Search

Monitoring chemical and physical properties of seawater is important to assess the status and predict future changes of marine environment. Among possible parameters, pH and temperature are frequently measured since they directly affect chemical and biological systems. Seawater assessment, conventionally performed in situ, is labour intensive and time consuming, but now remote sensor networks promise to become a viable tool to obtain spatial and temporal information over a wide range. Here we describe the development and validation of an autonomous system for the remote monitoring of pH and temperature in seawater. The device consists of a graphene-based pH sensor, a thermistor, an electronic readout, a smartphone and a power unit. After deployment in a marine testing site at the Livorno harbour in Italy, the system published on the web pH and temperature data for more than a week, whose accuracy was confirmed by comparison with a reference system.

Originally studied for their suitability to store information compactly, memristive networks are now being analysed as implementations of neuromorphic circuits. An extremely high number of elements is thus mandatory. To surpass the limited achievable connectivity - due to the featuring size - exploiting self-assemblies has been proposed as an alternative, in turn posing more challenges. In an attempt for offering insight on what to expect when characterizing the collective electrical response of switching assemblies, in this work, networks of memristive elements are simulated. Collective electrical behaviour and maps of resistance states are characterized upon different electrical stimuli. By comparing the response of homogeneous and heterogeneous networks, we delineate differences that might be experimentally observed when the number of memristive units is scaled up and disorder arises as an inevitable feature., Comment: Supplementary information comprises animated sequences of resistive maps corresponding to the internal state of each unit within the array both for the cycling experiment (Fig. 2 of the main text) and the sensitization one (Fig. 3 of the main) and is available upon request

International audience; This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world

Olfactory sense plays a fundamental role in human behaviour such as emotion regulation, memory formation, risk evaluation, and food appreciation. However, the effects of hedonic olfactory stimuli on autonomic nervous system response are still unclear. In this study we investigate heartbeat complexity in a group of 32 healthy subjects, after the elicitation with three odorants commonly considered to be pleasant, neutral, and unpleasant. Results show significant differences in complexity of cardiovascular system dynamics when subjects smell pleasant and unpleasant odors (p-value< 0.05).

Quality and safety of the cold chain undergo strict international regulations that identify storage and shipping temperatures. In fact, the improper handling and transportation of temperature-sensitive products such as food and pharmaceuticals may have harmful effects on human health and a negative economic impact. A passive RFID tag modified with a copper-doped ionic liquid was used to detect the crossing of a temperature threshold (8 °C) during the shipping of medical products. The tag was insensitive to humidity variations and irreversibly changed its status once temperature exceeded the ionic liquid melting point, which can be tuned by changing the concentration of dopant.

The relevance of pH assessment in clinical analysis, environmental and industrial control, has raised the demand for the development of portable, low cost and easy-to-use monitoring systems. This paper proposes a pH sensor printed on a paper support passivated with a solid-ink coating. The sensor exploits the pH sensitivity of a reduced graphene oxide functionalized with 3-(4-aminophenil)propionic acid. The sensor responded in the pH range [4], [10] and had a sensitivity of 46 mV/pH. Tests on human plasma and seawater proved this pH sensor to have similar performances than those of a commercial pH-meter with an uncertainty of 0.1 and 0.2 pH unit in plasma and seawater, respectively.

Exhaled air and breath condensate contain a large number of health biomarkers, such as volatile and semi-volatile organic compounds, proteins and lipids. Nowadays, the collection of breath samples is carried out by commercial or lab-made sampling systems that collect only one type of sample (e.g. gaseous or condensate phase), thus limiting the diagnostic capability of breath tests. This work presents a portable prototype optimized for the simultaneous collection of gaseous exhaled breath and exhaled breath condensate within five minutes. The system is fully portable and has a total weight of about 1 Kg. An illustrative determination of ethanol, isoprene, acetone, isopropyl alcohol, 1-propanol, 2-butanone, 2-pentanone, toluene and xylenes in breath, and cortisol and 8-iso-prostaglandin F 2α in breath condensate is discussed.

Acetylcholine is a neurotransmitter and a neuromodulator found in the autonomic, peripheral and central nervous systems. Diazinon is a pesticide with toxic effects on humans, such as the inhibition of acetylcholine. In this paper, a biosensor is proposed for the detection of acetylcholine (range 70 - 1000 μM) and diazinon (range 0.3 - 20000 ppb). This biosensor combines a pH-sensitive layer of reduced graphene oxide functionalized with 4-aminobenzoic acid and acetylcholinesterase. This enzyme was immobilized on reduced graphene oxide and it catalyzed the conversion of acetylcholine into choline and acetic acid, locally decreasing the pH value and triggering the sensor response. The limit of detection for the acetylcholine and diazinon were 70 μM and 0.3 ppb, respectively.

