Intermediate-Range Casimir-Polder Interaction Probed by High-Order Slow Atom Diffraction

At nanometer separation, the dominant interaction between an atom and a material surface is the fluctuation-induced Casimir-Polder potential. We demonstrate that slow atoms crossing a silicon nitride transmission nanograting are a remarkably sensitive probe for that potential. A 15% difference between nonretarded (van der Waals) and retarded Casimir-Polder potentials is discernible at distances smaller than 51 nm. We discuss the relative influence of various theoretical and experimental parameters on the potential in detail. Our work paves the way to high-precision measurement of the Casimir-Polder potential as a prerequisite for understanding fundamental physics and its relevance to applications in quantum-enhanced sensing.

Intracranial Hypertension Is Painless!

INTRODUCTION

Headache is usually considered a key symptom of intracranial hypertension (ICHT). However, there are no published experimental data to support the concept that increased intracranial pressure (ICP) is painful in humans.

MATERIALS AND METHODS

This prospective study was performed in 16 patients with suspected normal-pressure hydrocephalus, necessitating a lumbar infusion test with measurement of cerebrospinal fluid (CSF) hydrodynamics. During the test, ICP was increased from baseline to a plateau. Headache was scored on a visual analog scale (VAS) (0 = no pain, 10 = very severe pain) at baseline ICP and when ICP plateaued.

RESULTS

At baseline, mean ICP was 11 ± 3.6 mmHg and VAS was 0. At plateau, mean ICP was 28 ± 9.5 mmHg and VAS was 0. There was a significant increase in ICP (p <0.001), but no increase in headache intensity (VAS). An acute (20-min) moderate increase in ICP was not accompanied by a headache.

DISCUSSION

We demonstrate that an acute, isolated increase in CSF pressure does not produce a headache. To occur, a headache needs activation of the pain-sensitive structures (dura and venous sinuses) or central activation of the cerebral nociceptive structures. This peripheral or central activation does not occur with an isolated increase in CSF pressure.

Peripheral late reactivation of a previously typical monofocal Baló’s concentric sclerosis lesion

We report a 41-year-old woman with rapidly progressive left hemiparesis, revealing an inflammatory reactivation of a previously known parietal Baló’s concentric sclerosis lesion. The first attack occurred five years before. After a slow recovery following high-dose steroid infusions the patient stabilized. Because of recurrent ataxia and left hemiparesis a new magnetic resonance imaging was performed showing an extension of the initial lesion with a peripheral gadolinium enhancement on T1-weighted images. Such a reactivation pattern of an isolated Baló’s concentric sclerosis lesion, occurring some years later, is described for the first time.

Plasticity in secondary sexual characteristics in male freshwater blennies (Salaria fluviatilis)

Alternative reproductive tactics (ARTs) driven by environmental factors are common among fish. However, the flexibility of fish to adopt distinct tactics in response to the characteristics of their environment has received little attention. The aim of the present work was to study phenotypic plasticity in the adoption of dominant behaviour (“bourgeois tactic”) by male freshwater blennies (Salaria fluviatilis (Asso, 1801)). For this purpose, two simultaneous experiments in aquaria were performed to examine the effect of social cues and nest abundance on the acquisition of secondary sexual characteristics (SSCs). Experiments were conducted with small (individuals without SSCs), medium-sized (1-year-old individuals), and large older dominant males (more than 2 years old), all collected in the wild. In experiment 1, the three sizes of males were combined to compare the development of SSCs depending on intrasexual context. In experiment 2, the effect of nest abundance (two nests vs. six nests) was tested for each size of male. Medium-sized males showed phenotypic plasticity in response to the environmental conditions simulated in the two experiments. The absence of larger dominant males was found to be the main factor enhancing SSCs and the onset of parental behaviour. Nest shortage also influenced the degree of cephalic crest development among medium-sized males. This knowledge helps to understand how the population of freshwater blennies still persists when it is reduced to young individuals during the summer droughts in Mediterranean streams.

Functional neuroimaging of migraine

This review summarizes the history of migraine imaging and key findings of studies on functional neuroimaging in migraine and describes how these data have changed our view of the disorder. Functional neuroimaging during migraine attacks and also interictally has initiated the description of "the migraine brain". These studies have led to the demonstration of cortical spreading depression in migraine with aura, the crucial role for the brainstem during migraine attacks, and cortical hypersensitivity in migraineurs modulated by the trigeminal pathway, explaining sensory sensitization such as photophobia and osmophobia.

[Ovarian drilling by fertiloscopy: feasibility, results and predictive values]

OBJECTIVES

The aims of this study were to assess the effectiveness of the ovarian drilling, compare the techniques by fertiloscopy or by laparoscopy, and search for prognostic factors of success.

