Sustaining attention in affective contexts during adolescence: age-related differences and association with elevated symptoms of depression and anxiety.

Sustained attention, a key cognitive skill that improves during childhood and adolescence, tends to be worse in some emotional and behavioural disorders. Sustained attention is typically studied in non-affective task contexts; here, we used a novel task to index performance in affective versus neutral contexts across adolescence (N = 465; ages 11-18). We asked whether: (i) performance would be worse in negative versus neutral task contexts; (ii) performance would improve with age; (iii) affective interference would be greater in younger adolescents; (iv) adolescents at risk for depression and higher in anxiety would show overall worse performance; and (v) would show differential performance in negative contexts. Results indicated that participants performed more poorly in negative contexts and showed age-related performance improvements. Those at risk of depression performed more poorly than those at lower risk. However, there was no difference between groups as a result of affective context. For anxiety there was no difference in performance as a function of severity. However, those with higher anxiety showed less variance in their reaction times to negative stimuli than those with lower anxiety. One interpretation is that moderate levels of emotional arousal associated with anxiety make individuals less susceptible to the distracting effects of negative stimuli.

Susceptibility to prosocial and antisocial influence in adolescence.

INTRODUCTION: Adolescents are particularly susceptible to social influence and previous studies have shown that this susceptibility decreases with age. The current study used a cross-sectional experimental paradigm to investigate the effect of age and puberty on susceptibility to both prosocial and antisocial influence. METHODS: Participants (N = 520) aged 11-18 from London and Cambridge (United Kingdom) rated how likely they would be to engage in a prosocial (e.g. "help a classmate with their work") or antisocial (e.g. "make fun of a classmate") act. They were then shown the average rating (in fact fictitious) that other adolescents had given to the same question, and were then asked to rate the same behaviour again. RESULTS: Both prosocial and antisocial influence decreased linearly with age, with younger adolescents being more socially influenced when other adolescents' ratings were more prosocial and less antisocial than their own initial rating. Both antisocial and prosocial influence significantly decreased across puberty for boys but not girls (independent of age). CONCLUSIONS: These findings suggest that social influence declines with increasing maturity across adolescence. However, the exact relationship between social influence and maturity is dependent on the nature of the social influence and gender. Understanding when adolescents are most susceptible to different types of social influence, and how this might influence their social behaviour, has important implications for understanding adolescent social development.

Short-wavelength free-electron laser sources and science: a review.

This review is focused on free-electron lasers (FELs) in the hard to soft x-ray regime. The aim is to provide newcomers to the area with insights into: the basic physics of FELs, the qualities of the radiation they produce, the challenges of transmitting that radiation to end users and the diversity of current scientific applications. Initial consideration is given to FEL theory in order to provide the foundation for discussion of FEL output properties and the technical challenges of short-wavelength FELs. This is followed by an overview of existing x-ray FEL facilities, future facilities and FEL frontiers. To provide a context for information in the above sections, a detailed comparison of the photon pulse characteristics of FEL sources with those of other sources of high brightness x-rays is made. A brief summary of FEL beamline design and photon diagnostics then precedes an overview of FEL scientific applications. Recent highlights are covered in sections on structural biology, atomic and molecular physics, photochemistry, non-linear spectroscopy, shock physics, solid density plasmas. A short industrial perspective is also included to emphasise potential in this area.

Transform-limited x-ray pulse generation from a high-brightness self-amplified spontaneous-emission free-electron laser.

A method to achieve high-brightness self-amplified spontaneous emission (HB-SASE) in the free-electron laser (FEL) is described. The method uses repeated nonequal electron beam delays to delocalize the collective FEL interaction and break the radiation coherence length dependence on the FEL cooperation length. The method requires no external seeding or photon optics and so is applicable at any wavelength or repetition rate. It is demonstrated, using linear theory and numerical simulations, that the radiation coherence length can be increased by approximately 2 orders of magnitude over SASE with a corresponding increase in spectral brightness. Examples are shown of HB-SASE generating transform-limited FEL pulses in the soft x-ray and near transform-limited pulses in the hard x-ray. Such pulses may greatly benefit existing applications and may also open up new areas of scientific research.

Few-cycle pulse generation in an x-ray free-electron laser.