A D-optimal design was used to identify and model variables that affect the transit time of wound exudate through an illustrative dressing used for negative pressure wound therapy. Many authors have addressed the clinical benefits of negative pressure wound therapy, but limited information is available on how to assess performances of dressings. In this paper, the transit time of wound exudate through a dressing was chosen as a model parameter to show how experimental design (DOE) can be used for this purpose. Results demonstrated that rate of exudate production, temperature and dressing thickness were the variables with the largest impact on transit time. The DOE approach could be used to model other dressing properties, like for example capability of absorbing excess exudate or breathability.

In this paper a CMOS reading circuit for memristor-based RRAM (Resistive Random Access Memory) cell is described. Simulations for one cell, 4 by 4 nMOS-accessed-array and extension to N by N nMOS-accessed-array are presented. The proposed circuit is based on CMOS inverters, which result in a simple low area architecture and in a non-destructive operation. Resistive switching memristor is used as reading reference. Simulations were performed in $0.5\ \mu \text{m}$ and 180 nm CMOS technology and using memristor model available in bibliography.

A reliable method for the determination of carbonyl compounds in exhaled breath based on on-sorbent derivatization coupled with thermal desorption and gas chromatography-tandem mass spectrometry is described. The analytical performances were optimized for a mixture of C2-C9 aldehydes and C3-C9 ketones, particularly interesting for clinical applications, by using an internal standard and applying a 2(3) full factorial design. A volume of sample (250 ml) was loaded at 50 ml min(-1) into a Tenax GR sorbent tube containing 130 nmol of O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. All compounds showed a limit of detection lower than 200 pptv. The yield of the derivatization procedure was normalized by adding to the sample a known amount of D-6-acetone as an internal standard. This allowed halving the relative standard deviation to 10% and 15% for the mono-and di-carbonyl compounds, respectively, thus improving reliability. The optimized method was applied to the determination of carbonyl compounds in 12 breath samples collected from four patients suffering from heart failure during hospitalization.

Summary Objectives We developed a wearable sensor for the real time measurement of sweat rate in localized areas of the human body. This sensor represents the first step in the development of a wearable sensor network capable to estimate the global sweat rate via an ad hoc algorithm. Such device would be used to monitor athletes’ hydration status during training and improve their performances. Equipment and methods For this study, we tested our sensor on thirteen football players during a cycling test on a cycle ergometer. The sweat rate sensor was compared to a medical device that, although measuring a different physiological process, provides discrete data based on the same working principle, i.e. the diffusion of the water vapour emitted from the skin. Results Our sensor has a working range up to 400 g/m2·h. The statistical analysis and the Bland-Altman plot proved that our sensor is comparable to the medical device used as gold standard. At low sweat rate, the bias is 3.4 g/m2·h with a standard deviation of 7.6 g/m2·h. At maximum sweat rates, the bias is 2.3 g/m2·h with a standard deviation 6.9 g/m2·h. The P-values for the Bland-Altman plots at low and maximum sweat rate (0.1331 and 0.2477 obtained by Kolmogorov-Smirnov test, respectively) allow the hypothesis that there is a significant difference between our sweat rate sensor and the medical device to be rejected. Conclusion We presented a prototype of a wearable sweat rate sensor for localized measurements. The trials on thirteen athletes proved that the performance of our sensor is comparable to that of a commercial medical device. This sweat rate sensor can provide valuable information on athletes’ hydration status.

The aim of this study was to investigate the relationship between warfarin dosage, international normalized ratio, plasma and oral fluid concentrations of warfarin, and its metabolites, namely RR/SS- and RS/SR-warfarin alcohols. Nine patients on long-term warfarin therapy (4 with stable and 5 with unstable international normalized ratio values) were longitudinally monitored for over two months by recording warfarin dosage and measuring international normalized ratio, warfarin and warfarin alcohols concentrations in oral fluid and in plasma. At equivalent dose (20–30 mg week− 1), the international normalized ratio was in the range 2.0–2.5 and 1.5–3.1 for stable and unstable patients, respectively. Moreover, stable patients showed nearly double total and unbound plasma warfarin concentration, and nearly triple oral fluid warfarin concentrations compared to unstable patients. Correlations between warfarin dosage and total plasma concentration of warfarin (r = 0.65, p < 0.01) or RS/SR-warfarin alcohols (r = 0.66, p < 0.01), as well as between stimulated oral fluid and total plasma concentrations of warfarin (r = 0.72, p < 0.01) and RS/SR-warfarin alcohols (r = 0.95, p < 0.01) suggest that the relative changes of the oral fluid concentrations of these species may provide clinically useful information for monitoring individual patients. Follow-up data revealed that even in the absence of changes of warfarin dose, the oscillations of plasma and oral fluid of WAR and RS/SR-warfarin alcohols parallel oscillations of international normalized ratio. Due to the long delay of its biological action, monitoring the plasma concentration of warfarin might help to predict variations of international normalized ratio and prevent the risk of thrombotic or haemorrhagic events. The information collected suggests that non-invasive monitoring of warfarin in oral fluid might represent a suitable tool for this purpose

