Polarization eigenstates analysis of helically structured thin films.

The optical properties of thin films are generally determined by direct photometric quantities. We show that additional insight into the properties of anisotropic thin films can be obtained by computing the polarization eigenstates and eigenvalues of their Jones matrices. We consider helically structured thin films, which display intriguing optical response, such as the circular Bragg resonance. Using numerical simulations and actual measurements, we show that the eigenvectors are mutually orthogonal in most regions of the wavevector space, except near the circular Bragg and the oblique resonances. Special wavevector values, called exceptional points, are found where the Jones matrix becomes defective and its eigenvectors coalesce. Exceptional points are also found in pairs of wavevector values differing only by a sample rotation by π around the direction normal to the sample; this property is shown to arise from Saxton - de Hoop's reciprocity principle, which applies to lossy materials and contains time reversal symmetry, which only applies to lossless materials, as a special case.

Observation of exceptional points in helically structured thin films.

Exceptional points (EPs) in the polarization space were observed in reflection on helically structured thin films. These films have form anisotropy at the nanoscale introduced through dynamic control of crystalline growth geometry by changing the orientation of the substrate with respect to the impinging vapor. They are simpler alternatives to metasurfaces, because they can be produced at low cost using conventional thin-film deposition techniques. The EPs were experimentally confirmed by eigenstate swapping on a closed circuit surrounding them and were predicted by numerical calculations. Reflective surfaces operating at an EP could be used to make ultrasensitive sensors.

Elimination of spatial hole burning in solid-state lasers using nanostructured thin films.

Multimode laser emission generally takes place in homogeneously broadened gain media placed inside a standing-wave resonator due to spatial hole burning. Solutions proposed to eliminate this phenomenon have so far involved the use of intracavity elements, such as an etalon, wave plates or saturable absorbers. We propose a monolithic solution, wherein birefringent layers of TiO2 are deposited on both laser mirrors. This solution enables one to control the contrast of the interference pattern of the standing wave inside the resonator, and thus the strength of the spatial hole burning, by rotating one mirror around the optical axis. A monochromatic laser emission is demonstrated in a quasi-continuous-wave laser-diode-pumped Yb3+:YAG laser experiment.

Evaluation of the antidepressant- and anxiolytic-like effects of a hydrophilic extract from the green seaweed Ulva sp. in rats.

OBJECTIVES: The green seaweed Ulva sp. contains a large amount of ulvans, a family of sulphated polysaccharides. The present study was designed to investigate in rats the antidepressant- and anxiolytic-like effects of a hydrophilic extract of Ulva sp. (MSP) containing about 45% of ulvans. METHODS: After a 14-day administration of MSP at doses of 10, 20 and 40 mg/kg/day, 48 and 60 male adult Wistar rats were respectively tested in the elevated plus-maze (EPM) and the forced swimming test (FST). In the FST, MSP effects were compared to the reference antidepressant drug imipramine (IMI) (10 mg/kg/day). Acute and sub-chronic toxicities of the extract were also assessed in male and female rats following OECD guidelines. RESULTS: MSP treatment did not modify anxiety-related behaviour in the EPM. In contrast, MSP induced a dose-dependent reduction of immobility behaviour in the FST. At the highest tested dose of 40 mg/kg, MSP displayed a significant antidepressant-like effect similar to IMI. MSP did not modify the exploratory behaviour of rats in the open field test and did not produce any toxic effect. DISCUSSION: MSP may potentially represent a good adjunct or alternative to existing antidepressant therapeutics. Further studies are necessary to confirm the mechanism of action of MSP and its modulation of brain functioning.

Linearly polarized Q-switched ceramic laser made with anisotropic nanostructured thin films.

