bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of oral yohimbine on withdrawal jumping behaviour of morphine‐dependent mice
Authors: Iglesias V. , Alamo C. , Cuenca E. , Morales L. , Perez‐Garcia C. , Alguacil L. F.
Published: July 2002

Acute administration of the alpha‐2 adrenoceptor agonist clonidine and chronic administration of the alpha2 antagonist yohimbine both inhibit opioid withdrawal signs in experimental models of dependence and also in clinical studies with opiate abusers. There are exceptions to this general rule: restlessness or self‐reported abstinence in humans and withdrawal‐induced escape behaviour in rodents are resistant to inhibition by acute clonidine. We have explored the effect of the alpha‐2 antagonist yohimbine on morphine withdrawal‐induced escape behaviour in a mouse model that we have proposed to differentiate between the urge to escape (number of jumps) and non‐specific sedative/motor actions (height of jumps). Morphine dependence was induced by s.c. administration of a sustained‐release preparation (1 g/kg). Naloxone (1 mg/kg) was injected to precipitate withdrawal jumping 72 hours after morphine injection. Co‐treatment with yohimbine dissolved in the tap water (70 mg/l) decreased the number of jumps upon naloxone challenge, an effect which did not seem to be related with a sedative or toxic effect of the drug. This result confirms previous data and suggests that yohimbine could prevent the development of opioid dependence being active to decrease withdrawal‐induced escape behaviour. The mechanisms of this action are discussed.
Biochemical and genetic studies of Caucasian subjects with ethanol‐induced flushing reaction
Authors: Ward Roberta J. , Mccradden John , Tipton Keith , Sherwood Roy , Keating James , Peters Timothy J. , DE Witte Philippe
Published: July 2002

The prevalence of ethanol‐induced flushing was investigated in three different Caucasian student populations, namely Irish, Belgian and English. Approximately 45% of all female subjects reported a flushing reaction, while 33%, 17% and 9%, respectively, of male students reported this reaction. There was a high familial incidence of flushing in all groups, suggesting that a specific gene defect might be involved. Our previous investigations had inferred normal ALDH2 in such affected individuals, but low activities of erythrocyte ALDH1.1 Since the principal role of this cytosolic enzyme may be in the metabolism of biogenic amines, serotonin levels in platelet‐rich plasma and urinary adrenaline, noradrenaline and dopamine were assayed in affected individuals after an oral ethanol challenge. No consistent pattern was evident for any of these parameters in any of the subjects at the time intervals investigated. Genotyping for ADH31 and ADH32 showed a higher frequency for ADH31, 58%, than ADH32, 42%. This is comparable to the Caucasian controls and to our previously published data.
Myosin II Is Involved in the Production of Constitutive Transport Vesicles from the TGN
Authors: Müsch Anne , Cohen David , Rodriguez-Boulan Enrique
Published: July 2002

The participation of nonmuscle myosins in the transport of organelles and vesicular carriers along actin filaments has been documented. In contrast, there is no evidence for the involvement of myosins in the production of vesicles involved in membrane traffic. Here we show that the putative TGN coat protein p200 (Narula, N., I. McMorrow, G. Plopper, J. Doherty, K.S. Matlin, B. Burke, and J.L. Stow. 1992. J. Cell Biol. 114: 1113–1124) is myosin II. The recruitment of myosin II to Golgi membranes is dependent on actin and is regulated by G proteins. Using an assay that studies the release of transport vesicles from the TGN in vitro, we provide functional evidence that p200/myosin is involved in the assembly of basolateral transport vesicles carrying vesicular stomatitis virus G protein (VSVG) from the TGN of polarized MDCK cells. The 50% reduced efficiency in VSVG vesicle release from the TGN in vitro after depletion of p200/myosin II could be reestablished to control levels by the addition of purified nonmuscle myosin II. Several inhibitors of the actin-stimulated ATPase activity of myosin specifically inhibited the release of VSVG-containing vesicles from the TGN.
Identification of a Microtubule-associated Motor Protein Essential for Dendritic Differentiation
Authors: Sharp David J. , Yu Wenqian , Ferhat Lotfi , Kuriyama Ryoko , Rueger David C. , Baas Peter W.
Published: July 2002

The quintessential feature of the dendritic microtubule array is its nonuniform pattern of polarity orientation. During the development of the dendrite, a population of plus end–distal microtubules first appears, and these microtubules are subsequently joined by a population of oppositely oriented microtubules. Studies from our laboratory indicate that the latter microtubules are intercalated within the microtubule array by their specific transport from the cell body of the neuron during a critical stage in development (Sharp, D.J., W. Yu, and P.W. Baas. 1995. J. Cell Biol. 130:93– 104). In addition, we have established that the mitotic motor protein termed CHO1/MKLP1 has the appropriate properties to transport microtubules in this manner (Sharp, D.J., R. Kuriyama, and P.W. Baas. 1996. J. Neurosci. 16:4370–4375). In the present study we have sought to determine whether CHO1/MKLP1 continues to be expressed in terminally postmitotic neurons and whether it is required for the establishment of the dendritic microtubule array. In situ hybridization analyses reveal that CHO1/MKLP1 is expressed in postmitotic cultured rat sympathetic and hippocampal neurons. Immunofluorescence analyses indicate that the motor is absent from axons but is enriched in developing dendrites, where it appears as discrete patches associated with the microtubule array. Treatment of the neurons with antisense oligonucleotides to CHO1/MKLP1 suppresses dendritic differentiation, presumably by inhibiting the establishment of their nonuniform microtubule polarity pattern. We conclude that CHO1/MKLP1 transports microtubules from the cell body into the developing dendrite with their minus ends leading, thereby establishing the nonuniform microtubule polarity pattern of the dendrite.
The Tight Skin Mouse: Demonstration of Mutant Fibrillin-1 Production and Assembly into Abnormal Microfibrils
Authors: Kielty Cay M. , Raghunath Michael , Siracusa Linda D. , Sherratt Michael J. , Peters Reiner , Shuttleworth C. Adrian , Jimenez Sergio A.
Published: July 2002