The study was aimed to investigate the response in psoriatic patients of the two primary neuroendocrine systems, namely the Autonomic Nervous System and the Hypothalamic-Pituitary-Adrenal (HPA) axis, whose main biomarkers of activation are salivary α-amylase and cortisol, respectively. Reliable analytical procedures for the determination of salivary α-amylase enzymatic activity and cortisol concentration in oral fluid were developed. The non-invasive sampling that does not require trained personnel represents one of the main advantages of oral fluid analysis compared to the analysis of blood and its derivatives (e.g. plasma). Since oral fluid offers the advantage of a simple and stress free sample collection, it is particularly useful to quantify stress related molecules. α-amylase activity was measured by a spectrometric method, whereas salivary cortisol by Reversed-Phase High-Performance Liquid Chromatography coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry. The effect of salivary pH and flow rate on salivary α-amylase activity and cortisol were also investigated. Finally, both methods were preliminary tested on oral fluid samples of psoriatic volunteers underwent to a psychosocial stress task (the Trier Social Stress Test), as a first step of a more comprehensive study on the responsiveness of psoriatic subjects to stressors.

pH measuring and monitoring is fundamental to understand or control many chemical processes in biological, industrial or environmental fields. Potentiometric measurements by a glass electrode is the most common method to measure pH, although single-use paper strips are also widely used. Other methods include the use of hydrogen, quinhydron, and antimony electrodes, the imaging using pH-sensitive indicators such as dyes or proteins, and the use of ion-selective field effect transistor (ISFET). Due to the chemical reactivity of both sides of its 2D structure, nanometer thickness, high electron mobility, high reactivity to oxygen groups such as OH − , and ultrafast optical response, graphene has the potential to be used for the fabrication of nanoscale, wide-range, high-sensitivity and flexible pH sensors. This review describes how graphene, graphene oxide and reduced graphene oxide can be used to fabricate pH-sensitive devices (e.g. solution-gated FETs, solid-gate FETs, electrochemical sensors, and pH-sensitive quantum dots). The various configurations are reported along with the advantages and current limitations.

This study was aimed at evaluating the influence of sampling procedure on the determination of uric acid and lactate in oral fluid. Samples of non-stimulated and stimulated oral fluid were collected from 22 healthy volunteers. Different frequencies of stimulation were obtained by moving a polyester swab within the mouth at 50, 100 and 150 min − 1 . Three oral fluid samples were consecutively collected from a subgroup of 5 volunteers at a constant stimulation (70 min − 1 ) and at a self-selected pace to evaluate reproducibility. The urate concentration in oral fluid decreased with the increase of the stimulation and oral fluid flow rate (r = − 0.98, p = 0.01). Also, the lactate concentration was much (p = 0.03, two tailed) lower in samples collected under a mild stimulation (50 min − 1 ) than in samples collected without stimulation. Nevertheless, it progressively increased at higher stimulations (100 and 150 min − 1 ). A transfer process mediated by membrane carriers (i.e. urate transporter and organic anion transporters) was hypothesized to explain these results. Finally, a reduced variability (relative standard deviation below 10%) of the urate concentration was obtained when oral fluid was sampled at constant stimulation (70 min − 1 ), but it increased remarkably (20–50%) in case of sampling at self-selected pace. Nevertheless, expressing the salivary excretion of urate as a function of time (μg min − 1 ), the variability of sampling procedure at self-selected pace was lower than 15%.

Biliary complications remain a major challenge for long-term success after LT, as it is, as a rule, the most common technical - early and late - complication that occurs, and because these complications contribute to a significant number of late graft losses and retransplantations. In the pediatric age group, both biliary atresia, as the patient's condition, and the use of a left liver graft, obtained by a liver division technique, make it necessary for the use of a Roux-en-Y jejunal loop for the biliary reconstruction in the majority of cases. A slight modification of the technique is presented, consisting of a straight positioning along the cut surface (rather than the conventional position that results in a harpoon shape). A favorable outcome in terms of a technical complication and graft survival was observed. This way of doing this is an interesting variation and adds to the surgical armamentarium.

Acute and chronic wounds have a tremendous impact on patients’ life conditions. As wound healing involves a huge number of biochemical processes, biomedical sensors play a major role for wound monitoring and early detection of infections. This paper describes and discusses the sensors currently under research that can provide invaluable information on the different phases of wound healing. These sensors can allow wound healing to be continuously monitored, thus opening the path for personalized therapies and better patients’ quality of life.

