Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Non-cryogenic anatomical imaging in ultra-low field regime: hand MRI demonstration

Ultra-low field (ULF) MRI with a pulsed prepolarization is a promising method with potential for applications where conventional high-, mid-, and low-field medical MRI cannot be used due to cost, weight, or other restrictions. Previously, successful ULF demonstrations of anatomical imaging were made using liquid helium-cooled SQUIDs and conducted inside a magnetically shielded room. The Larmor frequency for these demonstrations was ∼3 kHz. In order to make ULF MRI more accessible, portable, and inexpensive, we have recently developed a non-cryogenic system. To eliminate the requirement for a magnetically shielded room and improve the detection sensitivity, we increased the frequency to 83.6 kHz. While the background noise at these frequencies is greatly reduced, this is still within the ULF regime and most of its advantages such as simplicity in magnetic field generation hardware, and less stringent requirements for uniform fields, remaining. In this paper we demonstrate use of this system to image a human hand with up to 1.5mm resolution. The signal-to-noise ratio was sufficient to reveal anatomical features within a scan time of less than 7 min. This prototype can be scaled up for constructing head and full body scanners, and work is in progress toward demonstration of head imaging.

Short range correlations and the EMC effect

This Letter shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering at intermediate x(B), 0.35≤x(B)≤0.7, is linearly related to the short range correlation (SRC) scale factor obtained from electron inclusive scattering at x(B)≥1. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free pn pair cross sections and F(2)(n)/F(2)(p), the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.

Level-set segmentation of pulmonary nodules in megavolt electronic portal images using a CT prior

PURPOSE

Pulmonary nodules present unique problems during radiation treatment due to nodule position uncertainty that is caused by respiration. The radiation field has to be enlarged to account for nodule motion during treatment. The purpose of this work is to provide a method of locating a pulmonary nodule in a megavolt portal image that can be used to reduce the internal target volume (ITV) during radiation therapy. A reduction in the ITV would result in a decrease in radiation toxicity to healthy tissue.

METHODS

Eight patients with nonsmall cell lung cancer were used in this study. CT scans that include the pulmonary nodule were captured with a GE Healthcare LightSpeed RT 16 scanner. Megavolt portal images were acquired with a Varian Trilogy unit equipped with an AS1000 electronic portal imaging device. The nodule localization method uses grayscale morphological filtering and level-set segmentation with a prior. The treatment-time portion of the algorithm is implemented on a graphical processing unit.

RESULTS

The method was retrospectively tested on eight cases that include a total of 151 megavolt portal image frames. The method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases. The treatment phase portion of the method has a subsecond execution time that makes it suitable for near-real-time nodule localization.

CONCLUSIONS

A method was developed to localize a pulmonary nodule in a megavolt portal image. The method uses the characteristics of the nodule in a prior CT scan to enhance the nodule in the portal image and to identify the nodule region by level-set segmentation. In a retrospective study, the method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases studied.

Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp

The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.

Abstract P6-04-16: Molecular Profiling of Stage II and III Breast Cancer in Latin American Women Receiving Standard-of-Care Treatment

Breast cancer, though genetically and clinically heterogeneous, still lacks reliable prognostic and predictive markers. Gene expression profiling studies have correlated with long-term survival and response to therapy. Multiple variables thought to modify gene expression (i.e., ancestry, socio-economical and cultural factors) are not always controlled when correlating molecular markers with clinical outcome. Breast cancer rates are lower in Latin America than in other countries; molecularly, variations in gene expression should reflect different genetic and epigenetic levels there. The United States-Latin America Cancer Research Network (US-LA CRN) launches its first breast cancer pilot study in 2010 in over 20 hospitals and research facilities across Argentina, Brazil, Chile, Mexico, and Uruguay, primarily to characterize molecular profile distribution (luminal A, luminal B, HER2-like, and basal) in Latin American women with non-metastatic stage II or III breast cancer. Molecular profiles determined by microarray will be correlated with epidemiological, histological, and clinical data, including pathologic response to standard neoadjuvant chemotherapy; a molecular signature that predicts response to neoadjuvant therapy in breast cancer will be defined. This prospective cohort study will not dispense investigational drugs. Part A characterizes molecular profiles of breast cancer in Latin America; Part B examines associations between response to neoadjuvant therapy and molecular profiles. Tissue samplesfor gene expression profiling will be collected during routine core biopsies or during surgery. Core biopsies and surgical resection specimens from participants will undergo histopathologic evaluation, tumor ER, PgR, HER2, and Ki67 status assessment. During Part B, patients will be sorted by hormone receptor and HER2 status and receive standard neoadjuvant chemotherapy. Tissue samples will be re-assessed to evaluate residual cancer burden for pathologic response to neoadjuvant treatment and gene expression. Five-year patient follow-up will determine associations between molecular profiles and disease evolution after standard treatment. Besides providing data on the effectiveness of standard chemotherapy in Latin American women, study infrastructure includes establishing biobanks in participating countries to conduct additional clinical trials incorporating complex genomic and pathologic biomarkers, including trials to evaluate investigational therapies.

