Photon blockade in an optical cavity with one trapped atom.

At low temperatures, sufficiently small metallic and semiconductor devices exhibit the 'Coulomb blockade' effect, in which charge transport through the device occurs on an electron-by-electron basis. For example, a single electron on a metallic island can block the flow of another electron if the charging energy of the island greatly exceeds the thermal energy. The analogous effect of 'photon blockade' has been proposed for the transport of light through an optical system; this involves photon-photon interactions in a nonlinear optical cavity. Here we report observations of photon blockade for the light transmitted by an optical cavity containing one trapped atom, in the regime of strong atom-cavity coupling. Excitation of the atom-cavity system by a first photon blocks the transmission of a second photon, thereby converting an incident poissonian stream of photons into a sub-poissonian, anti-bunched stream. This is confirmed by measurements of the photon statistics of the transmitted field. Our observations of photon blockade represent an advance over traditional nonlinear optics and laser physics, into a regime with dynamical processes involving atoms and photons taken one-by-one.

Are inflammatory and malnutrition markers associated with metabolic syndrome in patients with sarcoidosis?

OBJECTIVE: The study aimed to investigate the use of Neutrophil/lymphocyte ratio, C-reactive protein/albumin ratio, controlling nutritional status, and prognostic nutritional index immune, inflammatory, and malnutrition markers Metabolic syndrome+ in sarcoidosis patients, as an early-stage marker. METHOD: This is a single-center and cross-sectional study that determines the association of Metabolic syndrome in patients with sarcoidosis. Patients were evaluated based on the National Cholesterol Education Program's Adult Treatment Panel III criteria. Neutrophil/lymphocyte ratio, C-reactive protein/albumin ratio, controlling nutritional status, and prognostic nutritional index values were simultaneously determined through blood test. RESULTS: A total of 253 patients diagnosed with sarcoidosis were included in this study. Metabolic syndrome- was detected in 37.2% of patients. The prevalence was significantly higher in females (p<0.001). Any degree of malnutrition assessed by controlling nutritional status had higher Metabolic syndrome (p=0.035). The Neutrophil/lymphocyte ratio cutoff value was 2.24, sensitivity was 70.53, specificity was 60.13, and Area Under the Curve value was 0.663 for predicting Metabolic syndrome in sarcoidosis patients. CONCLUSION: Neutrophil/lymphocyte ratio and controlling nutritional status are associated with the Metabolic syndrome+ in sarcoidosis patients. Thus, close monitoring of Neutrophil/lymphocyte ratio and controlling nutritional status increase in terms of Metabolic syndrome and immune malnutrition may be important in sarcoidosis patients.

Experimental realization of a one-atom laser in the regime of strong coupling.

Conventional lasers (from table-top systems to microscopic devices) typically operate in the so-called weak-coupling regime, involving large numbers of atoms and photons; individual quanta have a negligible impact on the system dynamics. However, this is no longer the case when the system approaches the regime of strong coupling for which the number of atoms and photons can become quite small. Indeed, the lasing properties of a single atom in a resonant cavity have been extensively investigated theoretically. Here we report the experimental realization of a one-atom laser operated in the regime of strong coupling. We exploit recent advances in cavity quantum electrodynamics that allow one atom to be isolated in an optical cavity in a regime for which one photon is sufficient to saturate the atomic transition. The observed characteristics of the atom-cavity system are qualitatively different from those of the familiar many-atom case. Specifically, our measurements of the intracavity photon number versus pump intensity indicate that there is no threshold for lasing, and we infer that the output flux from the cavity mode exceeds that from atomic fluorescence by more than tenfold. Observations of the second-order intensity correlation function demonstrate that our one-atom laser generates manifestly quantum (nonclassical) light, typified by photon anti-bunching and sub-poissonian photon statistics.

The action of simulated and true weightlessness on the digestive tract of rats.

