Centrifugal microfluidic platforms: advanced unit operations and applications

Review on miniaturization, integration, and automation of laboratory processes within centrifugal microfluidic platforms. For efficient implementation of applications, building blocks are categorized into unit operations and process chains.

[Managing diversity in Swiss Health care]

The development of Migrant Friendly Hospitals is an important first step towards eliminating health care disparities in Switzerland and an important reminder to health policy makers and practitioners across the health care system of their responsibility to provide non-discriminatory quality health care to all patients.

The common antitussive agent dextromethorphan protects against hyperoxia-induced cell death in established in vivo and in vitro models of neonatal brain injury

Preterm infants are prematurely subjected to relatively high oxygen concentrations, even when supplemental oxygen is not administered. There is increasing evidence to show that an excess of oxygen is toxic to the developing brain. Dextromethorphan (DM), a frequently used antitussive agent with pleiotropic mechanisms of action, has been shown to be neuroprotective in various models of central nervous system pathology. Due to its numerous beneficial properties, it might also be able to counteract detrimental effects of a neonatal oxygen insult. The aim of the current study was to evaluate its therapeutic potential in established cell culture and rodent models of hyperoxia-induced neonatal brain injury. For in vitro studies pre- and immature oligodendroglial (OLN-93) cells were subjected to hyperoxic conditions for 48 h after pre-treatment with increasing doses of DM. For in vivo studies 6-day-old Wistar rat pups received a single intraperitoneal injection of DM in two different dosages prior to being exposed to hyperoxia for 24h. Cell viability and caspase-3 activation were assessed as outcome parameters at the end of exposure. DM significantly increased cell viability in immature oligodendroglial cells subjected to hyperoxia. In pre-oligodendroglial cells cell viability was not significantly affected by DM treatment. In vivo caspase-3 activation induced by hyperoxic exposure was significantly lower after administration of DM in gray and white matter areas. In control animals kept under normoxic conditions DM did not significantly influence caspase-3-dependent apoptosis. The present results indicate that DM is a promising and safe treatment strategy for neonatal hyperoxia-induced brain injury that merits further investigation.

Burden of copy number variation in common variable immunodeficiency

Common variable immunodeficiency (CVID) has been associated recently with a dramatic increase in total copy number variation burden, the cause of which is unclear. In order to explore further the origin and clinical relevance of this finding, we quantified the total genomic copy number variation (CNV) burden in affected patients and evaluated clinical details in relationship to total CNV burden. No correlation was found between total CNV burden and either patient age or time elapsed since symptom onset, and higher total burden did not correlate with incidence of malignancy or other subphenotypes. These findings suggest that the increased CNV burden is static and intrinsic to CVID as a disease.

Importance of intense male sexual behavior for inducing the preovulatory LH surge and ovulation in seasonally anovulatory female goats

The present study was carried out to determine whether the presence of photostimulated sedated male goats could stimulate the LH preovulatory surge and ovulation in seasonal anestrous goats. Sexually experienced male goats were treated with artificial long days (16 hours light per day) from 1 November to 15 January to stimulate their sexual activity in March and April, corresponding to the natural sexual rest. A female group of goats (n=20) was exposed to non-sedated males who displayed an intense sexual behavior and provided strong odor (non-sedated group). Another female group of goats (n=20) was exposed to the photo-stimulated male goats, but these males were sedated with Xylazine 2% to prevent the expression of sexual behavior (sedated group). The sedated males also provided a strong odor. Females of both groups had full physical and visual contact with non-sedated or sedated males. In both groups, the males remained with females during 4 days. The LH preovulatory surge of 10 female goats per group was measured by determination of LH plasma concentrations in samples taken every 3 hours. In addition, in all goats, (n=20 by group), ovulation was determined by measuring plasma concentrations of progesterone. The proportion of female goats showing a preovulatory LH surge was higher in goats exposed to non-sedated (10/10) than in those exposed to sedated bucks (0/10; P<0.0001). Similarly, most of does in contact with non-sedated males ovulated (19/20), but none of those in contact with sedated males did so (0/20; P<0.0001). We conclude that the expression of an intense sexual behavior by male goats is necessary to induce LH preovulatory surge and ovulation in seasonally anovulatory goats.