Objective: The wound bed score is a validated tool to monitor wound healing in chronic wounds, and depends on visual examination by trained personnel. This study describes the feasibility of adding some biochemical and immunohistochemical parameters to increase the objectivity and specificity of the wound bed score Method: Patients with chronic wounds on the lower leg with different durations were enrolled to assess the correlation between the wound bed score and specific wound-related biomarkers, namely MMP-9, MMP-2, NGAL, albumin, integrin α2/β1, and other histochemical (CD68, PK1, CD32, fractalkine, periostin) and immunocytochemical markers from biopsies and smears taken from wound edges and bed. Results: The study examined samples from 10 patients. Patients with an unfavourable wound bed score had a low expression of periostin and fractalkine in the wound bed tissue. CD68 PK1 showed a low or negative expression in the majority of the samples. Patients negative for CD68 PK1 were also negative for CD32. Principal component analysis revealed that the albumin level and the amount of proteins were associated with a high wound bed score. Two different subsets of patients could be discriminated either by integrin α2/β1 and albumin percentages or the MMP-9 and MMP-2 activities Conclusion: These preliminary results pave the way towards an improved wound status diagnosis and an advanced quality of wound care and management. These findings need confirming with a large number of patients and at different time points.

A method for the simultaneous determination of warfarin and its active metabolites (warfarin alcohols) in dried blood spots samples was developed and validated. The procedure consisted of the collection of blood sample spots on Whatman 903 filter paper and the liquid extraction of the analytes by a 3:1 v/v methanol/acetonitrile mixture from 6 mm diameter disks punched out from dried blood spots. Extracted samples were analyzed by ultra-high performance liquid chromatography coupled to electrospray positive ionization and tandem mass spectrometry. Chromatographic separation was carried out in isocratic condition at 25 °C on a Poroshell 120 EC-C18 reversed phase column with a mobile phase consisting of 65% water containing 0.1% (v/v) formic acid and 35% acetonitrile containing 0.1% (v/v) formic acid at a flow rate of 0.5 mL min − 1 . The method did not show any detectable interference or matrix effect. The limits of detection were 0.007, 0.006 and 0.004 ng/mL for RR/SS-warfarin alcohols, RS/SR-warfarin alcohols and warfarin, respectively. Warfarin and warfarin alcohols recovery from dried blood spots sample was almost quantitative (range 96–103%). The intra- and inter-day precision (expressed as relative standard deviation) was always below 10%. Time stability studies highlighted that the concentrations of warfarin and both diastereoisomers of warfarin alcohols in a pooled blood sample were stable for at least 1 month at − 20 °C and after 4 cycles of thaw–freeze. Moreover, warfarin, RR/SS- and RS/SR-warfarin alcohols concentrations in the dried blood spots were stable for at least 7 days at 25 °C. Hematocrit value had a minor influence on the analytical result compared to blood drop volume. The method was successfully applied to the analysis of 15 blood samples from patients undergoing warfarin therapy and demonstrated its suitability as an alternative for warfarin and warfarin alcohols measurement in plasma. Good correlations between concentrations in plasma and dried blood spots were demonstrated for all three analytes, with correlation coefficients r ≥ 0.95. Warfarin concentration in dried blood spot correlated well with warfarin dosage (r = 0.70, p These preliminary results highlighted that the developed method can provide useful information for the therapeutic drug monitoring of warfarin and its active metabolites, although further studies in a larger clinical trial are needed.

Point-of-care applications and patients' real-time monitoring outside a clinical setting would require disposable and durable sensors to provide better therapies and quality of life for patients. This paper describes the fabrication and performances of a temperature and a pH sensor on a biocompatible and wearable board for healthcare applications. The temperature sensor was based on a reduced graphene oxide (rGO) layer that changed its electrical resistivity with the temperature. When tested in a human serum sample between 25 and 43°C, the sensor had a sensitivity of 110±10Ω/°C and an error of 0.4±0.1°C compared with the reference value set in a thermostatic bath. The pH sensor, based on a graphene oxide (GO) sensitive layer, had a sensitivity of 40±4mV/pH in the pH range between 4 and 10. Five sensor prototypes were tested in a human serum sample over one week and the maximum deviation of the average response from reference values obtained by a glass electrode was 0.2pH units. For biological applications, the temperature and pH sensors were successfully tested for in vitro cytotoxicity with human fibroblast cells (MRC-5) over 24h.

