Signatures of the Optical Stark Effect on Entangled Photon Pairs from Resonantly Pumped Quantum Dots.

Two-photon resonant excitation of the biexciton-exciton cascade in a quantum dot generates highly polarization-entangled photon pairs in a near-deterministic way. However, the ultimate level of achievable entanglement is still debated. Here, we observe the impact of the laser-induced ac-Stark effect on the quantum dot emission spectra and on entanglement. For increasing pulse-duration-to-lifetime ratios and pump powers, decreasing values of concurrence are recorded. Nonetheless, additional contributions are still required to fully account for the observed below-unity concurrence.

Entanglement Swapping with Photons Generated on Demand by a Quantum Dot.

Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve state-of-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.

An Acute Bout of Barefoot Running Alters Lower-limb Muscle Activation for Minimalist Shoe Users.

Despite the abundance of barefoot running-related research, there have been no electromyography studies evaluating the effects of this mode of exercise on habitual users of minimalist footwear. The present study investigated differences in muscle activation during acute bouts of barefoot and shod running, in minimalist shoe users. 8 male participants ran on a motorized treadmill for 10 min under both conditions, at 70% maximal aerobic speed. Electromyographic data were sampled from the biceps femoris, gluteus maximus, gastrocnemius medialis, tibialis anterior, and vastus lateralis during both swing and stance. Root-mean-square analysis of electromyographic data was conducted to compare muscle activation between conditions. During stance, barefoot running resulted in greater muscle activity in gastrocnemius medialis and gluteus maximus, and lower muscle activity in tibialis anterior. During swing, barefoot running resulted in increased muscle activity in vastus lateralis and gastrocnemius medialus. These results indicate that, for minimalist shoe users, an acute bout of barefoot running results in significantly different lower-limb muscle activity. Increased activation in the above muscles presents a possible mechanism for injury, which should be considered during exercise prescription.

Pacing strategies during repeated maximal voluntary contractions.

PURPOSE: Pacing strategies have been reported to occur during continuous cyclical exercises. However, currently no studies have examined if pacing takes place during repeated maximal voluntary muscle contractions (MVCs). Accordingly, the purpose of this study was to examine if informing subjects on the number of MVCs they would perform would affect force and root mean squared electromyography (EMG), during similar fatiguing protocols. METHODS: Thirty well-trained male subjects completed three fatiguing protocols in a randomized order. In the control condition participants were informed they would perform 12 MVCs, and then completed all 12. In the unknown condition they were not told how many MVCs they would perform, but were stopped after 12. Lastly, in the deception condition they were initially told they would perform only 6 MVCs, but after the 6 contractions they were asked to perform a few more repetitions and were stopped after 12. RESULTS: Compared to the unknown condition, subjects demonstrated greater forces (p < 0.05, ES = 0.35-1.14, 2-7.5%) and biceps EMG (p < 0.05, ES = 0.6, 6%) in the deception condition during the first six MVCs. Additionally, under all conditions subjects applied greater forces in the last repetition (#12) relative to the previous one (#11) (p < 0.06, ES = 0.36-0.5, 2.8-3.8%). CONCLUSIONS: The anticipation of performing a certain number of MVCs led the subjects to utilize different pacing strategies. The results also question the assumption that subjects followed the instruction to exert maximal effort during repeated MVCs.

Anthropometric characteristics account for time to exhaustion in cycling.

This study examined the relationship between the phenotypic and anthropometric characteristics and the cycling time to exhaustion (Tlim) at the maximal aerobic power output (Pmax). 12 (7 men, 5 women) physically-active participants performed a square-wave test at Pmax to determine the maximal time limit. Muscle histochemistry, enzymatic activities and buffer capacity were determined from a vastus lateralis muscle biopsy, lean body mass (LBM) by hydrostatic weighing, and total (TV) and lean (LV) volumes of the thigh by anthropometric measurements. The mean (±SD) Tlim was 235±84 s (score range: 108-425 s). No relationship was found between Tlim and any muscle phenotypes. However, we observed a strong, linear relationship between Tlim and LBM (r=0.84, P<0.05). Thigh TV and LV displayed weaker correlation coefficients with Tlim (r=0.66 and r=0.73, respectively; P<0.05). We further estimated the femur length and found this measure to correlate with Tlim (r=0.81, P<0.05). This study suggests that muscle phenotypes may not be representative of Tlim. Rather, anthropometric characteristics account for such performance by conferring a biomechanical advantage in cycling. We conclude that, in addition to metabolic factors, anthropometric characteristics with reasonable accuracy predict Tlim in cycling, and may account for the large inter-subject variability observed in previous studies.

