Fabrication of a Highly NO2-Sensitive Gas Sensor Based on a Defective ZnO Nanofilm and Using Electron Beam Lithography

Hazardous substances produced by anthropic activities threaten human health and the green environment. Gas sensors, especially those based on metal oxides, are widely used to monitor toxic gases with low cost and efficient performance. In this study, electron beam lithography with two-step exposure was used to minimize the geometries of the gas sensor hotplate to a submicron size in order to reduce the power consumption, reaching 100 °C with 0.09 W. The sensing capabilities of the ZnO nanofilm against NO2 were optimized by introducing an enrichment of oxygen vacancies through N2 calcination at 650 °C. The presence of oxygen vacancies was proven using EDX and XPS. It was found that oxygen vacancies did not significantly change the crystallographic structure of ZnO, but they significantly improved the electrical conductivity and sensing behaviors of ZnO film toward 5 ppm of dry air.

Insights into the Sensing Mechanism of a Metal-Oxide Solid Solution via Operando Diffuse Reflectance Infrared Fourier Transform Spectroscopy

Recently, the influence of Nb addition in the oxide solid solution of Sn and Ti was investigated with regard to the morphological, structural and electrical properties for the production of chemoresistive gas sensors. (Sn,Ti,Nb)xO2-based sensors showed promising features for ethanol monitoring in commercial or industrial settings characterized by frequent variation in relative humidity. Indeed, the three-metal solid solution highlighted a higher response level vs. ethanol than the most widely used SnO2 and a remarkably low effect of relative humidity on the film resistance. Nevertheless, lack of knowledge still persists on the mechanisms of gas reaction occurring at the surface of these nanostructures. In this work, operando Diffuse Reflectance Infrared Fourier Transform spectroscopy was used on SnO2- and on (Sn,Ti,Nb)xO2-based sensors to combine the investigations on the transduction function, i.e., the read-out of the device activity, with the investigations on the receptor function, i.e., compositional characterization of the active sensing element in real time and under operating conditions. The sensors performance was explained by probing the interaction of H2O and ethanol molecules with the material surface sites. This information is fundamental for fine-tuning of material characteristics for any specific gas sensing applications.

New Approach for the Detection of Sub-ppm Limonene: An Investigation through Chemoresistive Metal-Oxide Semiconductors

R-(+)-limonene, one of the major constituents of citrus oils, is a monoterpene that is widely used as a fragrance additive in cosmetics, foods, and industrial solvents. Nowadays, its detection mainly relies on bulky and expensive analytical methods and only a few research works proved its revelation through affordable and portable sensors, such as electrochemical and quartz crystal microbalance sensors. In response to the demand for effective miniaturized sensing devices to be integrated into Internet of Things systems, this study represents a pioneering investigation of chemoresistive gas sensor capabilities addressed to R-(+)-limonene detection. An array of seven metal-oxide sensors was exploited to perform a complete electrical characterization of the target analyte. The experimental evidence allowed us to identify the WO₃-based sensor as the most promising candidate for R-(+)-limonene detection. The material was highly sensitive already at sub-ppm concentrations (response of 2.5 at 100 ppb), consistent with applicative parameters, and it resulted in selective vs. different gases at a lower operating temperature (200 °C) than the other sensors tested. Furthermore, it exhibited a humidity-independent behavior under real-life conditions (relative humidity > 20%). Finally, the WO₃ sensor also demonstrated a remarkable cross-selectivity, thus enabling its exploitation in cutting-edge applications.

Functionalization of Indium Oxide for Empowered Detection of CO2 over an Extra-Wide Range of Concentrations

Carbon capture, storage, and utilization have become familiar terms when discussing climate change mitigation actions. Such endeavors demand the availability of smart and inexpensive devices for CO₂ monitoring. To date, CO₂ detection relies on optical properties and there is a lack of devices based on solid-state gas sensors, which can be miniaturized and easily made compatible with Internet of Things platforms. With this purpose, we present an innovative semiconductor as a functional material for CO₂ detection. A nanostructured In₂O₃ film, functionalized by Na, proves to enhance the surface reactivity of pristine oxide and promote the chemisorption of even rather an inert molecule as CO₂. An advanced operando equipment based on surface-sensitive diffuse infrared Fourier transform is used to investigate its improved surface reactivity. The role of sodium is to increase the concentration of active sites such as oxygen vacancies and, in turn, to strengthen CO₂ adsorption and reaction at the surface. It results in a change in film conductivity, i.e., in transduction of a concentration of CO₂. The films exhibit excellent sensitivity and selectivity to CO₂ over an extra-wide range of concentrations (250-5000 ppm), which covers most indoor and outdoor applications due to the marginal influence by environmental humidity.