Mice carrying the Tight skin (Tsk) mutation harbor a genomic duplication within the fibrillin-1 (Fbn 1) gene that results in a larger than normal in-frame Fbn 1 transcript. In this study, the consequences of the Tsk mutation for fibrillin-containing microfibrils have been examined. Dermal fibroblasts from Tsk/+ mice synthesized and secreted both normal fibrillin (∼330 kD) and the mutant oversized Tsk fibrillin-1 (∼450 kD) in comparable amounts, and Tsk fibrillin-1 was stably incorporated into cell layers. Immunohistochemical and ultrastructural analyses of normal and Tsk/+ mouse skin highlighted differences in the gross organization and distribution of microfibrillar arrays. Rotary shadowing of high Mr preparations from Tsk/+ skin demonstrated the presence of abundant beaded microfibrils. Some of these had normal morphology and periodicity, but others were distinguished by diffuse interbeads, longer periodicity, and tendency to aggregate. The presence of a structurally abnormal population of microfibrils in Tsk/+ skin was unequivocally demonstrated after calcium chelation and in denaturating conditions. Scanning transmission electron microscopy highlighted the presence of more mass in Tsk/+ skin microfibrils than in normal mice skin microfibrils. These data indicate that Tsk fibrillin-1 polymerizes and becomes incorporated into a discrete population of beaded microfibrils with altered molecular organization.
The Dynamics of Protein Kinase B Regulation during B Cell Antigen Receptor Engagement
Authors: Astoul Emmanuelle , Watton Sandra , Cantrell Doreen
Published: July 2002

This study has used biochemistry and real time confocal imaging of green fluorescent protein (GFP)-tagged molecules in live cells to explore the dynamics of protein kinase B (PKB) regulation during B lymphocyte activation. The data show that triggering of the B cell antigen receptor (BCR) induces a transient membrane localization of PKB but a sustained activation of the enzyme; active PKB is found in the cytosol and nuclei of activated B cells. Hence, PKB has three potential sites of action in B lymphocytes; transiently after BCR triggering PKB can phosphorylate plasma membrane localized targets, whereas during the sustained B cell response to antigen, PKB acts in the nucleus and the cytosol. Membrane translocation of PKB and subsequent PKB activation are dependent on BCR activation of phosphatidylinositol 3-kinase (PI3K). Moreover, PI3K signals are both necessary and sufficient for sustained activation of PKB in B lymphocytes. However, under conditions of continuous PI3K activation or BCR triggering there is only transient recruitment of PKB to the plasma membrane, indicating that there must be a molecular mechanism to dissociate PKB from sites of PI3K activity in B cells. The inhibitory Fc receptor, the FcγRIIB, mediates vital homeostatic control of B cell function by recruiting an inositol 5 phosphatase SHIP into the BCR complex. Herein we show that coligation of the BCR with the inhibitory FcγRIIB prevents membrane targeting of PKB. The FcγRIIB can thus antagonize BCR signals for PKB localization and prevent BCR stimulation of PKB activity which demonstrates the mechanism for the inhibitory action of the FcγRIIB on the BCR/PKB response.
Costimulation by B7 Modulates Specificity of Cytotoxic T Lymphocytes: A Missing Link That Explains Some Bystander T Cell Activation
Authors: Zheng Pan , Liu Yang
Published: July 2002

It has been proposed that some bystander T cell activation may in fact be due to T cell antigen receptor (TCR) cross-reactivity that is too low to be detected by the effector cytotoxic T lymphocyte (CTL). However, this hypothesis is not supported by direct evidence since no TCR ligand is known to induce T cell proliferation and differentiation without being recognized by the effector CTL. Here we report that transgenic T cells expressing a T cell receptor to influenza virus A/NT/68 nucleoprotein (NP) 366-374:Db complexes clonally expand and become effector CTLs in response to homologous peptides from either A/PR8/34 (H1N1), A/AA/60 (H2N2), or A/NT/68 (H3N2). However, the effector T cells induced by each of the three peptides kill target cells pulsed with NP peptides from the H3N2 and H2N2 viruses, but not from the H1N1 virus. Thus, NP366–374 from influenza virus H1N1 is the first TCR ligand that can induce T cell proliferation and differentiation without being recognized by CTLs. Since induction of T cell proliferation was mediated by antigen-presenting cells that express costimulatory molecules such as B7, we investigated if cytolysis of H1N1 NP peptide–pulsed targets can be restored by expressing B7-1 on the target cells. Our results revealed that this is the case. These data demonstrated that costimulatory molecule B7 modulates antigen specificity of CTLs, and provides a missing link that explains some of the bystander T cell activation.
CD4+ T Cells Prevent Spontaneous Experimental Autoimmune Encephalomyelitis in Anti–Myelin Basic Protein T Cell Receptor Transgenic Mice
Authors: Van de Keere Fabienne , Tonegawa Susumu
Published: July 2002