A method is proposed to generate trains of few-cycle x-ray pulses from a free-electron laser (FEL) amplifier via a compact "afterburner" extension consisting of several few-period undulator sections separated by electron chicane delays. Simulations show that in the hard x ray (wavelength ~0.1 nm; photon energy ~10 keV) and with peak powers approaching normal FEL saturation (GW) levels, root mean square pulse durations of 700 zs may be obtained. This is approximately two orders of magnitude shorter than that possible for normal FEL amplifier operation. The spectrum is discretely multichromatic with a bandwidth envelope increased by approximately 2 orders of magnitude over unseeded FEL amplifier operation. Such a source would significantly enhance research opportunity in atomic dynamics and push capability toward nuclear dynamics.

The effect of leg length discrepancy on pelvis and spine kinematics during gait.

There are assumptions that leg length discrepancy (LLD) may cause low back pain by creating pelvis obliquity and lumbar scoliosis. Although individuals with LLD develop compensatory movements in the lower limbs and pelvis during walking, few investigations have attempted to identify kinematic variables of the upper body. This study aims to gain an understanding of how simulated LLD influences three-dimensional motion of the pelvis and spine. Seven male participants were required to walk barefoot at a preferred speed. Three LLD conditions (1, 2, and 3cm) were simulated using modified pieces of high density EVA attached to the right foot. An optoelectronic motion analysis system was used to record kinematic data of the pelvis and spine (lumbar, lower and upper thoracic segments) for each condition. Differences in range of motion and patterns of movement for the pelvis and lumbar spine were minimal between barefoot and LLD conditions. These observations could be attributed to various kinematic compensatory strategies within the lower limbs which require further in-depth investigation.

Randomised controlled clinical trial for the use of deracoxib during intense rehabilitation exercises after tibial plateau levelling osteotomy.

During intense physical exercise, the cyclo-oxygenase-2 (COX-2) pathway is upregulated which contributes to soreness. The aim of this study was to determine if there was a clinical affect of deracoxib (COX-2 selective antagonist) on dogs engaged in intense rehabilitation following tibial plateau levelling osteotomy for cranial cruciate ligament rupture. Our hypothesis was that dogs receiving deracoxib would demonstrate less lameness, better range-of-motion (ROM), and faster muscle mass recovery than the control dogs. Thirty dogs were randomised to the treatment (deracoxib at 1-2 mg/kg once daily by mouth) or control (no treatment) group. Outcomes including gait analysis, thigh circumference, and goniometry, were measured by one investigator, who was masked to group preoperatively, and at the end of each intense rehabilitation week (3, 5, and 7 weeks postoperatively). The only difference between groups for any outcome measure at any time point was a greater preoperative stifle ROM in the group receiving deracoxib (p = 0.04). This study showed that treatment with deracoxib did not provide better outcomes when dogs were subjected to intense rehabilitation after tibial plateau levelling osteotomy. Each patient should be evaluated individually to determine if administration of deracoxib is appropriate.

The effect of axial and abaxial release on meniscal displacement in the dog.

The meniscal release (MR) is used to minimize meniscal pathology after Tibial Plateau Leveling Osteotomy (TPLO) surgery. The purposes of this study were: (i) to describe meniscal orientation in a unaltered cadaveric canine stifle, a cruciate deficient stifle, TPLO repaired stifle with and without the MR using magnetic resonance imaging; (ii) to determine if the abaxial release is equivalent to the axial release in its ability to affect caudal pole displacement in a TPLO repaired stifle and (iii) to evaluate with MRI the effect of MR on the femorotibiol articular cartilage contact area in a TPLO repaired stifle. Briefly, cadaver limbs were placed into a jig designed to mimic a weight-bearing stance at 140 degrees and 90 degrees at the stifle. The limbs were sequentially evaluated from the unaltered state; after cranial cruciate ligament transection; after TPLO stabilization; and finally after a meniscal release. No significant difference was found between the intrameniscal area (IMA) of the abaxial and axial meniscal releases although there was an increase in the IMA after the meniscal release compared to the IMA in the normal, cranial cruciate ligament deficient stifle, and TPLO stabilized stifle. In the abaxial release, a meniscal remnant remained in situ and provided a space effect between the femur and the tibial plateau. This is in contrast to the axial meniscal release, where the entire caudal pole of the medial meniscus relocated caudolaterally and consequently permitted more direct femorotibial contact. Overall, however, there was evidence of caudal pole compression of the medial meniscus throughout the MRI series which was ameliorated by either of the MR procedures.

Distribution of serotonin 2A, 2C and 3 receptor mRNA in spinal cord and medulla oblongata.