Elucidating the Ambient Stability and Gas Sensing Mechanism of Nickel-Decorated Phosphorene for NO2 Detection: A First-Principles Study

In the field of layered two-dimensional functional materials, black phosphorus has attracted considerable attention in many applications due to its outstanding electrical properties. It has experimentally shown superior chemical sensing performance for the room temperature detection of NO₂, highlighting high sensitivity at a ppb level. Unfortunately, pristine black phosphorus demonstrated an unstable functionality due to the fast degradation of the material when exposed to the ambient atmosphere. In the present work, a deepened investigation by density functional theory was carried out to study how nickel decoration of phosphorene can improve the stability of the material. Further, an insight into the sensing mechanism of nickel-loaded phosphorene toward NO₂ was given and compared to pristine phosphorene. This first-principles study proved that, by introducing nickel adatoms, the band gap of the material decreases and the positions of the conduction band minimum and the valence band maximum move toward each other, resulting in a drop in the conduction band minimum under the redox potential of O₂/O₂ ^-, which may result in a more stable material. Studying the adsorption of O₂ molecules on pristine phosphorene, we also proved that all oxygen molecules coming from the surrounding atmosphere react with phosphorus atoms in the layer, resulting in the oxidation of the material forming oxidized phosphorus species (PO _x ). Instead, by introducing nickel adatoms, part of the oxygen from the surrounding atmosphere reacts with nickel atoms, resulting in a decrease of the oxidation rate of the material and in subsequent long-term stability of the device. Finally, possible reaction paths for the detection of NO₂ are given by charge transfer analyses, occurring at the surface during the adsorption of oxygen molecules and the interaction with the target gas.

Design of a Metal-Oxide Solid Solution for Sub-ppm H2 Detection

Hydrogen is largely adopted in industrial processes and is one of the leading options for storing renewable energy. Due to its high explosivity, detection of H₂ has become essential for safety in industries, storage, and transportation. This work aims to design a sensing film for high-sensitivity H₂ detection. Chemoresistive gas sensors have extensively been studied for H₂ monitoring due to their good sensitivity and low cost. However, further research and development are still needed for a reliable H₂ detection at sub-ppm concentrations. Metal-oxide solid solutions represent a valuable approach for tuning the sensing properties by modifying their composition, morphology, and structure. The work started from a solid solution of Sn and Ti oxides, which is known to exhibit high sensitivity toward H₂. Such a solid solution was empowered by the addition of Nb, which─according to earlier studies on titania films─was expected to inhibit grain growth at high temperatures, to reduce the film resistance and to impact the sensor selectivity and sensitivity. Powders were synthesized through the sol-gel technique by keeping the Sn-Ti ratio constant at the optimal value for H₂ detection with different Nb concentrations (1.5-5 atom %). Such solid solutions were thermally treated at 650 and 850 °C. The sensor based on the solid solution calcined at 650 °C and with the lowest content of Nb exhibited an extremely high sensitivity toward H₂, paving the way for H₂ ppb detection. For comparison, the response to 50 ppm of H₂ was increased 6 times vs SnO₂ and twice that of (Sn,Ti)_xO₂.

Investigation on Sensing Performance of Highly Doped Sb/SnO2

Tin dioxide (SnO₂) is the most-used semiconductor for gas sensing applications. However, lack of selectivity and humidity influence limit its potential usage. Antimony (Sb) doped SnO₂ showed unique electrical and chemical properties, since the introduction of Sb ions leads to the creation of a new shallow band level and of oxygen vacancies acting as donors in SnO₂. Although low-doped SnO₂:Sb demonstrated an improvement of the sensing performance compared to pure SnO₂, there is a lack of investigation on this material. To fill this gap, we focused this work on the study of gas sensing properties of highly doped SnO₂:Sb. Morphology, crystal structure and elemental composition were characterized, highlighting that Sb doping hinders SnO₂ grain growth and decreases crystallinity slightly, while lattice parameters expand after the introduction of Sb ions into the SnO₂ crystal. XRF and EDS confirmed the high purity of the SnO₂:Sb powders, and XPS highlighted a higher Sb concentration compared to XRF and EDS results, due to a partial Sb segregation on superficial layers of Sb/SnO₂. Then, the samples were exposed to different gases, highlighting a high selectivity to NO₂ with a good sensitivity and a limited influence of humidity. Lastly, an interpretation of the sensing mechanism vs. NO₂ was proposed.