PRO-FIT-CARE study: the feasibility assessment of a pilot online exercise intervention for persons living with obesity and female infertility.

Introduction: Moderate-to-high physical activity participation is associated with a reduced risk of infertility. Yet, exercise interventions that target cardiorespiratory fitness, independent of weight loss, are lacking in obesity and female fertility research. Purpose: The primary objective of the PRO-FIT-CARE (PROmoting FITness for CArdiometabolic & REproductive Health) study was to assess the feasibility of a moderate-to-high-intensity online exercise program for persons with obesity and female infertility. Methods: Feasibility, safety, acceptability, and efficacy were assessed by examining: (1) recruitment and consent rate, (2) study retention, (3) adverse events, (4) participant satisfaction, (5) adherence, and (6) cardiorespiratory fitness. Results: Eleven of thirty-two women contacted agreed to participate in the program (34.4% consent rate). Eight participants (72.7%) completed the study. One musculoskeletal injury was reported. There was a 30% adherence rate based on prescribed exercise intensity (60%-80% of heart rate maximum). One of eleven participants attended 80% of the exercise intervention. Based on a weekly satisfaction survey, the program had an overall high level of satisfaction. Compared to sex and age normative data, post-intervention, two of eight participants improved their cardiorespiratory fitness percentile rank. Conclusion: The study highlights challenges with adherence to an online exercise program. While the program was safe and participants reported high levels of program satisfaction, approaches to improve adherence must be incorporated.

Low expression of ANT1 confers oncogenic properties to rhabdomyosarcoma tumor cells by modulating metabolism and death pathways.

Rhabdomyosarcoma (RMS) is the most frequent form of pediatric soft-tissue sarcoma. It is divided into two main subtypes: ERMS (embryonal) and ARMS (alveolar). Current treatments are based on chemotherapy, surgery, and radiotherapy. The 5-year survival rate has plateaued at 70% since 2000, despite several clinical trials. RMS cells are thought to derive from the muscle lineage. During development, myogenesis includes the expansion of muscle precursors, the elimination of those in excess by cell death and the differentiation of the remaining ones into myofibers. The notion that these processes may be hijacked by tumor cells to sustain their oncogenic transformation has emerged, with RMS being considered as the dark side of myogenesis. Thus, dissecting myogenic developmental programs could improve our understanding of RMS molecular etiology. We focused herein on ANT1, which is involved in myogenesis and is responsible for genetic disorders associated with muscle degeneration. ANT1 is a mitochondrial protein, which has a dual functionality, as it is involved both in metabolism via the regulation of ATP/ADP release from mitochondria and in regulated cell death as part of the mitochondrial permeability transition pore. Bioinformatics analyses of transcriptomic datasets revealed that ANT1 is expressed at low levels in RMS. Using the CRISPR-Cas9 technology, we showed that reduced ANT1 expression confers selective advantages to RMS cells in terms of proliferation and resistance to stress-induced death. These effects arise notably from an abnormal metabolic switch induced by ANT1 downregulation. Restoration of ANT1 expression using a Tet-On system is sufficient to prime tumor cells to death and to increase their sensitivity to chemotherapy. Based on our results, modulation of ANT1 expression and/or activity appears as an appealing therapeutic approach in RMS management.

Effect of fluid ingestion on neuromuscular function during prolonged cycling exercise.

OBJECTIVES: To investigate the effects of fluid ingestion on neuromuscular function during prolonged cycling exercise. METHODS: Eight well trained subjects exercised for 180 minutes in a moderate environment at a workload requiring approximately 60% maximal oxygen uptake. Two conditions, fluid (F) and no fluid (NF) ingestion, were investigated. RESULTS: During maximal voluntary isometric contraction (MVC), prolonged cycling exercise reduced (p<0.05) the maximal force generating capacity of quadriceps muscles (after three hours of cycling) and root mean square (RMS) values (after two hours of cycling) with no difference between the two conditions despite greater body weight loss (p<0.05) in NF. The mean power frequency (MPF) for vastus lateralis muscle was reduced (p<0.05) and the rate of force development (RFD) was increased (p<0.05) only during NF. During cycling exercise, integrated electromyographic activity and perceived exertion were increased in both conditions (p<0.05) with no significant effect of fluid ingestion. CONCLUSIONS: The results suggest that fluid ingestion did not prevent the previously reported decrease in maximal force with exercise duration, but seems to have a positive effect on some indicators of neuromuscular fatigue such as mean power frequency and rate of force development during maximal voluntary contraction. Further investigations are needed to assess the effect of change in hydration on neural mechanisms linked to the development of muscular fatigue during prolonged exercise.