Reducing exposure to long days from 75 to 30 days of extra-light treatment does not decrease the capacity of male goats to stimulate ovulatory activity in seasonally anovulatory females

The response of male goats exposed to different durations of long days (LD) during an extra-light treatment in autumn-winter, and their ability to induce ovulations in seasonally anovulatory goats were investigated in 2 experiments. In experiment 1, control males were exposed to natural photoperiod (n = 5), whereas 4 additional groups (n = 5/group) were exposed to 16 h of light per d during 75, 45, 30, or 15 d of LD. In the 4 groups, photoperiodic treatments ended on January 15th. Plasma concentrations of testosterone were determined in blood samples obtained once a week from October 15th to May 30th. The rise of testosterone levels occurred earlier in males from the 75-LD and 45-LD groups than in those from the 30-LD, 15-LD, and control groups (P < 0.05). In addition, the time during which levels of testosterone remained >5 ng/mL was longer in males from the 75-LD and 45-LD than in those from the 30-LD and 15-LD groups (P < 0.05). In experiment 2, a group of anovulatory goats (n = 13) was isolated from males, while 3 additional groups were put in contact during 15 d with males previously exposed to 75, 45, or 30 days of LD (n = 25, 27, and 26 females/group, respectively and n = 3 males per group). The proportion of goats that ovulated was higher in the 3 groups in contact with the photo-stimulated males (range: 88%-92%) than in the group isolated from them (0%; P < 0.05). The proportion of pregnant females did not differ between the 3 groups of does in contact with photo-stimulated males (range: 78%-92%; P > 0.05). We conclude that, in our experimental conditions, a photoperiodic treatment as short as 30 d of LD during autumn-winter, stimulated testosterone secretion of bucks during their period of sexual rest and rendered them able to induce ovulations in seasonal anestrous goats and to obtain pregnancies in these females.

Two or 24 h of daily contact with sexually active males results in different profiles of LH secretion that both lead to ovulation in anestrous goats

Two experiments were conducted to (a) determine whether sexually active males are able to stimulate the sexual activity of anestrous female goats when duration of contact is reduced to an intermittent contact shorter than 4 daily hours and (b) compare the pattern of secretion of LH when anestrous goats are exposed either permanently or intermittently to males. In the first experiment, 4 groups of anovulatory goats were exposed to sexually active males for 24, 4, 2, or 1 h/d during 15 consecutive days, whereas control females remained isolated. More than 89% of females in the groups exposed to the sexually active bucks ovulated, whereas only 5% did so in the control group (P < 0.001). However, the proportion of females ovulating before day 4 was greater in the 2-, 4-, or 24-h contact groups than in the control, whereas it did not differ between the control group and the 1-h contact group (P = 0.02, <0.001, <0.001 and 0.23, respectively). In the second experiment, 3 groups of anovulatory goats were exposed permanently (24 h/d) or intermittently (2 h/d) to bucks during 5 d or remained isolated. We found that pulsatility of luteinizing hormone (LH) increased in the intermittent and permanent contact groups after males were introduced to females (P = 0.05); this pulsatility of LH remained elevated in the permanent-contact group, whereas it decreased in the intermittent-contact group, once the male was removed (P = 0.32 and 0.05, respectively). We conclude that 1 or 2 daily hours of contact with sexually active males is sufficient to stimulate ovulatory activity in anovulatory goats; however, ovulation is obtained through a different pattern of secretion of LH.

