Measurement of the Nucleon F_{2}

The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ^{3}H and ^{3}He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19

Probing Few-Body Nuclear Dynamics via

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.

Dietary starch promotes hepatic lipogenesis in barramundi (Lates calcarifer).

Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds.

First Observation of P-odd γ Asymmetry in Polarized Neutron Capture on Hydrogen.

We report the first observation of the parity-violating gamma-ray asymmetry A_{γ}^{np} in neutron-proton capture using polarized cold neutrons incident on a liquid parahydrogen target at the Spallation Neutron Source at Oak Ridge National Laboratory. A_{γ}^{np} isolates the ΔI=1, ^{3}S_{1}→^{3}P_{1} component of the weak nucleon-nucleon interaction, which is dominated by pion exchange and can be directly related to a single coupling constant in either the DDH meson exchange model or pionless effective field theory. We measured A_{γ}^{np}=[-3.0±1.4(stat)±0.2(syst)]×10^{-8}, which implies a DDH weak πNN coupling of h_{π}^{1}=[2.6±1.2(stat)±0.2(syst)]×10^{-7} and a pionless EFT constant of C^{^{3}S_{1}→^{3}P_{1}}/C_{0}=[-7.4±3.5(stat)±0.5(syst)]×10^{-11} MeV^{-1}. We describe the experiment, data analysis, systematic uncertainties, and implications of the result.

Risk factors and clinical outcomes of cytomegalovirus disease occurring more than one year post solid organ transplantation.

BACKGROUND: Cytomegalovirus (CMV) disease typically occurs during the first year after solid organ transplantation, after cessation of antiviral prophylaxis. CMV occurring after the first year is uncommon and not well described. METHODS: We conducted a case-control study to identify potential risk factors and a retrospective cohort study to evaluate 1-month mortality in solid organ transplant (SOT) recipients who developed CMV disease after the first year post transplant, or "very late CMV" (VLCMV), compared with those developing CMV within the first year (CMV Y1), adjusting for demographics, donor and recipient CMV serostatus, immunosuppression, rejection, and co-morbidities. RESULTS: We identified 85 SOT recipients with CMV disease at a single transplant center between January 2006 and October 2008: 23 (27%) had VLCMV and 62 (73%) had CMV Y1. Heart transplantation was independently associated with increased risk (adjusted odd ratio [OR] 4.11; 95% confidence interval [CI] 1.34-12.61; P = 0.01) for VLCMV. Patients with VLCMV had increased 1-month mortality (unadjusted OR 5.39; 95% CI 1.06-27.48; P = 0.02). Mortality was uncommonly attributable to CMV. CONCLUSIONS: CMV disease continues to occur after the first year post solid organ transplantation, particularly in heart transplant recipients, and can be associated with poor outcomes. CMV should be suspected in patients with symptoms or laboratory findings consistent with CMV, even if the patients present >1 year post transplant.

Balloon valvuloplasty versus closed commissurotomy for pliable mitral stenosis: a prospective hemodynamic study.

Closed surgical mitral valvotomy is the procedure of choice in most patients with symptomatic pliable mitral stenosis in developing countries. The procedure is efficacious and safe. Mitral valvotomy performed with a balloon has shown similar good results, with infrequent complications in selected subjects. Because there is a paucity of studies comparing the two techniques, this study was undertaken to compare the results of percutaneous balloon mitral valvuloplasty with those of closed commissurotomy as determined by catheterization studies. Forty-five patients with tight pliable mitral stenosis were randomly assigned to one of two groups: 23 patients had balloon valvuloplasty by the single catheter technique (group I) and 22 underwent closed surgical valvotomy (group II). The two groups were similar with regard to clinical and hemodynamic findings before intervention. Mitral valve area increased from 0.8 +/- 0.3 to 2.1 +/- 0.7 cm2 in group I (p less than 0.001) and from 0.7 +/- 0.2 to 1.3 +/- 0.3 cm2 in group II (p less than 0.001). Pulmonary artery pressure and pulmonary vascular resistance decreased in both groups, but these changes did not reach statistical significance in group II. Treadmill exercise time increased from 3.8 +/- 2.3 to 7.3 +/- 2.6 min in group I (p less than 0.001) and from 4 +/- 2.6 to 5.6 +/- 2.6 min in group II (p less than 0.001). There were no deaths. One patient in each group developed moderate (3+) mitral regurgitation. A small interatrial shunt (less than 1.5:1) was detected in three patients in group I immediately after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of histamine on the electrical activity of rat uterus.

