CO2 capture on natural zeolite clinoptilolite: Effect of temperature and role of the adsorption sites.

In this study, the adsorption capacity of the low-cost zeolite clinoptilolite was investigated for capturing carbon dioxide (CO2) emitted from industrial processes at moderate temperature. The CO2 adsorption capacity of clinoptilolite (a commercial natural zeolite) and ion-exchanged (with Na+ and Ca2+) clinoptilolite were tested under both dynamic (using a fixed-bed reactor operating with 10% vol. CO2 in N2) and equilibrium conditions (measuring single component adsorption isotherms). The dynamic CO2 adsorption capacity of bare clinoptilolite and ion-exchanged clinoptilolite were evaluated in the temperature range from 293 K to 338 K and the obtained breakthrough curves were compared with those of the commercial zeolite 13X (Z13X). Although the adsorption capacity of Z13X exceeded those of bare clinoptilolite and ion-exchanged clinoptilolite at 293 K, the clinoptilolite exhibited the highest CO2 uptake at a moderate temperature of 338 K (i.e. 25 % higher than Z13X). This feature appears in agreement with the lower isosteric heat of CO2 adsorption on clinoptilolite compared to the other samples. The surface species affecting the qiso and adsorption capacity were investigated through the FTIR spectroscopy using CO2 as probe molecule. As a whole, it has been observed that CO2 forms linear adducts onto K+ and Mg2+ cations of the bare clinoptilolite, and carbonate-like species onto its basic sites. With the Na-exchanged clinoptilolite, Na+ ions led to a decrease in surface basicity and to the formation of both single (Na+···OCO) and dual (Na+···OCO⋯Na+) cationic sites available for the formation of linear adducts. As a result of the remarkable adsorption capacity of clinoptilolite at 338 K, this material appears to be a promising adsorbent for the direct CO2 removal from different flue gases sources operating at such temperatures.

Pressure-induced penetration of guest molecules in high-silica zeolites: the case of mordenite.

A synthetic high-silica mordenite (HS-MOR) has been compressed in both non-penetrating (silicone oil, s.o.) and penetrating [methanol : ethanol : water (16 : 3 : 1) (m.e.w.), water : ethanol (3 : 1) (w.e.), and ethylene glycol (e.gl.)] pressure transmitting media (PTM). In situ high-pressure (HP) synchrotron X-ray powder diffraction (XRPD) experiments allowed the unit cell parameters to be followed up to 1.6, 1.8, 8.4, and 6.7 GPa in s.o., w.e., m.e.w., and e.gl., respectively. Moreover, e.gl. was also used as a PTM in in situ HP Raman and ex situ IR experiments. The structural refinement of HS-MOR compressed in e.gl. at 0.1 GPa - the lowest investigated pressure - revealed the presence of 3.5 ethylene glycol molecules per unit cell. The infrared spectrum of the recovered sample, after compression to 1 GPa, is consistent with the insertion of ethylene glycol molecules in the pores. XRPD and Raman spectroscopy experiments performed under pressure indicated the insertion of a small number of guest molecules. Ethylene glycol is partially retained inside mordenite upon pressure release. A symmetry lowering was observed in s.o. above 0.8 GPa, while above 1.6 GPa the patterns indicated a rapid loss of long range order. From ambient pressure (Pamb) to 1.6 GPa, a high cell volume contraction (ΔV = -9.5%) was determined. The patterns collected with penetrating PTM suggested the penetration of guest molecules into the porous host matrix, starting from a very low P regime. The entrapment of PTM molecules inside micropores contributes to the stiffening of the structure and, as a consequence, to the decrease of the compressibility with respect to that measured in s.o. From the structural point of view, HS-MOR reacts to compression and to the penetration of different guest species with appropriate framework deformations. Interestingly, ethylene glycol is partially retained inside mordenite upon pressure release, which is of importance for potential application of this composite material.

WO3 nanorolls self-assembled as thin films by hydrothermal synthesis.