Autoimmune diseases result from a failure of tolerance. Although many self-reactive T cells are present in animals and humans, their activation appears to be prevented normally by regulatory T cells. In this study, we show that regulatory CD4+ T cells do protect mice against the spontaneous occurrence of experimental autoimmune encephalomyelitis (EAE), a mouse model for multiple sclerosis. Anti–myelin basic protein (MBP) TCR transgenic mice (T/R+) do not spontaneously develop EAE although many self-reactive T cells are present in their thymi and peripheral lymphoid organs. However, the disease develops in all crosses of T/R+ mice with recombination-activating gene (RAG)-1 knockout mice in which transgenic TCR-expressing cells are the only lymphocytes present (T/R− mice). In this study, crosses of T/R+ mice with mice deficient for B cells, CD8+ T cells, NK1.1 CD4+ T (NKT) cells, γ/δ T cells, or α/β T cells indicated that α/β CD4+ T cells were the only cell population capable of controlling the self-reactive T cells. To confirm the protective role of CD4+ T cells, we performed adoptive transfer experiments. CD4+ T cells purified from thymi or lymph nodes of normal mice prevented the occurrence of spontaneous EAE in T/R− mice. To achieve full protection, the cells had to be transferred before the recipient mice manifested any symptoms of the disease. Transfer of CD4+ T cells after the appearance of symptoms of EAE had no protective effect. These results indicate that at least some CD4+ T cells have a regulatory function that prevent the activation of self-reactive T cells.
Activation of the p38 Mitogen-Activated Protein Kinase Pathway Arrests Cell Cycle Progression and Differentiation of Immature Thymocytes in Vivo
Authors: Diehl Nicole L. , Enslen Hervé , Fortner Karen A. , Merritt Chris , Stetson Nate , Charland Colette , Flavell Richard A. , Davis Roger J. , Rincón Mercedes
Published: July 2002

The development of T cells in the thymus is coordinated by cell-specific gene expression programs that involve multiple transcription factors and signaling pathways. Here, we show that the p38 mitogen-activated protein (MAP) kinase signaling pathway is strictly regulated during the differentiation of CD4−CD8− thymocytes. Persistent activation of p38 MAP kinase blocks fetal thymocyte development at the CD25+CD44− stage in vivo, and results in the lack of T cells in the peripheral immune system of adult mice. Inactivation of p38 MAP kinase is required for further differentiation of these cells into CD4+CD8+ thymocytes. The arrest of cell cycle in mitosis is partially responsible for the blockade of differentiation. Therefore, the p38 MAP kinase pathway is a critical regulatory element of differentiation and proliferation during the early stages of in vivo thymocyte development.
B1 B Lymphocytes Play a Critical Role in Host Protection against Lymphatic Filarial Parasites
Authors: Paciorkowski Natalia , Porte Patricia , Shultz Leonard D. , Rajan T.V.
Published: July 2002

Host defense against multicellular, extracellular pathogens such as nematode parasites is believed to be mediated largely, if not exclusively, by T lymphocytes. During our investigations into the course of Brugia malayi and Brugia pahangi infections in immunodeficient mouse models, we found that mice lacking B lymphocytes were permissive for Brugian infections, whereas immunocompetent mice were uniformly resistant. Mice bearing the Btkxid mutation were as permissive as those lacking all B cells, suggesting that the B1 subset may be responsible for host protection. Reconstitution of immunodeficient recombination activating gene (Rag)-1−/− mice with B1 B cells conferred resistance, even in the absence of conventional B2 lymphocytes and most T cells. These results suggest that B1 B cells are necessary to mediate host resistance to Brugian infection. Our data are consistent with a model wherein early resistance to B. malayi is mediated by humoral immune response, with a significant attrition of the incoming infectious larval load. Sterile clearance of the remaining parasite burden appears to require cell-mediated immunity. These data raise the possibility that the identification of molecule(s) recognized by humoral immune mechanisms might help generate prophylactic vaccines.
Helical Structure of the Cooh Terminus of S3 and Its Contribution to the Gating Modifier Toxin Receptor in Voltage-Gated Ion Channels
Authors: Li-Smerin Yingying , Swartz Kenton J.
Published: July 2002

The voltage-sensing domains in voltage-gated K+ channels each contain four transmembrane (TM) segments, termed S1 to S4. Previous scanning mutagenesis studies suggest that S1 and S2 are amphipathic membrane spanning α-helices that interface directly with the lipid membrane. In contrast, the secondary structure of and/or the environments surrounding S3 and S4 are more complex. For S3, although the NH2-terminal part displays significant helical character in both tryptophan- and alanine-scanning mutagenesis studies, the structure of the COOH-terminal portion of this TM is less clear. The COOH terminus of S3 is particularly interesting because this is where gating modifier toxins like Hanatoxin interact with different voltage-gated ion channels. To further examine the secondary structure of the COOH terminus of S3, we lysine-scanned this region in the drk1 K+ channel and examined the mutation-induced changes in channel gating and Hanatoxin binding affinity, looking for periodicity characteristic of an α-helix. Both the mutation-induced perturbation in the toxin–channel interaction and in gating support the presence of an α-helix of at least 10 residues in length in the COOH terminus of S3. Together with previous scanning mutagenesis studies, these results suggest that, in voltage-gated K+ channels, the entire S3 segment is helical, but that it can be divided into two parts. The NH2-terminal part of S3 interfaces with both lipid and protein, whereas the COOH-terminal part interfaces with water (where Hanatoxin binds) and possibly protein. A conserved proline residue is located near the boundary between the two parts of S3, arguing for the presence of a kink in this region. Several lines of evidence suggest that these structural features of S3 probably exist in all voltage-gated ion channels.
The product replacement algorithm and Kazhdan’s property (T)
Authors: Lubotzky Alexander , Pak Igor
Published: July 2002