PATIENTS AND METHODS

This retrospective study focused on 154 ovarian drilling carried out between June 1998 and December 2010 where the drilling has been proposed after failure of the clomifene and before stimulation by FSH among PCOS patients.

RESULTS

The post-drilling ovulation rate is 62%. The spontaneous on-going pregnancy rate is 31% and the total pregnancy rate scalable including secondary stimulation is 58%. No significant difference was found between laparoscopy and the fertiloscopy. The peroperative complications in fertiloscopy were more frequent but without consequences and 20% of the fertiloscopy had to be converted to laparoscopy, half of them for complications and half of them for technical difficulties. The only found preoperative predictors of success are an euthyroidy that increases the chances of pregnancy in general (including the side stimulation) and a lower FSH levels. However, it appears that the chances of pregnancy in FSH stimulation are dramatically decreased if the drilling did not induce ovulation versus the cases where it induced ovulation but no pregnancy (28.8% versus 58.1%, P<0.003).

DISCUSSION AND CONCLUSION

Fertiloscopy results are comparable with those of laparoscopy, which suggests an advantage to this technique in terms of cost, comfort, and length of hospital stay. No usable in practice patient selection criteria could be highlighted. The study suggests that the absence of ovulation after drilling may be a direct indication for IVF.

Optimal design of a microcavity organic laser device under electrical pumping

The quality factor of microcavity organic lasers, designed for operation under electric pumping, has been numerically investigated. The microcavity structure consists of an organic light emitting diode set in between multilayer dielectric mirrors centered for an emission at 620 nm. In order to optimize the quality factor, different parameters have been studied: the impact of high and low index materials used for the multilayer mirrors, the role of a spacer inserted in between the mirrors to obtain an extended cavity, and the effect of an absorbing electrode made of metallic or transparent conductive oxide layer. The results of our different optimizations have shown a quality factor (Q) as high as 15,000.

A PET study of photophobia during spontaneous migraine attacks

BACKGROUND

Photophobia is an abnormal sensitivity to light experienced by migraineurs during attacks. The pathophysiology of photophobia is poorly understood. Nevertheless, 2 facts appear to have a link with photophobia: visual cortex hyperexcitability on the one hand and interactions between visual pathway and trigeminal nociception on the other.

METHODS

We used H(2)(15)O PET to study photophobia induced by continuous luminous stimulation covering the whole visual field in 8 migraineurs during spontaneous migraine attacks, after headache relief by sumatriptan and during attack-free interval. The intensity of the luminous stimulation provoking photophobia with subsequent headache enhancement was specifically determined for each patient.

RESULTS

We found that low luminous stimulation (median of 240 Cd/m(2)) activated the visual cortex during migraine attacks and after headache relief but not during the attack-free interval. The visual cortex activation was statistically stronger during migraine headache than after pain relief.

CONCLUSION

These findings suggest that ictal photophobia is linked with a visual cortex hyperexcitability. The mechanism of this cortical hyperexcitability could not be explained only by trigeminal nociception because it persisted after headache relief. We hypothesize that modulation of cortical excitability during migraine attack could be under brainstem nuclei control.

Posterior Cerebral Hypoperfusion in Migraine Without Aura

In cerebral blood flow studies, migraine aura is characterized by a posterior cortical hypoperfusion. In contrast, only rare and mild changes in brain perfusion have been demonstrated in migraine without aura, suggesting two different haemodynamic patterns in migraine with and without aura. Our aim was to study hypoperfusion with positron emission tomography (PET) as early as possible during spontaneous migraine without aura attacks. We used H215O PET to investigate seven patients (six female, one male) with migraine without aura (International Classification of Headache Diseases-II code 1.1) in three situations: during the headache phase, after headache relief following sumatriptan injection, and during an attack-free interval. Statistical analysis was performed with SPM2. Within 4 h after the attack onset, significant relative bilateral posterior cortical hypoperfusion was found and persisted after headache relief following sumatriptan injection. A posterior cortical hypoperfusion demonstrated in migraine without aura could suggest a common pathogenesis in migraine with and without aura. The significance of relative posterior hypoperfusion in migraine without aura is discussed according to the current knowledge of migraine pathogenesis.

Chronic cluster headache: a French clinical descriptive study

BACKGROUND

Cluster headache (CH) is a relatively rare disease and episodic CH is more frequent than chronic CH. Few studies have described the characteristics of patients with chronic CH.