Significance of early intra-alveolar fibrotic lesions and integrin expression in lung biopsy specimens from patients with idiopathic pulmonary fibrosis.

To study the pulmonary structural remodeling in idiopathic pulmonary fibrosis (IPF), ultrastructural, immunohistochemical, and light microscopic morphometric observations were made on 11 pulmonary biopsy specimens from patients with IPF. The morphometric study was done using sequentially cut tissue sections stained for keratin-alcian blue periodic acid-Schiff (PAS), fibronectin, and type IV collagen-alcian blue PAS. Most of the early fibrotic lesions, which were alcian blue- and fibronectin-positive, were intra-alveolar in location. Intra-alveolar fibrosis is considered to be essential for the fusion of alveolar walls in IPF. A strong reaction for integrin alpha 5 beta 1 and vinculin was found in epithelial cells and mesenchymal cells in areas of intra-alveolar fibrosis. These findings show that these cells are active in adhesion to fibronectin in areas of early intra-alveolar fibrosis. Some of the epithelial cells, including cytoplasmic hyaline-laden cells, showed evidence of inadequate adhesion to the extracellular matrix, and this may constitute one of the mechanisms of progression of fibrosis in IPF.

Role of elastic fiber degradation in emphysema-like lesions of pulmonary lymphangiomyomatosis.

To study the pulmonary structural remodeling in pulmonary lymphangiomyomatosis, electron microscopy and light and electron microscopic immunohistochemical observations for elastin and alpha 1-antitrypsin were performed on five open lung biopsy samples. Lung specimens showed emphysema-like changes in areas of abnormally accumulated smooth muscle cells. In the alveolar walls having accumulated smooth muscle cells, elastic fibers were decreased in number, disrupted, granular, and occasionally accumulated. Ultrastructurally, elastic fibers in areas of smooth muscle cell accumulation showed poorly outlined amorphous components and a few microfibrils, and occasionally showed electron-dense granular deposits in and around the amorphous components. Spiraling collagen fibrils were frequently found associated with these abnormal elastic fibers. Immunohistochemistry for elastin showed even staining of amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. alpha 1-Antitrypsin was also detected evenly in amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. It is proposed that the emphysema-like lesions of lymphangiomyomatosis are mediated by the degradation of elastic fibers, and these degraded elastic fibers are related to an imbalance of the elastase/alpha 1-antitrypsin system similar to the probable pathogenesis of emphysema.

Pulmonary fibrosis following pneumonia due to acute Legionnaires' disease. Clinical, ultrastructural, and immunofluorescent study.

During a recent nosocomial outbreak, 20 critically ill patients with acute Legionnaires' disease were admitted to the intensive care unit of Hopital Bichat, Paris. Pulmonary specimens were obtained at surgery or immediately after death in 12 patients and were examined by light, immunofluorescent, and electron microscopy. Five of these 12 patients showed evidence of pulmonary fibrosis. In all of these five patients, infection with Legionella pneumophila was evidenced by bacteriologic methods, and other diseases known to cause fibrosis were excluded. The condition of four patients deteriorated rapidly with respiratory failure, and they died with pulmonary fibrosis. Only one patient finally recovered but was left with pulmonary sequelae. Two distinctive morphologic patterns were observed, one in which interstitial fibrosis was predominant and one in which intra-alveolar organization and fibrosis were also present. The alveolar epithelial lining and the basement membranes were disrupted in all patients, as evidenced by ultrastructural observations and by immunofluorescent studies showing gaps in the distribution of type 4 collagen and laminin. Types 1 and 3 collagen accumulated in areas corresponding to thickened interstitium and intra-alveolar fibrosis. Thus, some patients who survive the acute pneumonia of Legionnaires' disease may develop pulmonary fibrosis, and this process may lead to functional impairment or death despite prompt and appropriate treatment.

Smoking and interstitial lung disease. The effect of cigarette smoking on the incidence of pulmonary histiocytosis X and sarcoidosis.