The “product replacement algorithm” is a commonly used heuristic to generate random group elements in a finite group

G
G

, by running a random walk on generating

k
k

-tuples of

G
G

. While experiments showed outstanding performance, the theoretical explanation remained mysterious. In this paper we propose a new approach to the study of the algorithm, by using Kazhdan’s property (T) from representation theory of Lie groups.
An Eulerian-Lagrangian approach for incompressible fluids: Local theory
Authors: Constantin Peter
Published: July 2002

We study a formulation of the incompressible Euler equations in terms of the inverse Lagrangian map. In this formulation the equations become a first order advective nonlinear system of partial differential equations.
The reduction of large molecular profiles to informative
components using a Genetic Algorithm
Authors: Stefanini F. M. , Camussi A.
Published: July 2002

Motivation: Molecular profiles (DNA fingerprints) may be used to allocate an individual of unknown membership to one among the known groups of a reference population. Time and costs of profile assessment may be reduced by identifying informative profile components (markers).

Results: A genetic algorithm (GA) is proposed to identify promising candidate markers from a pilot experiment in which observations are supposed to be without measurement error. The analysis of simulated datasets suggests reasonable values for GA parameters and confirms that the GA finds components of the profile showing association with the considered groups. Our GA may be used to perform a first screening of candidate markers to be included in subsequent experiments.

Availability: The 32-bit executable (Windows 95, 98 and NT) is available at http://www.ds.unifi.it/~stefanin/bioinformatics.htm.

Contact: stefanin@ds.unifi.it

Supplementary Information: The algorithm is implemented for research purposes, i.e. a limited amount of input filtering and error messages are provided.

To whom correspondence should be addressed.
Stable gene expression from a mammalian artificial chromosome
Authors: Grimes Brenda R , Schindelhauer Dirk , McGill Nio I , Ross Andrew , Ebersole Thomas A , Cooke Howard J
Published: July 2002

We have investigated the potential of PAC‐based vectors as a route to the incorporation of a gene in a mammalian artificial chromosome (MAC). Previously we demonstrated that a PAC (PAC7c5) containing α‐satellite DNA generated mitotically stable MACs in human cells. To determine whether a functional HPRT gene could be assembled in a MAC, PAC7c5 was co‐transfected with a second PAC containing a 140 kb human HPRT gene into HPRT‐deficient HT1080 cells. Lines were isolated containing a MAC hybridizing with both α‐satellite and HPRT probes. The MACs segregated efficiently, associated with kinetochore proteins and stably expressed HPRT message after 60 days without selection. Complementation of the parental HPRT deficiency was confirmed phenotypically by growth on HAT selection. These results suggest that MACs could be further developed for delivering a range of genomic copies of genes into cells and that stable transgene expression can be achieved.
Fingerprinting taste buds: intermediate filaments and their implication for taste bud formation
Authors: Witt Martin , Reutter Klaus , Ganchrow Donald , Ganchrow Judith R.
Published: July 2002

Intermediate filaments in taste organs of terrestrial (human and chick) as well as aquatic (Xenopus laevis) species were detected using immunohistochemistry and electron microscopy. During development, the potential importance of the interface between the taste bud primordium and non–gustatory, adjacent tissues is evidenced by the distinct immunoreactivity of a subpopulation of taste bud cells for cytokeratins and vimentin. In human foetuses, the selective molecular marker for taste bud primordia, cytokeratin 20, is not detectable prior to the ingrowth of nerve fibres into the epithelium, which supports the hypothesis that nerve fibres are necessary for initiating taste bud development. Another intermediate filament protein, vimentin, occurs in derivatives of mesoderm, but usually not in epithelium. In humans, vimentin immunoreactivity is expressed mainly in border (marginal) epithelial cells of taste bud primordia, while in chick, vimentin expression occurs in most taste bud cells, whereas non–gustatory epithelium is vimentin immunonegative. Our chick data suggest a relationship between the degree of vimentin expression and taste bud cell proliferation especially during the perihatching period. It is suggested that surrounding epithelial cells (human) and mesenchymal cells (chick) may be contributing sources of developing taste buds. The dense perinuclear network of intermediate filaments especially in dark (i.e. non–sensory) taste disc cells ofXenopusindicates that vimentin filaments also might be associated with cells of non–gustatory function. These results indicate that the mechanisms of taste bud differentiation from source tissues may differ among vertebrates of different taxa.
Minimizing the number of segments in a delivery sequence for intensity‐modulated radiation therapy with a multileaf collimator
Authors: Dai Jianrong , Zhu Yunping
Published: July 2002

