Low-power spontaneous oscillations driven by band-filling effect.

We predict that self-sustained oscillations can be generated in a semiconductor nanocavity in which the dominant effect is band-filling dispersion. Linear stability analysis, validated through numerical integration of a mean-field model, leads us to envisage oscillations typically at tens of gigahertz, with onset at much lower input power (~100 µW) compared with those driven by two-photon absorption.

Optimizing pump-probe switching ruled by free-carrier dispersion.

We address theoretically and numerically pump-probe switching in a nonlinear semiconductor nanocavity where tuning is achieved via a dominant mechanism of free-carrier plasma dispersion. By using coupled-mode approach we give a set of guidelines to optimize the switching performances both in terms of avoiding self-pulsation and keeping switching power to the minimum, ending up by showing that such devices can achieve high-performances with relatively low-power consumption.

Temporal gap solitons and all-optical control of group delay in line-defect waveguides.

We show that a model based on anticrossing between highly group velocity-mismatched gap-guided and index-guided modes describes gap soliton propagation in photonic crystal waveguides. Such nonlinear solutions can be exploited for exploring new regimes such as all-optical control of group velocity (dispersionless slow light) over a submillimeter length scale, and propagation beyond the linear modal cutoff. The results are validated by means of finite-difference time domain simulations.

Control of gradient catastrophes developing from dark beams.

We investigate dispersive shock waves developing via a gradient catastrophe during propagation of a dark beam in Kerr defocusing media, showing that a good degree of control, and even shock suppression, is possible by introducing a suitable phase chirp. Insight into the process is obtained by means of a suitable reduction of the hydrodynamic limit of the governing nonlinear Schrödinger equation.

Intravesical infusion of resiniferatoxin by a temporary in situ drug delivery system to treat interstitial cystitis: a pilot study.

PURPOSE: Interstitial cystitis (IC), a syndrome characterized by motor and sensory dysfunction of the lower urinary tract, represents a diagnostic and therapeutic challenge even to highly skilled physicians. We investigated the technical feasibility and the clinical efficacy of a prolonged intravesical instillation of RTX by in situ drug delivery system in patients with IC. MATERIAL AND METHODS: 5 female patients (mean age 48.7 years) received a prolonged infusion of a saline solution containing 10nM of resiniferatoxin at the flow rate 25microl/h by the MiniMed 407C Infusion Pump (MiniMed Sylmar, CA, USA), connected to sovrapubic 5Fr mono Pigtail catheter, for 10 days. All patients reported frequency, nocturia and urgency, and symptoms of pelvic pain for at least six months. They showed the absence of urinary tract infection within the last three months, the absence of functional disorders of lower urinary tract and no other vesical or urethral pathology. The pre-treatment (PT) frequency/volume (FV) chart and a pain score (VAS score) were recorded. Patients were evaluated after 30 days from the end of infusion (primary end point, PEP) and after three months (secondary end point, SEP). RESULTS: At PEP frequency reduced from 11.3+/-1.39 to 7.4+/-1.51 (p<0.01) and nocturia from 3.6+/-0.54 to 1.2+/-0.44 (p<0.01). A highly significant reduction of pain score was observed at PEP: it decreased to 2.4+/-0.54 from 6.7+/-0.83 (p<0.01). The pain score remained significantly lower at SEP (3.2+/-0.44 p<0.05). Nocturia was also statistically reduced at SEP (1.9+/-0.74) as well as frequency (8.7+/-1.76). No side effects were reported during the infusion as well as after the removal of the catheter. CONCLUSION: The present study demonstrates that the prolonged intravesical instillation of a drug by in situ drug delivery system is a feasible procedure and seems to support the efficacy of RTX in the treatment of IC patients. However further studies are necessary and mandatory to confirm our results and to define the exact action mechanism of prolonged infusion of RTX, the dosage and the treatment schedule.

Neurophysiological evidence may predict the outcome of sacral neuromodulation.