Studying the molecular profile of breast cancer in Latin America will improve diagnosis and treatment, correlate molecular subtypes with long-term survival and response to therapy, and identify indolent-disease subpopulations of cancer patients, perhaps enabling future personalized cancer management.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-04-16.

Sealing distal proximal caries lesions in first primary molars: efficacy after 2.5 years

BACKGROUND

The prevalence of proximal caries in primary molar teeth is high in many countries.

AIMS

(1) To study by means of a split-mouth design the 1- and 2.5-year efficacy of sealing proximal lesions vs. flossing instructions (control) on primary molar teeth. (2) To assess children's behaviour and pain perception during the procedure.

METHODS

Ninety-one 4- to 6-year-old children from Bogotá, Colombia participated. Participants had to have at least two proximal lesions scored according to the following radiographic classification system: radiolucency (1) in enamel outer half, (2) restricted to enamel-dentine junction, or (3) restricted to dentine outer third. Baseline, 1- and 2.5-year follow-up bitewing radiographs were taken. Test and control lesions were randomly selected. After temporary separation test lesions were sealed (adhesive). Parents/caregivers received a flossing leaflet for their children. Progression of the lesions was assessed by means of independent reading of conventional bitewing radiographs.

RESULTS

One-year (n = 73) test vs. control lesion progression was 27.4 vs. 50.7%, respectively (p < 0.01, McNemar's test), and 2.5-year (n = 56) test vs. control lesion progression was 46.4 vs. 71.4%, respectively (p < 0.01). The dropouts did not differ from those who remained in the study regarding relevant caries baseline data. More than 88% of the participants presented positive to definitively positive behaviour and very low or low pain intensity at both first and second appointments.

CONCLUSION

The sealing technique was superior to flossing instructions both after 1 and 2.5 years of follow-up and the majority of the participants had no anxiety or pain during the treatment.

Effects of food deprivation and particle size of ground wheat on digestibility of food components in broilers fed on a pelleted diet

The first aim of the experiment was to study the effect of wheat (Triticum aestivum) particle size on the digestibility of starch in a pelleted diet given to broilers. The second aim was to study the consequences of food deprivation before the excreta collection period (from 21 to 24 d). Wheat from a strong hardness cultivar was incorporated at 546.1 g/kg in diets. The other main ingredients were soybean meal (353.5 g/kg) and rapeseed oil (55.0 g/kg). Diets were given as pellets. The experimental design was a 2 x 2 factorial design testing two particle sizes of wheat flour and two procedures of a balance experiment (with or without food deprivation). Birds given diet C (wheat coarse grinding before pelleting) had significantly greater gizzard weight than birds fed on diet F (wheat fine grinding before pelleting). Starch digestibility value was significantly increased when birds were fed on diet F. This effect was halved by food deprivation. No significant effect of grain particle size was observed for protein and lipid digestibility values. However, food deprivation decreased apparent protein digestibility, with an effect which was more pronounced for fine than for coarse grinding. AMEN of the diet was significantly improved by fine grinding of wheat and decreased by food deprivation. However, no significant differences in growth performance were induced by differences in wheat grinding. No significant effect of grinding was observed on the water excretion:feed intake ratio. No significant difference was observed for vent score between treatments. There was over-excretion of starch in the first hours of refeeding following food deprivation.