This work presents a computerized system to monitor mouth pressure, tidal volume, exhaled airflow, respiration rate and end-tidal partial pressure of CO 2 during breath collection. The system was used to investigate the effect of different respiratory rates on the volatile organic compounds (VOCs) concentrations in exhaled breath. For this purpose, VOCs with well-defined biochemical pathways and different chemical and physical properties were selected as biomarkers related to metabolism (acetone and isopropyl alcohol), cholesterol synthesis (isoprene) and intestinal microflora activity (ethanol). Mixed breath was collected from a nominally healthy volunteer in resting conditions by filling a Nalophan bag. The subject followed a regimented breathing pattern at different respiratory rates (10, 30 and 50 breaths per minute). Results highlight that ventilation pattern strongly influences the concentration of the selected compounds. The proposed system allows exhaled breath to be collected also in patients showing dyspnea such as in case of chronic heart failure, asthma and pulmonary diseases.

Nalophan, Tedlar and Cali-5-Bond polymeric bags were compared to determine the most suitable type for breath sampling and storage when volatile organic compounds are to be determined. Analyses were performed by thermal desorption gas chromatography mass spectrometry. For each bag, the release of contaminants and the chemical stability of a gaseous standard mixture containing eighteen organic compounds, as well as the CO2 partial pressure were assessed. The selected compounds were representative of breath constituents and belonged to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics, sulfurs and esters). In the case of Nalophan, the influence of the surface-to-volume ratio, related to the bag's filling degree, on the chemical stability was also evaluated. Nalophan bags were found to be the most suitable in terms of contaminants released during storage (only 2-methyl-1,3-dioxalane), good sample stability (up to 24 h for both dry and humid samples), and very limited costs (about 1 € for a 20 liter bag). The (film) surface-to-(sample) volume ratio was found to be an important factor affecting the stability of selected compounds, and therefore we recommended to fill the bag completely.

Textile-based sensors offer an unobtrusive method of continually monitoring physiological parameters during daily activities. Chemical analysis of body fluids, noninvasively, is a novel and exciting area of personalized wearable healthcare systems. BIOTEX was an EU-funded project that aimed to develop textile sensors to measure physiological parameters and the chemical composition of body fluids, with a particular interest in sweat. A wearable sensing system has been developed that integrates a textile-based fluid handling system for sample collection and transport with a number of sensors including sodium, conductivity, and pH sensors. Sensors for sweat rate, ECG, respiration, and blood oxygenation were also developed. For the first time, it has been possible to monitor a number of physiological parameters together with sweat composition in real time. This has been carried out via a network of wearable sensors distributed around the body of a subject user. This has huge implications for the field of sports and human performance and opens a whole new field of research in the clinical setting.

The analytical performances of needle trap micro-extraction (NTME) coupled with gas chromatography-tandem mass spectrometry were evaluated by analyzing a mixture of twenty-two representative breath volatile organic compounds (VOCs) belonging to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics and sulfurs). NTME is an emerging technique that guarantees detection limits in the pptv range by pre-concentrating low volumes of sample, and it is particularly suitable for breath analysis. For most VOCs, detection limits between 20 and 500 pptv were obtained by pre-concentrating 25 ml of a humidified standard gas mixture at a flow rate of 15 ml min-1. For all compounds, inter- and intra-day precisions were always below 15%, confirming the reliability of the method. The procedure was successfully applied to the analysis of exhaled breath samples collected from forty heart failure (HF) patients during their stay in the University Hospital of Pisa. The majority of patients (about 80%) showed a significant decrease of breath acetone levels (a factor of 3 or higher) at discharge compared to admission (acute phase) in correspondence to the improved clinical conditions during hospitalization, thus making this compound eligible as a biomarker of HF exacerbation.

Endogenous opioids modulate the growth of nervous and non-nervous cells. Hepatic stellate cells (HSCs) are the main cell phenotype involved in liver fibrogenesis, display molecular markers of neuronal cells and respond to neurotransmitters.To evaluate the role of endogenous opioids on liver fibrogenesis.Activated rat HSCs (passage 1-3) were used to evaluate cell proliferation and intracellular signalling pathway activation. Liver fibrosis was induced in rats by dimethylnitrosamine (DMN) administration.Opioid receptors showed a different pattern of expression when measured in quiescent and activated (in vitro and in vivo) HSCs. The activation of opioid receptors increased HSC proliferation and collagen accumulation. Opioid receptor stimulation induced a calcium-dependent protein kinase C alpha (PKC alpha)/extracellular regulated kinase (ERK)/phosphatidylinositol 3-kinase (PI3K) pathway activation that mediated the effect of endogenous opioids on HSC proliferation and collagen synthesis. In DMN-treated rats, the opioid antagonist naloxone reduced alpha-smooth muscle actin expression (as a marker of HSC activation) and collagen deposition, both measured by morphometry after 5 weeks of treatment. In both DMN-treated rats and human liver biopsies from chronic liver diseases, opioid receptors were observed in HSCs in area of active fibrogenesis. The endogenous opioid met-enkephalin increased its expression in zone 3 hepatocytes close to the area of necrosis after DMN administration and in the cellular target of chronic liver injury in human biopsies, and stimulated HSC proliferation and collagen synthesis.Endogenous opioids released during chronic liver injury participate in the process of liver fibrogenesis by stimulating HSC proliferation and collagen production in a paracrine manner.

