bluuebunny/crossref_metadata_2025 huggingface dataset:
Migraine Accompanied by Hemifacial Spasm: A Case Report
Authors: Husid Marc S.
Published: March 2005

A 36‐year‐old woman has had repeated episodes of concurrent hemifacial spasm and migraine for 8 years. Her history is summarized and possible pathophysiologic links are discussed.
Using Current Evidence in Selecting Antiepileptic Drugs for Use during Pregnancy
Authors: Pennell Page B.
Published: March 2005

Children born to mothers taking antiepileptic drugs (AEDs) are at increased risk for findings of fetal anticonvulsant syndrome. Accepted treatment paradigms to minimize fetal risks include use of AED monotherapy and folic acid supplementation. However, as data are acquired from several ongoing pregnancy registries, differential risks among the various AED monotherapy regimens are being defined, further improving fetal outcomes.
The highly variable RH locus in nonwhite persons hampers RHD zygosity determination but yields more insight into RH‐related evolutionary events
Authors: Grootkerk‐Tax Martine G.H.M. , Maaskant‐van Wijk Petra A. , Van Drunen Judith , Van Der Schoot C. Ellen
Published: March 2005

BACKGROUND: Knowledge about paternal RHD hemi‐ or homozygosity is of clinical interest in alloimmunized pregnant women. D negativity in white persons is usually caused by deletion of the RHD gene. Recently, the physical structure of the RH locus and the mechanism causing the deletion of the RHD gene have been explored, enabling RHD zygosity determination in white persons by specific detection of a hybrid Rhesus box characteristic for the RHD– locus.

STUDY DESIGN AND METHODS: RHD zygosity was determined in 402 samples from five different ethnic groups by polymerase chain reaction (PCR)‐restriction fragment length polymorphism and by a newly developed real‐time quantitative PCR. The Rhesus boxes of samples showing discrepancies between both tests were cycle sequenced.

RESULTS: In nonwhite persons, several mutated Rhesus boxes exist that hamper zygosity determination by detection of the RHD– locus. Such mutated Rhesus boxes in D+RHD homozygous black persons have a frequency of 0.22. In white persons, no mutated Rhesus boxes were encountered so far.

CONCLUSIONS: Owing to the high frequency of the mutated Rhesus boxes, zygosity determination by detection of the RHD– locus is not feasible in nonwhite persons. The cosegregation of variant RHD genes (RHDψ and (C)cdes) with specific mutated Rhesus boxes yields more insight into the evolutionary events concerning variant RHD genes and mutated Rhesus boxes.
Immunization against a low‐frequency human platelet alloantigen in fetal alloimmune thrombocytopenia is not a single event: characterization by the combined use of reference DNA and novel allele‐specific cell lines expressing recombinant antigens
Authors: Kroll Hartmut , Yates Julie , Santoso Sentot
Published: March 2005

BACKGROUND: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal immunization against a fetal platelet (PLT) alloantigen. In cases of FNAIT attributed to low‐frequency PLT alloantigens, the laboratory diagnosis is often hampered by the lack of adequate PLTs.

STUDY DESIGN AND METHODS: Three families with maternal immunization against fetal PLT antigens were analyzed. In Family 1, previous immunization of another female or woman has been observed. In Families 2 and 3, newborns presented with the typical clinical picture of FNAIT. Genotyping was performed by polymerase chain reaction‐restriction fragment length polymorphism and direct sequencing with reference to DNA from Epstein‐Barr virus–transformed B‐lymphoblastoid cell lines. Antibodies were characterized by glycoprotein (GP)‐specific immunoassay with a panel of stable Chinese hamster ovary cell lines expressing low‐frequency alloantigens.

RESULTS: In three families, maternal immunization associated with the low‐frequency alloantigens human PLT antigen (HPA)‐8bw (Sra), HPA‐11bw (Groa), and HPA‐13bw (Sita) was identified. Maternal serum samples showed positive reactions in an antigen capture assay with cell lines carrying recombinant GP IIb/IIIa (HPA‐8bw and ‐11bw) or GPIa/IIa (HPA‐13bw), respectively. These results could be confirmed by genotyping analysis of fathers and newborns.

CONCLUSION: This study demonstrates that cases of FNAIT attributed to low‐frequency PLT alloantigens cannot be regarded as single events. The availability of reference DNA and cell lines expressing recombinant PLT alloantigens can facilitate their identification.
Augmented mobilization and collection of CD34+ hematopoietic cells from normal human volunteers stimulated with granulocyte–colony‐stimulating factor by single‐dose administration of AMD3100, a CXCR4 antagonist
Authors: Liles W. Conrad , Rodger Elin , Broxmeyer Hal E. , Dehner Christine , Badel Karin , Calandra Gary , Christensen Jeff , Wood Brent , Price Thomas H. , Dale David C.
Published: March 2005

BACKGROUND: AMD3100, a selective antagonist of CXCR4, rapidly mobilizes CD34+ hematopoietic progenitor cells (HPCs) from marrow to peripheral blood with minimal side effects.