A polarizing laser mirror was made of an alternating sequence of low and high refractive index layers of titanium oxide using glancing angle deposition (GLAD). Large refractive index contrast and large birefringence, reaching 0.5 and 0.1, respectively, could be obtained from one single raw material by changing the deposition conditions. The laser mirror could withstand a train of 2.7 ns, single-mode pulses at 680 Hz, λ=1030 nm, and peak power density of 670 MW/cm2 when used as an output coupler of a passively Q-switched (Yb0.1Y0.9)3Al5O12 ceramic laser. The polarization extinction ratio was found to be better than 30 dB both in continuous-wave and pulsed regimes. These results indicate that polarizing laser mirrors made from nanostructured thin films with GLAD, in addition to being simple to fabricate, can withstand high pulse energy density.

Negative effect of clenbuterol on physical capacities and neuromuscular control of muscle atrophy in adult rats.

INTRODUCTION: Clenbuterol has been used to alleviate chronic obstructive pulmonary disease and elicit an anabolic response in muscles. The aim of this study was to determine the influence of muscle mass variation on physical capacities in rats. METHODS: The left hindlimbs of Wistar rats were immobilized for 20 days in plantarflexion with a splint and then remobilized for 16 days. The effect of a non-myotoxic dose of clenbuterol during the immobilization period was evaluated. Physical capacities were coordination, free locomotion, grip strength, and bilateral deficit. RESULTS: Immobilization induced a loss of muscle mass, coordination, and strength without any effect on free locomotion. The positive anabolic effect of clenbuterol did not prevent a loss of physical capacities resulting from immobilization. CONCLUSIONS: Muscle mass correlated strongly with coordination and isometric strength in untreated rats. Anabolic effect, fiber phenotype modification, and perturbation in neuromuscular communication with clenbuterol improved muscle mass, but it altered physical capacities.

Compact linearly polarized ceramic laser made with anisotropic nanostructured thin films.

A novel method is proposed for the fabrication of polarizing laser mirrors for compact solid-state lasers using glancing angle deposition. Changing the inclination angle and the azimuthal orientation of the substrate during deposition allows one to create and control in-plane birefringence of a deposited thin film by changing its nanostructure. Principal refractive indices of tungsten trioxide films were determined for various deposition angles using transmission and reflection ellipsometry. High-reflectance contrast between orthogonal linear polarization directions was obtained using a single material without any additional processing steps. These birefringent films were the building blocks of a Bragg mirror that was tested as an output coupler of a (Yb0.1Y0.9)3Al5O12 ceramic laser in a laser-diode end-pumped configuration. Continuous-wave, linearly polarized, transverse single-mode laser emission was obtained at a wavelength of 1030 nm with a polarization extinction ratio higher than 973 (30 dB).

p-Coumaric acid activates the GABA-A receptor in vitro and is orally anxiolytic in vivo.

The increasing prevalence and social burden of subclinical anxiety in the western world represents a significant psychosocial and financial cost. Consumers are favouring a more natural and nonpharmacological approach for alleviating the effects of everyday stress and anxiety. The gamma-aminobutyric acid (GABA) receptor is the primary mediator of central inhibitory neurotransmission, and GABA-receptor agonists are well known to convey anxiolytic effects. Using an in vitro screening approach to identify naturally occurring phytochemical GABA agonists, we discovered the plant secondary metabolite p-coumaric acid to have significant GABAergic activity, an effect that could be blocked by co-administration of the specific GABA-receptor antagonist, picrotoxin. Oral administration of p-coumaric acid to rodents induced a significant anxiolytic effect in vivo as measured using the elevated plus paradigm, in line with the effects of oral diazepam. Given that p-coumaric acid is reasonably well absorbed following oral consumption in man and is relatively nontoxic, it may be suitable for the formulation of a safe and effective anxiolytic functional food.

A New Moisturiser Improves DNCB-induced Atopic Dermatitis-like Symptoms and Restores Skin Barrier Function in BALB/c Mice.