Video-assisted thoracic surgery (VATS) in the diagnosis and treatment of pulmonary diseases has been used since the early 1990s, yet its impact on intraoperative and postoperative morbidity has not yet been fully evaluated. This report aims to provide a retrospective analysis of the literature and the authors' clinical experience with VATS in pulmonary surgery, with the goal of ascertaining rational criteria that explain operative complications and thus improve outcomes.Over a period of 15 years 1,615 VATS procedures were performed in our department, 743 of which involved only the lung. The accesses employed were based on the use of three ports through which a thoracoscope, endoscopic instruments, and an endostapler were inserted; for major pulmonary resections, a utility thoracotomy without rib spreader was added. Resections less than segmentectomy were performed using the endostapler directly on the parenchyma, whereas in the anatomic resections all the hilar structures were isolated and separately sectioned.The procedures performed were as follows: surgical biopsy, 98; wedge resection, 412; segmentectomy, 15; lobectomy, 217; pneumonectomy, 1. Besides the cases in which there were intraoperative complications that could be resolved thoracoscopically, it was necessary to convert to open surgery in 80 patients (10.8%): in 24 (3.3%), for general reasons linked to the technique of VATS itself; in 56 (7.5%), for specific causes correlated to the type of exeresis. The overall postoperative morbidity rate was 8.3% with no deaths.The analysis of the literature and our experience show that VATS is a reliable approach to the diagnosis and treatment of pulmonary diseases with low complication rate. To further reduce intraoperative and postoperative morbidity, however, it is necessary to select the patients carefully, to adhere strictly to oncological surgical principles, and to adopt a meticulous technique. Although conversion to open surgery represents failure of VATS, it is mandatory when the procedure is not completely safe.

An impedentiometric electronic tongue based on the combination of a composite sensor array and chemometric techniques aimed at the discrimination of soluble compounds able to elicit different gustative perceptions is presented. A composite array consisting of chemo-sensitive layers based on carbon nanotubes or carbon black dispersed in polymeric matrices and doped polythiophenes was used. The electrical impedance of the sensor array was measured at a frequency of 150 Hz by means of an impedance meter. The experimental set-up was designed in order to allow the automatic selection of a test solution and dipping of the sensor array following a dedicated measurement protocol. Measurements were carried out on 15 different solutions eliciting 5 different tastes (sodium chloride, citric acid, glucose, glutamic acid and sodium dehydrocholate for salty, sour, sweet, umami and bitter, respectively) at 3 concentration levels comprising the human perceptive range. In order to avoid over-fitting, more than 100 repetitions for each sample were carried in a 4-month period. Principal component analysis (PCA) was used to detect and remove outliers. Classification was performed by linear discriminant analysis (LDA). A fairly good degree of discrimination was obtained.

A study aimed at the characterization of five compounds with different chemical characteristics and gustative perceptions by measuring the variations of the electrical impedance of a composite sensor array is presented. The array was composed of five sensors of three different types based on carbon nanotubes or carbon black dispersed in polymeric matrices and doped polythiophenes. Measurements were carried out by evaluating the electrical impedance of the sensor array at a frequency of 150 Hz, and the data acquisition process was automated; a mechanical arm and a rotating platform controlled by a data acquisition card and a dedicated software allowed the sequential dipping of sensors in the test solutions. Fifty different solutions eliciting the 5 basic tastes (sodium chloride, citric acid, glucose, glutamic acid and sodium dehydrocholate for salty, sour, sweet, umami and bitter, respectively) at 10 concentration levels comprising the human perceptive range were analysed. More than 100 measurements were carried for each sample in a 4-month period to evaluate the system repeatability and robustness. The impedentiometric composite sensor array is shown to be sensitive, selective and stable for use in an electronic tongue.

Recently, a growing interest in artificial implementations of biological systems has been arising. In particular, several research groups have been working in mimicking the mammalian olfactory system with the so-called electronic noses (e-noses). The e-noses, which are based on a sensor array, a fluid-dynamic system, and a data processing unit, are systems devoted to detecting and analyzing volatiles, where a deep knowledge of the target application is needed. In order to achieve effective results the sampling system, the measurement protocols, the sensor array, and the pattern recognition techniques have to be carefully designed. The increasing complexity of such design poses issues in sensory feature extraction and fusion, drift compensation, and data processing, especially when high efficiency is required for real-time applications. The interconnection and cooperation of several modules devoted to processing different tasks, such as control, data acquisition, data filtering interfaces, feature selection, and pattern analysis, are already mandatory. Moreover, heterogeneous techniques used to implement such tasks may introduce module interconnection and cooperation issues. In this paper, we address the development of a dedicated instrument able to perform real-time transduction, fusion, and processing of chemoresistive sensor array signals. In particular, this instrument realizes a dynamic and efficient management of data processing techniques and automatically controls the measurement protocols and the sampling system. An array of conducting poly (alkoxy-bithiophenes) sensors, the fluid-dynamic system, the electronic section, the framework's base architecture, and the implementation of dedicated application processes are described. The classification task is based on a self-organizing map where models for artificial neurons and connections were derived from the base structures available in the framework core. According to the target application, this instrument is portable and easily tailored, calibrated, and trained. Classification of olive oil headspaces supports its utility in supplying high-efficiency routine for volatile organic compounds detection and analysis