STUDY DESIGN AND METHODS: To further investigate potential clinical utility of AMD3100 for CD34+ cell mobilization and collection, a Phase I study in normal volunteers was performed examining single‐dose administration of AMD3100 alone and in combination with a standard 5‐day granulocyte–colony‐stimulating factor (G–CSF) regimen.

RESULTS: AMD3100 (160 µg/kg × 1 on Day 5) significantly increased both G–CSF‐stimulated (10 µg/kg/day) mobilization of CD34+ cells (3.8‐fold) and leukapheresis yield of CD34+ cells. Moreover, collection of CD34+ cells was comparable between individuals mobilized by a single‐dose regimen of AMD3100 (240 µg/kg) and individuals mobilized with a 5‐day regimen of G–CSF. AMD3100‐mobilized leukapheresis products contained significantly greater numbers of T and B cells compared to G–CSF‐stimulated leukapheresis products.

CONCLUSION: These findings indicate that AMD3100 can be used alone or as an adjunct to G–CSF to mobilize cells for HPC transplantation.
Minimum conditions of major histocompatibility complex compatibility and recipient immune compromise required to establish donor white blood cell persistence in a murine transfusion model
Authors: Lee Tzong‐Hae , Wen Li , Montalvo Lani , Esho Olubukola , Lowell Cliff , Reed William , Busch Michael
Published: March 2005

BACKGROUND: In some patients multiply transfused to treat severe trauma, white blood cells (WBCs) from a single blood donor can persist for years, constituting up to 5 percent of all circulating WBCs. The immunologic mechanisms responsible for this are not known but, if understood, might allow manipulation of the human immune system to induce microchimerism for a variety of therapeutic purposes. To better characterize these mechanisms, a murine transfusion model was developed with a panel of immunologic knockouts as transfusion recipients. By conducting a systematic series of transfusion experiments, the purpose was to determine which recipient immune cell population, when abrogated, could lead to prolonged survival of donor cells (microchimerism).

STUDY DESIGN AND METHODS: Blood was transfused from normal donors to knockout recipients in syngeneic, allogeneic, and xenogeneic settings. Donor WBC survival was evaluated by quantitative polymerase chain reaction, and recipient lymphocyte subsets by fluorescence‐activated cell sorting.

RESULTS: In the syngeneic setting, donor WBCs persisted in C2ta, RAG‐1, and TCR knockout recipients. Allogeneic donor WBCs persisted in RAG‐2 and RAG‐2/Common gamma knockout recipients. Xenogeneic donor WBCs required RAG‐2/Common gamma and RAG‐2/Pfp double knockouts to persist.

CONCLUSION: It is concluded that donor‐recipient major histocompatibility complex (MHC) concordance alone is not sufficient to achieve microchimerism. Further, the degree of recipient immune compromise necessary to achieve persistent microchimerism is directly proportional to the degree of donor‐recipient MHC disparity.
Nucleic acid test screening of blood donors for orthopoxviruses can potentially prevent dispersion of viral agents in case of bioterrorism
Authors: Schmidt Michael , Roth W. Kurt , Meyer Hermann , Seifried Erhard , Hourfar Michael K.
Published: March 2005

BACKGROUND:Microbiologic agents such as variola virus (VAR) are very attractive for terrorism. As a result of international collaboration under the WHO eradication campaign, smallpox was declared eradicated in 1980. Therefore, the immunization programs were discontinued worldwide. Because most people are now immunologically naive, VAR is considered to be a potential threat agent or bioterrorist weapon. Real‐time polymerase chain reaction (PCR) followed by melting analysis was developed for fast and safe analysis and allows differentiation of VAR from other orthopoxviruses (OPVs) like vaccinia or camelpox virus.

STUDY DESIGN AND METHODS:A RealArtTMOrthopox LC PCR kit (Artus GmbH) was used to amplify OPV sequences from blood donor samples. A total of 31,500 blood donor samples were tested in minipools of up to 96 samples. To evaluate the sensitivity of the assay, routine donor minipools (90 ± 6 samples per pool) were spiked with vaccinia virus used as positive control.

RESULTS:Specificity was 100 percent because none of 31,500 blood donors was positive for the presence OPV. The detection limit of the assay was 10.6 copies per PCR procedure. Therefore, a sensitivity of 1590 copies per mL was calculated. Overall, 0.28 percent of test results had to be considered invalid owing to negative internal controls.

CONCLUSION:The RealArt Orthopox LC PCR kit enables reliable detection of OPV DNA in viremic blood donor samples, even at the beginning of the disease when patients present minor clinical symptoms, and could be implemented in our routine screening procedure immediately. Thus, the assay could potentially help to prevent dispersion of viral agents by blood transfusion in case of bioterrorism.
Plateletpheresis does not cause long‐standing platelet‐derived growth factor release into the donor blood
Authors: Zimmermann Robert , Loew Daniela , Weisbach Volker , Strasser Erwin , Ringwald Juergen , Zingsem Juergen , Eckstein Reinhold
Published: March 2005

BACKGROUND: Recently, long‐standing elevations of soluble growth factors released from platelets (PLTs) after contact with artificial surfaces during dialysis were described. They could be jointly responsible for the high frequency of death from cardiovascular diseases in dialysis patients. There are no comparable data on the extent and the duration of a growth factor release by plateletpheresis procedures.

