Discharging of dust particles in the afterglow of plasma with large dust density.

The discharging of dust particles in the afterglow of plasma with large dust density is studied. We used measured electron and metastable dependencies to calculate the rate describing collection of electrons by dust particles by solving the electron balance equation. This rate is compared with the rate calculated using the orbital motion limited (OML) theory. It is found that the OML theory may not be applied for description of dust charging at large afterglow times, and the energetic electrons generated in metastable-metastable collisions significantly affect charging of dust particles. The time dependence for dust charge is calculated by two different approaches: first, the "standard" approach is used, which assumes that ion and electron fluxes to the dust particles are different in the afterglow. Second, the dust charge is calculated by assuming that desorption of electrons from dust particles is very fast. Both approaches gave similar results for dust charging. In addition, the effects of secondary emission due to ion-dust and metastable-dust collisions on dust discharging are investigated. The main source of dust charging in the late afterglow of plasma with large dust density are the energetic electrons generated in Ar(m) metastable-metastable collisions.

Tumor size and karyometric variables in brain astrocytoma.

PURPOSE: To show any possible correlation of some karyometric variables with tumor size in patients with brain astrocytoma, in order to confirm karyometry as an objective histological method. PATIENTS AND METHODS: The study included 63 patients of different ages and both genders with brain astrocytoma histologically confirmed on the surgically removed material. In all patients maximal tumor excision was done, and all were postoperatively treated according to different therapeutic protocols. Tumor size (preoperative CT scan) was correlated with the duration of survival and the values of some karyometric tumor variables: area, density, maximal axis, mean axis, minimal axis, circumference, roundness, integrated optical density (IOD) and number of nuclei. RESULTS: Patients were separated into 3 groups according to the average tumor diameter. There were 34 cases of medium-sized tumors, 12 of small and 17 of large-sized tumors, and their respective survival was 83, 97 and 24 weeks. Patients with large tumors had statistically shorter survival compared to those with medium and small tumors (log-rank test, p=0.0122). Seven out of 9 examined karyometric variables were significantly related (p<0.05) to the tumor size: area, maximal axis, mean axis, minimal axis, circumference, roundness and IOD. CONCLUSION: Patients with larger tumors have shorter survival. The results of our morphometric analysis of the tumor cell nuclei, after correlation with CT findings, revealed that nuclear pleomorphism and larger nuclear size are associated with larger brain astrocytomas.

Human Dirofilaria repens infection in Serbia.

Human infection by Dirofilaria repens in Serbia has been increasing steadily. The first case was reported in 1971, presented in the form of a single subcutaneous nodule on the back of a young boy. As established by a literature search, eight additional cases were reported until mid-2001. The most frequent site of infection was subcutaneous tissue, with the exception of two cases, in which parasites were found in subconjunctiva and epididymis. Our study, conducted from 2001 to 2008, encompasses 19 new cases. Most of them (63.1%) presented as ocular or periocular infections, in which the parasite was typically found under the conjunctiva. In other cases a parasitic nodule was localized in the temporal region of the head, epididymis, testicle, abdomen, breast or arm. The diagnosis was made by morphological and histological analysis of the extracted intact worms and parasite sections from the tissue. Morphology of the filarial worms was well preserved in more than half of the cases (12/19) and there was never more than one parasite found inside the lesions. Adult worms and immature nematodes were observed in nine and seven cases, respectively. Furthermore, in two cases microfilariae were discovered inside the pseudocoelom, sections of the female reproductive tubes filled with clearly visible larval stages. Dirofilaria repens infection was diagnosed by its morphological features (17/19) or by performing polymerase chain reactions (PCR) using paraffin-embedded tissues (2/19) in the cases where the morphology was insufficient for identification and the parasites had been determined initially as Dirofilaria spp. The amplified 246 bp PCR product showed that the worms were D. repens.

Effect of transport of growing nanoparticles on capacitively coupled rf discharge dynamics.

