Interference effect of food and emotional stimuli in Stroop-like tasks for children and adults with Prader-Willi Syndrome

Interference effect of food and emotional stimuli in Stroop-like tasks for children and adults with Prader-Willi Syndrome. The aim of this work was to study the way items related to food or emotion are processed by a population known to have difficulties with dietary restriction, namely individuals with Prader-Willi Syndrome (PWS). Given the presence of intellectual disability (ID) in PWS, our experiments were designed to examine whether these difficulties were specific to PWS or linked with their ID. Two modified Stroop tasks (i.e., a food version and an emotional version) were administered to seventy-four children (aged between 6 and 16 years old) divided into three groups (one with PWS, one with ID matched on age and Intellectual Quotient (IQ), and one healthy group matched on age) and to eighty-four adults (aged between 18 and 48 years old) distributed in the same three groups. For both tasks, a picture version was used for the children and a word version for the adults. For the food Stroop task, (Experiment 1), materials were composed of low or high-caloric food items and stimuli not related to food. The results show a food Stroop effect for children and adults with PWS that was absent in the group of healthy participants. Moreover, a food Stroop effect was also significant for adults with ID. For the emotional Stroop task (Experiment 2), materials were composed of negative, positive and neutral stimuli. The emotional Stroop effect was also obtained for children and adults with PWS as well as for the healthy group, but not for the age- and IQ-matched group. For the PWS groups, results show a preservation to process positive pictures for children and difficulties to process negative stimuli for both age-groups. These results suggest that people with PWS have difficulties in disengaging their attention when food stimuli are present in their environment and poorer abilities to process negative ones. These difficulties endure in adulthood.

Infrared thermotransmittance-based temperature field measurements in semitransparent media

Contactless temperature field measurements in or at the surfaces of semitransparent media are a scientific challenge as classical thermography techniques based on proper material emission cannot be used. In this work, an alternative method using infrared thermotransmittance for contactless temperature imaging is proposed. To overcome the weakness of the measured signal, a lock-in acquisition chain is developed and an imaging demodulation technique is used to retrieve the phase and amplitude of the thermotransmitted signal. These measurements, combined with an analytical model, enable the estimation of the thermal diffusivity and conductivity of an infrared semitransparent insulator (wafer of Borofloat 33 glass) and the monochromatic thermotransmittance coefficient at 3.3 µm. The obtained temperature fields are in good agreement with the model, and a detection limit of ±2 °C is estimated with this method. The results of this work open new opportunities in the development of advanced thermal metrology for semitransparent media.

Emotional lability and irritability have specific associations with symptomatology in children with attention deficit hyperactivity disorder

Irritability and emotional lability have been shown to be severity and impairment factors in community and clinical sample studies and are frequent comorbid features of Attention Deficit Hyperactivity Disorder (ADHD). However, while irritability and emotional lability seem to be closely linked, the differential effect of these two features has received little attention. This study assessed the distinct associations of irritability and emotional lability on symptomatology in children with ADHD. One hundred and eight children diagnosed with ADHD participated in the study. Children were rated by parents on ADHD and comorbid symptomatology with the Conners Rating Scale - Revised. Irritability was the most significant predictive factor of the severity of anxiety and oppositional symptoms. Regarding emotional lability, it was significantly predictive of the severity of hyperactivity symptoms. While emotional lability shares common theoretical characteristics with irritability, each seems to be associated with specific areas. Irritability is a symptom of Oppositional Defiant Disorder, a frequent ADHD comorbidity, and also seems to be related to internalizing disorder (e.g. anxiety). Emotional lability seems to be related to ADHD severity symptoms per se. Both could be clinically informative in the diagnosis of ADHD and its comorbidities.

Virtual Remediation Versus Methylphenidate to Improve Distractibility in Children With ADHD: A Controlled Randomized Clinical Trial Study

Objective: Virtual environments have been used to assess children with ADHD but have never been tested as therapeutic tools. We tested a new virtual classroom cognitive remediation program to improve symptoms in children with ADHD. Method: In this randomized clinical trial, 51 children with ADHD (7-11 years) were assigned to a virtual cognitive remediation group, a methylphenidate group, or a psychotherapy group. All children were evaluated before and after therapy with an ADHD Rating Scale, a Continuous Performance Test (CPT), and a virtual classroom task. Results: After therapy by virtual remediation, children exhibited significantly higher numbers of correct hits on the virtual classroom and CPT. These improvements were equivalent to those observed with methylphenidate treatment. Conclusion: Our study demonstrates for the first time that a cognitive remediation program delivered in a virtual classroom reduces distractibility in children with ADHD and could replace methylphenidate treatment in specific cases.