Histamine produces a reduction in the spike frequency and the degree of depolarization which accompany spontaneous and induced contractions of rat uterus. Concentrations of 0.5 mug/ml can cause complete inhibition of both mechanical and electrical activity without producing any change in the resting membrane potential. Concentrations as high as 100 mug/ml cause no appreciable change in membrane potential.

Some effects of histamine in the depolarized rat uterus.

1. The relaxant effect of histamine in the isolated rat uterus remained after the preparation was depolarized in a potassium Ringer.2. The effect was abolished by the calcium-chelating agent, ethyleneglycol bis-aminoethyl ether-tetraacetic acid (EGTA).3. Histamine caused relaxation during calcium-induced contractures in a depolarized uterus treated with EGTA, but did not produce relaxation during barium-induced contractures.4. While responses of a normally polarized rat uterus to acetylcholine were inhibited by histamine, those of a depolarized uterus were enhanced by histamine. The inhibitory effects of isoprenaline and papaverine on acetylcholine responses were maintained in depolarized preparations.5. Both the enhancing effect of histamine on responses to acetylcholine and the relaxation of calcium-induced contractures were abolished by burimamide, indicating that H(2)-receptors mediate the effects of histamine in the depolarized tissue.6. A reduction in the rate of exchange of calcium across the depolarized cell membrane was demonstrated with high concentrations of histamine.7. The results are consistent with the hypothesis that in the rat uterus, the stimulation of H(2)-receptors by histamine is accompanied by a reduction in calcium exchange across the membrane which may result in a decrease in the concentration of free intracellular calcium available to stimulate contraction of the myofilaments. Histamine may act by increasing the binding of calcium within the cell.

Repeated measurement of respiratory function and bronchoconstriction in unanesthetized mice.

A noninvasive forced oscillation technique was used to determine respiratory function in unanesthetized and spontaneously breathing mice. Pseudorandom noise pressure variations in a frequency range of 16-208 Hz were applied to the body surface, and the flow response was measured at the nose. From the pressure-flow relationship, respiratory transfer impedance was calculated. Study of intra-animal variability on a short- and a long-term basis revealed that the real part of respiratory transfer impedance was reproducible within 9%. The imaginary part appeared less reproducible (within 22%). Furthermore, bronchoconstrictive responses were investigated and analyzed by evaluation of respiratory resistance as measured at 16 Hz (Rrs16). During the first 15 min after ovalbumin challenge in ovalbumin-sensitized mice, Rrs16 was significantly increased [49 +/- 7% (SE)]. Inhalation of methacholine in untreated mice induced an increase in Rrs16 of 75 +/- 16% (SE). In saline-challenged animals, no significant changes were observed. This method enables evaluation of long-term respiratory function in mice and appeared to be a sensitive measure for bronchoconstriction.

Pneumonectomy for inflammatory lung disease.

OBJECTIVE: Recent surgical literature has highlighted the dangers of pneumonectomy for inflammatory lung disease; therefore the assessment of the risk/benefit ratio of our departmental policy. METHODS: Patients undergoing pneumonectomy for inflammatory lung disease during two 2-year periods, 1991-1992 and 1996-1997 inclusive, were retrospectively analyzed. Clinical indications for investigation and surgery, and radiographic findings were determined. Some comparisons between the two periods were drawn. Rates of morbidity and mortality were the principle outcome measures. RESULTS: One hundred and fifty-five patients, 116 males, 39 females, with an average age of 30.2 years ranging from 1-68 years, underwent pneumonectomy for ongoing features of productive cough, haemoptysis (two emergencies) and chronic empyema all with either bronchographic or computed tomography (CT) evidence of destroyed lung. One hundred and fourteen (72%) had or had had tuberculosis at time of surgery. Histology showed bronchiectasis in 53 (34%), end-stage disease in 49 (31.6%) and active tuberculosis in 48 (30.9%). Over 90% of the patients were free of disease at discharge. Mortality was two (1.2%). Morbidity (23%) included post-pneumonectomy empyema 23 (14.8%), bleeding three (1.9%), broncho-pleural fistula three (1.9%), with wound sepsis in one (0.6%) and thoracic duct injury in one (0.6%). Three groups were identified, (1) pneumonectomy through empyema - a risk group, (2) pneumonectomy in active tuberculosis and (3) pneumonectomy in children. Twenty-three post-pneumonectomy empyemas (PPE) occurred with 21 of these following pneumonectomies through empyema (PTE), six PPEs followed 27 PTEs for active tuberculosis. Fourteen of the 21 empyemas following pneumonectomy through empyema were initially sterilized. Finally 15/23 (65%) of all PPEs were sterilized. Pneumonectomy in active tuberculosis did not carry the mortality or morbidity experienced by others. Pneumonectomy in children was remarkably uncomplicated, with one PPE occurring. CONCLUSIONS: This ongoing study shows pneumonectomy for inflammatory lung to be safe, with good results. Tuberculosis, being so common, adequate pre-operative and operative cover with anti-tuberculosis drugs may enhance results.