It is known that 5-HT receptors have significant roles in nociceptive and motor functions. We have compared the cellular localization of the mRNAs encoding serotonin 5-HT(2A,) 5-HT(2C,) 5-HT(3) receptor subtypes within different levels of the rat spinal cord and medulla. In the spinal cord, 5-HT(2C) receptor mRNA is expressed at high levels in most of the gray matter, except for lamina II. In contrast, 5-HT(2A) receptor mRNA is expressed exclusively in lamina IX. 5-HT(3) receptor mRNA has a low level and diffuse pattern of expression increasing towards the ventral horn. In both gray and white matter, there is a characteristic presence of a few highly stained cells. For each subtype, the expression pattern is similar in all four levels of the spinal cord. In the medulla, 5-HT(2C) receptor mRNA is at high levels in many nuclei including the hypoglossal nucleus, the gigantocellular reticular nucleus alpha and the parvocellular reticular nucleus alpha, the spinal nucleus of the trigeminal tract, the facial, and the dorsal medullary reticular field. Moderate to low levels of expression are seen in the spinal vestibular nucleus, the vagus, the solitary nuclei and the raphe. 5-HT(2A) receptor is expressed at high levels in some nuclei such as the hypoglossal nucleus, the intercalate nucleus, the inferior olive and the lateral reticular nucleus. Moderate to low levels of expression are seen in the facial, the medial vestibular nuclei, the nucleus ambiguous, the vagus, and the gigantocellular reticular nucleus. 5-HT(3) receptor mRNA is present at low levels in most of the nuclei examined, with a few scattered strongly labeled cells. The results show a distinct distribution of the three subtypes of receptors supporting their physiological roles and will help to understand the mechanisms of nociception and motor function.

The influence of four wound dressings on the kinetics of human walking.

OBJECTIVES: This in vivo study (the second phase of a research project first described in the February issue of Journal of Wound Care) reports on the influence of various wound dressings on the dynamics of human walking. Allevyn (Smith and Nephew), Biatain (Coloplast), Lyofoam (Seton Scholl) and Tielle (Johnson and Johnson) were used in this study. The investigation aimed to assess the ground reaction forces in the foot while the dressings were applied to the plantar surface of the foot. METHOD: A strain gauge force plate system was used. Six subjects with 'normal' gait patterns and no foot pathology were recruited into the study. Eight trials were recorded for each subject. The peak push-off force, in the vertical component of the ground reaction force, and the maximum braking and propulsive forces in the medial-lateral component of the ground reaction force were estimated and reported. RESULTS: Among the various dressings tested, Allevyn performed closest to barefoot in the peak push-off force and demonstrated an increased braking force at the deceleration point in the gait cycle. CONCLUSION: These findings may have implications for clinicians selecting wound dressings for the treatment of certain foot ulcerations. However, further clinical research is warranted in this area.

Comparative safety of filgrastim versus sargramostim in patients receiving myelosuppressive chemotherapy.

STUDY OBJECTIVE: To compare rates of adverse events with filgrastim versus sargramostim when given prophylactically to patients receiving myelosuppressive chemotherapy. DESIGN: Retrospective review with center crossover. SETTING: Ten United States outpatient chemotherapy centers. PATIENTS: Four hundred ninety patients treated for lung, breast, lymphatic system, or ovarian tumors. INTERVENTION: Prophylactic use of filgrastim or sargramostim, with dosages at investigator discretion. MEASUREMENTS AND MAIN RESULTS: The frequency and severity of adverse events and the frequency of switching to the alternative CSF were assessed. There was no difference in infectious fever. Fever unexplained by infection was more common with sargramostim (7% vs 1%, p<0.001), as were fatigue, diarrhea, injection site reactions, other dermatologic disorders, and edema (all p<0.05). Skeletal pain was more frequent with filgrastim (p=0.06). Patients treated with sargramostim switched to the alternative agent more often (p<0.001). CONCLUSION: Adverse events were less frequent with filgrastim than with sargramostim, suggesting that quality of life and treatment costs also may differ.

Iatrogenic coronary artery dissections extending into and involving the aortic root.

We set out to determine the incidence of iatrogenic coronary artery dissection extending into the aorta and to characterize the aortic lesions. We reviewed the data from 43,143 cardiac catheterizations from September 1993 through September 1999 and found 9 coronary artery-aortic dissections for an overall incidence of 0.02%. Four of these patients were undergoing treatment for acute myocardial infarction (AMI) and aortic dissection was more common than for non-AMI patients (0.19% vs. 0.01%, P < 0.0006). Histologic analysis of tissue samples from 2 cases revealed age related changes only and no evidence of predisposing pathology. Patients with limited aortic involvement were successfully managed with stenting of the coronary dissection entry point whereas aortic dissection extending up the aorta >40 mm from the coronary os required surgical intervention.