Detection of Surface-Immobilized Components and Their Role in Viscoelastic Reinforcement of Rubber-Silica Nanocomposites

Immobilized polymer fractions have been claimed to be of pivotal importance for the large mechanical reinforcement observed in nanoparticle-filled elastomers but remained elusive in actual application-relevant materials. We here isolate the additive filler network contribution to the storage modulus of industrial styrene-butadiene rubber (SBR) nanocomposites filled with silica at different frequencies and temperatures and demonstrate that it is viscoelastic in nature. We further quantify the amount of immobilized polymer using solid-state NMR and establish a correlation with the mechanical reinforcement, identifying a direct, strongly nonlinear dependence on the immobilized polymer fraction. The observation of a temperature-independent filler percolation threshold suggests that immobilized polymer fractions may not necessarily form contiguous layers around the filler particles but could only reside in highly confined regions between closely packed filler particles, where they dominate the bending modulus of aggregated particles.

Ice skating promotes postural control in children

High fall rates causing injury and enormous financial costs are reported for children. However, only few studies investigated the effects of balance training in children and these studies did not find enhanced balance performance in postural (transfer) tests. Consequently, it was previously speculated that classical balance training might not be stimulating enough for children to adequately perform these exercises. Therefore, the aim of this study is to evaluate the influence of ice skating as an alternative form of balance training. Volunteers of an intervention (n = 17; INT: 13.1 ± 0.4 years) and a control group (n = 13; CON: 13.2 ± 0.3 years) were tested before and after training in static and dynamic postural transfer tests. INT participated in eight sessions of ice skating during education lessons, whereas CON participated in normal physical education. Enhanced balance performance was observed in INT but not in CON when tested on an unstable free-swinging platform (P < 0.05) or when performing a functional reach test (P < 0.001). This is the first study showing significantly enhanced balance performance after ice skating in children. More importantly, participating children improved static and dynamic balance control in postural tasks that were not part of the training.

Fractionation and identification of Euglena gracilis cytoplasmic and chloroplastic tRNAs and mapping of tRNA genes on chloroplast DNA

The cytoplasmic and chloroplast tRNAs of Euglena gracilis Z strain were fractionated by two-dimensional gel electrophoresis and identified by aminoacylation. Purified chloroplast tRNAs, labeled in vitro with |(32)P|, were hybridized to endonuclease restriction fragments of chloroplast DNA, allowing the corresponding tRNA genes to be localized on the physical map of Euglena chloroplast DNA.

[Diagnosis of and therapy for hepatocellular carcinoma]

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence- and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

Prospective study of risk factors for suicidal behavior in individuals with anxiety disorders

BACKGROUND

Anxiety disorders are very common and increase risk for suicide attempts. Little is known about predictors of increased risk specifically among individuals with anxiety disorders. The purpose of this study was to investigate whether specific anxiety disorders and other co-morbid psychiatric disorders, physical health, or work or social functioning increased the future likelihood of a suicide attempts among individuals with anxiety disorders. Method In this prospective study, 676 individuals with an anxiety disorder were followed for an average of 12 years.

RESULTS

As hypothesized, we found that post-traumatic stress disorder, major depressive disorder (MDD), intermittent depressive disorder (IDD), epilepsy, pain, and poor work and social functioning all predicted a shorter time to a suicide attempt in univariate analyses. In multivariate analyses, baseline MDD and IDD were independent predictors of time to suicide attempt, even when controlling for a past history of suicide attempt. No specific anxiety disorder was an independent predictor of time to attempt in this anxiety-disordered sample. Adding baseline physical health variables and social functioning did not improve the ability of the model to predict time to suicide attempt.

CONCLUSIONS

Mood disorders and past history of suicide attempts are the most powerful predictors of a future suicide attempt in this sample of individuals, all of whom have an anxiety disorder.

