Specific Heat Study of 1D and 2D Excitations in the Layered Frustrated Quantum Antiferromagnets Cs_{2}CuCl_{4-x}Br_{x}.

We report an experimental and theoretical study of the low-temperature specific heat C and magnetic susceptibility χ of the layered anisotropic triangular-lattice spin-1/2 Heisenberg antiferromagnets Cs_{2}CuCl_{4-x}Br_{x} with x=0, 1, 2, and 4. We find that the ratio J^{'}/J of the exchange couplings ranges from 0.32 to ≈0.78, implying a change (crossover or quantum phase transition) in the materials' magnetic properties from one-dimensional (1D) behavior for J^{'}/J<0.6 to two-dimensional (2D) behavior for J^{'}/J≈0.78. For J^{'}/J<0.6, realized for x=0, 1, and 4, we find a magnetic contribution to the low-temperature specific heat, C_{m}∝T, consistent with spinon excitations in 1D spin-1/2 Heisenberg antiferromagnets. Remarkably, for x=2, where J^{'}/J≈0.78 implies a 2D magnetic character, we also observe C_{m}∝T. This finding, which contrasts the prediction of C_{m}∝T^{2} made by standard spin-wave theories, shows that Fermi-like statistics also plays a significant role for the magnetic excitations in spin-1/2 frustrated 2D antiferromagnets.

Near room temperature dielectric transition in the perovskite formate framework [(CH3)2NH2][Mg(HCOO)3].

We report that the hybrid organic-inorganic compound [(CH3)2NH2][Mg(HCOO)3] shows a marked dielectric transition around Tt∼ 270 K, associated to a structural phase transition from SG R3[combining macron]c (centrosymmetric) to Cc (non-centrosymmetric). This is the highest Tt reported so far for a perovskite-like formate that is thus a promising candidate to display electric order very close to room temperature.

Sex Pheromones of Summer Fruit Tortrix Moth Adoxophyes orana: Two Synergistic Isomers.

Both cis-9-and cis-11-tetradecenyl acetate were isolated from 2500 virgin females of the summer fruit tortrix moth Adoxophyes orana (F.v.R.) by gel permeation, column chromatography on silica gel, and gas chromatography. Their chemical, physical, and biological properties were identical to those of the synthetic compounds. In contrast to the single compounds, mixtures of these pheromones were highly active in laboratory and field tests. Catches, in traps, with the pheromone mixture were comparable to those obtained when live females were used as bait. This is the first example of a member of the lepidoptera in which the presence of two isomers is an absolute requirement for activity in laboratory and in field experiments.

Reproductive isolation of two tortricid moth species by different ratios of a two-component sex attractant.

Two tortricid mitoth species, Adoxophyes orana and Clepsis spectrana, utilize the samne two isomers, cis-9- and cis-l1-tetradecenyl acetate, as their sex attractant. Commnlunication between the sexes of each species is separated effectively by a different blendinig of both compounds by the females and a different response to these blends by the males.

In situ Fc receptor-bearing cells in two murine tumors. I. Isolation and identification.

The in situ inflammatory response was studied in 2 different tumors, the T1699 mammary adenocarcinoma in inbred DBA/2 mice and a sarcoma induced in inbred C57BL/6 mice by murine sarcoma virus. The presence of Fc receptors (FcR's) on infiltrating host cells was determined by rosette formation with antibody-coated sheep red blood cells (EA). Differences in FcR-binding activity among various cells were detected with the use of EA prepared with a range of antibody concentrations. Cells bearing FcR represented one-third or more of the inflammatory cell population in both tumors. The FcR-positive cells were heterogeneous in regard to both cell type and FcR activity. Monocytes and macrophages had greater FcR activity than did lymphocytes. Different populations of FcR-positive cells could be isolated by their EA-binding characteristics.

Embryonic and larval development of jundiá (Rhamdia quelen, Quoy and Gaimard, 1824, Pisces, TeleosteI), a South American catfish.