This paper proposes a sequencing algorithm for intensity‐modulated radiation therapy with a multileaf collimator in the static mode. The algorithm aims to minimize the number of segments in a delivery sequence. For a machine with a long verification and recording overhead time (e.g., 15 s per segment), minimizing the number of segments is equivalent to minimizing the delivery time. The proposed new algorithm is based on checking numerous candidates for a segment and selecting the candidate that results in a residual intensity matrix with the least complexity. When there is more than one candidate resulting in the same complexity, the candidate with the largest size is selected. The complexity of an intensity matrix is measured in the new algorithm in terms of the number of segments in the delivery sequence obtained by using a published algorithm. The beam delivery efficiency of the proposed algorithm and the influence of different published algorithms used to calculate the complexity of an intensity matrix were tested with clinical intensity‐modulated beams. The results show that no matter which published algorithm is used to calculate the complexity of an intensity matrix, the sequence generated by the algorithm proposed here is always more efficient than that generated by the published algorithm itself. The results also show that the algorithm used to calculate the complexity of an intensity matrix affects the efficiency of beam delivery. The delivery sequences are frequently most efficient when the algorithm of Bortfeld et al. is used to calculate the complexity of an intensity matrix. Because no single variation is most efficient for all beams tested, we suggest implementing multiple variations of our algorithm.
Correcting kernel tilting and hardening in convolution/superposition dose calculations for clinical divergent and polychromatic photon beams
Authors: Helen Liu H. , Mackie T. Rock , McCullough Edwin C.
Published: July 2002

To account for clinical divergent and polychromatic photon beams, we have developed kernel tilting and kernel hardening correction methods for convolution dose calculation algorithms. The new correction methods were validated by Monte Carlo simulation. The accuracy and computation time of the our kernel tilting and kernel hardening correction methods were also compared to the existing approaches including terma divergence correction, dose divergence correction methods, and the effective mean kernel method with no kernel hardening correction. Treatment fields of (field size at source to axis distance (SAD)) with source to source distances (SSDs) of 60, 80, and 100 cm, and photon energies of 6, 10, and 18 MV have been studied. Our results showed that based on the relative dose errors at a depth of 15 cm along the central axis, the terma divergence correction may be used for fields smaller than with a SSD larger than 80 cm; the dose divergence correction with an additional kernel hardening correction can reduce dose error and may be more applicable than the terma divergence correction. For both these methods, the dose error increased linearly with the depth in the phantom; the 90% isodose lines at the depth of 15 cm were shifted by about 2%–5% of the field width due to significant underestimation of the penumbra dose. The kernel hardening effect was less prominent than the kernel tilting effect for clinical photon beams. The dose error by using nonhardening corrected kernel is less than 2.0% at a depth of 15 cm along the central axis, yet it increased with a smaller field size and lower photon energy. The kernel hardening correction could be more important to compute dose in the fields with beam modifiers such as wedges when beam hardening is more significant. The kernel tilting correction and kernel hardening correction increased computation time by about 3 times, and 0.5–1 times, respectively. This can be justified by more accurate dose calculations for the majority of clinical treatments.
A wavelet‐based algorithm for detecting clustered microcalcifications in digital mammograms
Authors: Lado Marı́a J. , Tahoces Pablo G. , Méndez Arturo J. , Souto Miguel , Vidal Juan J.
Published: July 2002

A computerized scheme to detect clustered microcalcifications in digital mammograms has been developed. Detection of individual microcalcifications in regions of interest (ROIs) was also performed. The mammograms were previously classified into fatty and dense, according to their breast tissue. The most appropriate wavelet basis and reconstruction levels were selected. To select the wavelet basis, 40 profiles of microcalcifications were decomposed and reconstructed using different types of wavelet functions and different combinations of wavelet coefficients. The symlets with a basis of length 8 were chosen for fatty tissue. For dense tissue, the Daubechies' wavelets with a four‐element basis were employed. Two methods to detect individual microcalcifications were evaluated: (a) two‐dimensional wavelet transform, and (b) one‐dimensional wavelet transform. The second technique yielded the best results, and was used to detect clustered microcalcifications in the complete mammogram. When detecting individual microcalcifications by using two‐dimensional wavelet transform we have obtained, for fatty ROIs, a sensitivity of 71.11% at a false positive rate of 7.13 per image. For dense ROIs the sensitivity was 60.76% and the false positive rate, 7.33. The areas under the AFROC curves were and respectively. The one‐dimensional wavelet transform method yielded 80.44% of sensitivity and 6.43 false positives per image for fatty ROIs, and 62.17% and 5.82 false positives per image for dense ROIs. For the detection of clusters of microcalcifications in the entire mammogram, the sensitivity was 80.00% with 0.94 false positives per image for fatty mammograms, and 72.85% of sensitivity at a false positive detection rate of 2.21 per image for dense mammograms. Globally, a sensitivity of 76.43% at a false positive detection rate of 1.57 per image was obtained.
Electron beam modeling and commissioning for Monte Carlo treatment planning
Authors: Jiang Steve B. , Kapur Ajay , Ma C.‐M.
Published: July 2002