Spontaneous clearance and treatment of acute hepatitis C infection in HIV-positive men with 48 weeks of interferon-alpha and ribavirin

Acute hepatitis C infection in the context of HIV is an emerging problem in men who have sex with men (MSM). We conducted a retrospective cohort study of MSM diagnosed with and treated for acute hepatitis C infection over 10 years. Genotype 1 was the commonest type representing 69% of cases; the spontaneous clearance rate was 20%. The overall sustained virological response (SVR) rate on an intention-to-treat basis was 83%; SVR and was 92% for those completing 48 weeks of treatment. The presence of detectable RNA at week 12 had a 100% negative predictive value for SVR. This is the largest single cohort treated with 48 weeks of interferon and ribavirin and the treatment SVR is one of the highest reported. We propose that a 48-week treatment regimen may be superior to shorter (24-week) regimens though we acknowledge the need for a randomized controlled trial.

Dynamics of olfactory and hippocampal neurogenesis in adult sheep

Although adult neurogenesis has been conserved in higher vertebrates such as primates and humans, timing of generation, migration, and differentiation of new neurons appears to differ from that in rodents. Sheep could represent an alternative model to studying neurogenesis in primates because they possess a brain as large as a macaque monkey and have a similar life span. By using a marker of cell division, bromodeoxyuridine (BrdU), in combination with several markers, the maturation time of newborn cells in the dentate gyrus (DG) and the main olfactory bulb (MOB) was determined in sheep. In addition, to establish the origin of adult-born neurons in the MOB, an adeno-associated virus that infects neural cells in the ovine brain was injected into the subventricular zone (SVZ). A migratory stream was indicated from the SVZ up to the MOB, consisting of neuroblasts that formed chain-like structures. Results also showed a long neuronal maturation time in both the DG and the MOB, similar to that in primates. The first new neurons were observed at 1 month in the DG and at 3 months in the MOB after BrdU injections. Thus, maturation of adult-born cells in both the DG and the MOB is much longer than that in rodents and resembles that in nonhuman primates. This study points out the importance of studying the features of adult neurogenesis in models other than rodents, especially for translational research for human cellular therapy.

Neuroprotective effects of the sigma-1 receptor ligand PRE-084 against excitotoxic perinatal brain injury in newborn mice

Excessive glutamate release followed by N-methyl-D-aspartate receptor (NMDAR) activation plays a crucial role in perinatal brain injury. We have previously shown that dextromethorphan, a low-affinity NMDAR antagonist with anti-inflammatory properties, is neuroprotective against neonatal excitotoxic brain injury. Of interest, dextromethorphan is also a sigma-1 receptor (σ1R) agonist. The pharmacologic class of σ1R agonists has yielded propitious results in various animal models of adult central nervous system pathology. In an established neonatal mouse model of excitotoxic brain injury, we evaluated the effect of the selective σ1R agonist 2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate (PRE-084). A single intraperitoneal injection of 0.1 μg/g (low dose) or 10 μg/g (high dose) bodyweight (bw) PRE-084, given 1h after the excitotoxic insult, significantly reduced lesion size in cortical gray matter 24 h and 120 h after the insult. Repetitive injections of 0.1 μg/g PRE-084 proved to be equally effective. PRE-084 treatment resulted in a decrease in cell death indicated by reduced TUNEL positivity and caspase-3 activation. Furthermore, it lowered the number of isolectin B4-positive, activated microglial cells. PRE-084 had no effect on developmental apoptosis in the undamaged brain. In vitro findings in primary hippocampal neurons suggest that PRE-084 treatment provides partial protection against glutamate induced morphological and functional changes. For excitotoxicity as playing a crucial role in the pathogenesis of perinatal brain injury, we demonstrate for the first time that systemic treatment with the highly selective σ1R agonist PRE-084 protects against NMDAR-mediated excitotoxic brain damage.

Regenerative therapies in neonatology: clinical perspectives

Regenerative therapy based on stem cells is applied as standard therapy in pediatric oncology. Furthermore, they are frequently used to treat immunodeficiency disorders of infants. For severe neonatal diseases, e. g. hypoxic-ischemic encephalopathy in term neonates or bronchopulmonary dysplasia in preterm infants, animal models have been established. According to some first preclinical results stem cell administration appears as a promising tool to improve the clinical outcome in high-risk infants. Provided the benefit of regenerative therapies can further be evaluated in appropriate preclinical neonate models, carefully controlled clinical trials to assess the significance of regenerative therapies, such as autologous stem cell administration, are indicated.

