From morphological heterogeneity at alveolar level to the overall mechanical lung behavior: an in vivo microscopic imaging study.

In six male anesthetized, tracheotomized, and mechanically ventilated rabbits, we imaged subpleural alveoli under microscopic view (60×) through a "pleural window" obtained by stripping the endothoracic fascia and leaving the parietal pleura intact. Three different imaging scale levels were identified for the analysis on increasing stepwise local distending pressure (P ld) up to 16.5 cmH2O: alveoli, alveolar cluster, and whole image field. Alveolar profiles were manually traced, clusters of alveoli of similar size were identified through a contiguity-constrained hierarchical agglomerative clustering analysis and alveolar surface density (ASD) was estimated as the percentage of air on the whole image field. Alveolar area distributions were remarkably right-skewed and showed an increase in median value with a large topology-independent heterogeneity on increasing P ld. Modeling of alveolar area distributions on increasing P ld led to hypothesize that absolute alveolar compliance (change in surface area over change in P ld) increases fairly linearly with increasing initial alveolar size, the corollary of this assumption being a constant specific compliance. Clusters were reciprocally interweaved due to their highly variable complex shapes. ASD was found to increase with a small coefficient of variation (CV <25\%) with increasing P ld. The CV of lung volume at each transpulmonary pressure was further decreased (about 6\%). The results of the study suggest that the considerable heterogeneity of alveolar size and of the corresponding alveolar mechanical behavior are homogenously distributed, resulting in a substantially homogenous mechanical behavior of lung units and whole organ

Spontaneous breathing pattern as respiratory functional outcome in children with spinal muscular atrophy (SMA)

Introduction: SMA is characterised by progressive motor and respiratory muscle weakness. We aimed to verify if in SMA children 1)each form is characterized by specific ventilatory and thoracoabdominal pattern(VTAp) during quiet breathing(QB); 2)VTAp is affected by salbutamol therapy, currently suggested as standard treatment, or by the natural history(NH) of SMA; 3)the severity of global motor impairment linearly correlates with VTAp. Materials and methods: VTAp was analysed on 32 SMA type I (SMA1, the most severe form), 51 type II (SMA2, the moderate), 8 type III (SMA3, the mildest) and 20 healthy (HC) using opto-electronic plethysmography. Spirometry, cough and motor function were measured in a subgroup of patients. Results: In SMA1, a normal ventilation is obtained in supine position by rapid and shallow breathing with paradoxical ribcage motion. In SMA2, ventilation is within a normal range in seated position due to an increased respiratory rate(p0.05) while tachypnea occurred in type I NH. A linear correlation(p<0.001) was found between motor function scales and VTAp. Conclusion: A negative or reduced %ΔVRC,P, indicative of ribcage muscle weakness, is a distinctive feature of SMA1 and SMA2 since infancy. Its quantitative assessment represents a non-invasive, non-volitional index that can be obtained in all children, even uncollaborative, and provides useful information on the action of ribcage muscles that are known to be affected by the disease. Low values of motor function scales indicate impairment of motor but also of respiratory function

Efficacy of lung volume optimization maneuver monitored by optoelectronic pletismography in the management of congenital diaphragmatic hernia

Newborns affected by congenital diaphragmatic hernia (CDH) need cardio-respiratory stabilization before undergoing surgical repair. Open lung strategy is a well-established approach to optimize lung volume in preterm infants with Respiratory Distress Syndrome (RDS), using both High Frequency Oscillatory Ventilation (HFOV) and Conventional Mechanical Ventilation (CMV). We report a case of left CDH with severe lung hypoplasia, managed applying open lung strategy in HFOV (pre-surgery period) and in Assist-Control with Volume Guarantee (post-surgery period), guided by SpO2changes, TcPO2and TcPCO2monitoring. Opto-electronic plethysmography was used to measure end-expiratory chest wall volume changes (ΔEEcw) related to lung volume variations occurring during pressure changes. OEP confirmed the efficacy of using SpO2and transcutaneous gas monitoring during this recruitment maneuver

ACUTE EFFECTS OF VOLUME-ORIENTED INCENTIVE SPIROMETRY ON CHEST WALL VOLUMES IN PATIENTS AFTER STROKE.