INTRODUCTION: Atopic dermatitis (AD) is a chronic, inflammatory skin disorder with eczematous and pruritic lesions. Topical moisturisers and either topical corticosteroids or calcineurin inhibitors are usually recommended. Restoring the skin barrier function alleviates AD symptoms. OBJECTIVE: To evaluate the efficacy of a new moisturiser compared to commercially available products in an AD murine model. METHODS: Experimental AD was induced with topical applications of 2,4-DiNitroChloroBenzene (DNCB) on the shaved back skin of BALB/c mice from Day 1 to Day 38. Mice were randomized to either Vehicle/-, DNCB/-, or DNCB/Eczekalm (test product), DNCB/Atopiclair®, or DNCB/Lipikar (reference products) groups. Once daily application of either Eczekalm or Atopiclair® or Lipikar on the AD lesion was performed from Day 32 to Day 38. The AD severity index (ADSI) and animal behaviour were monitored throughout the study. The trans-epidermal water loss (TEWL) was measured on the sacrifice day (Day 39). RESULTS: At Day39, ADSI in the DNCB/Eczekalm, DNCB/Lipikar, and DNCB/Atopiclair® groups were significantly lower by -70%, -68%, and -57%, respectively, as compared to DNCB/- (p < 0.001). No sign of erythema was observed in the DNCB/Eczekalm group. Mean scores of skin oedema, excoriation, and dryness in the DNCB/Eczekalm, DNCB/Lipikar, and DNCB/Atopiclair® groups were significantly lower than in the DNCB/-. No significant difference was observed between DNCB/Eczekalm and DNCB/Lipikar groups. Mean TEWL in DNCB/Eczekalm group was significantly lower than the ones of DNCB/Atopiclair® (-43%, p < 0.001) and DNCB/Lipikar (-15%, p < 0.05). CONCLUSION: Eczekalm treatment significantly reduced the inflammatory effects due to AD and itching episodes and restored the skin barrier function.

Effects of ID-alG™ on weight management and body fat mass in high-fat-fed rats.

Seaweed extract of Ascophyllum nodosum, ID-alG™, was evaluated for its chronic effects on weight management in high-fat-fed Sprague-Dawley rats. ID-alG™ was orally administered daily during 9 weeks at doses of 40 and 400 mg/kg/day with fat-enriched diet (FED) in comparison with two control groups consuming standard diet (negative control) or FED (positive control) and orally treated with vehicle. Body weight, percentage of body fat mass and lipid parameters were measured. After 9 weeks, the oral administration of ID-alG™ at both doses decreased significantly the mean body weight gains (MBWG) of rats submitted to the FED in comparison to the positive control (-6.8% and -11.8%). ID-alG™ at both doses improved significantly the MBWG of rats and decreased significantly the percentage of body fat mass of rats (-9.8% and -19.0%), in comparison to the positive control. In the same way, the triglyceride blood level was also significantly improved for the dose of 400 mg/kg/day (-30.6% vs. +49.9% for the positive control); and the dose of 40 mg/kg/day just lead to a trend. Moreover, in both controls and ID-alG™-treated groups, total cholesterol, LDL and HDL blood levels were not modified. The seaweed extract of Ascophyllum nodosum, ID-alG™, demonstrated beneficial effects on weight management of rats submitted to a high-fat diet.

Antitumor Effect and Induced Immune Response Following Exposure of Hexaminolevulinate and Blue Light in Combination with Checkpoint Inhibitor in an Orthotopic Model of Rat Bladder Cancer.

Previous studies have found that use of hexaminolevulinate (HAL) and blue light cystoscopy (BLC) during treatment of bladder cancer had a positive impact on overall survival after later cystectomy, indicating a potential treatment effect beyond improved diagnostic accuracy. The aim of our study was to determine whether HAL and BL mimicking clinically relevant doses in an orthotopic rat model could have therapeutic effect by inducing modulation of a tumor-specific immune response. We also assessed whether administration with a checkpoint inhibitor could potentiate any effects observed. Rats were subjected to HAL BL alone and in combination with anti-PD-L1 and assessed for anti-tumor effects and effects on immune markers. Positive anti-tumor effect was observed in 63% and 31% of rats after, respectively, 12 and 30 days after the procedure, together with a localization effect of CD3+ and CD8+ cells after 30 days. Anti-tumor effect at 30 days increases from 31% up to 38% when combined with intravesical anti-PD-L1. In conclusion, our study demonstrated treatment effects with indications of systemic immune activation at diagnostic doses of HAL and blue light. The observed treatment effect seemed to be enhanced when used in combination with intravesically administrated immune checkpoint inhibitor.

Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects.

In a previous clinical study, a probiotic formulation (PF) consisting of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 (PF) decreased stress-induced gastrointestinal discomfort. Emerging evidence of a role for gut microbiota on central nervous system functions therefore suggests that oral intake of probiotics may have beneficial consequences on mood and psychological distress. The aim of the present study was to investigate the anxiolytic-like activity of PF in rats, and its possible effects on anxiety, depression, stress and coping strategies in healthy human volunteers. In the preclinical study, rats were daily administered PF for 2 weeks and subsequently tested in the conditioned defensive burying test, a screening model for anti-anxiety agents. In the clinical trial, volunteers participated in a double-blind, placebo-controlled, randomised parallel group study with PF administered for 30 d and assessed with the Hopkins Symptom Checklist (HSCL-90), the Hospital Anxiety and Depression Scale (HADS), the Perceived Stress Scale, the Coping Checklist (CCL) and 24 h urinary free cortisol (UFC). Daily subchronic administration of PF significantly reduced anxiety-like behaviour in rats (P < 0·05) and alleviated psychological distress in volunteers, as measured particularly by the HSCL-90 scale (global severity index, P < 0·05; somatisation, P < 0·05; depression, P < 0·05; and anger-hostility, P < 0·05), the HADS (HADS global score, P < 0·05; and HADS-anxiety, P < 0·06), and by the CCL (problem solving, P < 0·05) and the UFC level (P < 0·05). L. helveticus R0052 and B. longum R0175 taken in combination display anxiolytic-like activity in rats and beneficial psychological effects in healthy human volunteers.

Preventive effects of different probiotic formulations on travelers' diarrhea model in wistar rats : preventive effects of probiotics on TD.

A new animal model of travelers' diarrhea has been developed by infecting rats orally with a strain of enterotoxigenic Escherichia coli in order to assess the efficacy of three probiotic formulations for the prevention of travelers' diarrhea. Five groups of six rats were given daily (by oral gavage) either a placebo (negative and positive control groups), the suspension of bacterial probiotics called FF1, the yeast probiotic Saccharomyces boulardii, or a combination of both, called Protecflor(TM). After 14 days of treatment, all groups except the negative control one were infected by oral administration of E. coli. Body temperature, body weight, food and water consumption, stools consistency, behavior, and cytokines secretion were disturbed following E. coli infection. Probiotics-treated groups generally displayed less-pronounced symptoms, the combination of probiotics Protecflor(TM) being the most effective.

Diuretic and antioxidant effects of Cacti-Nea, a dehydrated water extract from prickly pear fruit, in rats.

Dehydrated extract of the prickly pear fruit Opuntia ficus indica, Cacti-Nea, was evaluated for its chronic diuretic and antioxidant effects in Wistar rats. Cacti-Nea was orally administered daily for seven days at the dose of 240 mg/kg/day. A positive group was orally treated with hydrochlorothiazide at the dose of 10 mg/kg/day and a control group with vehicle. Daily measurements of body weight, urine volume, and concentration of sodium, potassium and uric acid in urine were performed for each rat. At the end of the study, the blood globular level of glutathione peroxidase was determined. Cacti-Nea significantly increased the urine volumes excreted by rats in comparison with the control group and it showed a trend to reduce significantly the body weight gain of rats. No significant differences were observed in the urine concentration of sodium, potassium and uric acid in comparison with the control group. The chronic diuretic effects of Cacti-Nea were comparable with that of the standard drug hydrochlorothiazide. Chronic oral administration of Cacti-Nea significantly increased the blood globular levels of glutathione peroxidase in comparison with control and hydrochlorothiazide groups. The prickly pear fruit extract Cacti-Nea demonstrated chronic diuretic and antioxidant effects in Wistar rats with respect to the excretion of the metabolites.