Rats on board the Soviet Cosmos 936 satellite for l8 1/2 days showed a decreased glycoprotein secretion from the salivary mucous glands, stomach and intestine, and an increased leucine aminopeptidase and acid phosphatase content from the small intestine. Grimelius positive cells were activated. One group of rats were centrifuged at 1 g during the flight to simulate terrestrial gravity. Some investigations have suggested that under these conditions muscular and cardiac disorders diminished. In the digestive tract the benefits of centrifugation at 1 g are minimal and limited to a few glycoprotein components. The digestive changes are probably the expression of a stress response, unrelated to weightlessness. Similar changes, concomitant with a glycocorticoid hypersecretion, were found in rats after 15 days of hypokinesia on Earth. These digestive changes persisted even in adrenalectomized rats.

Digestive histochemical reactions in rats after space flight of different duration.

Different histochemical reactions were searched in the digestive tract of rats that flighted on Soviet biosatellites, 5, 7, 13, 14 and 18 1/2 days (2). Space flight decreased glycoprotein (GP) content of sublingual glands and of gastric and intestinal mucosa, and increased reactions for leucin-aminopeptidase (LAP) and acid phosphatase (ACP) of the small intestine. These responses were in relation with the duration of the flight. For searching some possible mechanism by which they occurred, same investigations were done in rats submitted at soil level to a contention hypokinesia (HK), for mimicking space flight. After HK, similar histochemical responses were founded as after the true flight. The evolution of histochemical responses paralleled the corticosterone hypersecretion, suggesting a causal correlation, but they were also the same in adrenalectomised rats. Effectory hormonal pathways are thus further to be searched, as well as a correlation with the intermediary metabolism, as a similar evolution was founded in pancreatic, insulin secreting, B cells.

Reversible state transfer between light and a single trapped atom.

We demonstrate the reversible mapping of a coherent state of light with a mean photon number (-)n approximately equal to 1.1 to and from the hyperfine states of an atom trapped within the mode of a high-finesse optical cavity. The coherence of the basic processes is verified by mapping the atomic state back onto a field state in a way that depends on the phase of the original coherent state. Our experiment represents an important step toward the realization of cavity QED-based quantum networks, wherein coherent transfer of quantum states enables the distribution of quantum information across the network.

Cooling to the ground state of axial motion for one atom strongly coupled to an optical cavity.

Localization to the ground state of axial motion is demonstrated for a single, trapped atom strongly coupled to the field of a high finesse optical resonator. The axial atomic motion is cooled by way of coherent Raman transitions on the red vibrational sideband. An efficient state detection scheme enabled by strong coupling in cavity QED is used to record the Raman spectrum, from which the state of atomic motion is inferred. We find that the lowest vibrational level of the axial potential with zero-point energy variant Planck's over 2 h omega a/2kB = 13 microK is occupied with probability P0 approximately 0.95.

Histochemistry of the gastrointestinal tract in pregnant rats subjected to cosmic flight and in their progeny (Cosmos 1514).

Investigations were carried out in the digestive tract of pregnant rats submitted to 5 days orbital flight, as well as in rats aged 30 and 100 days, to which the pregnant experimental rats had given birth. The flight produces, in pregnant rats, a mild reduction of the glycoproteins of the salivary glands, of the gastric mucosa and the goblet cells of the small intestine, as well as an augmented activity of some intestinal enzymes. The progeny born after flight presents at 30 days a mild decrease of the glycoproteins in the sublingual gland and stomach and a slight increase in the activity of some enzymes in the small intestine. In 100-day-old rats, the differences between control and experimental group are not significant.

Histochemical alterations in the digestive tract of rats after 13 days of flight in the "Cosmos 1887" biosatellite.

In rats recovered after 13 days of cosmic flight a diminution of acid and neutral glycoproteins was observed in the gastric mucosa and proximal segments of the small intestine: the decrease was less evident in the sublingual glands and colon. Leucine aminopeptidase and acid phosphatase in the small intestine were intensified. No significant changes were observed in the other enzymes investigated. Acid phosphatase showed a more intense activity in the endocrine pancreas B cells. The alterations observed after 13 days of flight in the "Cosmos 1887" biosatellite are significant but less marked than after 18 days of flight, and more accentuated than after 5-7 days of flight.