Air Stable Nickel-Decorated Black Phosphorus and Its Room-Temperature Chemiresistive Gas Sensor Capabilities

In the rapidly emerging field of layered two-dimensional functional materials, black phosphorus, the P-counterpart of graphene, is a potential candidate for various applications, e.g., nanoscale optoelectronics, rechargeable ion batteries, electrocatalysts, thermoelectrics, solar cells, and sensors. Black phosphorus has shown superior chemical sensing performance; in particular, it is selective for the detection of NO2, an environmental toxic gas, for which black phosphorus has highlighted high sensitivity at a ppb level. In this work, by applying a multiscale characterization approach, we demonstrated a stability and functionality improvement of nickel-decorated black phosphorus films for gas sensing prepared by a simple, reproducible, and affordable deposition technique. Furthermore, we studied the electrical behavior of these films once implemented as functional layers in gas sensors by exposing them to different gaseous compounds and under different relative humidity conditions. Finally, the influence on sensing performance of nickel nanoparticle dimensions and concentration correlated to the decoration technique and film thickness was investigated.

Development of a dedicated instrumentation for electrical and thermal characterization of chemiresistive gas sensors

This work presents the design and validation of a measuring instrumentation for an easy, complete, and tunable characterization of chemiresistive gas sensors based on metal-oxide semiconductors. The equipment, described in depth both as hardware and as software, was designed to monitor the electrical behavior of gas sensors in controlled thermodynamic conditions. The main goal of this setup is to synchronize the electrical characterization with different measuring conditions, i.e., operating temperature, relative humidity, and gas target concentration. This operation allows us to automate various measurement protocols, otherwise impossible to obtain manually. In particular, this instrumentation permits to correlate the response of a chemiresistive gas sensor to the applied voltage, to its working temperature, and to the gas concentration, automating the acquisition of the current-voltage characteristic and the current-temperature characteristic (Arrhenius plot) of sensing films. The experimental setup was validated by reporting the electrical characterization of a standard metal-oxide-based gas sensing material, such as SnO₂, working under different thermodynamic conditions.

A systematic review of the psychometric properties of the Jebsen-Taylor Hand Function Test (JTHFT)

This systematic review of the literature aimed to identify studies examining the psychometric properties of the Jebsen-Taylor Hand Function Test (JTHFT) in various international populations on. The search was conducted in MEDLINE, SCOPUS, CINAHL and Web Of Science, with no restrictions on publication period, the country in which the study was conducted, or the age of the patients. Eligible studies were selected on the basis of inclusion criteria and data were extracted. Study quality and the risk of bias were assessed using the COnsensus-based Standards to select the health Measurement Instruments (COSMIN) checklist. 805 articles were identified; after removing duplicates, there were 361 single studies. 338 articles did not concern the psychometric properties of JTHFT. The remaining 23 studies were selected for full text review, and all were included. They comprised 8 languages and 9 pathologies. These findings suggest the JTHFT is a useful test of manual dexterity in activities of daily living. This study provides specific information on the instrument's psychometric properties in different populations and supports clinicians in making informed decisions when choosing instruments for upper-limb evaluations.

First-Principles Study of Electronic Conductivity, Structural and Electronic Properties of Oxygen-Vacancy-Defected SnO₂

The use of computer simulations has become almost essential for prediction and interpretation of device's performance. In gas sensing field, the simulation of specific conditions, which determine the physical-chemical properties of widely used metal oxide semiconductors, can be used to investigate the performance of gas sensors based on these kinds of materials. The aim of this work was to evaluate the physical-chemical properties of tin dioxide employed for environmental and health gas sensing application and to investigate the influence of oxygen vacancies on its properties by means of density functional theory. Two samples, having different concentration of oxygen vacancies, were deeply studied in terms of their structural, electronic and electrical properties. It was proved the influence of oxygen vacancies on lattice parameter. By increasing oxygen vacancies concentration, the increased number of impurity states took these closer to the conduction band minimum, which can lead to an easier adsorption process of oxygen species and their availability to be exchanges with the molecules of the target gases. In this way a reduction of the operating temperature can be observed, thus reducing the power consumption of devices, while keeping the catalytic performance of the material.