The aim of the present study was to assess how volume-oriented incentive spirometry (IS) applied to patients after stroke modify total and compartmental chest wall volume variations, including right and left hemithorax compared to controls.20 post-stroke patients (stroke group, SG) and 20 age-matched healthy subjects (control group, CG) were studied by optoelectronic plethysmography during spontaneous quiet breathing (QB), IS and in the recovery period after IS.IS determined an increase of chest wall volume and its rib cage and abdominal compartments in both groups (p = 0.0008) and between the three instances (p < 0.0001). Compared to healthy control subjects, tidal volume of patients with stroke was 24.7\%, 18\% and 14.7\% lower during QB, , IS and post-IS, respectively. In all the three conditions the contribution of the abdominal compartment to tidal volume was greater in the stroke patients (54.1, 43.2 and 48.9\%) than controls (43.7, 40.8 and 46.1\%, p = .039). In the vast majority of patients 13/20 and 18/20 during QB and IS, respectively), abdominal expansion led rib cage expansion during inspiration. A greater asymmetry between the right and left hemithoracic expansion occurred in stroke patients compared to controls but it decreased during IS (62.5\% (p = 0.0023) QB; 19.7\% IS; and 67.6\% (p = 0.135) post-IS.IS promotes an increased expansion in all compartments of the chest wall and reduces the asymmetric expansion between right and left pulmonary rib cage and therefore it should be considered as a tool for rehabilitation

ESPRESSO: The next European exoplanet hunter

The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined-Coud\'e Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coud\'e trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm/s level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year.Comment: 12 pages, figures included, accepted for publication in Astron. Nach

SOXS: a wide band spectrograph to follow up transients

SOXS (Son Of X-Shooter) will be a spectrograph for the ESO NTT telescope capable to cover the optical and NIR bands, based on the heritage of the X-Shooter at the ESO-VLT. SOXS will be built and run by an international consortium, carrying out rapid and longer term Target of Opportunity requests on a variety of astronomical objects. SOXS will observe all kind of transient and variable sources from different surveys. These will be a mixture of fast alerts (e.g. gamma-ray bursts, gravitational waves, neutrino events), mid-term alerts (e.g. supernovae, X-ray transients), fixed time events (e.g. close-by passage of minor bodies). While the focus is on transients and variables, still there is a wide range of other astrophysical targets and science topics that will benefit from SOXS. The design foresees a spectrograph with a Resolution-Slit product ~ 4500, capable of simultaneously observing over the entire band the complete spectral range from the U- to the H-band. The limiting magnitude of R~20 (1 hr at S/N~10) is suited to study transients identified from on-going imaging surveys. Light imaging capabilities in the optical band (grizy) are also envisaged to allow for multi-band photometry of the faintest transients. This paper outlines the status of the project, now in Final Design Phase.Comment: 12 pages, 14 figures, to be published in SPIE Proceedings 1070

Design and Validation of a Wearable System for Enhanced Monitoring of Lower Limb Lymphedema