The jundiá (Rhamdia quelen, Quoy and Gaimard) is an endemic South American fish species. Because this species supports cold winters and grows faster during warm months, it has begun to be viewed as an ideal species for fish production in southern South America. In the present study, jundiá oocytes used were obtained by extrusion from females after hormone injection. Soon after hydration, the eggs were transferred to 50 L conic glass incubators, with constant and controlled water influx. Samples of fertilized eggs were transferred to Petri dishes and, examined under a stereoscopic microscope, were spherical, demersal, and non-adhesive with defined perivitelline space and resistant chorion. Cleavage stages occurred during the first 3.5 h. After hatching, larvae were transferred to 200 L glass fiber incubators. First signs of embryo movement were observed 21 h after fertilization; larval eclosion occurred 30.5 h after fertilization. Present findings may provide a basis for studies aimed at determining the complete ontogeny of jundiá and may be useful in eco-toxicological studies.

A randomized, placebo-controlled study of topiramate in primary generalized tonic-clonic seizures. Topiramate YTC Study Group.

BACKGROUND AND OBJECTIVE: Topiramate is effective as adjunctive treatment of partial-onset seizures in adults. The efficacy and safety of topiramate as adjunctive therapy for the treatment of primary generalized tonic-clonic (PGTC) seizures were investigated in a randomized, double-blind, placebo-controlled study. METHODS: Eighty patients, 3 to 59 years old, who experienced three or more PGTC seizures during an 8-week baseline phase were randomly assigned to treatment with either topiramate (n = 39) or placebo (n = 41). Topiramate was titrated to target doses of approximately 6 mg/kg/day over 8 weeks and maintained for another 12 weeks. RESULTS: The median percentage reduction from baseline in PGTC seizure rate was 56.7% for topiramate patients and 9.0% for placebo patients (p = 0.019). The proportion of patients with 50% or higher reduction in PGTC seizure rate was 22/39 (56%) and 8/40 (20%) for the topiramate and placebo groups, respectively (p = 0.001). The median percentage reduction in the rate of all generalized seizures was 42.1% for topiramate patients and 0.9% for placebo patients (p = 0.003). The proportions of patients with 50% or higher reductions in generalized seizure rate were 18/39 (46%) and 7/41 (17%) for the topiramate and placebo groups, respectively (p = 0.003). The most common adverse events were somnolence, fatigue, weight loss, difficulty with memory, and nervousness. Treatment-limiting adverse events occurred in one patient in the topiramate group (anorexia and weight loss) and one in the placebo group (granulocytopenia and thrombocytopenia). CONCLUSION: Topiramate is well-tolerated and effective for the adjunctive treatment of PGTC seizures.

A double-blind, randomized trial of topiramate in Lennox-Gastaut syndrome. Topiramate YL Study Group.

OBJECTIVE: To evaluate the efficacy and safety of topiramate as adjunctive therapy for Lennox-Gastaut syndrome in a multicenter, double-blind, placebo-controlled trial. BACKGROUND: Conventional antiepileptic drugs are frequently ineffective against multiple-seizure types of Lennox-Gastaut syndrome. METHODS: Ninety-eight patients >1 year to <30 years of age, with slow spike-and-wave patterns on EEG, seizure types including drop attacks, and either a history of or active atypical absence seizures, were assigned to an 11-week, double-blind treatment phase with either topiramate or placebo. Topiramate was titrated to target doses of approximately 6 mg/kg/d. RESULTS: For drop attacks, the most severe seizures associated with this syndrome, the median percentage reduction from baseline in average monthly seizure rate was 14.8% for the topiramate group and -5.1% (an increase) for the placebo group (p = 0.041). Topiramate-treated patients demonstrated greater improvement in seizure severity than did placebo-treated patients based on parental global evaluations (p = 0.037). The percentage of patients with a > or = 50% reduction from baseline in major seizures (drop attacks and tonic-clonic seizures) was greater in the topiramate group (15/46 or 33%) than in the control group (4/50 or 8%; p = 0.002). The most common adverse events in both groups were CNS related; there were no discontinuations from topiramate therapy due to adverse events. CONCLUSIONS: Topiramate adjunctive therapy was effective in reducing the number of drop attacks and major motor seizures and in improving seizure severity as determined by parental global evaluation.