Cigarette smoking produces marked alterations in the lung parenchyma and in the population of immune and inflammatory cells present in the lower respiratory tract. These cigarette-induced changes appear to influence the incidence of two different interstitial lung diseases, histiocytosis X and sarcoidosis. Smoking is a strong risk factor for the development of pulmonary histiocytosis X, since the incidence of smoking is very high among patients with histiocytosis X: 90% of the patients with histiocytosis X were smokers; 46% of the controls were smokers (p less than .001). In contrast, smoking appears to reduce the incidence of sarcoidosis: 31% of the patients with sarcoidosis were smokers (p less than .05 compared to controls). In an effort to understand how cigarette smoking influences the incidence of these two disorders, we compared the numbers and types of immune and inflammatory cells recovered by bronchoalveolar lavage from nonsmoking and smoking controls and patients with histiocytosis X and sarcoidosis. Although nonsmoking patients with histiocytosis X did not have a significant increase in the number of alveolar macrophages recovered by lavage (p greater than .2 compared to normals), smoking patients had an increase in the number of alveolar macrophages similar to that observed in the control population. In contrast, the number of macrophages recovered from patients with sarcoidosis who smoked was considerably less than that observed in normal smokers (p less than .05 comparing patients with sarcoidosis and controls who smoked 1-20 cigarettes/day). This difference in the intensity of the cigarette-induced macrophage alveolitis observed in the two patient groups may be important in explaining the opposite effects of cigarette smoking on the incidence of histiocytosis X and sarcoidosis.

Langerhans cell histiocytosis research. Past, present, and future.

This article reviews the various investigative events that led to the endorsement of the term Langerhans cell histiocytosis for the various clinicopathologic conditions previously called Hand-Schüller-Christian disease, Abt-Letterer-Siwe disease, eosinophilic granuloma of bone, and histiocytosis X. The different denominations reflect the changing conceptual approaches to the so-called reticuloendothelial system and the successive acquisition of new ultrastructural and immunocytochemical data.

Peroxidatic activity distinct from myeloperoxidase in human monocytes cultured in vitro and in alveolar macrophages.

Human monocytes develop a peroxidatic activity (PA) in rough endoplasmic reticulum (RER) after adherence or after culture in semi-solid medium. This enzyme activity disappears after three days of culture in the majority of macrophages derived from adult monocytes but persists for one week in macrophages derived from neonatal monocytes. The PA is due to an enzyme distinct from myeloperoxidase (MPO), since monocytes from a patient with MPO deficiency develop the same PA as that of normal monocytes after adherence. By its localization and other characteristics, PA of adherent monocytes resembles that of rodent macrophages. We therefore investigated whether human alveolar macrophages exhibit PA, using a sensitive cytochemical method which prevents inhibition by aldehyde in adherent monocytes. In various pathological cases, four types of macrophages could be identified: the majority were peroxidase-negative, a small percentage was of exudate type exhibiting a PA in granules as blood monocytes, while few macrophages were intermediate, possessing only PA in RER i.e. of type resident and a smaller proportion had PA in RER and in granules i.e. exudate-resident macrophages. These findings demonstrate that human macrophages and adherent monocytes may exhibit PA in RER as has been reported for rodent macrophages. The true nature and function of the enzyme responsible for this PA, which is distinct from MPO, remains unknown, but some arguments seem to suggest its role in prostaglandin synthesis.

Target speed alone influences the latency and temporal accuracy of interceptive action.

When intercepting a mobile object or an apparent movement, participants show a temporal bias. They are in advance when dealing with a slow-moving stimulus and late with a fast-moving one. We studied participants intercepting an apparent movement by sliding a disk on a table. Using a fast and a slow stimulus speed, we varied three factors: duration of presentation of the stimulus, distance covered by the stimulus, and speed context (constant or varied) of stimulus presentation. In addition to the temporal bias, spatial accuracy and kinematic measures were collected. The temporal bias created by speed was evident across all three factors. Speed, in addition to strongly determining the temporal bias, significantly affected the throwing strategy adopted by the participants, as revealed by latency, movement time, and disk trajectory duration.

[Histiocytosis]. / Les histiocytoses.

Current ideas about the histiocyte-macrophage system are briefly reviewed and the functions attributed to the system are defined. An anatomico-clinical classification of histiocytic diseases into four categories is suggested: - secondary of associated histiocytosis illustrating, in particular, macrophage function in immune response; - histiocytosis due to dystrophia or overload illustrating mainly phagocyte function and ability to store fats; - Langerhans histiocytosis characterized by the presence of numerous Langerhans cells. - Neoplastic histiocytosis, which is the only genuine malignant tumoral proliferation of the histiocyte-macrophage system.

[Pulmonary dendritic cells]. / Les cellules dendritiques pulmonaires.