METHODS

This was a descriptive study carried out by eight tertiary care specialist headache centres in France participating in the Observatory of Migraine and Headaches (OMH). From 2002 to 2005, OMH collected data from 2074 patients with CH, of whom 316 had chronic CH. From January to June 2005, 113 patients with chronic CH were interviewed using standardised questionnaires during a consultation.

RESULTS

The male to female ratio was 4.65:1. Median age was 42 years. The majority of patients were smokers or former smokers (87%). 46% had primary chronic CH (chronic at onset) and 54% secondary chronic CH (evolving from episodic CH). Most patients had unilateral pain during attacks and 7% had sometimes bilateral pain during an attack. 48% reported a persisting painful state between attacks. Symptoms anteceding pain onset (mainly discomfort/diffuse pain, exhaustion, mood disorders) and auras were reported by 55% and 20% of patients, respectively. The functional impact of chronic CH was estimated as severe by 74% of patients, and 75.7% suffered from anxiety, as assessed by the Hospital Anxiety and Depression scale. There was no substantial difference in clinical presentation between primary and secondary CH.

DISCUSSION

This study confirms the existence of auras and interictal signs and symptoms in patients with chronic CH, and male sex and smoking as CH risk factors. Primary and secondary chronic CH appear equally prevalent. Male sex does not appear to favour the shift from episodic to chronic CH.

Amazonian plants from Peru used by Quechua and Mestizo to treat malaria with evaluation of their activity

Indigenous Quechua and Mestizo populations from distinct areas in Loreto, Peru, were interviewed about traditional medication for the treatment of malaria. An ethnographic survey concerning the native theory of illness aetiology in the specific case of malaria permitted the elaboration of an efficient ethnopharmacological enquiry. The survey took place on three main zones corresponding to villages on the Napo and the Pastaza rivers (for the Quechua), and in the surroundings of Iquitos (for the Mestizos) and led to the collection of 14 plants. Serial extractions in hexane, dichloromethane, and methanol were performed on the different parts of the plants collected. The extracts were then tested for antiplasmodial activity in vitro. Seven plants displayed antiplasmodial activity (IC(50) from 2 to 25 microg/mL) and usually low cytotoxicity, indicating their antiplasmodial specificity. The results give scientific validation to the traditional medical knowledge of Quechua and Mestizo populations from Loreto and confirm a source of potentially active plants.

Molluscicidal activity against Bulinus truncatus of Croton campestris

The bark of Croton campestris provided three furano-clerodane named, respectively, velamone, velamolone acetate and velamolone. Fractions containing these diterpenoids were investigated for their molluscicidal activity against Bulinus truncatus, one of the aquatic snail vectors of schistosomiasis. A dichloromethanic extract of root barks, rich in furano-clerodane and molluscicidal at 20ppm was promising as natural molluscicide. Enriched fraction with velamone gave 80% mortality from 25ppm, while its LD(100) was at 50ppm. The LD(80) was ca. at 45ppm, while LD(100) was at 60ppm for the enriched fraction containing velamolone acetate. The velamolone-enriched fraction was less efficient and gave a mortality of 90% at 90ppm. The pure compounds, velamone and velamolone acetate were active at 100% at 3 and 6ppm, respectively. Velamolone showed a molluscicidal activity at 20ppm.

Sleep disruption, daytime somnolence and 'sleep attacks' in Parkinson's disease: a clinical survey in PD patients and age-matched healthy volunteers

Recent case reports of 'sleep attacks' (SA) in patients with Parkinson's disease (PD) generated concerns about drug-induced daytime somnolence in this population. However, there are nearly no comparative data on sleep and vigilance problems between PD patients and normal controls. We performed a cross-sectional survey in PD patients and age-matched controls using a structured questionnaire on PD history, treatments, co-morbidity, activities of daily living, habits, exercise, sleep pattern, driving, pre-existing nocturnal problems, daytime somnolence, episodes of SA and the circumstances in which such episodes occurred. Daytime somnolence was also measured with the Epworth Sleepiness Scale (ESS) and sleep quality with the Pittsburgh Sleep Quality Index (PSQI). 176 PD patients and 174 controls were included. The same proportion of PD patients (27%) and controls (32%) reported episodes of SA, but these were more frequent in PD patients and occurred more frequently during situations requiring attention (10.8% vs. 1.7%, p<10(-3)). More PD patients had abnormal daytime somnolence (ESS) and poor sleeping quality (PSQI). The most consistent factor associated with SA was the duration of levodopa therapy and the predictive value of an abnormal ESS score was rather poor (40.7%). Abnormal daytime somnolence and poor sleep quality at night are more frequent in PD patients than in normals. However, SA are reported in both groups, although less frequently in the normals during activities that requires attention.