Pneumonectomy in children.

OBJECTIVES: Surgical literature carries relatively scant information on pneumonectomy in children. We reviewed our experience over 7 years, determined the risk/benefit ratio and compared our experience with reports from the literature. METHODS: The records of children undergoing pneumonectomy, 14 years and younger, over a 7-year period from January 1991 to December 1997, are analysed, the techniques used to determine the need for and extent of surgery are studied, whilst the problems and outcome of surgery in this age group are determined. RESULTS: Fifty-nine children, 40 males, 19 females, aged 6 months to 14 years, average age of 7.5 years, underwent pneumonectomy. A history of pulmonary infection/s and a chest radiograph suggestive of lung destruction were indicators for investigation by bronchography and/or computerized axial tomography of the chest (HRCT scan). This determined the nature and extent of disease and the possibility and extent of surgery required. Bronchus blockers (22), five others in combination with the prone operating position, prone position (six) and a double lumen tube in one, were used to protect the healthy lung at surgery. Spill of pus was recognized once with a bronchus blocker and the prone position used in combination. Six intra-operative complications (10.1%) were recognized: bronchial spill (one) without consequence, conversion of bi-lobectomy to pneumonectomy due to pulmonary artery injury (one), cardiac arrest (with resuscitation, one), bradycardia with hypotension (one), excessive bleeding (one) and intra-pleural spill of debris (one), the last without consequence. Seven post-operative complications (11.8%) occurred: one empyema (sterilized), bleeding one, pulmonary infection two, suspected but unproven broncho-pleural fistulae two, prolonged antibiotics in one, reason unrecorded. One pneumonectomy through an empyema was uncomplicated. The main histological features were bronchiectasis (38), active tuberculosis (eight), end-stage lung (five), collapse and pulmonary haemorrhage (one), lobar emphysema (one). Histology unrecorded (one). No death occurred. All patients left hospital well. CONCLUSIONS: Careful preparation, often including anti-tuberculosis cover, and timing of pneumonectomy are essential. Meticulous anaesthetic and surgical technique and co-operation are critical. Bronchus blockers functioned well but are not without risk. Attention to detail makes pneumonectomy safe in childhood.

Satisfaction and continuity of care: staff views of care in a midwife-managed delivery unit.

OBJECTIVE: to examine whether there are differences in the midwife's role in, and satisfaction with, intrapartum care and delivery of women at low obstetric risk in a midwife-managed delivery unit compared to a consultant-led labour ward. DESIGN: a pragmatic randomised controlled trial. Subjects were randomised in a 2:1 ratio between the midwives' unit and the labour ward. SETTING: Aberdeen Maternity Hospital, Grampian, UK. SUBJECTS: midwives within the delivery suite who cared for the 2844 women at low obstetric risk receiving care in a pragmatic randomised controlled trial of the two delivery areas. PRIMARY OUTCOME MEASURES: continuity of carer and midwife satisfaction. FINDINGS: midwives looking after women in the midwives' unit group were significantly more likely to be of a higher grade, more qualified and have a longer length of experience than those in the labour ward group. There was greater continuity of carer both during labour and after delivery in the midwives' unit group. Despite a small but statistically significant difference in overall satisfaction between the groups, area of 'booking' or area of delivery were not important in predicting midwife satisfaction. Autonomy and continuity of carer were the best predictors of midwife satisfaction. CONCLUSIONS: midwife-managed intrapartum care increases continuity of carer and, therefore, midwife satisfaction. Extending this outside the delivery suite requires a system of care that is acceptable to midwives as well as women. Such systems will depend to a large extent on geography, consumer demand and availability of resources. However, midwife satisfaction should also be considered. In order to do this further research is required to fully evaluate the effect these systems have on the midwives working in them.

Midwife managed delivery unit: a randomised controlled comparison with consultant led care.