The dendritic cells were initially described in lymphoid organs and have been recently shown in the normal human lung at the level of the bronchioles, preferentially in the peribronchiolar connective tissue and in the alveolar parenchyma. Langerhans cells, which constitute a sub-population amongst the dendritic cells are equally present, but virtually exclusively limited to the bronchiolar epithelium. The pulmonary Langerhans cells probably derive from dendritic cells as in the skin. The number and state of differentiation of pulmonary dendritic cells vary as a function of the epithelial microenvironment which seems necessary in the differentiation of dendritic cells into Langerhans cells. Langerhans cells are frequently seen in zones of alveolar hyperplasia and/or alveolar metaplasia induced by tobacco or by inflammatory lesions. Dendritic cells and Langerhans cells have a potent capacity for presenting an antigen to lymphocytes. Their presence in the normal lung and their differentiation in the course of certain pathological pulmonary processes strongly suggest that they have a significant role in the pulmonary immune response as well as in the pathogenesis of certain diseases.

[Exploratory bronchoalveolar lavage]. / Le lavage broncho-alvéolaire d'exploration.

Bronchoalveolar lavage is a simple technique, complementary to fiberoptic bronchoscopy. The material yielded comprises cells and supernatant, and both components may provide information about the distal lung structures. A few counter-indications should be respected. Normally, the cell differential comprises: 93 +/- 5% alveolar macrophages, 7 +/- 1% lymphocytes and about 1% neutrophils, eosinophils and basophils. Total cellularity and cell differentials are altered in many conditions, according to different patterns, which permits a classification. The increase in numbers may relate to macrophages (smokers, pneumoconiotic disorders...), to lymphocytes (sarcoidosis, hypersensitivity pneumonitis...) and to neutrophils and/or eosinophils (fibrotic disorders, chronic eosinophilic pneumonia, histiocytosis X...). In the last disease, the diagnosis may be established by detecting Langerhans cells. In other conditions, bronchoalveolar lavage mostly provides a trend to diagnosis. Usually well tolerated, bronchoalveolar lavage may usefully be repeated for monitoring patients with chronic interstitial lung disorders. It also gives an insight into the pathogenesis of many pulmonary pathological processes.

[Stewart-Treves pseudo-syndrome caused by cutaneo-lymphatic metastases of contralateral breast carcinoma]. / Pseudo-syndrome de Stewart-Treves par métastases cutanéo-lymphatiques d'un carcinome mammaire contro-latéral.

The pathogenesis of Stewart-Treves syndrome remains controversial: angiosarcoma or epithelial cell metastases from a mammary carcinoma? The case reported here, with clinical signs of Stewart-Treves syndrome on one side and mastectomy for carcinoma on the other side of the body, revives the debate. Case-history. The patient was an 89-year old woman whose left breast had been removed in June, 1981 for carcinoma with lymph node involvement. One year after the operation, multiple lymphadenopathy developed in her right armpit and subclavian region. In December, 1984, her right arm became swollen by lymphoedema, while Kaposi-like and nodular skin lesions appeared on her right upper chest and upper back and on her right shoulder and arm. Radiography of the chest showed right pleural effusion, bronchial lymph node enlargement and a reticulate image in the right lung. In spite of chemotherapy, the patient died in April, 1985. Pathology. Pathological examinations included standard histology (HPS, PAS and Gordon-Sweet staining), immunohistochemistry, using anti-factor VIII, anti-keratin KL1 and anti-EMA antisera, and electron microscopy. Results. Irrespective of the skin area biopsied, the histological images were always the same, showing carcinomatous lymphangitis with a varying degree of invasion of the surrounding dermis. Staining of the reticulum enhanced the vascular basal membranes but did not mark the intraluminal tumoral cell population. Post-mortem examination confirmed that the malignant lymphangitis extended to the lung tissue, the oesophageal wall and the adrenal glands, and that the axillary and subclavian lymph nodes were invaded by metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

[Lymphomatoid granulomatosis: cyclic nodular lymphomatoid panniculitis with immunologic deficiency]. / Hypodermite nodulaire lymphomatoide ascendante a évolution cyclique avec déficit immunitaire: granulomatose lymphomatoide

The case of a 66 years old woman having presented an unusual cyclic dermatosis of 11 months duration is reported. The cutaneous elements were successively located in a subcutaneous, dermal and epidermal situation, and presented a spontaneous healing with sometimes deep retractive residual scars after an ulceration or not. Pathologically, the lesions consisted in dense mononuclear infiltrates and vascular lesions. This disease was associated with an immuno-deficiency state characterized by extremely low levels of circulating IgM. This deficit was found to be persistant as it was still present two years later. However during this lapse of observation no cutaneous lesions recurred. The possible connexions of such a case with those of lymphomatous granulomatosis are discussed. In the absence of pulmonary lesion in the case reported here, no identification to the syndrome isolated by Liebow seems permitted. The authors offer a new denomination for this unusual entity.