Modifications of the digestive tract in rats submitted to an orbital flight aboard the Soviet satellite Cosmos 1129.

Investigations carried out on the digestive tract of rats submitted to an 18 1/2-day orbital flight aboard the Soviet biosatellite Cosmos 1129 revealed that flight produces a reduction of the glycoproteins (GP) of the submaxillary glands, gastric mucosa and the goblet cells of the small and large intestine, the last being the most nonreactive, as well as an augmented staining for leucine-aminopeptidase (LAP) and acid phosphatase (AP). In lamina propria an accumulation of eosinophils was noticed. These changes were more intense than those produced in the groups of rats maintained "synchronous" under environmental conditions similar to flight. On the basis of previous data obtained by various authors and by ourselves on hypokinetic rats from the biosatellite Cosmos 936, it can be concluded that these reactions have a nonspecific, stress character. A stress of restraint applied daily for 2 1/2 hours during a period of 6 days to the animals immediately after landing produced modifications similar to those following flight but more intense, thus underlying the hypothesis of a stress reaction.

Histochemical changes in the digestive tract in irradiated rats.

Wistar rats (110-125 g) were irradiated with a single dose of 500 R. Histochemical studies were done concerning the glycoproteins (GP) of sublingual glands, gastric, small intestine and colon mucosa, and some intestinal enzymes: acid and alkaline phosphatase (ACP, ALP) leucineaminopeptidase (LAP), Mg-dependent ATP-ase, NADH-diaphorase, lactic dehydrogenase (LDH). After irradiation all these reactions were diminished, with a maximal effect between 3-5 days. This impairment is in accord with the maximal lethality in this interval after such a degree of irradiation that produced the gastrointestinal syndrome. Cocarboxylase, a radioprotector, improved these changes regarding the structures of the small intestine and also the GP of sublingual glands, stomach, small intestine and colon, demonstrating there its efficiency.

The digestive tract of rat after flight in the biosatellite Cosmos 1667.

From the histochemical investigation carried out on the digestive tract of rats after 7 days space flight in the soviet biosatellite Cosmos 1667 it resulted that neutral and acid glycoproteins diminished slightly in the sublingual gland, stomach, small intestine and the colon. Some intestinal enzymes augmented (leucineaminopeptidase, acid phosphatase, adenosinetriphosphatase and glucose-6-phosphatase). The changes observed after this flight were less marked than after an 18 day flight (in the Soviet biosatellite Cosmos 936 and 1129) and similar to those revealed after 7 days of hypokinesia. The glycoprotein changes were close to those observed after a 5-day flight (Cosmos 1514) but in which there were pregnant rats; after these last flights, the enzymes were not studied.

Digestive tract of rats after hypokinesia and hypergravitation.

We found in rats submitted to a 7 days interval of hypokinesia a decreased glycoprotein content in salivary mucous glands, gastric and intestinal mucosa, an increased glycoprotein content and an increased content of leucine-aminopeptidase, acid and alkaline phosphatase. Similar changes were found after a short interval of centrifugation (+6 Gz, 10 min). These nonspecific responses were more accentuated if the hypergravitation was performed after 7 days of hypokinesia. We reproduced this way this events that occurred in space flight and deacceleration before landing.

Digestive structural modifications in rats submitted to 15 days of hypokinetical conditions.

Restraining rats for 14 days in special cages in order to determine a hypokinetical state decreased mucopolysaccharide secretion in submaxillary glands and gastric mucosa. In the small intestine and in the colon, concomitantly with an enzymatic (leucine-aminopeptidase and acid phosphatase) hypersecretion as results from specific histochemical reactions. These modifications show maximum intensity at the end of the interval. The corticosterone plasmatic level determined in the same interval also increased, suggesting this way to a causal relation. The histomorphological changes presented delayed reaction. This material is in accord with our previous investigations as well as with some literature data.

The digestive tract after 7 days of restraining conditions in normal and adrenalectomized rats.