OBJECTIVE: To examine whether intrapartum care and delivery of low risk women in a midwife managed delivery unit differs from that in a consultant led labour ward. DESIGN: Pragmatic randomised controlled trial. Subjects were randomised in a 2:1 ratio between the midwives unit and the labour ward. SETTING: Aberdeen Maternity Hospital, Grampian. SUBJECTS: 2844 low risk women, as defined by existing booking criteria for general practitioner units in Grampian. 1900 women were randomised to the midwives unit and 944 to the labour ward. MAIN OUTCOME MEASURES: Maternal and perinatal morbidity. RESULTS: Of the women randomised to the midwives unit, 647 (34%) were transferred to the labour ward antepartum, 303 (16%) were transferred intrapartum, and 80 (4%) were lost to follow up. 870 women (46%) were delivered in the midwives unit. Primigravid women (255/596, 43%) were significantly more likely to be transferred intrapartum than multi-gravid women (48/577, 8%). Significant differences between the midwives unit and labour ward were found in monitoring, fetal distress, analgesia, mobility, and use of episiotomy. There were no significant differences in mode of delivery or fetal outcome. CONCLUSIONS: Midwife managed intrapartum care for low risk women results in more mobility and less intervention with no increase in neonatal morbidity. However, the high rate of transfer shows that antenatal criteria are unable to determine who will remain at low risk throughout pregnancy and labour.

An experience with cardiopulmonary bypass in HIV-infected patients.

Having noted the good clinical status of some HIV patients who were referred for but refused surgery, we undertook surgery with the aim of determining outcome, risk-to-benefit ratio and, if possible, the effect of surgery with cardiopulmonary bypass (CPB) on the progression of their HIV disease. Antiretroviral drugs (ARVD) were not available to these patients. The records of 49 patients, 17 males and 32 females, aged between 17 and 67 years, undergoing surgery with cardiopulmonary bypass over a nine-year period, were reviewed. Forty-eight of these underwent cardiac surgery and one aortic dissection repair. Four HIV-infected patients underwent surgery with good early outcome. Thereafter an absolute CD4 cell count greater than 400/microl (normal 550*1 955/microl) and the absence of the stigmata of AIDS in patients fulfilling the normal criteria for surgery allowed cardiac surgery using CPB. Fifty operations were performed. Three patients with CD4 counts of 37, 868 and 1 245/microl died early, giving a 30-day mortality of 6% for 50 procedures. Six patients with active infective endocarditis (IE) underwent emergency surgery. Three of these, one with a pre- and two with only post-operative counts all below 250/microl, died within three months. Sixteen complications occurred in the remaining 46 patients (34.7%). Pre-operative CD4 cell counts taken in 42 patients averaged 685/microl. Pre- and post-operative counts known in eight showed variations, as did repeated counts in those awaiting surgery. Forty-one patients left hospital in the New York Heart Association (NYHA) class I, five in class II and one in class III. Prior to surgery, the majority (38) were in class III and seven were in class IV. Follow up ranging from two to 70 months averaged 23.1 months. Eight late deaths occurred, three related to AIDS. We found surgery to be worthwhile in selected HIV-infected patients. Early outcome paralleled that in the uninfected, giving a low risk-to-benefit ratio. Emergency surgery in those with active infective endocarditis and marked immune compromise met with high mortality. It is essential in our population to test and stage all patients for HIV. We could not show that CPB accelerated progression to AIDS. This experience and the present availability of ARVDs would enable us to review our selection criteria for surgery.

The homeostatic rôle of bronchoconstriction.

This article argues in favour of the hypothesis that the homeostatic rôles of bronchoconstriction are to retract the airway tree during expiration, and to assist in the expulsion of mucus from peripheral airways by increasing the velocity of outgoing air. In asthma, this function may be dangerously exaggerated because of the presence of unusually viscous airway secretions and the remodelling of airway walls.

Haematogenous amoebic lung abscess. A case report.

Left upper lobe amoebic lung abscess without established hepatic amoebiasis in a young Black man is described and the pathogenesis is briefly discussed.

Early adolescents' significant others: Grade and gender differences in perceived relationships with familial and nonfamilial adults and young people.

In order to provide a fuller and more satisfying description of the significant others in the social world of an adolescent, the Social Relations Questionnaire was developed and then administered to almost 3000 seventh-through tenth-graders in a midwestern suburban school district. The sample was randomly split in half and analyses were run on both halves separately to test for replicability. Results indicated that parents and siblings are almost always listed as significant others by adolescents in all four grade levels. Furthermore, the majority of adolescents listed at least one extended family adult and at least one nonrelated adult as important in their lives. The nonrelated adults lived closer to the adolescents and were seen more frequently and in more contexts than extended family members. Fewer extended family adults were listed in the older grades. Females listed more significant others than males both overall and in terms of both same- and opposite-sex nonrelated young people. As hypothesize, an increasing number of opposite-sex young people was listed as a function of grade level. Most nonrelated young people listed (a loose definition of peers) were from the same grade, same school, and same neighborhood as the respondent. The authors conclude that age-segregation in this community is not extreme (over 40% of the significant others listed were adults) and that the Social Relations Questionnaire provides a useful and holistic description of an adolescent's social world.