Soft wheat instead of hard wheat in pelleted diets results in high starch digestibility in broiler chickens

(1) The aim of the experiment was to re-examine variations in digestibilities of food components in 3-week-old broiler chickens fed on pelleted diets based on wheats differing in lipase activity and hardness. Fourteen wheat (Triticum aestivum) samples, each from a different cultivar, were included at 550 g/kg in 14 different diets given to male Ross broiler chicks from 7 d of age. The other main ingredients consisted of soyabean meal (353 g/kg) and rapeseed oil (55 g/kg). A 15th diet containing durum wheat (Triticum durum) was also tested. (2) Hardness of wheats (Triticum aestivum) varied between 14 (very soft) and 88 (very hard), and lipase activity of wheats varied from 1 to 13.1 (relative scale). No significant correlation was found between in vitro viscosities and other parameters such as hardness, particle size of wheat flours and lipase. Hardness was correlated with the mean particle size of wheat flours and durability of pellets. (3) Individual lipid digestibilities were negatively correlated with in vitro viscosities of wheats. (4) Individual starch digestibilities were negatively correlated with wheat hardness, particle size of wheat flour before pelleting, and pellet durability. The ratio of measured AME(N) to predicted AME(N) was also negatively correlated with wheat hardness. Simple regression calculation showed that a 100-point increase in wheat hardness resulted in a 3% decrease in the AME(N) value of diets. Multiple regression calculation showed the food/gain ratio (d 10 to d 21) to be positively related to wheat hardness and negatively related to pellet durability. (5) Wheat lipase activity was positively correlated with individual starch digestibility, which was the reverse of a result obtained in a previous experiment. Thus, wheat lipase activity did not seem consistent for predicting starch digestibility and AME(N) values. (6) Among all wheat samples, durum wheat showed the highest protein content and the lowest content of water-insoluble cell-wall. Starch digestibility of durum wheat tended to be lower than that of other wheats (0.916 vs 0.936). However, no significant difference in AME(N) was observed between the durum wheat sample and other wheats. (7) Gut morphometric data measured at d 24 did not show significant differences between dietary treatments.

Probing quark-gluon interactions with transverse polarized scattering

We have extracted QCD matrix elements from our data on doubly polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element d˜2, which arises strictly from quark-gluon interactions, to be unambiguously nonzero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer.

Assessment of symptoms during gastric emptying scintigraphy to correlate symptoms to delayed gastric emptying

BACKGROUND

Symptoms of gastroparesis based on patient recall correlate poorly with gastric emptying. The aim of this study is to determine if symptoms recorded during gastric emptying scintigraphy (GES) correlate with gastric emptying and with symptoms based on patient recall.

METHODS

Patients undergoing GES completed the Patient Assessment of GI Symptoms (PAGI-SYM) assessing symptoms over the prior 2 weeks and a questionnaire for which patients graded six symptoms during GES. A Symptom Severity Index (SSI) represented the mean of six symptoms at each time point.

KEY RESULTS

A total of 560 patients underwent GES for clinical evaluation of symptoms. Of 388 patients included in the study: 232 patients had normal GES (NGES), 156 delayed GES (DGES), and 11 rapid GES (RGES). Symptom severity index increased pre to postprandial for each group: NGES: 0.51 +/- 0.07 to 0.92 +/- 0.03, DGES: 0.60 +/- 0.09 to 1.13 +/- 0.05, and RGES: 0.56 +/- 0.12 to 0.79 +/- 0.13. Delayed gastric emptying scintigraphy patients had a higher postprandial SSI than NGES patients (1.13 +/- 0.05 vs 0.92 +/- 0.03, P < 0.05). Postprandial symptoms of stomach fullness (1.9 +/- 0.12 vs 1.5 +/- 0.09; P = 0.011), bloating (1.4 +/- 0.11 vs 1.1 +/- 0.09; P = 0.033), and abdominal pain (1.1 +/- 0.08 vs 0.7 +/- 0.12; P = 0.012) were higher in DGES than NGES. Symptom severity based on PAGI-SYM for 2 weeks prior to GES correlated with symptoms during the test for nausea (NGES, r = 0.61; DGES, r = 0.70), stomach fullness (NGES, r = 0.47; DGES, r = 0.60), and bloating (NGES, r = 0.62, DGES, r = 0.66).

CONCLUSIONS & INFERENCES

Stomach fullness, bloating, and abdominal pain recorded during GES were higher in patients with delayed gastric emptying than in patients with normal gastric emptying. Symptoms recorded during GES correlated with those during daily life by patient recall.