The association of cigarette smoking with alveolar bone loss in postmenopausal females.

BACKGROUND, AIMS: The purpose of this 2-year longitudinal clinical study was to determine the impact of smoking on alveolar bone height and density changes in postmenopausal females. METHODS: 59 postmenopausal women completed this study, including 38 non-smokers and 21 smokers. All subjects had a history of periodontitis, participated in 3- to 4-month periodontal maintenance programs and were within 5 years of menopause at the study outset. 4 vertical bite-wing radiographs of posterior sextants were taken at baseline and 2-year visits. Radiographs were evaluated using computer-assisted densitometric image analysis (CADIA); changes in interproximal alveolar bone density and changes in alveolar bone height were determined. Relative clinical attachment levels (RCAL) and presence/absence of plaque and bleeding on probing were recorded. RESULTS: Smokers exhibited a higher frequency of alveolar bone height loss (p<0.05) and crestal (p<0.03) and subcrestal (p<0.02) density loss relative to non-smokers. Smokers exhibited a trend (p<0.08) toward a higher frequency of > or =2.0 mm RCAL loss over the 2-year period. Plaque and bleeding on probing did not differ between smokers and non-smokers. A significant interaction, determined by repeated measures ANOVA, was noted between systemic bone mineral density (BMD) at the lumbar spine and smoking on alveolar bone density change (p<0.05). Only non-smoking patients with normal BMD realized a mean net gain in alveolar bone density; osteoporotic/osteopenic subjects (n=25) and smokers lost alveolar bone density. CONCLUSION: Postmenopausal female smokers were more likely to lose alveolar bone height and density than non-smokers with a similar periodontitis, plaque and gingival bleeding experience. In addition, both smoking and osteoporosis/osteopenia provided a negative influence on alveolar bone.

Egocentric empathy gaps between owners and buyers: misperceptions of the endowment effect.

In 5 studies, the authors examined people's perceptions of the endowment effect, or the tendency to value an object more once one owns it. In the 1st 2 studies, the authors documented egocentric empathy gaps between owners and buyers regarding the endowment effect: Both owners and buyers overestimated the similarity between their own valuation of a commodity and the valuation of people in the other role. The next 2 studies showed that these empathy gaps may lead to reduced earnings in a market setting. The final study showed that egocentric empathy gaps stem partly from people's misprediction of what their own valuation would be if they were in the other role.

Improving the oral hygiene of institutionalized mentally retarded clients.

PURPOSE: The quality of oral health care of persons with mental retardation has been reported in the literature to be less than that of their normal peers. The purpose of this study, set in a Midwest institution for persons with developmental retardation, was to determine if a change in policy followed by staff training and monitored by an interested third party would improve the oral hygiene of clients living on wards. METHODS: Methods used to train staff in proper toothbrushing were developed. Three living units were randomly selected for study: control, training plus accountability (experimental group I), and training without accountability (experimental group II). The direct care staff of both experimental groups were trained in proper toothbrushing techniques. Staff of the control group received no training. A dental hygienist visited the living unit periodically to evaluate and provide feedback on the plaque index scores taken by the caregivers in both experimental groups. RESULTS: The plaque indexes of group I showed significant improvement over the control group and group II. CONCLUSION: The results of this pilot study support the other findings of higher plaque indexes for residents with mental retardation and that modifying toothbrushing policies and staff training are not as critical to the improvement of the clients' oral hygiene as is the presence of an involved, interested third party.

Feeling "holier than thou": are self-serving assessments produced by errors in self- or social prediction?

People typically believe they are more likely to engage in selfless, kind, and generous behaviors than their peers, a result that is both logically and statistically suspect. However, this oft-documented tendency presents an important ambiguity. Do people feel "holier than thou" because they harbor overly cynical views of their peers (but accurate impressions of themselves) or overly charitable views of themselves (and accurate impressions of their peers)? Four studies suggested it was the latter. Participants consistently overestimated the likelihood that they would act in generous or selfless ways, whereas their predictions of others were considerably more accurate. Two final studies suggest this divergence in accuracy arises, in part, because people are unwilling to consult population base rates when predicting their own behavior but use this diagnostic information more readily when predicting others'.

The use of distraction osteogenesis to induce new suprabony periodontal attachment in the beagle dog.