Intracranial EEG versus flumazenil and glucose PET in children with extratemporal lobe epilepsy.

OBJECTIVE: To compare abnormalities determined in 2-deoxy-2-[18F]fluoro-D-glucose (FDG) and [11C]flumazenil (FMZ) PET images with intracranial EEG data in patients with extratemporal lobe epilepsy. BACKGROUND: Although PET studies with FDG and FMZ are being used clinically to localize epileptogenic regions in patients with refractory epilepsy, the electrophysiologic significance of the identified PET abnormalities remains poorly understood. METHODS: We studied 10 patients, mostly children (4 boys, 6 girls, aged 2 to 19 years; mean age, 11 years), who underwent FDG and FMZ PET scans, intracranial EEG monitoring, and cortical resection for intractable epilepsy. EEG electrode positions relative to the brain surface were determined from MRI image volumes. Cortical areas of abnormal glucose metabolism or FMZ binding were determined objectively based on asymmetry measures derived from homotopic cortical areas at three asymmetry thresholds. PET data were then coregistered with the MRI and overlaid on the MRI surface. A receiver operating characteristics (ROC) analysis was performed to determine the specificity and sensitivity of PET-defined abnormalities against the gold standard of intracranial EEG data. RESULTS: FMZ PET detected at least part of the seizure onset zone in all subjects, whereas FDG PET failed to detect the seizure onset region in two of 10 patients. The area under the ROC curves was higher for FMZ than FDG PET for both seizure onset (p = 0.01) and frequent interictal spiking (p = 0.04). Both FMZ and FDG PET showed poor performance for detection of rapid seizure spread (area under the ROC curve not significantly different from 0.5). CONCLUSIONS: [11C]flumazenil (FMZ) PET is significantly more sensitive than 2-deoxy-2-[18F]fluoro-D-glucose (FDG) PET for the detection of cortical regions of seizure onset and frequent spiking in patients with extratemporal lobe epilepsy, whereas both FDG and FMZ PET show low sensitivity in the detection of cortical areas of rapid seizure spread. The application of PET, in particular FMZ PET, in guiding subdural electrode placement in refractory extratemporal lobe epilepsy will enhance coverage of the epileptogenic zone.

Caustic ingestion and subsequent damage to the oropharyngeal and digestive passages.

The characteristics, diagnosis, and management of oropharyngeal and digestive passage lesions due to ingestion of caustic agents are presented. Previous experimental and clinical studies are reviewed with discussion of the peculiar qualities of the newer caustics. Differentiation in treatment of burns caused by solid and liquid agents is stressed.

A clinical and anatomical study of the various techniques of irrigation of the maxillary sinus.

Irrigation of the maxillary sinus is a common procedure in clinical practice for removing the contents of the antrum for either diagnosis or therapy. For many years, it has been accomplished by inserting a trocar in either the natural ostium or the medial wall of the sinus under the inferior turbinate. Recently, the anterior wall of the maxillary sinus has been re-introduced as a better route. It is more direct and is the only one suited for use in a child whose sinus is underdeveloped. The anterior route has been termed the canine fossa technique and is the preferred route since it has a high degree of patient acceptance and safety and can be done easily and quickly by the clinician through a familiar anatomical pathway.

Vocal cord paralysis in postpoliomyelitis syndrome.