PURPOSE: Chronic stimulation of the sacral nerves has now become one of the most accepted stimulation therapies for functional lower urinary tract symptoms refractory to conservative treatment. Despite the existence of a large amount of literature on sacral neuromodulation (SNM) showing a fairly high percent of significant improvement in clinical outcome there are few experimental studies of SNM stimulus parameters and/or neurophysiological monitoring. We evaluated the specific action of SNM on the primary sensory cortical area. Somatosensory evoked potentials (SEPs) of the pudendal and posterior tibial nerves were evaluated in patients implanted with a monolateral permanent quadripolar electrode. MATERIALS AND METHODS: A total of 24 patients underwent stage 1 monolateral sacral nerve implantation. Three SEP patterns were evaluated; namely before implantation, 1 month after stage 1 with stimulation set at 21 Hz and again with a pulse rate of 40 Hz. RESULTS: In all patients SNM produced a significant decrease in pudendal SEP latency of the first positive deflection between baseline SNM stimulation at different pulse rates at the ipsilateral and contralateral implant sites. This finding was evidence of the effect of S3 SNM on the cortical sensory area and the specificity of pudendal SEPs in measuring how SNM modulates the afferent pathway from the spinal nerve to the cortical sensory area. CONCLUSIONS: Our study confirms previous observations that SNM acts by the afferent pathway at the cortical site level and it sheds light on so-called idiopathic lower urinary tract symptoms. A modification of SEPs induced by SNM seems to be a prognostic factor of clinical outcomes. The action of SNM on the afferent pathway from the sacral area to the somatosensory cortex is specific and neurophysiological evaluation via pudendal SEPs provides evidence to this effect.

O medo na cidade do Rio de Janeiro / The dread in Rio de Janeiro city

O presente trabalho pretende enfocar a difusão do medo do caos e da desordem para detonar estratégias de neutralização e disciplinamento das massas empobrecidas, a partir da hegemonia conservadora. Partindo dos medos urbanos contemporâneos, busca-se analisar os discursos sobre segurança na conjuntura de pânico no Rio de Janeiro na década de 90 do século XX através de uma abordagem histórica. Paralelamente, procura-se dissecar os medos cariocas do século XIX, principalmente em torno da rebelião escrava muçulmana na Bahia em 1835, conhecida como a Revolta dos Malês, para observar rupturas e permanências em relação aos medos de hoje. Investigando fontes primárias e secundárias, a pesquisa histórica analisa os discursos do medo do ponto de vista político, jurídico-penal, médico e na imprensa local, demonstrando como uma abordagem que hiperboliza o perigo das ôclasses perigosasõ tem conseqüências concretas na cidade. Os discursos apartadores abrem caminho para políticas de segurança exterminadoras, em que os inimigos construídos são desumanizados. Cria-se então uma violência naturalizada no cotidiano que tem conseqüências estéticas, cria monumentos, hierarquiza a cartografia da cidade, infundindo lugares e sentimentos verticais e seletivos, bem como a brutalização e criminalização da pobreza e do povo brasileiro. A pesquisa histórica aponta as contradições jurídicas da legislação penal de 1830, onde o escravo aparece como coisa perante o ordenamento jurídico das relações privadas, mas como pessoa perante o direito penal. Mostra também como, a partir da década de 30 do século XIX, instaura-se a normatização da medicina no Brasil e a patologização do africano, como metáfora dos males nacionais. É na confluência do discurso médico e do discurso jurídico que o fim do século XIX produzirá a criminologia positivista e a incorporação do social-darwinismo e do lombrosianismo no Brasil. A partir do grande paradoxo da implantação do liberalismo no Brasil, sem a ruptura com a escravidão, na conjuntura da Independência, observa-se como até os dias de hoje o medo do crime e da violência urbana carrega as marcas das matrizes do extermínio, da desqualificação jurídica, da estética da escravidão. Só a ruptura radical dessa memória do medo possibilitará a derrubada das fronteiras invisíveis de apartação urbana, criando então a possibilidade de um outro futuro e de uma outra história.

Erectile dysfunction in men with obstructive sleep apnea: an early sign of nerve involvement.

Erectile dysfunction (ED) is common in men with obstructive sleep apnea (OSAS) but no completely convincing hypotheses about the underlying pathogenic mechanisms have been published in the literature. The aims of the present study were to assess the presence of ED in a group of OSAS patients without daytime respiratory failure and to determine whether this dysfunction was related to peripheral nerve involvement. Evaluation of the bulbocavernosus reflex (BCR) and the somato-sensory evoked potentials of pudendal nerve (PSEPs), the most widely established method of documenting pudendal neuropathies as being the cause of impotence, was performed in 25 patients. Data on BCR were compared with those of 25 healthy males volunteers matched for age. BCR was altered in 17 patients: in 6 it was elicited while in 11 it had a prolonged latency and reduced amplitude. Patients with altered BCR presented an higher AHI, an higher percentage of sleep time spent with SaO2 <90% (TST90) and a lower daytime PaO2. Six patient had clinically silent neurophysiological signs of mild polyneuropathy. The degree of OSAS and gas exchange alteration was more severe in patients with polyneuropathy than in those with isolated BCR alteration. ED is a common finding in OSAS patients and this alteration seems to be related to a nerve dysfunction. The development of nerve dysfunction is associated with a more severe degree of OSAS and nocturnal hypoxia.

Effects of hypnosis on diffuse noxious inhibitory controls.