STUDY DESIGN AND METHODS: A total of 37 plateletpheresis procedures were performed with two different devices. PLT‐derived growth factor (PDGF) isoform AB, transforming growth factor (TGF)‐β1, and β‐thromboglobulin (β‐TG) were measured in the donors’ plasma samples, and PLT activation and function were measured by cytometry and aggregometry before and after plateletpheresis and 1 and 24 hours later.

RESULTS: Before apheresis, the following mean plasma levels were found: β‐TG, 98.6 ± 37.3 IU per mL; PDGF‐AB, 71.5 ± 38.5 pg per mL; and TGF‐β1, 2.24 ± 0.80 ng per mL. At the end of the apheresis procedures, the mean PDGF‐AB level had increased by a factor of 1.8 (p < 0.05). One hour later, the mean PDGF‐AB level had normalized again. No significant change in the levels of β‐TG and TGF‐β1 was found by the apheresis procedures. There was no influence of the blood cell separator type on the results.

CONCLUSION: Only a slight and rapidly reversible increase in soluble PDGF‐AB was found during plateletpheresis and no increase in soluble TGF‐β1 and β‐TG was found. This change should not be harmful to the donor.
Genetic mechanisms of Rhesus box variation
Authors: Wagner Franz F. , Moulds Joann M. , Flegel Willy A.
Published: March 2005

BACKGROUND: The RHD gene is flanked by two highly homologous DNA segments of approximately 9000 bp, the upstream and downstream Rhesus boxes. In haplotypes with an RHD deletion, the fusion of the two Rhesus boxes generates the single‐hybrid Rhesus box, the detection of which has been applied for RHD zygosity determination. Aberrant Rhesus boxes can confound this application and appear to be frequent among African individuals.

STUDY DESIGN AND METHODS: A total of 5850 bp of the upstream and of the downstream Rhesus boxes were sequenced in 18 samples that were representative for all four D clusters and of the hybrid Rhesus boxes in four samples that were mistyped in assays for the hybrid Rhesus box.

RESULTS: The known differences between upstream and downstream Rhesus boxes were in part restricted to subsets of RHD alleles. Forty‐six additional polymorphisms were detected and caused by single‐nucleotide substitutions, short insertions, or deletions. Gene conversions were found in the upstream Rhesus boxes of RHDψ, DAU‐1, and DAU‐3 and in the downstream Rhesus boxes of Ccdes, weak D type 4.1, type 4.2 (DAR), and DAU‐0. Recombinations between haplotypes were likely in several alleles like DIII type 4. Four nonstandard hybrid Rhesus boxes were suggestive of multiple RHD deletion events.

CONCLUSION: There is considerable variation of Rhesus box sequences associated with distinct RHD alleles. RHD zygosity diagnostics in African persons is best based on quantitative polymerase chain reaction or amplification of the full‐length hybrid Rhesus box. Because aberrant Rhesus boxes were observed among European persons, use of more than one method for hybrid Rhesus box detection may even be advisable in European persons.
An alternative hibernation strategy involving sun‐exposed ‘hotspots’, dispersal by flight, and host plant finding by olfaction in an alpine leaf beetle
Authors: Kalberer Nicole M. , Turlings Ted C. J. , Rahier Martine
Published: March 2005

Oreina cacaliae (Schrank) (Coleoptera: Chrysomelidae) has a 2‐year life cycle that it has to complete within the short warm seasons of the harsh alpine environment. Three years of field observations and experiments revealed that not all beetles overwintered in the soil next to their principal host Adenostyles alliariae (Asteraceae), as was previously assumed, but that many O. cacaliae left their host in autumn and flew to overwintering sites that were extensively sun‐exposed. In spring, these individuals became active 2 months earlier than their conspecifics that had remained in the soil close to the host plant. These early beetles flew from their hibernation sites against the direction of the prevailing wind. After a random landing in snow, they walked to the spring host Petasites paradoxus (Asteraceae) and fed on its floral stalks, the only plant parts present at that time. A few weeks later, they took flight again to locate newly emerging A. alliariae on which they would feed and deposit larvae as did individuals that had overwintered close to A. alliariae. Leaves of A. alliariae contain pyrrolizidine alkaloids (PAs), which the beetles sequester for their own defence. The dominating PA (seneciphylline) was also found to be present in the floral stalks of P. paradoxus. With additional behavioural assays in the field and laboratory, we demonstrated the importance of plant odours in the short‐range host location process. This study reveals a unique hibernation behaviour in which part of the beetle population uses exceptionally warm locations from which they emerge in spring, long before all the snow has melted. This early, but risky emergence allows them to exploit a second, highly suitable host plant, which they locate first by wind‐guided flight and then by odour‐guided walking. The well‐fed beetles then use odour again to move to their principal host plant, on which they reproduce.
Evidence for regional diversity and host adaptation in Iranian populations of the Russian wheat aphid
Authors: Dolatti L. , Ghareyazie B. , Moharramipour S. , Noori‐Daloii M. R.
Published: March 2005