We report a novel type of WO3 nanostructure, i.e. nanorolls obtained as a self-assembled thin film on a transparent conductive substrate. The mild conditions of preparation, avoiding the use of HCl, result in an eco-friendly hydrothermal method with reduced crystallization time. FESEM and HR-TEM show that WO3 nanocrystals are made of rolled nanoflakes with a telescope-like appearance at their tip. For their nano-porosity, electrochemical accessibility, good adhesion to substrates and the envisaged presence of nanocavities between the WO3 layers, these materials hold tremendous promise in nano-electronics, electrochromic devices, water photo-splitting cells, Li-ion batteries and nano-templated filters for UV radiation.

Panax notoginseng (Burk.) effects on fibrinogen and lipid plasma level in rats fed on a high-fat diet.

Several studies have shown that notoginsenoides improve diastolic function in hypertensive subjects, induce the fibrinolytic system in in vitro models and act as antiproliferative agents on vessel leiomyocytes. Our aim was to evaluate their effect on fibrinogen and lipid plasma levels compared with a well-known HMGCoA reductase inhibitor. Seventy Wistar male adult rats on a fat-enriched diet were treated orally with P. notoginseng pulverized root (43 mg/kg/day or 86 mg/kg/day; 20 animals per group), fluvastatin (3 mg/kg/day; 20 animals) or physiological saline (5 mL/kg/day; 10 animals). The ten rats on a normocaloric diet were also treated with 5 mL/kg/day of physiological saline. After a 28-day treatment, the rats were killed and their blood analysed with standard procedures. Treatment with 43 mg/kg/day of P. notoginseng or 3 mg/kg/day of fluvastatin showed similar activity in decreasing total cholesterol (-23.70%, -19.29%, respectively) and triglycerides (-21.59%, -18.55%). The most evident effect of P. notoginseng was the reduction of fibrinogenaemia in treated rats compared with the control values (-38.10%; p < 0.001), no dose-relationship being shown in this effect. Moreover, no significant variation in HDL cholesterol and glucose levels was observed nor did relevant behavioural changes occur in association with the root intake. Besides a moderate, non dose-related decrease in the plasma lipid levels, P. notoginseng appeared to induce a significant reduction in the rat fibrinogenaemia.

Hexanic Maca extract improves rat sexual performance more effectively than methanolic and chloroformic Maca extracts.

Lepidium meyenii (Maca) is traditionally employed in the Andean region for its supposed properties in improving fertility. The aim of this study was to determine the effect of subacute oral administration of hexanic, methanolic and chloroformic extracts of Maca root on sexual performance in inexperienced male rats. The following sexual performance parameters were evaluated: 1st mount, 1st intromission, ejaculation and post-ejaculatory latencies, intercopulatory interval and copulatory efficacy. All the tested fractions significantly decreased intromission latency and intercopulatory interval and increased intromission frequency and copulatory efficacy (P < 0.05) as compared to controls. Hexanic and methanolic extracts were able to increase mount frequency (MF), while only hexanic fraction significantly improved mount latency (ML) (P=0.038). Globally, only the hexanic fraction significantly improved the majority of the sexual parameters measured. Sub-acute oral administration of hexanic Maca extract improved sexual performance parameters in sexually inexperienced male rats most effectively.

Influence of estrogens and oxytocin on germ cells death in the neonatal mammalian ovary.

During mammalian oogenesis, some processes involve proliferation and others drastic reduction of germ cells. This study reports on the role played by two hormones, estradiol monobenzoate and oxytocin, in the control of the number of germ cells in the neonatal mouse ovary. Female neonatal mice were treated with doses ranging between 0.1 and 1 microg/mouse of estradiol monobenzoate or oxytocin and sacrificed at 5 days of postnatal age. The results showed that in the animals treated with estrogen, follicular development was more advanced than that of controls. Further the number of germ cells in apoptosis was drastically reduced. In the animals treated with oxytocin, the follicular development was arrested at the stage of primary follicles. In addition, the number of apoptotic germ cells increased if compared with that of the controls.

Effects of estrogens and oxytocin on the development of neonatal mammalian ovary.