A hybrid approach for commissioning electron beam Monte Carlo treatment planning systems has been studied. The approach is based on the assumption that accelerators of the same type have very similar electron beam characteristics and the major difference comes from the on‐site tuning of the electron incident energy at the exit window. For one type of accelerator, a reference machine can be selected and simulated with the Monte Carlo method. A multiple source model can be built on the full Monte Carlo simulation of the reference beam. When commissioning electron beams from other accelerators of the same type, the energy spectra in the source model are tuned to match the measured dose distributions. A Varian Clinac 2100C accelerator was chosen as the reference machine and a four‐source beam model was established based on the Monte Carlo simulations. This simplified beam model can be used to generate Monte Carlo dose distributions accurately (within 2%/2 mm compared to those calculated with full phase space data) for electron beams from the reference machine with various nominal energies, applicator sizes, and SSDs. Three electron beams were commissioned by adjusting the energy spectra in the source model. The dose distributions calculated with the adjusted source model were compared with the dose distributions calculated using the phase space data for these beams. The agreement is within 1% in most of cases and 2% in all situations. This preliminary study has shown the capability of the commissioning approach for handling large variation in the electron incident energy. The possibility of making the approach more versatile is also discussed.
Measurement of bulk moduli and ratio of specific heats of gases using Rüchardt’s experiment
Authors: de Lange O. L. , Pierrus J.
Published: July 2002

Three factors are discussed which affect the measurement of bulk modulus and ratio of specific heats of a gas in Rüchardt’s experiment: damping, departure from adiabatic conditions, and molecular interactions. The experiment is most readily interpreted at small volumes of gas, where the oscillations are of one kind (intermediate between adiabatic and isothermal extremes) and the effect of damping is negligible. For larger volumes of gas a striking effect is observed, namely amplitude dependence of the oscillations: An initial set of intermediate oscillations is followed, as the amplitude decreases due to damping, by oscillations of lower frequency. The bulk moduli deduced from the latter are equal to isothermal values for monatomic and diatomic gases, but not for polyatomic gases. The amplitude, below which “isothermal” oscillations occur, increases with the volume of gas. Results for bulk moduli and ratio of specific heats are presented for eighteen gases with atomicity ranging from 1 to 12.
Binaural detection with narrowband and wideband reproducible noise maskers: II. Results for rabbit
Authors: Zheng Ling , Early Susan J. , Mason Christine R. , Idrobo Fabio , Harrison J. Michael , Carney Laurel H.
Published: July 2002

Binaural detection with narrowband and wideband noise maskers was examined by using a Pavlovian-conditioned eyeblink response in rabbits. The target was a tone at 500 Hz, and the maskers were ten individual noise samples having one of two bandwidths, 200 Hz (410 Hz to 610 Hz) or 2900 Hz (100 Hz to 3 kHz). The narrowband noise maskers were created by filtering the wideband noise maskers such that the two sets of maskers had identical spectra in the 200-Hz frequency region surrounding the tone. The responses across the set of noise maskers were compared across bandwidths and across interaural configurations (N0S0 and N0Sπ). Responses across the set of noise waveforms were not strongly correlated across bandwidths; this result is inconsistent with models for binaural detection that depend only upon the narrow band of energy centered at the frequency of the target tone. Responses were correlated across interaural configurations for the wideband masker condition, but not for the narrowband masker. All of these results were consistent with the companion study of human listeners [Evilsizer et al., J. Acoust. Soc. Am. 111, 336–345 (2002)] and with the results of human studies of binaural detection that used only wideband [Gilkey et al., J. Acoust. Soc. Am. 78, 1207–1219 (1985)] or narrowband [Isabelle and Colburn, J. Acoust. Soc. Am. 89, 352–259 (1991)] individual noise maskers.
Two alternative expressions for the spherical wave expansion of the time domain scalar free-space Green’s function and an application: Scattering by a soft sphere
Authors: Buyukdura O. Merih , Koc S. Sencer
Published: July 2002

The importance of expanding Green’s functions, particularly free-space Green’s functions, in terms of orthogonal wave functions is practically self-evident when frequency domain scattering problems are of interest. With the relatively recent and widespread interest in time domain scattering problems, similar expansions of Green’s functions are expected to be useful in the time domain. In this paper, two alternative expressions, expanded in terms of orthogonal spherical wave functions, for the free-space time domain scalar Green’s functions are presented. Although the two expressions are equivalent, one of them is seen to be more convenient for the calculation of the scattered field for a known equivalent source density, whereas the second expression is more suitable for setting up an integral equation for the equivalent source density. Such an integral equation may be setup, for example, by the application of a time domain equivalent of the T-matrix (extended boundary condition) method.
The method of fundamental solutions for axisymmetric acoustic scattering and radiation problems
Authors: Karageorghis Andreas , Fairweather Graeme
Published: July 2002

The method of fundamental solutions (MFS) is applied to acoustic scattering and radiation for axisymmetric bodies and boundary conditions. The fundamental solution of the governing equation and its normal derivative, which are required in the formulation of the MFS, can be expressed in terms of complete elliptic integrals, which are evaluated using library software. The method is tested on several problems from the literature and the results compared with existing solutions. Numerical experiments demonstrate that the fictitious eigenfrequency problem which is encountered with the boundary element method is not present in the MFS.
Iterative time reversal in the ocean
Authors: Song H. C. , Kuperman W. A. , Hodgkiss W. S. , Akal T. , Ferla C.
Published: July 2002