Postpoliomyelitis syndrome is characterized by new neuromuscular symptoms, including weakness, developing years after recovery from acute polio. Bilateral vocal cord paralysis is presented as a new manifestation of this syndrome. Other clinical features of post-poliomyelitis syndrome in this report are discussed. The etiology of this syndrome is unknown, though attrition or immune-mediated destruction of collateral muscular innervation appears likely. The pathologic findings include scattered individual muscle fiber atrophy as well as evidence of chronic denervation and reinnervation. This form of motor deterioration is not life-threatening, but potentially may cause increasing disability in a large number of polio survivors. Proper supportive care of facial, laryngeal, and pharyngeal weakness is crucial in the management of these patients.

Salivary gland involvement in systemic diseases.

The salivary glands participate in systemic illnesses because they are secretory structures allied with the gastrointestinal tract. Thus they are involved in systemic inflammatory, allergic, and neoplastic conditions. Perhaps the most common condition is that of mumps in the acute phase. Of the chronic diseases, Mikulicz's disease or Sjögren's syndrome is most frequently noted. In most instances of systemic involvement, the salivary gland enlargement is the rule, with the gland being tense, soft, and enlarged, and with progressive growth over a period of time. Usually all glands are involved. The diagnosis should be suspected from the history and the physical examination, noting that all the glands are equally involved by the enlargement. If there is any question, a biopsy should be performed. In the case of Sjögren's syndrome, the biopsy specimen may be taken either from a major salivary gland or from one of the minor ones, or the nasal mucous membrane or oral cavity. In general, definitive therapy is unsuccessful for the systemic illness involving the salivary glands, and in most instances has to be supportive.

Sinoscopy and sinus disease in children.

Sinus disease in children is usually ethmoidal in location. Acute illness is common and responds well to antibiotics. Sometimes the infection causes ipsilateral orbital cellulitis or rarely an orbital abscess. Systemic administration of antibiotics is usually effective in bringing about resolution. Surgery is not often needed. Acute maxillary sinus disease occurs more often in the older child in the second decade of life. It is manifested by pain in the cheek and teeth, nasal obstruction, and discharge. Treatment with antibiotics is usually effective. For chronic illness, irrigations in most cases bring about resolution. However, occasionally Caldwell-Luc surgery may be necessary.

Unusual weak magnetic exchange in two different structure types: YbPt2Sn and YbPt2In.

We present the structural, magnetic, thermodynamic and transport properties of the two new compounds YbPt(2)Sn and YbPt(2)In. X-ray powder diffraction shows that they crystallize in different structure types, the hexagonal ZrPt(2)Al and the cubic Heusler type, respectively. Despite quite different lattice types, both compounds present very similar magnetic properties: a stable trivalent Yb(3+), no evidence for a sizeable Kondo interaction and very weak exchange interactions with a strength below 1 K as deduced from specific heat C(T). Broad anomalies in C(T) suggest short range magnetic ordering at about 250 mK and 180 mK for YbPt(2)Sn and YbPt(2)In, respectively. The weak exchange and the low ordering temperature result in a large magnetocaloric effect as deduced from the magnetic field dependence of C(T), making these compounds interesting candidates for magnetic cooling. In addition we found in YbPt(2)In evidences for a charge density wave transition at about 290 K. The occurrence of such transitions within several RET2X compound series (RE = rare earth, T = noble metal, X = In, Sn) is analyzed.

Multipoint vibrometry with dynamic and static holograms.

We report on two multipoint vibrometers with user-adjustable position of the measurement spots. Both systems are using holograms for beam deflection. The measurement is based on heterodyne interferometry with a frequency difference of 5 MHz between reference and object beam. One of the systems uses programmable positioning of the spots in the object volume but is limited concerning the light efficiency. The other system is based on static holograms in combination with mechanical adjustment of the measurement spots and does not have such a general efficiency restriction. Design considerations are given and we show measurement results for both systems. In addition, we analyze the sensitivity of the systems which is a major limitation compared to single point scanning systems.