Mesquite pod extract modifies the reproductive physiology and behavior of the female rat

Phytoestrogens are non steroidal compounds that can bind to estrogen receptors, mimicking some effects of estradiol (E(2)). These compounds are widespread among legumes, which are used as pasture, and their importance in animal agriculture has increased. Mesquite (Prosopis sp) is a widespread legume, widely used to feed several livestock species in Mexico. The main product of mesquite is the pod, which is considered high quality food. As a legume, it could be assumed that mesquite contains some amounts of phytoestrogens which might induce potential estrogenic effects. However, to our knowledge, there are no reports regarding the possible estrogenic activity of this legume either in livestock or in animal models such as the rat. Therefore, in this study, we evaluated the potential estrogenic effects of mesquite pod extract on several aspects of behavior and reproductive physiology of the female rat. The effects of the extract were compared with those of E(2) and two isoflavones: daidzein (DAI) and genistein (GEN). The following treatments were given to groups of intact and ovariectomized (OVX) female rats: vehicle; mesquite pod extract; E(2); GEN; DAI. Compared to vehicle groups, mesquite pod extract, DAI, GEN, and E(2) increased uterine weight and induced growth in vaginal and uterine epithelia. In intact rats, mesquite pod extract, GEN and DAI altered estrous cyclicity, decreased lordotic quotient and intensity of lordosis. In OVX rats, mesquite pod extract, DAI and GEN induced vaginal estrus, increased vaginal epithelium height, and induced lordosis, although its intensity was reduced, compared with intact rats in estrus and E2-treated rats. These results suggest that mesquite pod extract could have estrogenic activity. However, the presence of phytoestrogens in this legume remains to be confirmed.

Feasibility of cerebral MRI in non-sedated preterm-born infants at term-equivalent age: report of a single centre

AIM

MRI is gaining in importance as an imaging tool for brain development and injury in preterm infants. The aim of this study was to evaluate the feasibility of performing MRI in non-sedated preterm-born infants at term-equivalent age (TEA).

METHODS

A total of 89 infants born before 32 gestational weeks were recruited. Infants were scanned without sedation. Duration of the entire examination including scan repetition and interruptions was registered.

RESULTS

Of the 89 infants, 56 (63%) underwent MRI at TEA. Out-patients required a significantly shorter total MR examination time than did in-patients (32 ± 12 vs. 54 ± 10 min, p < 0.01). Of the 56 infants, 39 (69.6%) were examined without interruption. Only four (7.2%) of the 56 scans were unusable because of motion artefacts. Mean duration of all scans was 36 ± 14 min. In cases with no interruptions, sessions were completed within 32 ± 12 min; MR sessions with interruption lasted 45 ± 13 min.

CONCLUSION

A well-trained team is indispensable in obtaining best-quality images as a prerequisite for good counselling. From our experience, we worked out a guideline to ensure that scans in stable non-sedated preterm-born infants at TEA run smoothly and provide high-quality images.

Quality of life after restorative proctocolectomy and ileal pouch-anal anastomosis in patients with familial adenomatous polyposis: a matter of adjustment

AIM

Favourable outcomes for health-related quality of life (HRQL) have been reported in patients with familial adenomatous polyposis (FAP) after restorative proctocolectomy and ileal pouch-anal anastomosis (RPC). However, less is known about patients' subjective experience and adjustment to postoperative impairment. Using a multidimensional psychometric assessment, we investigated patient-reported HRQL to determine the impact of the patient's subjective experience together with medical, functional and psychosocial factors on HRQL.

METHOD

In this cross-sectional study, 116 FAP patients who had undergone RPC on average 8 years earlier completed standardized and study-specific questionnaires and participated in a personal interview. The impact of medical, functional and psychosocial factors on patients' HRQL was determined by regression analyses.