The iterative time-reversal process focusing on the strongest scatterer in a multitarget medium has been described theoretically in terms of eigenvalues and eigenvectors of a time-reversal operator K*K in ultrasonics [Prada et al., J. Acoust. Soc. Am. 97, 62–71 (1995)]. In this paper, we extend the concept of iterative time-reversal to waveguide propagation in the ocean. For a single target, the iterative time-reversal process results in a minor improvement in spatial focusing. However, data from a recent experiment in the Mediterranean Sea [Kuperman et al., J. Acoust. Soc. Am. 103, 25–40 (1998)] illustrates the importance of the waveguide and source transducer characteristics even in the single target case. When the ocean contains several reflectors, iterative time-reversal focuses on the target corresponding to the largest eigenvalue of the time-reversal operator, which depends not only on the reflectivity of the targets, but also on the complex propagation effects between the targets and time-reversal mirror. Analysis of the experimental data for a single target and simulation results with multiple targets in the ocean are presented.
Optoacoustic technique for remote control of underwater oceanographic instrumentation
Authors: Egerev Sergey V. , Morozov Andrey K.
Published: July 2002

A sound source excited through the irradiation of a water surface with a powerful laser pulse is called an optoacoustic (OA) source. This phenomenon makes possible the remote control of submerged oceanographic devices (buoys) directly from a flying vehicle equipped with a pulse laser. The principal factors are analyzed (i.e., reverberation, ambient noise, etc.) which influence the efficiency of OA digital data transfer. The gap between the two neighboring laser pulses is the only parameter of signal that allows the transmitting of data through this remote technique. This makes different versions of pulse-position modulation preferable. Algorithms for processing detected signals are described. The optoacoustic communication system was tested at the White Sea. A CO2 laser on board a research vessel was used to launch an OA source. The acoustic signal level of about 105 Pa at a 1-m depth was achieved within the frequency band of up to 100 kHz. Test data messages at a rate of 2 bits per second for laser pulse repetition rate of about 0.5 Hz were transmitted along an experimental vessel-to-vessel 480-m line. The OA technique works well for devices submerged to depths of 2000 m and possibly more. [Work supported by RFBR.]
The effect of sensor placement errors on cylindrical near-field acoustic holography
Authors: Carroll Gerard P.
Published: July 2002

This paper presents the results of a numerical investigation of the effects of sensor placement errors on the accuracy of cylindrical near-field acoustic holography (NAH). Results are presented using two data sets, one corresponding to numerically generated hologram plane pressures for a periodically ribbed cylindrical shell, and the other to measured hologram plane pressures for an identical small scale (1/50 scale) physical model. The numerically generated hologram plane pressures are valid in the range ka<4.0, while the experimental data are valid up to ka<20. The motivation for this investigation is to determine whether or not large scale implementation of NAH is feasible given the potentially increased sensor placement inaccuracies which are likely to be encountered at large scale. The effect of both random and systematic axial, circumferential, and radial sensor placement errors are assessed and compared. The majority of the results are presented as wave number comparisons of contaminated and uncontaminated surface pressure reconstructions. It is shown that, as is known to be the case for contamination by background noise, sensor placement errors also result in high wave number noise. Therefore, the success of implementing NAH at large scale when these sensor placement errors are present relies on the selection of a low-pass wave number filter suitable for removing these contaminating factors while preserving the cylinders actual wave number response.
Nearfield broadband array design using a radially invariant modal expansion
Authors: Abhayapala Thushara D. , Kennedy Rodney A. , Williamson Robert C.
Published: July 2002

This paper introduces an efficient parameterization for the nearfield broadband beamforming problem with a single parameter to focus the beamformer to a desired operating radius and another set of parameters to control the actual broadband beampattern shape. The parameterization is based on an orthogonal basis set of elementary beampatterns by which an arbitrary beampattern can be constructed. A set of elementary beamformers are then designed for each elementary beampattern and the desired beamformer is constructed by summing the elementary beamformers with frequency and source-array distance dependent weights. An important consequence of our result is that the beamformer can be factored into three levels of filtering: (i) beampattern independent elementary beamformers; (ii) beampattern shape dependent filters; and (iii) radial focusing filters where a single parameter can be adjusted to focus the array to a desired radial distance from the array origin. As an illustration the method is applied to the problem of producing a practical array design that achieves a frequency invariant beampattern over the frequency range of 1:10 (which is suitable for speech acquisition using a microphone array), and with the array focused either to farfield or nearfield where at the lowest frequency the radial distance to the source is only three wavelengths.
Application of diffraction instrumental monitoring to the analysis of diffraction patterns from a Round Robin project on KCl
Authors: Berti Giovanni
Published: July 2002

The outcome of the analysis of data from a Round Robin on a KCl sample is reported. The research project has led to a definition of a working protocol for the treatment of X-ray diffraction data from powders (XRPD). The protocol is based on the method of “Diffraction Instrumental Monitoring” (DIM), whose main characteristics are briefly illustrated. When experimental data are referred to the expected standard values of the lattice parameter, the method enables comparison with data obtained from differing instrumentation found in different laboratories. Application of DIM to the KCl Round Robin demonstrates the ability of DIM to effectively evaluate systematic contribution. Accuracy on the cell parameter is obtained as a direct consequence; in this application, where the knowledge of the KCl d-spacing was not a problem, the accuracy of lattice parameter is a feedback for constraining the evaluation of the effective values of the experiment-related parameters.
X-ray powder diffraction analysis of methionine sulfoxide
Authors: Corbi Pedro P. , Melnikov Petr , Massabni Antonio C.
Published: July 2002