Effective pest management is greatly facilitated by knowledge of the genetic structure and host adaptation of the pest species in question. The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) (Homoptera: Aphididae: Macrosiphini), is an important economic pest in many cereal‐growing areas of the world, and in this study we investigated these aspects of its populations, using microsatellite markers and host plant response assays. Diuraphis noxia was sampled from 38 locations in Iran and genotyped at four polymorphic microsatellite loci that had been isolated from various Sitobion species. We identified 50 multilocus genotypes in 376 individuals. The overall observed heterozygosity was 0.134. F‐statistics showed a regional partitioning in D. noxia populations with overall FST = 0.231. In addition, there was a significant correlation between genetic and geographic distances. In order to test for the ecological consequences of genetic variability in D. noxia, biotypic variation amongst the isolates collected from wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) was evaluated on a number of resistant and susceptible wheat varieties. The plant variables we measured were damage rating (based on leaf chlorosis, leaf rolling, wilting, and death of the host plant), host plant dry weight, and root length. Damage rating was the best criterion for detecting biotypic variation in D. noxia. Discriminant analysis correctly classified the isolates in respective groups in 80–91.8% of the cases. The barley isolate showed no differences in performance on resistant and susceptible wheat, indicating a lack of gene‐by‐gene relationship with wheat plants. In contrast, wheat isolates differentially damaged the resistant and susceptible plants and showed moderate to severe virulence.
Effects of the Cry1Ac toxin of Bacillus thuringiensis on Microplitis mediator, a parasitoid of the cotton bollworm, Helicoverpa armigera
Authors: Liu Xiaoxia , Zhang Qingwen , Zhao Jian‐Zhou , Cai Qingnian , Xu Huanli , Li Jiancheng
Published: March 2005

Interactions between the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), its larval parasitoid Microplitis mediator (Haliday) (Hymenoptera: Braconidae), and the Cry1Ac toxin of Bacillus thuringiensis Berliner were evaluated under laboratory conditions. The growth of H. armigera larvae was delayed and its pupal rate and pupal weight decreased when they were fed on a diet containing Cry1Ac toxin. Due to the lowered growth rate of the host larvae, the time available for parasitization of H. armigera by M. mediator increased when the host larvae were reared on a diet containing Cry1Ac toxin at concentrations of 0.5, 1, 2, and 4 µg g−1. The longevity of female and male parasitoids was not significantly affected when newly emerging wasps fed on honey solutions containing three different concentrations of Cry1Ac toxin (125, 250, and 500 µg ml−1). When female parasitoids were fed on honey solutions containing Cry1Ac, their offsprings’ egg and larval development period, pupal weight, length of pupation, adult weight, and adult longevity did not change significantly in most of the treatments compared with controls. When the female parasitoids parasitized host larvae that had been fed on a diet containing 0.5, 1, 2, 4, and 8 µg g−1 Cry1Ac toxin, their offsprings’ eggs and larvae were significantly delayed. Their pupal weight, adult weight, and adult longevity were also significantly less than controls.
Prevalence and distribution of oral lesions: a cross‐sectional study in Turkey
Authors: Mumcu G , Cimilli H , Sur H , Hayran O , Atalay T
Published: March 2005

Objectives:  The purpose of this study was to evaluate the prevalence and distribution of oral lesions (OLs) in Turkish population.

Subjects and Methods:  In this cross‐sectional study, 765 residents (F/M: 375/390) were selected by the cluster sampling method and examined according to WHO criteria.

Results:  Excessive melanin pigmentation (6.9%) was the most common lesion in the study population. The tongue lesions observed in this study were as follows: fissured tongue (5.2%), varices (4.1%), hairy tongue (3.8%), geographic tongue (1.0%), atrophic tongue papillae (0.7%) and ankyloglossia (0.3%). The denture‐related lesions were denture stomatitis (4.3%), suction irritation (0.8%), denture hyperplasia and torus palatinus as bony lesion (0.5%) and traumatic ulcers (0.3%). In regression analysis, being 65 years old and over was found as a statistically significant risk factor for the occurrence of pigmentation, fissured tongue, varices, hairy tongue, denture stomatitis and petechiae (P < 0.05).

Conclusions:  Pigmentation, fissured tongue and denture stomatitis were observed to be the most common lesions in Turkish population. Elderly population was a significant risk factor for occurrence of some OLs.
A case of chronic calcium pyrophosphate dihydrate crystal disease (tophaceous pseudogout) in the temporomandibular joint
Authors: Meul B , Ernestus K , Neugebauer J , Kuebler AC
Published: March 2005

Pseudogout is a rare joint disease which is characterized by the presence of calcium pyrophosphate dihydrate crystals in the intraarticular and periarticular tissue. The crystals tend to attach to fibrocartilage tissue. Pseudogout principally affects the knee and wrist joints. Involvement of the temporomandibular joint (TMJ) is very rare. There have been <20 cases reported world‐wide. Both acute and chronic manifestations have been described. We present here an unusual case that necessitated a high condylectomy.
Expression and description of chronic pain by older people
Authors: Gartrell Margaret
Published: March 2005

Chronic or persistent pain is a complex phenomenon. The incidence of chronic pain is common among older people and unfortunately it is often disabling. The experience of chronic pain is highly individual and influenced by a range of factors. Expression and description of one's pain experience is also individual in nature. Health care providers are often involved in the identification, treatment and management of persistent pain conditions. Do they really listen to and understand what older people are saying and describing? An investigation of factors relating to pain expression and description by older people will be undertaken in this literature review. Further research is recommended to gain a better understanding of how older people express pain. The issues relating to health care provider's understanding of older people's description and expression of pain also warrants further exploration.
Addressing elder abuse: Western Australian case study
Authors: Boldy Duncan , Horner Barbara , Crouchley Kathy , Davey Margaret , Boylen Stephen
Published: March 2005

Objective:  To explore the extent of elder abuse in Western Australia and associated aspects, such as the relationship of the abuser to the victim, risk factors and desirable interventions, and current knowledge and use of relevant protocols.