The preservation and death of germ cells in the neonatal mammalian ovary are linked with the presence of hormones. Estrogens and oxytocin are present at birth in all mammalian vertebrates. The aim of this study was to examine their role in the development of the neonatal ovary and also in the preservation and death of germ cells in the neonatal period: apoptotic phenomena play a fundamental role in the control of their number. Female neonatal mice were treated at birth with estradiol monobenzoate or oxytocin and sacrificed after 5 days. The ovaries were sectioned in toto into semi-thin sections, in order to calculate their volume. Thin sections were also carried out to verify, under the transmission electron microscope (T.E.M.), the cells in apoptosis. The ovaries treated with the greater concentration of estradiol monobenzoate showed a volume that was significantly greater than that of the controls and a reduction of germ cells in apoptosis. The ovaries treated with oxytocin at all degrees of concentration had a volume significantly less than the controls and they also had a higher number of germ cells in apoptosis.

Behavioral and developmental outcomes of prenatal and postnatal vanadium exposure in the rat.

The developmental and behavioral outcomes of uninterrupted exposure to vanadium was studied in the rat. Starting 3 days before birth and up to the 100th day of extrauterine life, rats received as drink either a water solution of vanadyl sulphate (300 mg l(-1)containing 70 mg l(-1)of vanadium element, which is equal to an ingested dose of about 10 mg kg(-1)per day of vanadium element) plus NaCl 5 g l(-1), or a water solution of NaCl 5 g l(-1), or plain water [up to weaning (25th day of extrauterine life) treatment was given to dams and offspring]. At weaning, survivors were fewer and body weight was found to be significantly lower in the offspring of vanadium plus NaCl-treated dams than in the offspring of the other two groups. After weaning, growth retardation continued to be significant in both vanadium plus NaCl- and NaCl-treated rats. Such an effect was more pronounced in males than in females. Locomotor activity--evaluated at 1 month of age--was not significantly different in the three groups of rats. In the open-field, male (but not female) vanadium plus NaCl-treated rats had a reduced outer ambulation, rearing posture and grooming activity, and an increased defecation, in comparison with the males of the NaCl group, and reduced rearing in comparison with control males. As concerns ingestive behaviors, the only significant datum was an increased water intake in NaCl-treated males. Finally, at the 100th day of life, working memory was significantly impaired in both vanadium plus NaCl- and NaCl-treated rats.

Lepidium meyenii Walp. improves sexual behaviour in male rats independently from its action on spontaneous locomotor activity.

Lepidium meyenii Walpers (Maca) is traditionally employed in the Andean region for its supposed properties to improve energy and fertility. The aim of this study was to evaluate the effect of acute and chronic Maca pulverised root oral administration on rat sexual behaviour. Sixty male sexually experienced rats (20 group) were daily treated for 15 days with Maca 15 mg kg(-1), Maca 75 mg kg(-1) or saline 0.5 ml kg(-1). The following sexual performance parameters were evaluated at first and last day of treatment: 1st mount (ML), 1st intromission (IL), ejaculation (EL) and postejaculatory (PEL) latencies, intercopulatory interval (ICI) and copulatory efficacy (CE). An activity cage test was carried out to evaluate if Maca-induced locomotion changes could indirectly improve rat sexual performances. It was observed that both lower and higher Maca doses acutely decreased ML, IL and ICI in a significant way (P < 0.05), while only the 75 mg kg(-1) dose decreased the PEL (T = 29, P < 0.05). This effect seems to be the only one dose-dependent. After 15 days of treatment, both doses are able to significantly decrease ML, IL, EL and PEL, while the 75 mg kg(-1) dose decreased the ICI (T = 40, P < 0.05) too. IL, EL and PEL variations seem to be dose-related after chronic treatment. Moreover, chronic Maca treatment induced an apparently not dose-related increase in rat locomotion, during the second 10-min period of observation in the activity cage. The late in Maca-induced locomotion modification excludes that improvement of tested sexual performance parameters is related to an increase in rat aspecific activity. Thus, it was concluded that both acute and chronic Maca oral administration significantly improve sexual performance parameters in male rats.