Nanostructured Chemoresistive Sensors for Oncological Screening and Tumor Markers Tracking: Single Sensor Approach Applications on Human Blood and Cell Samples

Preventive screening does not only allow to preemptively intervene on pathologies before they can harm the host; but also to reduce the costs of the intervention itself; boosting the efficiency of the NHS (National Health System) by saving resources for other purposes. To improve technology advancements in this field; user-friendly yet low-cost devices are required; and various applications for gas sensors have been tested and proved reliable in past studies. In this work; cell cultures and blood samples have been studied; using nanostructured chemoresistive sensors; to both verify if this technology can reliably detect tumor markers; and if correlations between responses from tumor line metabolites and the screening outcomes on human specimens could be observed. The results showed how sensors responded differently to the emanations from healthy and mutant (for cells) or tumor affected (for blood) samples, and how those results were consistent between them, since the tumoral specimens had higher responses compared to the ones of their healthy counterparts. Even though the patterns in the responses require a bigger population to be defined properly; it appeared that the different macro-groups between the same kind of samples are distinguishable from some of the sensors chosen in the study; giving promising outcomes for further research.

Crystalline Microporous Organosilicates with Reversed Functionalities of Organic and Inorganic Components for Room-Temperature Gas Sensing

A deepened investigation on an innovative organic-inorganic hybrid material, referred to as ECS-14 (where ECS = Eni carbon silicates), revealed the possibility to use them as gas sensors. Indeed, among ECS phases, the crystalline state and the hexagonal microplateletlike morphology characteristic of ECS-14 seemed favorable properties to obtain continuous and uniform films. ECS-14 phase was used as functional material in screen-printable compositions and was thus deposited by drop coating for morphological, structural, thermal, and electrical characterizations. Possible operation at room temperature was investigated as technological progress, offering intrinsic safety in sensors working in harsh or industrial environments and avoiding high power consumption of most common sensors based on metal oxide semiconductors. Electrical characterization of the sensors based on ECS-14 versus concentrations of gaseous analytes gave significant results at room temperature in the presence of humidity, thereby demonstrating fundamental properties for a good quality sensor (speed, reversibility, and selectivity) that make them competitive with respect to systems currently in use. Remarkably, we observed functionality reversal of the organic and inorganic components; that is, in contrast to other hybrids, for ECS-14 the functional site has been ascribed to the inorganic phase while the organic component provided structural stability to the material. The sensing mechanism for humidity was also investigated.

Structural organization of NadADelta(351-405), a recombinant MenB vaccine component, by its physico-chemical characterization at drug substance level

The physico-chemical characterization of NadADelta(351-405), a recombinant protein discovered by reverse vaccinology, component of a candidate vaccine against Neisseria meningitidis serotype B is presented. Analytical methods like mass spectrometry, electrophoresis, optical spectroscopy and SEC-MALLS have been applied to unveil the structure of NadADelta(351-405), and to evaluate Product-Related Substances. Moreover, analysis of the protein after intentional denaturation has been applied in order to challenge the chosen methods and to determine their appropriateness and specificity. All the obtained results were inserted in a model allowing in-depth understanding of the antigen NadADelta(351-405): it is present in solution as a homo-trimer, retaining a high percentage of alpha-helix secondary structure, and able to reassemble from monomeric subunits after thermal denaturation; this structural organization is consistent with that foreseen for MenB NadA (Neisseria Adhesin A). The analytical data sets produced during process development for clinical phases I-III material confirm product quality and manufacturing consistency.