Methods:  A mail‐out questionnaire was sent to over 1000 organisations and 129 general practitioners (GPs). Recipients were asked to identify any known or suspected cases of elder abuse encountered during the previous 6 months.

Results:  The estimated prevalence of elder abuse was 0.58% (in individuals 60+ years). Females and those 75 years and older were more at risk than males or those younger. Financial abuse was the most common, and frequently more than one type of abuse was suffered by the same person. The main abusers were adult children or other relatives.

Conclusion:  The importance of education targeted at professionals, the general public and older people themselves was evident. Important direct interventions identified included respite care, advocacy and counselling.
Well‐being in later life through music
Authors: Hays Terrence
Published: March 2005

Objectives:  This qualitative study maps the diversity of the experience of music for older people and focuses on the emotional, social and time management roles that music plays in their lives.

Methods:  In‐depth and focus group interviews were used to explore the meaning, importance and function of music for 54 older people living in the community aged 60 years and older.

Results:  The findings revealed that music provides people with ways of understanding and developing their self‐identity and maintaining well‐being. Music contributes to positive ageing by providing ways for people to maintain positive self‐esteem, feel competent, independent, and avoid feelings of isolation and loneliness.

Conclusions:  The study argues that music can be used by older people to facilitate and improve well‐being, and the need for gerontologists to become more aware of the potential of music.
Another minority group: use of aged care day programs and community leisure services by older people with lifelong disability
Authors: Bigby Christine , Balandin Susan
Published: March 2005

Objective:  This study examined the extent to which programs available to the general aged community are accessible to older people with lifelong disability.

Method:  Forty Victorian generic aged day activity and community leisure programs used by older people responded to a survey that sought information on the extent to which such services are used by older people with a lifelong disability.

Results:  More than half of these services are accessed by a small number of people with lifelong disability and overall there was a willingness to include this group in generic services. Barriers and solutions to successful generic service use were reported.

Conclusions:  The findings indicate that the issues for people with lifelong disability differ little from those of other minority groups. It is proposed that disability services have a role in brokering services for their older clients, and continued planning and collaboration between disability and aged services will benefit all older people.
Living and giving: older Australians and charitable donations
Authors: Steinberg Margaret A , Crow Rebekah , Cain Lara , Milford Cate
Published: March 2005

Objectives:  With shifts in the age structure of the Australian population having profound effects on individuals, families and society, including giving, this study aims to better understand the role of older Australians in donations to charity.

Method:  The availability of unique, one‐off, customised Australian Tax Office data for the year 1999–2000, provided to the Centre of Philanthropy and Nonprofit Studies at the Queensland University of Technology, has allowed an examination of the relationship between age and charitable giving.

Results:  The proportionate number of donors and the percent of money donated by Australians were higher amongst older Australians.

Conclusion:  Older Australians play a significant role in supporting charitable organisations.
Phase‐dependent and task‐dependent modulation of stretch reflexes during rhythmical hand tasks in humans
Authors: Xia Ruiping , Bush Brian M. H. , Karst Gregory M.
Published: March 2005

Phase‐dependent and task‐dependent modulation of reflexes has been extensively demonstrated in leg muscles during locomotory activity. In contrast, the modulation of reflex responses of hand muscles during rhythmic movement is poorly documented. The objective of this study was to determine whether comparable reflex modulation occurs in muscles controlling finger motions during rhythmic, fine‐motor tasks akin to handwriting. Twelve healthy subjects performed two rhythmic tasks while reflexes were evoked by mechanical perturbations applied at various phases of each task. Electromyograms (EMGs) were recorded from four hand muscles, and reflexes were averaged during each task relative to the movement phase. Stretch reflexes in all four muscles were found to be modulated in amplitude with respect to the phase of the rhythmic tasks, and also to vary distinctly with the tasks being conducted. The extent and pattern of reflex modulation differed between muscles in the same task, and between tasks for the same muscle. Muscles with a primary role in each task showed a higher correlation between reflex response and background EMG than other muscles. The results suggest that the modulation patterns observed may reflect optimal strategies of central–peripheral interactions in controlling the performance of fine‐motor tasks. As with comparable studies on locomotion, the phase‐dependency of the stretch reflexes implies a dynamically fluctuating role of proprioceptive feedback in the control of the hand muscles. The clear task‐dependency is also consistent with a dynamic interaction of sensory feedback and central programming, presumably adapted to facilitate the successful performance of the different fine‐motor tasks.
After‐effects of near‐threshold stimulation in single human motor axons
Authors: Bostock Hugh , Lin Cindy Shin‐Yi , Howells James , Trevillion Louise , Jankelowitz Stacey , Burke David
Published: March 2005