Gelatin microspheres crosslinked with D,L-glyceraldehyde as a potential drug delivery system: preparation, characterisation, in vitro and in vivo studies.

To overcome the restriction in using crosslinked gelatin in the pharmaceutical field, D,L-glyceraldehyde (GAL), a non-toxic crosslinking agent, was proposed. Gelatin microspheres crosslinked with different concentrations of GAL (0.5, 1 or 2%, w/v) and for different time periods (1 or 24 h) were prepared. The effect of the preparation variables was evaluated analysing the extent of crosslinking, the morphological aspect, the particle size and the swelling behaviour. To evaluate the pharmaceutical properties, an antihypertensive drug, clonidine hydrochloride, was chosen as drug model and loaded into the microspheres. Either the increase of the crosslinker concentration or of the crosslinking time period decreased both the swelling and the in vitro drug release processes of the microspheres. After the subcutaneous injection, the loaded microspheres crosslinked with the lowest GAL concentration (0.5%, w/v) or for the shortest time period (1 h) showed a reduction of systolic blood pressure (SBP) similar to that recorded with a clonidine hydrochloride solution having the same drug concentration. Instead, the microspheres crosslinked for 24 h with concentrations of GAL higher than 0.5% (w/v) produced a more gradual and sustained SBP reduction and the antihypertensive effect was maintained until 52-72 h. The biocompatibility studies showed that the microspheres crosslinked with GAL are well tolerated in vivo. These results suggest the potential application of gelatin microspheres crosslinked with GAL as a suitable drug delivery system for the subcutaneous administration.

Orally administered Panax notoginseng influence on rat spontaneous behaviour.

Panax notoginseng root is highly prized in China for its supposed hemorheological properties. Its behavioural effects are still not scientifically investigated; therefore, our preliminary study aim is to evaluate the influence of this phyto-drug on rats spontaneous behaviour. High quality P. notoginseng root dry extract has been orally administered through gastric tube for 10 days in two doses (43 and 86 mg/kg in a volume of 5 ml/kg per day) and its effects on locomotion, emotional reactivity and nutrition have been evaluated in different groups of Wistar rats (ten per group) versus animals treated with 5 ml/kg per day of saline. Actimeter test, open field test and microstructural analysis of unconditioned behaviour were carried out. The data were processed by ANOVA-test followed by the Student's one-tail t-test and a 0.05 significance level was chosen for all statistical tests. A significant increase in spontaneous motility being not associated to an increase in grooming episodes duration and number was found in all tests (P<0.05). Feeding behaviour appeared not to be affected by the treatment. Observed effects did not seem dose-related. Reduction of grooming episodes duration and number and increase of inner crossings in open field suggested that notoginsenoides can modulate emotional responses in rats.

Long-lasting regulation of galanin, opioid, and other peptides in dorsal root ganglia and spinal cord during experimental polyarthritis.

Mechanisms involved in transition from acute to chronic pain are still not well understood and our means to therapeutically influence this transition are limited. Moreover, very little is known about long-lasting consequences of prolonged exposure to painful stimuli with regard to phenotypic changes and pain experience. In this study we have analyzed long term behavioral and neurochemical effects of intradermal tail injection of heat-killed mycobacterium butyricum suspended in complete Freund's adjuvant. Calcitonin gene-related peptide (CGRP) and galanin mRNA levels were investigated in dorsal root ganglia of polyarthritic rats during the acute (21-) and the remission stage (79 days postinjection), and opioid peptide mRNAs and receptors were studied in the spinal cord. Most of the increases in peptide mRNA levels observed during the acute stage of arthritis were still present in the remission stages. Thus, CGRP and galanin mRNAs in DRGs, and opioid peptide mRNAs and opioid receptors in the spinal cord were still strongly up-regulated, when animals do not exhibit spontaneous pain behavior and inflammation. Hot-plate test in the presence of naloxone, performed in the remission stage, indicated that opiates participate in pain threshold regulation after prolonged painful condition. Finally, X-ray examination revealed a complete destruction of joint structure, thus suggesting a parallel lesion of peripheral nerve endings. These results suggest that in the remission stage of chronic joint inflammation several types of mechanisms are activated aiming at counteracting both inflammatory and neuropathic pain. Thus, opioid systems in the dorsal horn as well as galanin in DRG neurons are upregulated, both alternating pain.