Anti-inflammatory senescence actives 5203-L molecule to promote healthy aging and prolongation of lifespan.

The aging process depends on genetic stability, metabolic control, and resistance to stress; longevity in particular seems related to resistance to stress. Responses to stress anticipate adaptation to an unacceptable disparity between real or imagined personal experience and expectation, including adaptive stress, anxiety, and depression. However, if stress persists, it may lead to chronic diseases, ranging from inflammation and cancer to degenerative diseases. For some time, only remarkable stress was acknowledged to induce immune and vascular alterations, such as infection or hypertension. Now it is known that moderate stress independent of conventional risk factors can induce a potent alteration of health conditions and consequently shorten life quality and lifespan. Inflammation is a critical defense mechanism, that, uncontrolled, contributes to chronic conditions with inflammatory pathogenesis. Stressful life conditions turn out to induce a diffuse (systemic) pro-inflammatory status. Subclinical chronic inflammation is an important pathogenic factor in the development of metabolic syndrome, a cluster of common pathologies, including cardiovascular disease. Markers include mediators associated with endothelial activation and dysfunction. This work reports the in vitro and in vivo effects of the monoterpene AISA 5203-L on human vascular endothelial cells in reversing replicative senescence in preventing and alleviating nonpathological stress, as assessed by a functional observational battery (FOB) of 44 tests, addressing behavioral, neurological, and physiological criteria.

Protective effect of Acticoa powder, a cocoa polyphenolic extract, on prostate carcinogenesis in Wistar-Unilever rats.

The effects of Acticoa powder on prostate carcinogenesis were investigated using the N-methylnitrosourea and testosterone propionate prostate tumor model. Sixty male Wistar-Unilever rats were randomly divided in four groups of 15 rats: one control group not induced but treated with vehicle (not induced+vehicle) and three chemo-induced groups. Two weeks before prostate tumor induction and then throughout the experiment, chemo-induced rats were orally treated with Acticoa powder at 24 (chemo-induced+Acticoa powder24) or 48 (chemo-induced+Acticoa powder48) mg/kg or with vehicle (chemo-induced+vehicle), daily from Monday to Friday. Survival, body weight, food and water consumption were recorded throughout the experiment. Six rats per group were randomly killed 9 months after the prostate tumor induction for histopathological analysis of prostates. A reduction in the incidence of prostate tumors was observed for the chemo-induced+Acticoa powder48-treated group in comparison with the chemo-induced+vehicle-treated group and no tumors were observed in the chemo-induced+Acticoa powder24-treated group as in the not induced+vehicle-treated group after 9 months. The nine remaining rats per group were maintained in a long-term survival study. The life span of the chemo-induced+Acticoa powder24-treated group was significantly increased in comparison with the chemo-induced+Acticoa powder48 and the chemo-induced+vehicle-treated groups, close to the one of the not induced+vehicle-treated group. A significant reduction in the incidence of prostate tumors was also observed for the chemo-induced+Acticoa powder24 and chemo-induced+Acticoa powder48-treated groups in comparison with the chemo-induced+vehicle-treated group. In conclusion, Acticoa powder at 24 mg/kg protected rats from prostate carcinogenesis when chronically given before the initiation and promotion phases of induction.

Effects of long-term administration of a cocoa polyphenolic extract (Acticoa powder) on cognitive performances in aged rats.

Numerous studies have indicated that increased vulnerability to oxidative stress may be the main factor involved in functional declines during normal and pathological ageing, and that antioxidant agents, such as polyphenols, may improve or prevent these deficits. We examined whether 1-year administration of a cocoa polyphenolic extract (Acticoa powder), orally delivered at the dose of 24 mg/kg per d between 15 and 27 months of age, affects the onset of age-related cognitive deficits, urinary free dopamine levels and lifespan in old Wistar-Unilever rats. Acticoa powder improved cognitive performances in light extinction and water maze paradigms, increased lifespan and preserved high urinary free dopamine levels. These results suggest that Acticoa powder may be beneficial in retarding age-related brain impairments, including cognitive deficits in normal ageing and perhaps neurodegenerative diseases. Further studies are required to elucidate the mechanisms of cocoa polyphenols in neuroprotection and to explore their effects in man.