Subthreshold electrical stimuli can generate a long‐lasting increase in axonal excitability, superficially resembling the phase of superexcitability that follows a conditioning nerve impulse. This phenomenon of ‘subthreshold superexcitability’ has been investigated in single motor axons in six healthy human subjects, by tracking the excitability changes produced by conditioning stimuli of different amplitudes and waveforms. Near‐threshold 1 ms stimuli caused a mean decrease in threshold at 5 ms of 22.1 ± 6.0% (mean ±s.d.) if excitation occurred, or 6.9 ± 2.6% if excitation did not occur. The subthreshold superexcitability was maximal at an interval of about 5 ms, and fell to zero at 30 ms. It appeared to be made up of two components: a passive component linearly related to conditioning stimulus amplitude, and a non‐linear active component. The active component appeared when conditioning stimuli exceeded 60% of threshold, and accounted for a maximal threshold decrease of 2.6 ± 1.3%. The passive component was directly proportional to stimulus charge, when conditioning stimulus duration was varied between 0.2 and 2 ms, and could be eliminated by using triphasic stimuli with zero net charge. This change in stimulus waveform had little effect on the active component of subthreshold superexcitability or on the ‘suprathreshold superexcitability’ that followed excitation. It is concluded that subthreshold superexcitability in human motor axons is mainly due to the passive electrotonic effects of the stimulating current, but this is supplemented by an active component (about 12% of suprathreshold superexcitability), due to a local response of voltage‐dependent sodium channels.
In vivo recordings from rat geniculate ganglia: taste response properties of individual greater superficial petrosal and chorda tympani neurones
Authors: Sollars Suzanne I. , Hill David L.
Published: March 2005

Coding of gustatory information is complex and unique among sensory systems; information is received by multiple receptor populations located throughout the oral cavity and carried to a single central relay by four separate nerves. The geniculate ganglion is the location of the somata of two of these nerves, the greater superficial petrosal (GSP) and the chorda tympani (CT). The GSP innervates taste buds on the palate and the CT innervates taste buds on the anterior tongue. To obtain requisite taste response profiles of GSP neurones, we recorded neurophysiological responses to taste stimuli of individual geniculate ganglion neurones in vivo in the rat and compared them to those from the CT. GSP neurones had a distinct pattern of responding compared to CT neurones. For example, a small subset of GSP neurones had high response frequencies to sucrose stimulation, whereas no CT neurones had high response frequencies to sucrose. In contrast, NaCl elicited high response frequencies in a small subset of CT neurones and elicited moderate response frequencies in a relatively large proportion of GSP neurones. The robust whole‐nerve response to sucrose in the GSP may be attributable to relatively few, narrowly tuned neurones, whereas the response to NaCl in the GSP may relate to proportionately more, widely tuned neurones. These results demonstrate the diversity in the initial stages of sensory coding for two separate gustatory nerves involved in the ingestion or rejection of taste solutions, and may have implications for central coding of gustatory quality and concentration as well as coding of information used in controlling energy, fluid and electrolyte homeostasis.
Dispersion analysis of reflection and transmission by a plane boundary—a graphical approach
Authors: Kong J. A.
Published: March 2005

A graphical method is illustrated to treat reflection and transmission of a plane wave by a stationary boundary. The method is simple and useful in introducing Snell’s law, critical angles, evanescence, backward waves, and in dealing with wave behavior at interfaces separating nonisotropic, linear media.
Resource letter MA-1: Musical acoustics
Authors: Rossing Thomas D.
Published: March 2005

Prepared at the request of the AAPT Editorial Board for Resource Letters. This is one of a series of Resource Letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course contents in specified fields. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter on some of the main subjects of interest. Comments on these materials as well as suggestions for future topics will be welcomed. Please send such communications to Professor Aaron Owens, Editor, Resource Letter Board, Department of Physics, Lake Forest College, Lake Forest, IL 60045.

Reprints: When ordering, request Resource Letter MA-1. Enclose 75 cents per copy (not in stamps) together with a stamped and self-addressed envelope and send to: Executive Office, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, NY 11794.
Relativistic rotation of axes under successive Lorentz transformations
Authors: Weihofen William H.
Published: March 2005

Expressions for the relative rotation of coordinate systems resulting from translational Lorentz transformations are derived heuristically. Both the general case and useful first order (in v/c) approximation are treated. The exact results for circular motion and for uniform rectilinear velocity changes are given in practicable form.
Irreversibility, entropy production, and thermal efficiency
Authors: Leff Harvey S. , Jones Gerald L.
Published: March 2005