We present experimental and numerical studies of the properties of a capacitively coupled 13.56MHz discharge in a mixture of Ar and C2H2 with growing nanosize particles. It is found that at the initial stage of the growth, nanoparticles are accumulated near the sheath-plasma boundaries, where the ionization by electrons is maximal. The nanoparticles suppress the ionization due to the absorbing fast electrons and stimulate a quick change of the plasma parameters followed by a transition between different modes of discharge operation. At that moment the peaked distribution of the dust particles transforms into a flat one.

Ketorolac as a pre-emptive analgesic in retinal detachment surgery: a prospective, randomized clinical trial.

OBJECTIVE: Retinal detachment surgery is associated with a high incidence of post-operative pain, nausea and vomiting. Previous studies demonstrated a beneficial role of pre-emptive analgesia using regional anesthetic blocks for this type of surgery. The aim of the present study was to evaluate the pre-emptive analgesic effect of ketorolac in patients undergoing retinal detachment surgery under general anesthesia. METHODS: With the approval of the Institutional Ethics Committee and written informed consent, 60 adult patients were randomized prospectively, in a double-masked manner, to receive intravenously either ketorolac 30 mg or saline placebo 30 min before operation. Pain scores at 2, 6, 12, 18 and 24 h after surgery, the number of patients requiring post-operative analgesia, total consumption of analgesics, the incidence of oculocardiac reflex as well as the incidence and severity of post-operative nausea and vomiting were recorded. RESULTS: The ketorolac group required post-operative analgesia less frequently than the placebo group (p < 0.0001). The ketorolac group had significantly lower pain scores at all measurement time points (p < 0.001) and lower intra- and post-operative total consumption of analgesics (p < 0.01). The incidence and severity of nausea and vomiting were lower in patients given ketorolac when compared with placebo-treated patients (p < 0.05). The incidence of oculocardiac reflex was not significantly different between groups (p = 0.14). CONCLUSIONS: The use of ketorolac for pre-emptive analgesia is effective in patients undergoing retinal detachment surgery under general anesthesia.

Peritumoral edema and karyometric variables in astrocytoma of the brain.

PURPOSE: The aim of this study was to evaluate karyometry as a quantitative and objective histological method by showing correlation of some karyometric variables with the severity of peritumoral edema in patients with brain astrocytoma. PATIENTS AND METHODS: 63 patients of different ages and both genders were enrolled. The patients were diagnosed with astrocytoma of the brain, histologically confirmed on the surgically removed material. Maximal tumor excision was performed in all patients, who were postoperatively treated according to current oncologic therapeutic protocols. The intensity of perifocal edema (preoperative CT scan) was correlated to the duration of survival and the values of 9 karyometric tumor variables: area, density, maximal axis, mean axis, circumference, roundness, integrated optical density and number of nuclei. RESULTS: There were 17 cases with small perifocal edema, 19 with medium-sized and 27 with large perifocal edema, and their respective survival was around 149, 62 and 48 weeks. Those with small edema had statistically significant prolonged survival compared to those with medium and large perifocal edema (log-rank test, p=0.045). Six out of 9 karyometric variables examined were significantly related (p<0.05) to the intensity of peritumoral edema: long and mean axis, circumference, roundness, integrated optical density and number of nuclei. CONCLUSION: Patients with larger peritumoral edema have shorter survival. Correlation of karyometric variables with CT findings revealed that higher degrees of tumor cellularity and nuclear wrinkling with increased integrated optical density is associated with larger peritumoral edema.

Secondary electron emission of carbonaceous dust particles.