UNLABELLED Controversy remains about the best line of division for liver splitting, through Segment IV or through the umbilical fissure. Both techniques are currently used, with the choice varying between surgical teams in the absence of an evidence-based choice. We conducted a single-center retrospective analysis of 47 left split liver grafts that were procured with two different division techniques: "classical" (N = 28, Group A) or through the umbilical fissure and plate (N = 19, Group B). The allocation of recipients to each group was at random; a single transplant team performed all transplantations. Demographics, characteristics, technical aspects, and outcomes were similar in both groups. The grafts in Group A, prepared with the classical technique, were procured more often with a single BD orifice compared with the grafts in Group B; however, this was not associated with a higher incidence of biliary problems in this series of transplants (96% actual graft survival rate [median ± s.d. FOLLOW-UP 26 ± 20 months]). Both techniques provide good quality split grafts and an excellent outcome; surgical expertise with a given technique is more relevant than the technique itself. The classical technique, however, seems to be more flexible in various ways, and surgeons may find it to be preferable.

This work presents a breath sampler prototype automatically collecting end-tidal (single and multiple breaths) or dead space air fractions (multiple breaths). This result is achieved by real time measurements of the CO2 partial pressure and airflow during the expiratory and inspiratory phases. Suitable algorithms, used to control a solenoid valve, guarantee that a Nalophan (R) bag is filled with the selected breath fraction even if the subject under test hyperventilates. The breath sampler has low pressure drop (

Background The radiologic evaluation of the transplanted bowel is largely unknown and rather complex because it involves several techniques that depend on indications and times that have not been fully defined. Methods From December 2000 to November 2002 in the Section of Radiology I of the University of Modena and Reggio Emilia (Modena, Italy), 11 patients with transplanted bowel were studied with different methods: traditional radiologic evaluation with contrast agent (all patients), evaluation of transit time with radiopaque markers (five patients), ultrasonographic (US) evaluation of the intestinal wall and Doppler US of the vascular axes (five patients), computed tomographic (CT) evaluation (all patients), and magnetic resonance (MR) evaluation of the bowel and the vascular axes (five patients). Traditional contrast examination enabled evaluation of the gastroesophageal transit and cardia functionality; anatomy and integrity of the anastomoses (proximal and distal); time of gastric emptying; morphology, tone, and kinesis of the transplanted small bowel loops and time of global transit. The study of transit with radiopaque markers was carried out in five patients to define the time of transit through the entire transplanted bowel, confirm recovery of intestinal motility, and identify possible abnormalities. The US examination was carried out in five patients to evaluate the morphology, thickness, and echo structural features of the intestinal loops. Color Doppler was performed to visualize the superior mesenteric artery and a wall arteriole of the sampled loop. CT examination was performed 2 to 4 weeks after surgery to evaluate the anatomy of the transplanted organs, arterial and venous anastomoses in case of complications identified with other methods or suspected, and periodically in the follow-up of patients who underwent transplantation due to Gardner syndrome. The protocol for MR evaluation of the bowel included coronal single-shot fast spin-echo T2-weighted sequences, axial and/or sagittal single-shot fast spin-echo T2-weighted sequences, coronal fast multiplanar spoiled gradient-echo (FMP- SPGR) sequences, coronal FMPSPGR sequences with and without administration of intravenous paramagnetic contrast agent, and axial or sagittal FMPSPGR fat-saturated sequences performed after dynamic gadolinium administration. Results and conclusion The study of transit with radiopaque markers was useful in patients with chronic intestinal pseudo-obstruction because it identified recovery and normalization of motility. Traditional contrast examination of the gastrointestinal tract continues to play an important role in transplanted patients because it is a simple examination that allows evaluation of the graft anatomy and recovery of motility of the residual native bowel and the transplanted loops. Moreover, it plays a crucial role in early detection of major postoperative complications such as intestinal obstruction, perforation, fistulas, and anastomotic complications (stenosis and dehiscence). CT examination is crucial for the detection of fluid collections, abscesses, and fistulas because it can serve as a guide of drainage and during follow-up of patients with Gardner syndrome can be used to investigate all possible sites in which desmoids might arise in addition to their relation to the graft. Because patients with transplanted bowel are generally rather a young population of reproductive age and because of technologic advances, MR may represent an effective method that does not use ionizing radiation and can therefore substitute for traditional radiologic evaluation. US represents a quick examination technique that is easily available and well tolerated by patients, and it has a role to play in the follow-up of transplanted patients and in the identification of major postoperative complications. However, its role in monitoring possible rejection remains to be defined with studies on wider and more representative samples.