RESULTS

When using a generic psychometric measure, FAP patients' overall HRQL was comparable with that of the general population. Impaired HRQL, however, was found in patients reporting poor pouch function in contrast to those reporting good or moderate functional outcome. Findings from a personalized interview also suggested that a good functional result does not necessarily translate into good HRQL. Personal resources predicted patients' physical and psychological well-being, whereas little variance of HRQL was explained by medical factors and function.

CONCLUSION

Patients' HRQL is, to a substantial degree, the result of adjustment to the adverse impact of RPC. By using personal resources the majority of patients may achieve satisfactory HRQL levels even when bowel function is impaired. A multidimensional assessment that comprises medical, functional and psychosocial aspects is required to ascertain an adequate evaluation of FAP patients after RPC.

Plasticity of the parental brain: a case for neurogenesis

Profound behavioural changes occur in the mother at parturition, together with extensive remodelling of neural circuits. These changes include neurochemical, morphological and functional plasticity. The continuous generation of new neurones in the hippocampus and the olfactory system is an additional form of neuroplasticity that contributes to motherhood. This review describes the reciprocal relationships between hippocampal and olfactory neurogenesis and parental behaviour. Studies in rodents demonstrate that parturition and interactions with the young affect both cell proliferation and survival in a different manner across neurogenic zones. Species in which an individual recognition of the offspring is formed, such as sheep, show a down-regulation of neurogenesis during the perinatal period. This would function to decrease cell competition, favouring the selection of newborn neurones involved in olfactory recognition of the young. Also, in biparental species, increases in olfactory neurogenesis occur in the father in response to pup exposure during the early postpartum period. Oestradiol, corticosterone and prolactin changes associated with parturition are the main physiological factors involved in the regulation of neurogenesis that have been determined so far. In the father, prolactin mediates an enhancement of olfactory neurogenesis. Contradictory evidence indicates a functional link between neurogenesis and parenting behaviour. Mice receiving focal irradiation of the olfactory neurogenic subventricular zone show few disturbances in the expression of maternal behaviour, whereas a reduction of both hippocampal and olfactory neurogenesis as a result of the infusion of an anti-mitotic agent induces behavioural deficits. Disrupting prolactin signalling abolished increased paternal neurogenesis and offspring recognition by the father, and rescuing this neurogenesis restored recognition behaviour. More studies that selectively suppress the changes of neurogenesis are needed to confirm the role of new neurones in regulating parenting behaviour.

Mother-young relationships in sheep: a model for a multidisciplinary approach of the study of attachment in mammals

The onset of maternal responsiveness and the development of mother-young attachment in sheep are under the combined influence of hormonal and sensory stimulations. In the mother, the prepartum rise in oestrogen and vaginocervical stimulation caused by expulsion of the foetus act on the main olfactory system and on hypothalamic regions. This induces maternal care through the central release of oxytocin, modulated by opiates and corticotrophin-releasing hormone. In parallel, activation of the main olfactory network enables the learning of individual lamb odour and maternal attachment. In the neonate, the first suckling episodes and the concomitant activation of the cholecystokinin, opioids and oxytocin systems facilitate the development of a preference for the mother. Gastrointestinal signals activate the brain stem, the hypothalamus and the amygdala. Within 72 h of parturition, the mother-young attachment shifts from proximal to distal recognition based on visual and auditory cues after which vocal cues become more salient. Although olfaction remains a key element in the display of selective maternal nursing, maternal attachment relies on a multisensory mental image of the lamb. These findings support the view that sheep are amongst the most appropriate animal models for the study of maternal and filial attachment in mammals.

Nasally inhaled pulsating aerosols: lung, sinus and nose deposition

OBJECTIVES

Topical delivery of drugs to the sinuses is challenging and requires also particular administration manoeuvres from the patient. This study was conducted to investigate 1) the delivery efficiency of a pulsating aerosol (Vibrent prototype device) to the sinuses and the nose, 2) the aerosol fraction that will deposit in the lungs and 3) potential differences regarding sinus and nasal deposition ratio when comparing aerosol administration during two different administration routes.