Powder X-ray diffraction data for methionine sulfoxide, C5H11NO3S, obtained from the commercial amino acid, are presented in this work. Monoclinic cell parameters are: a=15.500 Å; b=3.820 Å; c=13.490 Å; β=97.300 °.
SARS-CoV-2 Omicron Variant in Human Saliva Samples in Cell-Free Form
Authors: Imai Kenichi , Ikeno Ryo , Tanaka Hajime , Takada Norio
Published: January 2023

This cross-sectional study investigates cell-free viral loads in saliva samples from patients who have been infected with the Omicron variant of SARS-CoV-2.
Evaluation of the Association Between Congenital Cytomegalovirus Infection and Pediatric Acute Lymphoblastic Leukemia
Authors: Geris Jennifer M. , Schleiss Mark R. , Hooten Anthony J. , Langer Erica , Hernandez-Alvarado Nelmary , Roesler Michelle A. , Sample Jeannette , Williams Lindsay A. , Dickens David S. , Mody Rajen J. , Ravindranath Yaddanapudi , Gowans Kate L. , Pridgeon Matthew G. , Spector Logan G. , Nelson Heather H.
Published: January 2023

Importance

Acute lymphoblastic leukemia (ALL) is the most common form of pediatric cancer, and a leading cause of death in children. Understanding the causes of pediatric ALL is necessary to enable early detection and prevention; congenital cytomegalovirus (cCMV) has recently been identified as a potential moderate-to-strong factor associated with risk for ALL.

Objective

To compare the prevalence of cCMV infection between ALL cases and matched controls.

Design, Setting, and Participants

In this population-based case-control study of ALL cases and matched controls, cases consisted of children aged 0 to 14 years between 1987 and 2014 with an ALL diagnosis identified through the Michigan Cancer Surveillance Program and born in Michigan on or after October 1, 1987. Cancer-free controls were identified by the Michigan BioTrust for Health and matched on age, sex, and mother’s race and ethnicity. Data were analyzed from November to May 2022.

Exposures

cCMV infection measured by quantitative polymerase chain reaction in newborn dried blood spots.

Main Outcomes and Measures

ALL diagnosed in children aged 0 to 14 years.

Results

A total of 1189 ALL cases and 4756 matched controls were included in the study. Bloodspots were collected from participants at birth, and 3425 (57.6%) participants were male. cCMV was detected in 6 ALL cases (0.5%) and 21 controls (0.4%). There was no difference in the odds of cCMV infection comparing ALL cases with controls (odds ratio, 1.30; 95% CI, 0.52-3.24). Immunophenotype was available for 536 cases (45.1%) and cytogenetic data for 127 (27%). When stratified by subtype characteristics, hyperdiploid ALL (74 cases) was associated with 6.26 times greater odds of cCMV infection compared with unmatched controls (95% CI, 1.44-27.19).

Conclusions and Relevance

In this case-control study of cCMV and pediatric ALL, cCMV was associated with increased risk of hyperdiploid ALL. These findings encourage continued research.
Triple Benign Paroxysmal Positional Vertigo and the Strength of Remote Video-Based Management
Authors: Strupp Michael , Mavrodiev Vergil , Goldschagg Nicolina
Published: January 2023

This case report describes remote video-based diagnosis and management of triple posttraumatic benign paroxysmal positional vertigo.
Indigenous Peoples‐related environmental research within the basin of the Laurentian Great Lakes: A systematic map protocol
Authors: Serville‐Tertullien Marsha , Pirie Emma , Buell Mary‐Claire , Wall Barbara Moktthewenkwe , Furgal Chris
Published: January 2023

The North American Great Lakes Basin is the homeland for many First Nations, Métis and Native American Tribes. The terrestrial and aquatic ecological systems within this multinational region, which is of spiritual, cultural and subsistence significance to a diversity of Indigenous Peoples, are facing several natural and anthropogenic pressures. While there are many current and past research efforts and projects to address those pressures, the nature and range of environment‐related projects involving Indigenous Peoples or organizations remains unknown. This gap in knowledge presents a unique opportunity to identify and map past and current environmental and ecological research within the Great Lakes involving Indigenous Peoples.

A systematic search strategy will be applied to identify and capture peer‐reviewed publications that pertain to past and current environmental research within the Great Lakes basin that involve or are connected to Indigenous Peoples, following the procedures outlined in this systematic mapping protocol. Publications that pertain to environmental and ecological research with, for and by Indigenous Peoples within the Great Lakes, as determined by the use of suitable keywords, will be retrieved from four proposed online bibliographic platforms and databases. Searches will only include peer‐reviewed publications in the English language.

Final captures of the search results will be screened in two stages to identify potentially relevant papers. This will take place through (1) title and abstract screening and (2) full‐text analysis. Following the completion of the screening process, remaining papers will be coded and analysed through a narrative synthesis approach and descriptive statistics will be conducted. Environmental research captured through this systematic protocol will be geospatially mapped using the ArcGIS mapping software.

It is anticipated that the information obtained from the resulting systematic map will be beneficial for identifying gaps in environmental research to support and inform future initiatives for environmental research planning, policy and decision‐making with, for and by Indigenous Communities within the Great Lakes basin.