A measurement chamber for the dynamic exposure of a sensor array to gaseous or liquid samples is presented. The device has been designed to optimise sensor response signals in terms of stability, reproducibility, response time and amplitude. This chamber has a radially symmetric flow splitter, which allows homogeneous flow conditions with low velocity gradients, and avoids significant recirculating zones and stagnant volumes. These characteristics, together with the fact that sample paths from the inlet to the sensors and from the sensors to the outlet have the same length, guarantee that all sensors are always exposed to the same chemical sample under the same experimental conditions. Through mathematical models, the introduction of a tracer in the form of a square wave concentration signal was simulated, and the effects of the working tolerances of the device main component on flow conditions were discussed.

Over the last few years, breath analysis for the routine monitoring either of metabolic disorders caused by specific diseases or occupational exposure to toxic substances has become more and more attractive due to its noninvasiveness. Several approaches have been proposed for sample collection, treatment, and analysis. This paper gives a critical overview of the analytical devices and procedures used for breath analysis. Results on the identification of chemicals in human breath for a selection of diseases are discussed.

A fluid dynamic study of a sensor chamber used in a hit-commercial electronic nose is presented. In order to optimise the sensor signals in terms of stability, repeatability as well as amplitude and response time, the influence of many factors of the sampling device has to be kept under control. Concerning the characteristics of flow, the existence of a time-window where each sensor is exposed to a constant odour concentration has to be assured. This condition can be achieved by the proper dimensioning of the chamber volume and by other modifications to the inlet and outlet. The numerical analysis was performed by a CFD code which solves the Navier–Stokes equations for a dilatable fluid in 3D enclosures, discretised with finite volume elements. Two configurations were simulated: a basic case, referring to the conditions existing in the commercial device, and an optimised case. In each case, a static solution was calculated for the flow field and then the dynamic evolution of odour concentration was simulated by solving the transient transport equation of a tracer injected as a square pulse flow. Far from optimum conditions were found for the basic case; the improvement achieved through simple modifications in the geometry of the chamber for the optimised case was discussed.

An anomaly of the left hepatic vein was discovered in a deceased donor for whole liver transplantation. This vein was attached by a thin bridge of tissue to the suprahepatic inferior vena cava cuff, which received the right and middle hepatic vein in a common trunk. The left hepatic vein and the common trunk drained together into the right atrium. The thin bridge of tissue connecting the 2 independent vessels was severed, and ex situ reduction of the left lateral segments was using a harmonic scalpel. Although a graft with reduced size is not ideal, ex situ reduction should be considered a valuable option when viability of the left lateral segments is uncertain in the donor or at the back table.

Indications for the use of video-assisted thoracic surgery (VATS) lobectomy are a controversial matter. This study aims to provide a retrospective evaluation of VATS lobectomy in typical bronchopulmonary carcinoids.Patient selection criteria for VATS lobectomy were as follows: (a) typical carcinoids with clear diagnosis; (b) centrally located lung tumors not amenable to bronchial resection with bronchoplastic procedures, or tumors located in peripheral lung tissues; (c) no hilar or mediastinal lymph node enlargement; and (d) normal respiratory function. Between January 1995 and December 1999, 12 patients (eight men and four women with a mean age of 57 years) were treated, seven with a peripheral and five with a centrally located tumor. Preoperative examination included chest roentgenograms, computed tomography (CT) of the chest, bronchoscopy, and spirometry; diagnosis was established by direct bronchoscopy in five cases, transbronchial biopsy in two cases, transthoracic biopsy in two cases, and video thoracoscopic wedge resection in three cases. Eleven VATS lobectomies and one VATS bilobectomy were performed. All patients underwent hilar lymphadenectomy and mediastinal sampling.There were no intraoperative complications. The only postoperative complication, hematothorax (8.3%), required VATS reoperation. Mean postoperative hospital stay was 5.33 days. Pathological examination of the resected specimens confirmed that the procedure was radical in all 12 patients and revealed eight T1N0 and four T2N0. At a mean follow-up of 30 months, no signs of recurrence were recorded.VATS lobectomy in the treatment of selected typical carcinoids, both central and peripheral, seems to yield favorable results and is therefore preferable to thoracotomy since it is less invasive.