Using a technique called distraction osteogenesis (DO), orthopedic surgeons are capable of reconstructing 4 to 5 cm of bone and soft tissue without bone grafts or pedicle flap procedures. DO has been used recently to generate maxillofacial bone as an alternative to maxillary and mandibular osteotomies. Using DO methodology, this study attempted to regenerate supraalveolar buccal periodontium on the mandibular second, third, and fourth premolars of beagle dogs. A small but statistically significantly greater amount of new cementum was generated in experimental teeth, with no difference found between experimental and control groups with respect to regenerating alveolar bone. Further studies using modifications of this technique are warranted to explore the potential of DO as an alternative to conventional regenerative approaches.

GABA(A) receptor-mediated miniature postsynaptic currents and alpha-subunit expression in developing cortical neurons.

Previous studies have described maturational changes in GABAergic inhibitory synaptic transmission in the rodent somatosensory cortex during the early postnatal period. To determine whether alterations in the functional properties of synaptically localized GABA(A) receptors (GABA(A)Rs) contribute to development of inhibitory transmission, we used the whole cell recording technique to examine GABAergic miniature postsynaptic currents (mPSCs) in developing cortical neurons. Neurons harvested from somatosensory cortices of newborn mice showed a progressive, eightfold increase in GABAergic mPSC frequency during the first 4 wk of development in dissociated cell culture. A twofold decrease in the decay time of the GABAergic mPSCs, between 1 and 4 wk, demonstrates a functional change in the properties of GABA(A)Rs mediating synaptic transmission in cortical neurons during development in culture. A similar maturational profile observed in GABAergic mPSC frequency and decay time in cortical neurons developing in vivo (assessed in slices), suggests that these changes in synaptically localized GABA(A)Rs contribute to development of inhibition in the rodent neocortex. Pharmacological and reverse transcription-polymerase chain reaction (RT-PCR) studies were conducted to determine whether changes in subunit expression might contribute to the observed developmental alterations in synaptic GABA(A)Rs. Zolpidem (300 nM), a subunit-selective benzodiazepine agonist with high affinity for alpha1-subunits, caused a reversible slowing of the mPSC decay kinetics in cultured cortical neurons. Development was characterized by an increase in the potency of zolpidem in modulating the mPSC decay, suggesting a maturational increase in percentage of functionally active GABA(A)Rs containing alpha1 subunits. The relative expression of alpha1 versus alpha5 GABA(A)R subunit mRNA in cortical tissue, both in vivo and in vitro, also increased during this same period. Furthermore, single-cell RT-multiplex PCR analysis revealed more rapidly decaying mPSCs in individual neurons in which alpha1 versus alpha5 mRNA was amplified. Together these data suggest that changes in alpha-subunit composition of GABA(A)Rs contribute to the maturation of GABAergic mPSCs mediating inhibition in developing cortical neurons.

Qualitative and quantitative determination of dental amalgam restoration volume.

STATEMENT OF PROBLEM: Volume of tooth structure replaced by an existing restoration, as assessed by visual and radiographic examination, is one diagnostic measure used by dental practitioners and dental insurance agencies to determine the relative need to restore a tooth with a full-coverage cast restoration. However, use of these methods has not been validated. PURPOSE: This study compared the volume of a range of dental amalgam restorations placed in typodont teeth, as estimated by dentists, dental students and laypersons, with the actual volume of each restoration. METHODS AND MATERIAL: Sixty subjects (20 dental school faculty, 20 dental students, and 20 clerical staff [laypersons]) participated. After reviewing photographic images of typodont teeth with mesial-occlusal-distal dental amalgam restorations, subjects estimated the volume of each restoration using various restorations on different teeth as a percentage of its tooth's coronal volume. The actual volume of each dental amalgam restoration and that of the coronal portion of the prepared teeth was calculated with a volumetric displacement technique. The single sample 2-sided t test with a.05 level of significance was used to evaluate the null hypothesis (H0 ): The survey participant's estimates of each restoration's percentage volume are the same as the measured volume values versus the alternative hypothesis (H1 ): estimates differed from the measured volume values. One-way analysis of variance was used to determine the significance of any difference between the estimates of the 3 survey test groups. RESULTS: Average volumes reported by all 3 groups were significantly different than the measured volume values (P <.05). Experience and dental training did not significantly affect a participant's ability to evaluate restoration volumes with greater accuracy. Results reported by dentists, dental students, and laypersons were not significantly different (P >.05). CONCLUSIONS: The volume of a restoration is inaccurately assessed by visual and radiographic examination.