Hair analysis versus conventional methods of drug testing in substance abusers seeking organ transplantation

As substance abusers need to demonstrate abstinence prior to transplant, valid/reliable drug tests are needed. Patients may deny use, fearing surgery will be delayed. Breath, blood and urine tests have brief detection windows that allow patients to evade detection. Routine laboratory tests do not include all substances of abuse. Hair analysis overcomes these barriers, increasing the likelihood that active users will be identified. This study compared results for alcohol, opioids and cocaine based on 445 self-report, breath, urine and hair samples from 42 patients who had been denied a transplant due to recent substance abuse. Compared to hair toxicology, sensitivity for conventional drug tests was moderate for cocaine and opioids, but poor for alcohol. Of positive hair tests, only half were corroborated through other tests. In contrast, specificity was high across tests and substances, with positive findings from conventional tests confirmed through hair toxicology. Based on a 90-day detection window for hair analysis, two negative tests suggest 6 months of continuous abstinence. Hair testing should be considered as an alternative approach for monitoring substance use in the transplant population, either as a routine procedure or when the veracity of findings from conventional tests is in doubt.

Epidemiological study of canine trypanosomosis in an urban area of Ivory Coast

Following confirmed cases of trypanosomosis in military working dogs, a cross-sectional study was undertaken to evaluate the source of infection and determine the prevalence of canine infection with Trypanosoma congolense in the urban focus of Abidjan, Ivory Coast. Blood from 123 dogs were collected and subjected to PCR using specific primers for Trypanosoma congolense "forest type". In addition, an entomological study was conducted in an urban area near the forest surronding the military camp. The observed prevalence was 30.1% and PCR positivity to Trypanosoma congolense was not significantly associated with sex or age of animals. This study demonstrates the high contamination rate of dogs in enzootic zones, the potential risk of introduction of the disease in free animal populations and the ability of Glossina palpalis to adapt to urban areas and to transmit trypanosomosis in such areas. The factors leading to a possible emergence of canine trypanosomiasis in enzootic zones need further investigations.

Effect of anaesthesia of the palmar digital nerves on proximal interphalangeal joint pain in the horse

REASONS FOR PERFORMING STUDY

Anaesthesia of the palmar digital nerves is claimed to attenuate lameness in some horses that are lame because of pain in the proximal interphalangeal (PIP) joint.

OBJECTIVE

To determine the response of horses with pain in the PIP joint to anaesthesia of the palmar digital nerves.

METHODS

Horses were video recorded trotting before and after induction of pain in the PIP joint and 10 mins after anaesthesia of the palmar digital nerves. The palmar digital nerves were anaesthetised 3 times at different sites, and the video recorded gaits were scored subjectively.

RESULTS

The median lameness score of gaits after administration of 2% mepivacaine 1 cm proximal to the cartilages of the foot was not significantly different from the median lameness score before anaesthesia of the palmar digital nerves (P > or = 0.05), although that of 1 of 6 horses improved markedly. The median lameness score was significantly (P < or = 0.05) improved after mepivacaine was administered 2 and 3 cm proximal to the cartilages of the foot.

CONCLUSIONS

The PIP joint is unlikely to be anaesthetised when the palmar digital nerves are anaesthetised at the proximal margin of the cartilages of the foot.

POTENTIAL RELEVANCE

Pain within the PIP joint cannot be excluded as a cause of lameness when lameness is attenuated by anaesthesia of the palmar digital nerves at any site proximal to the proximal margin of the cartilages of the foot.

BME education program and research activities at the National Autonomous University of Mexico (UNAM)

Biomedical engineering at the Universidad Nacional Autónoma de Mexico (UNAM - National Autonomous University of Mexico) has been developing slowly compared to other local universities. A BME-closing module was established as an elective one for the bachelors of electronic and computer engineering degrees and it has been offered recently. This approach enables the students to apply the principles of physics and engineering in a biomedical context. The popularity of the BME-closing module is growing and more students are opting for this module. This paper presents the BME activities at the UNAM and the experience of the elective module.

High-resolution spectroscopy of Lambda16N by electroproduction

An experimental study of the (16)O(e,e'K(+))(Lambda)(16)N reaction has been performed at Jefferson Lab. A thin film of falling water was used as a target. This permitted a simultaneous measurement of the p(e,e'K(+))Lambda, Sigma(0) exclusive reactions and a precise calibration of the energy scale. A ground-state binding energy of 13.76+/-0.16 MeV was obtained for (Lambda)(16)N with better precision than previous measurements on the mirror hypernucleus (Lambda)(16)O. Precise energies have been determined for peaks arising from a Lambda in s and p orbits coupled to the p(1/2) and p(3/2) hole states of the (15)N core nucleus.