Effects of lifelong intervention with an oligofructose-enriched inulin in rats on general health and lifespan.

Ageing is associated with changes in physiology and morphology; nutritional strategies to decrease morbidity and to prolong life are of high interest. The aim of the study was to investigate the effects of lifelong supplementation with an oligofructose-enriched inulin on morphological and biological markers and lifespan in male and female rats. Male and female rats, age 3 months, were randomised into two groups to receive either a diet with 10 % of an oligofructose-enriched inulin (Synergy 1) or a standard diet (control) for 27 months. The rats were weighed every 2 weeks and their food intake was evaluated on four successive days every 4-6 weeks. Samples were taken at 12, 18 and 24 months of age. During the whole intervention period, male rats receiving Synergy 1 (SYN1-M) displayed lower body weight, cholesterol and plasma triacylglycerolaemia compared with the controls (Cont-M). The survival rate at 24 months of age of SYN1-M rats was 35.3 % greater than that of Cont-M rats. In female rats, the Synergy 1 supplementation (SYN1-F) group also reduced body weight, cholesterol and triacylglycerolaemia levels, but results were less consistent over the experiment. The survival rate at 24 months of age in SYN1-F rats was 33.3 % greater compared with that of the control (Cont-F) group. To conclude, lifelong intervention with Synergy 1 improved biological markers during ageing and survival rate (lifespan) of rats.

Antidepressant-like effects of a cocoa polyphenolic extract in Wistar-Unilever rats.

Depression is a major public health problem affecting about 12% of the world population. Drugs exist but they have many side effects. In the last few years, natural substances (e.g. flavonoids) have been tested to cure such disorders. Cocoa polyphenolic extract is a complex compound prepared from non-roasted cocoa beans containing high levels of flavonoids. The antidepressant-like effect of cocoa polyphenolic extract was evaluated using the forced swimming test in rats. Cocoa polyphenolic extract significantly reduced the duration of immobility at both doses of 24 mg/kg/14 days and 48 mg/kg/14 days, although no change of motor dysfunction was observed with the two doses tested in the open field. The results of the forced swimming test after a subchronic treatment and after an additional locomotor activity test confirm the assumption that the antidepressant-like effect of cocoa polyphenolic extract in the forced swimming test model is specific. Further, it can be speculated that this effect might be related to its content of active polyphenols.

Preventive effects of ACTICOA powder, a cocoa polyphenolic extract, on experimentally induced prostate hyperplasia in Wistar-Unilever rats.

Plant extracts are useful in the management of benign prostatic hyperplasia (BPH). This study investigates whether ACTICOA (Barry Callebaut France, Louviers, France) powder (AP), a cocoa polyphenolic extract, could prevent prostate hyperplasia induced by testosterone propionate (TP) in rats. Male Wistar-Unilever rats were randomly divided in four groups of 12 rats: one negative control group receiving subcutaneous injections of corn oil and treated with vehicle and three groups injected subcutaneously with TP and treated with the vehicle (positive control) or AP at 24 (AP24) and 48 (AP48) mg/kg/day. Treatments were given orally and started 2 weeks before the induction of prostate hyperplasia. The influence of TP and AP on body weights and food and water consumption of rats was examined. On day 36, rats were sacrificed, and the prostates were removed, cleaned, and weighed. The prostate size ratio (prostate weight/rat body weight) was then calculated. TP significantly influenced the body weight gain of the rats and their food and water consumption, while AP at both doses tested reduced significantly these differences. TP significantly increased prostate size ratio (P < .001), and this induced increase was significantly inhibited in AP-treated rats in comparison with positive controls (P < .001) in a dose-dependent manner. We conclude that AP can prevent TP-induced prostate hyperplasia and therefore may be beneficial in the management of BPH.