Synchronization of Optomechanical Nanobeams by Mechanical Interaction

The synchronization of coupled oscillators is a phenomenon found throughout nature. Mechanical oscillators are paradigmatic examples, but synchronizing their nanoscaled versions is challenging. We report synchronization of the mechanical dynamics of a pair of optomechanical crystal cavities that, in contrast to previous works performed in similar objects, are intercoupled with a mechanical link and support independent optical modes. In this regime they oscillate in antiphase, which is in agreement with the predictions of our numerical model that considers reactive coupling. We also show how to temporarily disable synchronization of the coupled system by actuating one of the cavities with a heating laser, so that both cavities oscillate independently. Our results can be upscaled to more than two cavities and pave the way towards realizing integrated networks of synchronized mechanical oscillators.

Mechanisms behind the enhancement of thermal properties of graphene nanofluids

While the dispersion of nanomaterials is known to be effective in enhancing the thermal conductivity and specific heat capacity of fluids, the mechanisms behind this enhancement remain to be elucidated. Herein, we report on highly stable, surfactant-free graphene nanofluids, based on N,N-dimethylacetamide (DMAc) and N,N-dimethylformamide (DMF), with enhanced thermal properties. An increase of up to 48% in thermal conductivity and 18% in specific heat capacity was measured. The blue shift of several Raman bands with increasing graphene concentration in DMF indicates that there is a modification in the vibrational energy of the bonds associated with these modes, affecting all the molecules in the liquid. This result indicates that graphene has the ability to affect solvent molecules at long-range, in terms of vibrational energy. Density functional theory and molecular dynamics simulations were used to gather data on the interaction between graphene and solvent, and to investigate a possible order induced by graphene on the solvent. The simulations showed a parallel orientation of DMF towards graphene, favoring π-π stacking. Furthermore, a local order of DMF molecules around graphene was observed suggesting that both this special kind of interaction and the induced local order may contribute to the enhancement of the fluid's thermal properties.

Nanocrystalline silicon optomechanical cavities

Silicon on insulator photonics has offered a versatile platform for the recent development of integrated optomechanical circuits. However, there are some constraints such as the high cost of the wafers and limitation to a single physical device level. In the present work we investigate nanocrystalline silicon as an alternative material for optomechanical devices. In particular, we demonstrate that optomechanical crystal cavities fabricated of nanocrystalline silicon have optical and mechanical properties enabling non-linear dynamical behaviour and effects such as thermo-optic/free-carrier-dispersion self-pulsing, phonon lasing and chaos, all at low input laser power and with typical frequencies as high as 0.3 GHz.

Is emotional lability a marker for attention deficit hyperactivity disorder, anxiety and aggression symptoms in preschoolers?

BACKGROUND

Emotional lability (EL) is frequent in school-aged children with attention deficit hyperactivity disorder (ADHD) and is associated with more frequent comorbidities and more severe impairment. However, little research has investigated the association between EL, ADHD and comorbid symptoms in preschoolers. This study assessed dimensional EL in preschoolers and its link with ADHD symptoms (e.g. hyperactivity-impulsivity and inattention) and behavioural and emotional problems (e.g. aggression and anxiety).

METHOD

One hundred and fifty-four preschoolers aged 3-6 years old were rated on questionnaires by parents. EL was assessed with the index from the Conners Rating Scale-Revised and behavioural and emotional problems with an adapted version of the Social Behavior Questionnaire. Multiple linear regressions analyses were conducted.

RESULTS

Higher EL was associated with higher hyperactivity-impulsivity, inattention, anxiety and aggression problems. After controlling for other behavioural and emotional problems and sociodemographic variables, EL remained associated with hyperactivity-impulsivity and anxiety.

CONCLUSIONS

Emotional lability seems to be a potential marker for ADHD symptoms with internalizing problems in preschoolers and could be a target for diagnosis and early interventions. This finding should be treated with caution as the study was limited by the low response rate of the participants and consequently the small sample size.

Evaluation of cardiorespiratory functional reserve from arm exercise in the elderly

BACKGROUND

When the subject is not able to satisfy traditional testing procedures, alternative exercises or indices such as arm cranking or the oxygen uptake efficiency slope (OUES) have been proposed. However, the OUES has not yet been used on elderly subjects from an exercise performed with the arms.

OBJECTIVE

The aim of our study was to evaluate the possibility of using the OUES as an index of the cardiorespiratory functional reserve in the elderly when the exercise evaluation test is performed with the arms and when this parameter is estimated from submaximal responses.