In this paper we present measurements of the secondary electron emission yield (gamma) of a carbonaceous dust particle material, which was grown in argon diluted acetylene plasmas. One aim was to reach a better understanding of charging and discharging processes of dust particles in complex plasmas due to secondary electron emission and consequently to try to explain the anomalous behavior of electron density observed in afterglows of pulsed rf plasmas. We compared the results of a simple model and of a Monte Carlo simulation to the previously measured time dependence of the electron density in complex plasma afterglow. It was found that the value of the intrinsic secondary electron yield from the carbonaceous dust material is too low to explain the increase of electron density in the afterglow. It is, however, possible that the electrons charging the particles are weakly attached so that they may be released with high efficiency by ion bombardment due to field induced emission or by other mechanisms.

The ability of estradiol to induce Fos expression in a subset of estrogen receptor-alpha-containing neurons in the preoptic area of the ewe depends on reproductive status.

In the ewe, seasonal anestrus results from a change in the hypothalamic responsiveness to estradiol (E2) negative feedback. Considerable evidence has implicated a specific group of dopaminergic neurons (the A15 group) in this seasonally dependent E2 effect, but these neurons do not appear to contain estrogen receptor-alpha (ERalpha). This apparent discrepancy raises the possibility that at least one other neural system is also involved in mediating E2 inhibition. The purpose of this study was to determine whether ERalpha-containing neurons are activated by the negative feedback action of E2 in anestrus. In Exp 1, we examined the effects of E2 on expression of the immediate early gene products, Fos and Fos-related antigens, in ERalpha-positive cells in anestrous ewes. ERalpha and Fos/Fos-related antigens were colocalized using a dual immunofluorescence procedure in sections throughout the hypothalamus from ovariectomized and E2-treated ovariectomized anestrous ewes. A low dose E2 treatment that inhibited LH pulse frequency and induced Fos in A15 dopaminergic neurons in a previous study significantly increased the percentage of ERalpha-containing neurons expressing Fos (17.8% vs. 1.7%) in the medial preoptic area, but not in other hypothalamic areas. In Exp 2, we determined whether there was a seasonal difference in the effect of E2 on Fos/ERalpha colocalization in this region. E2 treatment produced a 3-fold increase in the percentage of ERalpha-positive cells expressing Fos (15.1% vs. 3.4%) in anestrus, but failed to increase ERalpha/Fos colocalization (1.8% vs. 3.5%) during the breeding season. These data raise the possibility that a subset of ERalpha-containing neurons in the medial preoptic area plays a role in the seasonal change in response to E2 negative feedback in the ewe.

[Lumbar spinal stenosis. Symptomatology and methods of treatment]. / Lumbalna spinalna stenoza. Simptomatologija i nacin lecenja.