The neurophysiological mechanisms of hypnotic analgesia are still under debate. It is known that pain occurring in one part of the body (counterstimulation) decreases pain in the rest of the body by activating the diffuse noxious inhibitory controls (DNICs). The aim of this study was to explore the effects of hypnosis on both pain perception and heterotopic nociceptive stimulation. The A forms of both the Harward Group Scale of Hypnotic Susceptibility and the Stanford Hypnotic Susceptibility Scale were administered to 50 healthy students. Twenty subjects were selected and assigned to two groups: group A, consisting of 10 subjects with high hypnotic susceptibility; and group B, consisting of 10 subjects with low hypnotic susceptibility. The subjects were then randomly assigned first to either a control session or a session of hypnotic analgesia. The nociceptive flexion reflex (RIII) was recorded from the biceps femoris muscle in response to stimulation of the sural nerve. The subjective pain threshold, the RIII reflex threshold, and the mean area with suprathreshold stimulation were determined. Heterotopic nociceptive stimulation was investigated by the cold-pressor test (CPT). During and immediately after the CPT, the subjective pain threshold, pain tolerance, and mean RIII area were determined again. The same examinations were repeated during hypnosis. Hypnosis significantly reduced the subjective pain perception and the nociceptive flexion reflex. It also increased pain tolerance and reduced pain perception and the nociceptive reflex during the CPT. These effects were found only in highly susceptible subjects. However, the DNIC's activity was less evident during hypnosis than during the CPT effects without hypnosis. Both hypnosis and DNICs were able to modify the perception of pain. It seems likely that DNICs and hypnosis use the same descending inhibitory pathways for the control of pain. The susceptibility of the subject is a critical factor in hypnotically induced analgesia.

Chemiluminescent and Colorimetric Detection of Erwinia amylovora by Immunoenzymatic Determination of PCR Amplicons from Plasmid pEA29.

A molecular diagnostic technique (polymerase chain reaction enzyme-linked immunosorbent assay [PCR-ELISA]) for detection of Erwinia amylovora was developed. The protocol is based on the immunoenzymatic determination of PCR products. For in vitro amplification, we used previously published primers able to detect the cryptic plasmid pEA29, which is ubiquitous in E. amylovora. Amplicons were labeled with 11-digoxigenin (DIG)-dUTP during the amplification reaction, captured by hybridization to a biotinylated oligonucleotide in streptavidin-coated ELISA microplates, and then detected with anti-DIG-Fab'-peroxidase conjugated antibodies. The specificity of the assay was verified using E. amylovora strains from different host plants and geographical origins in addition to other plant-associated bacteria (either phytopathogenic or saprophytic) belonging to the genera Erwinia, Pseudomonas, and Agrobacterium. In detection threshold experiments with pure cultures, as few as 30 and 3 CFU/reaction tube were detected when the ABTS (colorimetric) and ECL (chemiluminescent) detection assays, respectively, were used. PCR-ELISA coupled with chemiluminescent detection was able to detect as few as 4 × 102 CFU/g of artificially infested pear twigs. The assay was further shown to be suitable for detection of E. amylovora in naturally infected plant organs, and the results were compared to those obtained using standard PCR assays with electrophoretic separation of amplicons.

Work-related posttraumatic upper limb disorder. A case report.

In this paper we describe a patient with mor-sensory loss in the right forearm and hand, which persisted more than 2 years after work-related crush trauma of the left hand. Radiographic and electromyographic investigations, somatosensory evoked potentials, CT scans of the encephalus as well as the Minnesota Multiphasic Personality Inventory and the Roarschach test have been performed. On the basis of these investigations, we think this represents a case of conversion disorder with somatic features. Included is a brief overview of other psychological illness with physical findings involving the upper limb.

Twitch response of striated muscle in patients with progressive external ophthalmoplegia, mitochondrial myopathy and focal cytochrome c-oxidase deficiency.

Some aspects of the contractile properties of skeletal muscle in patients with progressive external ophthalmoplegia (PEO), mitochondrial myopathy and focal cytochrome c-oxidase deficiency were investigated by studying the twitch response (TR) of the tibialis anterior muscle both at rest and after maximum isometric contraction. The results of needle electromyography were normal in four of the six examined patients, and myopathic in the remaining two. A slowing in muscle relaxation was the most frequently observed abnormality; significantly prolonged muscle contraction times and reduced twitch torque potentiation values after isometric contraction were also detected. TR abnormalities in PEO patients may be due either to a dysfunction of the contractile machinery depending upon impaired muscle energy supply or to altered muscle fiber characterized by the predominance of type I slow fiber. In addition to conventional electromyographic investigations, TR study may be a useful diagnostic tool in PEO patients.