METHODS

Seventeen adults (62-82 years) undergoing total joint arthroplasty of the hip took part in this study. Maximal incremental exercise tests were performed on an arm crank ergometer 1 month before (T₁) and 2 months after (T₂) surgery. Gas exchanges were measured continuously to determine oxygen consumption at peak exercise (V˙O₂ peak) and were used to calculate the OUES. The correlation coefficient was calculated between V˙O₂ peak and OUES, and their relative changes between T₁ and T₂.

RESULTS

V˙O₂ peak was not significantly different between T₁ and T₂: 10.3 ± 0.7 and 9.8 ± 0.5 mL/min per kilogramme respectively. The OUES estimated from submaximal responses did not show a significant difference between T₁ and T₂. Significant correlations were observed between individual V˙O₂ peak and OUES, as well as at T₁ and T₂.

CONCLUSION

The use of arm cranking exercises and the calculation of the OUES from the submaximal respiratory response can be used for the objective quantification of cardiorespiratory functional reserve in the elderly.

Ultrafractionated radiation therapy (3x per day) for glioblastoma: Preliminary results of a phase II study

1570

Background: Ultrafractionation radiation therapy consists in irradiating cells or tumors several times daily, delivering low doses at which hyperradiosensitivity occur. We recently reported the high efficiency of ultrafractionation radiotherapy in glioma cell lines and xenografts, and are now conducting a phase II clinical trial to determine the effect of an ultrafractionation regimen for glioblastoma patients. Methods: A prospective, multicenter, phase II study has opened for accrual in September 2003. Patients over 18 years of age who are able to give informed consent and have histologically proven, newly diagnosed and unresectable, supratentorial glioblastoma (WHO grade IV) are eligible. Three doses of 0.75 Gy spaced by at least four hours are delivered daily, five days a week for six consecutive weeks for a total of 67.5 Gy. Conformal irradiation includes the tumor bulk including a margin of 2.5 cm. Tolerance and toxicity are the primary endpoints; survival and progression-free survival are secondary endpoints. Results: To date 25 patients have been enrolled in this study, 19 currently evalualbe: 11 men and 8 women, median age 58 (range 37 to 76), median Karnofsky performance status (80 range from 70 to 100). The median time between histological diagnosis and the start of treatment is 7 weeks. The ultrafractionated radiation therapy has been well tolerated; no acute grade 3 and/or 4 CNS toxicity has been observed. Minor responses at the end of irradiation were seen in 5 patients. Median survival from initial diagnosis was 13.5 months, nine patients remain alive. Conclusions: Ultrafractionated radiation therapy is safe and well tolerated. No acute CNS toxicitiy has been observed. Overall survival of over 13 months for patients without prior debulking surgery compares favorably with other reports. Updated definitive results will be presented.

No significant financial relationships to disclose.

Plasma glutamine response to enteral administration of glutamine in human volunteers (free glutamine versus protein-bound glutamine)

The goal of the present work was to compare the plasma glutamine response to exogenous glutamine administration in human volunteers; glutamine was provided as a free amino acid, bound to proteins, or in the form of peptides. Plasma glutamine concentrations were measured in eight human volunteers at 30, 60, 90, 120, and 240 min after receiving a drink containing 30 g of protein from one of the five different proteins tested (sodium caseinate, sodium caseinate + free glutamine, carob germ flour, carob protein concentrate, and carob protein hydrolysate). Peak plasma glutamine concentrations were 42% higher than postabsorptive basal values when exogenous glutamine was administered in the form of free glutamine added to caseinate (925.9 +/- 67.7 versus 651.3 +/- 44.0 micromol/L, respectively). In contrast, when glutamine was offered 100% bound to proteins (carob proteins), peak plasma glutamine concentration increased only between 18% and 23% from basal values, possibly because of the lower digestibility of carob proteins versus that of caseinate + free glutamine, to a different glutamine utilization at the gut level, or to a different response in endogenous glutamine kinetics to enteral administration of glutamine, depending on the molecular form of the glutamine source (free or protein bound).

[Tumors of the upper urinary tract in patients following bladder tumors: multicentric locations or seeding? Apropos of 14 cases]

The occurrence of upper urinary tract tumors has been studied in 479 patients followed for bladder cancer: The incidence rate is low (2.9%) but increases with time (mean: 58 months). Some patients are more exposed: those who underwent repeated transurethral resections of Ta-T1 multifocal bladder carcinoma. Retrograde and voiding cystourethrogram seems to be useful to select a group "at risk" during the follow-up of patients with bladder tumors treated by endoscopic resection: a yearly excretory urography for upper urinary tract survey should then be performed.