Lymphedema, characterized by limb swelling, is typically treated with Complex Decongestive Therapy (CDT), which includes physical exercise. This study seeks to design and validate a wearable device aimed at enhancing CDT by monitoring patient adherence to prescribed exercises and tracking changes in the range of motion of the affected limbs. A wearable device, constituted by two boards with 2 IMUs, connected by a flexible flat cable, was designed and developed for placement across targeted joints. It communicates wirelessly with PCs, where raw data from IMUs are collected. Through the application of the Madgwick filter, orientation of the units is obtained and finally joints angles are computed. The device was validated through bench testing using an orthopedic goniometer and field testing with an optoelectronic system. The in vivo validation involved 18 volunteers, including 10 healthy individuals and 8 individuals with lymphedema, who performed flexion-extension movements and walked on a treadmill (at speeds of 3 km/h and 5 km/h). Bench testing demonstrated strong correlation and agreement (r2=0.999, mean percentage error = -0.51°, standard deviation = 2.00°). Once worn by the participants, the device enabled the measurement of joint angles during flexion-extension exercises (r2=0.852, mean percentage error = 1.44°, standard deviation = 11.7°) and the extraction of step counting, step time and toe off during walk at different speeds. The developed wearable device exhibited robust performance in both bench and field testing. This device, designed specifically for lymphedema patients, offers valuable insights into limb function and exercise adherence, potentially improving personalized treatment strategies

A data-driven model to estimate breathing-induced intra-trunk blood shifts during exercise.

The pressure swings generated by the respiratory muscles induce blood shifts (Vbs) between the trunk and the extremities. Vbs varies with swing amplitude and breathing pattern and can reach sizable volumes. Although Vbs was successfully explored using double-body plethysmography, the extent of intra-trunk blood shifting (between abdomen and thorax, Vbs &lt;sub&gt;IT&lt;/sub&gt; ) remains to be quantified. We here present an electrical model of the cardiovascular system that allows to derive quantitative estimates of breath-by-breath Vbs &lt;sub&gt;IT&lt;/sub&gt; . We first validated the model with experimental data collected from healthy participants performing exercise with various breathing patterns, including spontaneous (CTRL), abdominal (AB), and rib cage breathing (RC), and with external expiratory flow limitation (EFLe). We then fed the model with other experimental data to derive Vbs &lt;sub&gt;IT&lt;/sub&gt; in a proof-of-concept fashion. Breath-by-breath fluctuations in Vbs derived from the model matched experimental data. Computations of Vbs &lt;sub&gt;IT&lt;/sub&gt; were in line with expectations, showing small fluctuations with spontaneous breathing and substantial increases during AB, RC, and EFLe. Intra-breath Vbs &lt;sub&gt;IT&lt;/sub&gt; showed a close relationship with intra-breath transdiaphragmatic pressure during inspiration in all conditions and during expiration in AB and RC, reflecting the net effect of hydraulic pressure fluctuations on blood displacement between the two compartments. This model may benefit further work investigating (patho)physiological mechanisms of various conditions affecting cardiorespiratory function, both at rest and during exercise.NEW &amp; NOTEWORTHY This study presents an electrical model of the cardiovascular system, capable of estimating breath-by-breath intra-trunk blood shifting (Vbs &lt;sub&gt;IT&lt;/sub&gt; ) between the abdomen and thorax. The model was validated using data from healthy participants performing various breathing patterns during exercise. It allowed quantifying Vbs &lt;sub&gt;IT&lt;/sub&gt; fluctuations, with significant increases during abdominal and rib cage breathing and expiratory flow limitation. This model offers a valuable tool for exploring cardiorespiratory function in health and disease, including COPD and heart failure

Structural and functional diversity of ferredoxin-NADP+ reductases

Although all ferredoxin-NADP+ reductases (FNRs) catalyze the same reaction, i.e. the transfer of reducing equivalents between NADP(H) and ferredoxin, they belong to two unrelated families of proteins: the plant-type and the glutathione reductase-type of FNRs. Aim of this review is to provide a general classification scheme for these enzymes, to be used as a framework for the comparison of their properties. Furthermore, we report on some recent findings, which significantly increased the understanding of the structure–function relationships of FNRs, i.e. the ability of adrenodoxin reductase and its homologs to catalyze the oxidation of NADP+ to its 4-oxo derivative, and the properties of plant-type FNRs from non-photosynthetic organisms. Plant-type FNRs from bacteria and Apicomplexan parasites provide examples of novel ways of FAD- and NADP(H)-binding. The recent characterization of an FNR from Plasmodium falciparum brings these enzymes into the field of drug design