The relationships between the entropy production per cycle and the thermal efficiency are investigated for a class of irreversible cyclic processes. Examples are given that pinpoint specific sources of irreversibility and their thermodynamic consequences. It is found that an increase (decrease) in an irreversible cycle’s thermal efficiency does not necessarily lead to a decrease (increase) in its entropy production even if the work done per cycle is held constant. Only for the case of a reversible Carnot cycle is it guaranteed that a change (negative for this case) in the efficiency is met by an entropy production change of opposite algebraic sign. Sufficiency conditions are found for which the entropy production and the efficiency η are inversely related for more general cyclic processes. For a given set of heat reservoirs and specified values of the work output W, the absolute minimum and maximum entropy productions are determined and are shown to be monotonically decreasing functions of η for fixed W. It is shown also that, for an irreversible cycle with maximum and minimum temperatures T+ and T−, respectively, η? (1−T−/T+)(1+T−ΔS/W)−1, where ΔS is the entropy production per cycle. The equality holds only for a cycle employing two reservoirs. The potential relevance of these results to environmental and technological problems is mentioned.
Conserved and piecewise-conserved Runge vectors for the isotropic harmonic oscillator
Authors: Buch Lawrence H. , Denman Harry H.
Published: March 2005

A procedure for constructing a Runge vector for a particle moving (classically or relativistically) under any central force has been given by Fradkin. Serebrennikov and Shabad have pointed out that such vectors may be piecewise conserved, rather than constants for the entire motion. It is shown herein that, for the classical isotropic harmonic oscillator, the above procedure can lead to a piecewise-conserved Runge vector as well as to a conserved one (of the same magnitude). We relate this ambiguity to the symmetries of the orbit.
Binding energy of the deuteron: A laboratory experiment
Authors: Mudhole T.S. , Umakantha N.
Published: March 2005

The binding energy of the deuteron is determined by studying the monoenergetic photons produced in the capture of thermal neutrons by protons. (AIP)
The universe as a black hole
Authors: Freeman Ira M.
Published: March 2005

Using only Newtonia’s law of gravitation and the classical expression for centripetal force, the black hole radius is derived. (AIP)
Quantum heuristics of angular momentum
Authors: Lévy-Leblond Jean-Marc
Published: March 2005

An elementary approach to the quantum theory of angular momentum is sketched. The quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus are introduced without using operators or commutation relations. The purpose is to focus the attention on angular momemtum as a very important practical concept of quantum physics, as well as on its specifically quantum-theoretical aspects, right from the beginning of an introductory course. Since the heuristic arguments employed here closely parallel the rigorous derivations of a formal approach, the intuitive presentation does not contradict, but rather supports, the theoretical concepts to be introduced at a later stage.
Bound-state models from Gelfand–Levitan theory
Authors: Klein James R.
Published: March 2005

The Gelfand–Levitan formulation of the inverse problem is briefly reviewed and then used as a source of exactly solvable bound-state models which are suitable for examples in quantum mechanics courses. The case of one bound state is discussed in detail with emphasis on the role of the arbitrary normalization constant and its connection with physical parameters. An application to the deuteron is given. Possible pedagogical uses of these models are cited.
Appearance of a rapidly moving sphere: A problem for undergraduates
Authors: Hollenbach David
Published: March 2005

A simplification of the problem concerning the visual appearance of a rapidly moving sphere is presented. The approach brings out the uncontracted appearance of the sphere and its apparent rotation through the angle ϑ=sin−1(v/c) when viewed at an angle perpendicular to its motion. The problem is shown to be sufficiently simple to be a homework assignment in an undergraduate relativity course.
Energy and momentum transport in string waves
Authors: Juenker D. W.
Published: March 2005

Formulas are derived for the energy, momentum, and angular momentum transmitted by waves of arbitrary shape in an inextensible string and by pure transverse waves in a suitably extensible string. The analysis is based on Tait’s procedure of viewing the wave from a moving frame of reference, and its application to the inextensible string, at least, is simple enough for use in elementary physics courses. The same method is used to find the elastic condition on an extensible string necessary for the propagation of mutually coherent shape and density waves. It is shown that the perfect transverse string waves referred to in textbooks can only be propagated in strings of the ideal Slinky spring type, and that they are incapable of carrying net momentum.
General physics as a major
Authors: Peckham Donald C. , Romer Alfred
Published: March 2005

A three-year general physics major has been in operation for five years. It uses a single text from which a sequence of three one-year courses has been constructed by using a modified spiral approach. Laboratory work is required in each course, culminating in an experimental project during the sixth semester. The advantages gained are unity of presentation and economy of time. This economy benefits the physics staff; it also benefits the students by permitting a wider election of courses. The three-year sequence can be entered directly by well-prepared freshmen or preceded by a college-level introductory course. A special program during the opening of the fall semester helps freshmen to choose between the two options.
Conservation of angular momentum—a demonstration
Authors: Klostergaard Henry
Published: March 2005

An induction motor is modified to allow its housing (H) and its armature (A) to rotate freely and independently about their common axis. When an alternating potential difference is applied, H and A start rotating in opposite directions, which suggests conservation of angular momentum; this is quantitatively verified by finding that no torque is required to tilt the direction of the axis of rotation. If, however, either H or A is prevented from rotating, a considerable torque is required for tilting.
Importance of proper phase analysis in using Fourier transforms
Authors: Sheahen Thomas P.
Published: March 2005