METHODS

An open label deposition study in healthy volunteers was conducted using 99mTc-DTPA radiolabeled pulsating aerosols in comparison to nasal pump sprays. Deposition and retention of pulsating aerosols was assessed by gamma camera imaging during spontaneous nasal breathing and during closed soft palate administration.

RESULTS

Aerosol administration during nasal breathing vs. application with closed soft plate results in significant lung, nasal and sinus deposition. No significant differences were observed for nasal clearance. In comparison, drug delivery using nasal pump sprays resulted in non-significant sinus, 100 % nasal and non-significant lung deposition. The clearance kinetics after nasal pump spray delivery was significantly accelerated.

DISCUSSION

The standard application mode of pulsation aerosols with closed soft palate results in negligible lung deposition and therefore limits drug delivery to the nasal cavity only, minimizing unwanted side effects. Administration during spontaneous nasal breathing shows only 10% lung deposition, which is tolerable during drug administration. Relevant paranasal sinus deposition is noted during both application modes and clearance kinetics remains essentially unchanged. In contrast, nasal pump sprays do not show sinus drug delivery and nasal drug residence time is shortened.

CONCLUSION

Pulsating aerosols offer advantageous topical nasal and sinus drug delivery options.

EFFECT OF CURING ADDITIVES ON THE DISPERSION KINETICS OF CARBON BLACK IN RUBBER COMPOUNDS)

The effect of curing additives on the dispersion kinetics of carbon black (CB) in styrene butadiene rubber (SBR) compounds was investigated by means of the method of the online measured electrical conductance. Addition of curing additives such as stearic acid and diphenylguanidine (DPG) accelerates the CB dispersion process significantly. The viscosity of the rubber matrix was not changed after their addition. The addition of stearic acid and DPG may alter the filler–filler interaction that consequently leads to faster dispersion processes. The obtained difference in morphologies of SBR mixtures containing stearic acid and DPG, respectively, are caused by their different infiltration behavior, which may lead to different dispersion mechanisms. Addition of ZnO could not improve the dispersion process of CB because of its limited interaction with CB. Sulfur and N-cyclohexylbenzothiazole-2-sulfenamide decelerate the CB dispersion process. The strong effect of the rubber microstructure such as styrene content and molecular weight on the CB dispersion in SBR mixtures without additives was found and discussed by taking into consideration the known dispersion mechanisms. The influence of addition of curing additives on the CB dispersion in low styrene-content SBR mixtures is much more pronounced than that in high styrene-content SBR mixtures.

Vaginocervical stimulation of Ewes induces the rapid formation of a new bond with an alien young without interfering with a previous bond

Ewes form a selective olfactory memory for their lambs after 2 hr of mother-young interaction following parturition. Mothers will subsequently reject any strange lamb at suckling. The present study investigated whether artificial vaginocervical stimulation (VCS) allows the formation of a selective bond with an unfamiliar lamb and whether it interferes with the maintenance of the bond formed with the familiar lamb. At 2 hr postpartum, mothers were separated from their familiar lamb after having formed a selective bond with it and were given 10 min of mechanical VCS. In the "VCS + lamb" group (n = 24) an unfamiliar lamb was left with the ewe for 2 hr whereas in the "VCS no lamb" group (n = 26) the mother was left alone for the same period of time. Ewes of the "no VCS" group (n = 14) did not receive any VCS. In the majority of animals of the "VCS + lamb" group (23/24) VCS induced a complete acceptance of the unfamiliar lamb without any disruption of the bond previously formed with the familiar lamb. VCS or 2 hr of separation did not disrupt the maintenance of the selective bond initially formed with the familiar lamb since all the ewes of the "VCS no lamb" and "no VCS" groups accepted it at suckling.