INTRODUCTION: Lumbar spinal stenosis (LSS) may be defined as any type of the narrowing of the spinal nerve root canal (the lateral recess), intervertebral foramina, or its combination. It may be local, segmental or generalized; it can be caused by bone or soft tissue, and the narrowing can involve the bony canal or the dural sac or both. The normal sagital diameter of the lumbar canal is 15 to 25 mm and measurements below this are regarded as suggestively abnormal; a diameter less than 12 mm confirms the presence of stenosis. On the other hand, the lateral recess height less than 3 mm is suggestive, and less than 2 mm is a diagnostic sign of stenosis. There are two large groups of LSS: congenital-developmental stenosis and acquired stenosis with many subgroups (Scheme 1). The number of surgical operations due to LSS is increased during the ensuing years especially in elderly persons. This is why we would like to emphasize the important role of this phenomenon as there are only a few published papers in domestic literature. MATERIAL AND METHODS: In a consecutive series of 38 patients with LSS diagnosed for the last five years (January 1990-December 1994), aged from 20 to 70 years (average age 48.55) there were 21 males (Table 1); 34 of them had LSS as a result of bony changes, while the rest of 4 were iatrogenic (3 after disc extirpation and one after laminectomy) (Fig. 1). Herniation of the nucleus pulposus in combination with LSS was found in 12 patients (31.57%). Local segmental stenosis was identified in 16 patients (42.10%). (Graph. 1) (Fig. 2); the others had the generalized type of stenosis involving two levels (17 patients-44.7%); three levels (4 patients-10.52%) or 4 levels (one patient-2.63%) (Fig. 3). As far as symptomatology is concerned 31 patients had low-back pain with acute radicular complaints and motor weakness as the result of lesion of one or two spinal roots (20 patients). There were no neurogenic claudication or cauda equina compression syndromes. Electromyoneurographic studies (EMNG) in surgically treated patients revealed preoperative signs of muscle denervation in 15 patients (7.42%) (Table 2); the rest of them had signs of chronic irritative lesions of the corresponding root. RESULTS: Twenty one patients were operated on: 19 with signs and symptoms of generalized type of LSS and only two with lateral recess stenosis (Table 2). Congenital developmental stenosis was identified in 6 young patients (20 to 40 years of age) (Fig. 4). Single-level laminectomy with medial facetectomy and nerve root decompression was performed in 10 patients, and the rest of them had two level or three level decompressive laminectomies with medial facetectomy and roots decompression (Fig. 5). Dissectomy was done in 8 patients (Graph 2). None of our patients had concomitant arthrodesis, or needed reoperation. Postoperative EMNG improvement was confirmed in 13 patients of 15 (86.66%); this is about 61.90% in comparison to all operated patients (Table 3). The main complaints after the operation were: low-back pain (70%), leg numbness (70%), slight walking difficulties (60%); however all were able to walk more than 500 meters. The answer to the question how they felt after the operation, 15 patients responded to feel better or much better (71.42%), 3 felt the same (14.28%), and 3 felt worse than before the operation. Five patients retired before the operation, 7 changed their occupation taking an easier job, 9 returned to the same job, and none retired after the operation (Table 3). DISCUSSION: A certain number of patients had congenital-developmental stenosis with thickening of the laminae and development of short, squat pedicles with a decreased anterior-posterior diameter of the spinal canal. There are numerous variations of this pattern which remain asymptomatic until later developmental changes precipitate the typical radiculopathy and cauda equina changes in LSS. (ABSTRACT TRUNCATED)

[Multiple intracranial aneurysms and asymmetrical circle of Willis]. / Multiple intrakranijalne aneurizme i asimetricni Willisov prsten.

In a consecutive series of 268 patients harboring saccular aneurysms confirmed by digital subtraction angiography (DSA) all major blood vessels of the brain, 36 patients (13.4%) with multiple aneurysms were identified. Majority of them (around 58%) were between 40 to 60 years of age, around 22% were below 40 years of age, but no was younger than 30 years of age. The asymmetric Willis circle was identified in 26 patients (74.2%) A hypoplastic A1 segment of the anterior cerebral artery was revealed in 10 patients; a combination of the hypoplastic A1 segment and the fetal type of the posterior communicating artery with a hypoplastic P1 segment of the posterior cerebral artery were found in 9 cases, while 7 patients had only the fetal posterior communicating artery. A suggestion was put that the asymmetric circle of Willis, prenatal or acquired in postnatal life is inclined of developing aneurysm (multiple aneurysms) only if there exist a hemodynamic stress in postnatal life producing degenerative lesions of the circle of Willis at the site of the augmented hemodynamic vascular wave.

[Antiphagocytic activity of human amniotic fluid]. / Antifagocytárna aktivita l'udskej plodovej vody.

The preincubation of PMN leukocytes in amniotic fluid obtained at the end of the gestation period resulted in decreased values of phagocytic activity (about 37%), phagocytic index (about 21.5%) and mainly of the candidacidal capacity to C. albicans (about 72%). The level of lysozyme (11.8 +/- 7.2 mg.l-1) and the level of alpha 1-antitrypsin (0.745 +/- 0.53 g.l-1) were also determined in amniotic fluid. The level of alpha 2-macroglobulin and the proteolytic activity at acidic and mildly alkaline pH could not be established by the methods applied. (Fig. 1, Ref. 23.)