Hypokinesia produced specific reactions in tissues related to motion (bones, skeletal muscles and myocardium) and nonspecific in others, as that of the digestive tract after 7 days of hypokinesia. A decreased content of glycoproteins from mucous salivary glands, stomach, small intestine and colon, and an increased intestinal content of leucine-aminopeptidase and acid and alkaline phosphatase were found as a result of histochemical reactions. An important plasmatic corticosterone increase was also found. The same histochemical modifications appeared in adrenalectomized rats in which the plasma corticosterone was substantially diminished. Therefore these glycoproteins and enzymatic secretions are not dependent on the glucocorticoid response.

The influence of malathion on the brain serotonin and reproductive function in rats.

By researches carried out in adult female rats we followed the effect of chronic administration of malathion on the serotonin level from hypothalamus, rhynencephalon, mesencephalon and cerebral cortex and on the hypophysio-ovarian system. The obtained results showed that malathion produces: 1) the increase of cerebral serotonin level through the active phases of the gonadal cycle (proestrus + oestrus); 2) the increase of the percent incidence of the gonadal active phases; 3) the decrease of the LH synthesis through the oestral cycle; 4) the increase of the FSH release during the active phases and the decrease of the LH release in the inactive phases of the ovarian cycle. The data show that malathion influences the reproductive function both by its cellular toxic action and by affecting the encephalic regulatory serotoninergic, besides acetylcholinergic, mechanism of the reproductive functions.

Effect of simulated valvular stenoticity on predicted flow area for a bileaflet valve using the Gorlin equation.

The possibility that the discharge coefficient (Cd) for a mechanical heart valve (MHV) is affected by valvular stenosis is addressed. A 29 mm bileaflet (Si. Jude Medical) mitral valve is tested on a cardiovascular duplicator (CVD) in its normal state and under two degrees of simulated stenosis. Stenoticity is simulated by bracing the occluders such that full opening is impossible. The pressure drop through the valve is described by a two-term second-order polynomial in flow, from which it is shown that the Cd should be a nonlinear function of the flow rate through the valve. The average difference between measured and calculated areas decreased from 74%, when a constant value of 0.7 was used for the Cd, to 3.7%, when the Cd was a nonlinear function of the flow rate.

Effects of a seven-day hypokinesia on the digestive tract of nonpregnant and pregnant rats.

Hypokinesia (HK) produced by a 7-day contention of pregnant rats in small cages is followed by a discrete decrease of PAS reaction for glycoproteins in the submandibular and sublingual glands, in the mucosa of the stomach, duodenum, small intestine and colon, and also by a small but evident increase of that for leucineaminopeptidase and acid phosphatase in the duodenum and in the intestine. The moderation of these reactions may be explained by the small interval of contention, and not by pregnancy, because the changes are similar in male rats after the same interval. After a longer interval, these reactions change in the same manner but they are more evident, as results from our previous studies. They are not connected with a corticosterone hypersecretion (the principal glucocorticoid in rat) because adrenalectomy does not influence them as results from our previous research. HK increases the 4 and 5 isoenzymes of lactic dehydrogenase (LDH) in the stomach. In the small intestine appeared only the LDH 4 and 5 isoenzymes, HK increases LDH5 isoenzyme. Adrenalectomy increases all LDH isoenzymes of gastric mucosa, and in the small intestine all five fractions appeared, but with a slight activity of LDH 1 and 2. This relation between adrenal hormones and these isoenzymes must be further studied, especially after HK. After a 7-day HK, nonpregnant female rats present an augmented total gastric acid output (TAO), as previously found by us in males. After adrenalectomy this acid hypersecretion disappeared. Even smaller values for TAO were found. Pregnancy considerably increased TAO which may be due, as we have already found, to a blood pH decrease. After HK this hypersecretion decreased remaining nevertheless great. Progeni born of rats submitted to HK have, after 30 days of life, an augmented TAO. Parts of this research were carried out in order to reproduce by HK, at ground level, the 5-day orbital flight conditions of the soviet Cosmos 1514 biosatellite containing pregnant rats in which we studied some identical parameters.