L -sulpiride, at antidepressant dosage, prevents conditioned-fear stress-induced gastric lesions in rats.

It has been previously shown that long-term treatment with low doses of l-sulpiride is highly effective in rat models of depression and of anticipatory anxiety/panic behavior. The present study was aimed at investigating whether the same treatment can prevent the ulcerogenic effect of repeated inescapable stresses. In adult rats, the repeated (7 consecutive days) exposure to an uncontrollable stressful condition (inescapable 2.5 mA scrambled shock for 60 s) produced the development of gastric lesions (multiple punctiform telangiectasias in all rats, with superficial erosions or more severe ulcerations in 10 out 13 rats; score 4.67 +/- 0.44). l-sulpiride, intraperitoneally injected once a day at an antidepressant dose level (4 mg kg(-1) per day), starting 21 days before the beginning of the 7-day sequence of inescapable punishments ( = 28 daily treatments), almost completely prevented the stress-induced gastric injury (score 1.67 +/- 0.29; P< 0.001 vs saline-treated rats, Mann-Whitney U test). These results show that, in rats, a long-term treatment with low doses of l-sulpiride prevents the development of gastric lesions induced by chronic exposure to uncontrollable stress.

Antitussive effect of K+ channel openers.

The effect of the K(ATP) channel openers, pinacidil and cromakalim, on coughing was studied in guinea pigs exposed to a nebulized aqueous solution of citric acid (0.50 M). Both pinacidil and cromakalim, subcutaneously administered 45 min before the test, inhibited coughing. The D50 (95% CI) were 0.95 +/- 0.90 mg/kg for cromakalim and 3.25 +/- 0.92 mg/kg for pinacidil. Under our experimental conditions, the D50 (95% CI) of codeine was 1.74 +/- 0.75 mg/kg. The combination of cromakalim and pinacidil with codeine produced an additive effect. An additive effect was also produced by the combination of pinacidil with the selective tachykinin NK2 receptor antagonist MEN 10,627 = [cyclo(Met-Asp-Trp-Phe-Dap-Leu)cyclo(2beta-5beta)]. The antitussive effect of pinacidil and cromakalim was not a consequence of a bronchodilating effect, which was absent at these dose levels under our experimental conditions. These results indicate that K(ATP) channel openers have an opioid-like antitussive effect and may suggest a novel approach to the symptomatic treatment of coughing.

Stimulating property of Turnera diffusa and Pfaffia paniculata extracts on the sexual-behavior of male rats.

Sexually potent and sexually sluggish/impotent male rats were treated orally with different amounts of Turnera diffusa and Pfaffia paniculata fluid extracts (0.25, 0.50, 1.0 ml/kg). While having no effect on the copulatory behavior of sexually potent rats, both plant extracts--singly or in combination--improved the copulatory performance of sexually sluggish/impotent rats. The highest dose of either extract (1 ml/kg) (as well as the combination of 0.5 ml/kg of each extract) increased the percentage of rats achieving ejaculation and significantly reduced mount, intromission and ejaculation latencies, post-ejaculatory interval and intercopulatory interval. Neither extract affected locomotor activity. These results seem to support the folk reputation of Turnera diffusa and Pfaffia paniculata as sexual stimulants.

l-Sulpiride, at a low, non-neuroleptic dose, prevents conditioned fear stress-induced freezing behavior in rats.