Physical systems containing phase information may yield subtle discrepancies in their analysis if complex variables are manipulated carelessly. Modern Fourier transform methods discourage numerical hand-checking of computer outputs, with the result that errors in handling phase can easily escape detection. An illustration of this possibility is drawn from the field of Fourier spectroscopy, but the applicability is much wider.
Multiple rainbows from single drops of water and other liquids
Authors: Walker Jearl D.
Published: March 2005

The scattering of light by spherical drops and the theory of rainbows are reviewed in detail to predict the angular positions of rainbows from single drops. The angular positions of the first 13 rainbows of water, observed from a drop suspended in a student spectrometer, were compared to these theoretical positions. Since the rainbows were dependent on the refractive index, the positions shifted with drops of other fluids having other refractive indices. Light corn syrup yielded 11 rainbows, including the 17th-order one. The light emerging from the drops was white except for the multicolors of the rainbows and the faint blue of the rays that had been nearly tangentially incident to the drops. With a hand-held polarized filter, all of the observed rainbows appeared to be polarized parallel to the plane of incidence. Using the 6328-Å light from a student He–Ne laser, one of the interference patterns composing all natural rainbows was created and photographed. The angular positions of the principal maxima of this pattern differed from the theoretical rainbow positions predicted by geometrical optics by amounts dependent on the drop radius.
Freshman physics laboratory in a small college overseas
Authors: Behroozi F.
Published: March 2005

The difficulties facing small colleges in setting up and operating a freshman laboratory have received little attention in print. The two main problems are limited funds for purchasing laboratory equipment and the small size of the staff. In an attempt to solve the first problem, some small colleges set up all the experiments in advance, and arrange for the students to perform them on a rotating basis. In this way, only one setup for each experiment is required. To deal with the staff shortage, we introduce a scheme in which the students, after proper initiation and orientation, take an active part in teaching one another under the guidance of the instructor. Routine report writing is avoided by having a laboratory logbook for each student, kept in the laboratory, in which he records his work and thoughts as he performs the experiment. We report on how these ideas worked in a small college in Iran.
A method for calculating Fermi energy and carrier concentrations in semiconductors
Authors: Gaylord T. K. , Linxwiler J. N.
Published: March 2005

An efficient numerical method is described for calculating the Fermi energy, the free electron and free hole concentrations, and the ionized impurity concentrations in a semiconductor material. The method allows freedom with respect to type of material, temperature, and amount and type of donor and acceptor impurities.
Resource Letter SEG-1: Solid-earth geophysics
Authors: Bender Paul A.
Published: March 2005

Prepared at the request of the AAPT Editorial Board for Resource Letters. This is one of a series of Resource Letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course contents in specified fields. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one Letter on some of the main subjects of interest. Comments on these materials as well as suggestions for future topics will be welcomed. Please send such communications to Professor Aaron Owens, Editor, Resource Letter Board, Department of Physics, Kenyon College, Gambier, Ohio 43022.

N o t a t i o n: The letter E after an item number indicates elementary level; the letter I indicates intermediate level; and the letter A indicates advanced material. An asterisk (*) indicates those references we feel to be especially helpful.

R e p r i n t s: When ordering, request Resource Letter SEG-1. Enclose 75 cents per copy (not in stamps) together with a stamped and self-addressed envelope and send to Melba Phillips, Acting Executive Officer, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, New York 11794.
Magnetic monopole and charged particle ionization cross sections
Authors: Snyder Ralph
Published: March 2005

Classical mechanics is used to show why magnetic monopoles can be distinguished from charged particles by their ionization properties. Also, simple derivations are given of ion–atom ionization cross sections.
An interesting exactly soluble one-dimensional Hartree problem
Authors: Foldy L. L.
Published: March 2005

We examine an interesting one-dimensional problem involving two particles in an external field for which the Hartree equation can be solved analytically when both particles are in the same space orbital. The problem has close similarities to the three-dimensional problem for the helium atom, although the external potential and the interaction potential are taken to be Dirac δ functions. The δ functions share an identical virial theorem with Coulomb potentials but are otherwise very different. The similarities of results in the two cases nevertheless extend to eigenvalues and wave functions. Some interesting generalizations are considered, including the one-dimensional analog of the hydrogen molecule problem. These models and their solutions should prove useful as an introduction to the Hartree method for atomic and molecular physicists and chemists.
Comment on ’’Simple formula for the distortions in a Gaussian representation of a Poisson distribution’’
Authors: Gersch H. A.
Published: March 2005

The scattering of slow neutrons as a function of the target structure factor in the impulse approximation is used as an example of the distortions of a Gaussian or Poisson distribution. (AIP)
Hartree–Fock approximation for the one-dimensional ’’helium atom’’
Authors: Nogami Y. , Vallières M. , van Dijk W.
Published: March 2005

An exact solution is obtained for the Hartree–Fock equation as applied to the one-dimensional helium atom. (AIP)
Structure for a large enrollment, self-paced, mastery oriented astronomy course
Authors: Safko John L.
Published: March 2005

We describe the structure of a three-semester sequence of self-paced, mastery oriented astronomy courses developed at the University of South Carolina for nonscience majors. The course as structured is able to handle large enrollments with a successful completion rate as high as in a lecture format. Factors leading to this success are considered.