
gene forms a bicistronic operon with the downstream located
ypmP
gene, encoding a protein of unknown function. The
ypmP
gene is also directly preceded by a promoter sharing the regulatory pattern of the
ilvA
promoter. The
ilv-leu
operon revealed complex posttranscriptional regulation: three mRNA species of 8.5, 5.8, and 1.2 kb were detected. Among them, the 8.5-kb full-length primary transcript exhibits the shortest half-life (1.2 min). Endoribonucleolytic cleavage of this transcript generates the 5.8-kb mRNA, which lacks the coding sequences of the first two genes of the operon and is predicted to carry a stem-loop structure at its 5′ end. This processing product has a significantly longer half-life (3 min) than the full-length precursor. The most stable transcript (half-life, 7.6 min) is the 1.2-kb mRNA generated by the processing event and exonucleolytic degradation of the large transcripts or partial transcriptional termination. This mRNA, which encompasses exclusively the
ilvC
coding sequence, is predicted to carry a further stable stem-loop structure at its 3′ end. The very different steady-state amounts of mRNA resulting from their different stabilities are also reflected at the protein level: proteome studies revealed that the cellular amount of IlvC protein is 10-fold greater than that of the other proteins encoded by the
ilv-leu
operon. Therefore, differential segmental stability resulting from mRNA processing ensures the fine-tuning of the expression of the individual genes of the operon.