Antidepressant drugs are effective in anxiety states, including panic disorder. Both clinical and animal studies indicate that l-sulpiride, at low, non-neuroleptic doses, has antidepressant activity. The present study examined the effect of an antidepressant dose of l-sulpiride (4 mg/kg per day SC), compared with a well-established antidepressant drug (fluoxetine, 3 mg/kg per day SC), in a rat model of anticipatory anxiety/panic behavior: conditioned fear stress-induced freezing behavior. Long-term (26 days) administration of l-sulpiride almost completely abolished freezing, a similar effect being produced by fluoxetine (freezing duration, in seconds: controls, 148.1 +/- 29.6; l-sulpiride, 27.5 +/- 8.3; fluoxetine, 72.0 +/- 15.2). The same doses of l-sulpiride (4 mg/kg SC) and fluoxetine (3 mg/kg SC) had no effect when administered for shorter periods (1, 5, or 12 days). No effect was produced by the long-term (26 days) administration of a neuroleptic dose of l-sulpiride (20 mg/kg per day SC). These results demonstrate that long-term administration of low, non-neuroleptic doses of l-sulpiride, is highly effective in an animal model of anticipatory anxiety/panic behavior.

Diabetic rats are unresponsive to the penile erection-inducing effect of intracerebroventriculary injected adrenocorticotropin.

The penile erection-inducing effect of intracerebroventricularly (i.c.v.) injected adrenocorticotropin-(1-24) [ACTH-(1-24)] (4 or 10 microg/animal) was almost completely absent in diabetic rats, either 8 days or 2 months after streptozotocin administration. The other behavioral symptoms (stretching, yawning, excessive grooming) were unevenly affected: stretching was significantly reduced either in early or in long-standing diabetes; yawning was practically absent in early diabetes and significantly reduced at the highest dose of ACTH-(1-24) in long-standing diabetes; grooming was reduced only at the highest dose of ACTH-(1-24), both in early and in long-standing diabetes. The fact that ACTH-induced penile erections (a centrally mediated effect) are practically absent even a few days after streptozotocin injection suggests that diabetes mellitus-induced penile dysfunction occurs, at least in part, through central mechanisms, and is not solely the consequence of peripheral nerve and vascular lesions.

Sexual impotence is associated with a reduced production of oxytocin and with an increased production of opioid peptides in the paraventricular nucleus of male rats.

Oxytocin plays a physiological stimulatory role on sexual behavior. Conversely, opioid neuropeptides play a physiological inhibitory role. Here we show that in sexually impotent rats there is a reduced expression of oxytocin mRNA and an increased expression of proenkephalin and pro-dynorphin mRNA in the paraventricular nucleus of hypothalamus (PVN), a brain structure of key importance for sexual behavior. These data suggest that an imbalance in the production of oxytocin and of opioid peptides in the PVN, with prevalence of opioid peptides, may underlie a condition of sexual impotence.

General and cardiac toxicity of doxorubicin-loaded gelatin nanoparticles.

General and cardiac toxicity of doxorubicin loaded gelatin nanoparticles cross-linked by glutaraldheyde were investigated in healthy rats. The rats were treated with free doxorubicin (DXR), unloaded nanoparticles (UNp), physical mixture of doxorubicin and unloaded nanoparticles (DRX/UNp), and DXR-loaded nanoparticles (DXR-Np). Each group of animals received the same dose of DXR (3 mg/kg) via i.p. once a week. Both electrocardiogram (ECG) parameters and body weight were measured 24 h before each administration. Rats treated with UNp behaved as controls. DXR/UNp provoked the same toxic effects as free DXR. On the contrary, DXR-Np resulted more toxic since significant variations of both the body weight and the ECG parameters were observed during the first week of treatment. In addition, the rats treated with DXR-Np died between the 3rd and the 5th day after the 2nd administration. These results demonstrate that, in these experimental conditions, the couplage of DXR to nanoparticles enhanced the cardiotoxicity of the drug. Since DXR was linked to the protein matrix of nanoparticles via glutaraldehyde, the high toxicity of DXR-loaded nanoparticles could be due to the covalent binding of the drug to the carrier.

Galantide improves social memory in rats.

The role of galanin in memory paradigms has been largely evaluated. The galanin-antagonist galantide, a chimeric peptide obtained from amino acids 1-13 of galanin attached to the C-terminal fragment of bradykinin, has been found to improve social memory in 'social recognition' test when i.c.v. administered at doses varying from 6-6000 nmoles.