Size determination of bacterial capsular oligosaccharides used to prepare conjugate vaccines against Neisseria meningitidis groups Y and W135

The glycoconjugate vaccines against Neisseria meningitidis groups Y and W135 consist of pools of selected oligosaccharides conjugated to the protein carrier (CRM197). Consistent production of these vaccines requires control and thus determination of the average degree of polymerisation of the oligosaccharides used for conjugation. Acid hydrolysis generates group Y and W135 oligosaccharides with N-acetylneuraminic acid at the reducing end. A method, involving NaBH4 reduction and quantification of this terminal N-acetylneuraminic acid by use of high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) following acid hydrolysis (2M TFA), was developed. The average degree of polymerisation is calculated from the ratio of reduced N-acetylneuraminic acid to total N-acetylneuraminic acid. The assay was qualified by application to group C, Y and W135 oligosaccharide standards characterised by liquid chromatography, mass and NMR spectroscopy.

Surgical technique and haemodynamic changes in adrenalectomy for secreting neoplasia. Personal experience and review of the literature

BACKGROUND

Laparoscopic adrenalectomy is now used worlwide and is a great advance in laparoscopic technology. The reported benefits of this approach include decreased blood loss, better intraoperative haemodynamic control and shorter hospital stay, however some doubts on its indication for adrenal secreting tumors are still present. The aim of this retrospective study is to compare the physiologic alterations on blood pressure during laparoscopic and laparotomic adrenalectomy in patients with adrenal secreting adenoma, the intraoperative blood loss and mean hospital stay in the 2 groups of patients. A review of the literature is included.

METHODS

Laparoscopic adrenalectomy was performed in 13 patients (Conn's syndrome with adrenal adenoma in 10, pheochromocytoma in 3). Laparotomy was used for adrenalectomy in 9 patients: 4 with pheochromocytoma and 5 with Conn's adenoma. All the selected patients in the 2 groups had benign adenoma with tumor size less than 6 cm. During surgery the following data were determined: blood pressure before inducing anaesthesia, pressure peaks, episodes of hypertension and of hypotension, blood loss and operating times. The mean hospital stay was also recorded.

RESULTS

No differences were found in the blood-pressure values of the 2 groups of patients. The blood loss was minimal in all but 2 patients. The mean hospital stay was significantly longer in those patients who underwent laparotomy. No significant differences were recorded in the mean operating time.

CONCLUSIONS

The 2 techniques seem to have the same physiological consequences in the cardiovascular system, and the operating times for laparoscopic and laparotomic adrenalectomy are not so different. Laparoscopic adrenalectomy is a safe technique to treat small benign adrenal secreting adenomas.

A case of "silent" pheochromocytoma presenting as spontaneous retroperitoneal hematoma

Pheochromocytoma of the adrenal gland can be the cause of massive and lethal retroperitoneal haemorrhage presenting as acute abdomen. Here we report a case of retroperitoneal hematoma, with concomitant peritoneal spillage, due to the spontaneous rupture of a silent pheochromocytoma. The main clinical findings of this disease will be described. Therapy and prognosis will be also discussed.

[The role of laparoscopy in the identification of peritoneal carcinosis from abdominal neoplasms. Analysis of our initial experience]

BACKGROUND

The authors reviewed the experience on the use of laparoscopy performed since January 1997 in malignant neoplasms at their institution. The aim of the study was to evaluate the real effectiveness of this procedure in the staging of abdominal neoplasms which were considered resectable at preoperative examinations and in particular in the detection of peritoneal metastases not evidenced with traditional imaging techniques.

METHODS

Twenty-eight patients with malignant neoplasms: colo-rectum (15), stomach (5), pancreas (4), gallbladder (2), cardias (1), liver (1), were studied. All the patients were preoperatively examined with abdominal computed tomography (CT). In the 2 patients with gallbladder neoplasm a MR cholangiography was also performed. An explorative laparoscopy with peritoneal washing was then performed in all the patients. The diagnostic and therapeutic choices were subsequently done on the basis of laparoscopy results.

RESULTS

Therapeutic approach was modified in 21% of cases, as a result of the detection of peritoneal metastases which were not evidenced with imaging examinations. On the contrary, peritoneal washing was not responsible of any preoperative evaluation.

CONCLUSIONS

Laparoscopy performed in patients with abdominal neoplasms allows the detection of peritoneal micrometastases not previously evidenced through preoperative CT, thus modifying the therapeutic approach.

[Transperitoneal anterior access in video-laparoscopic adrenalectomy]

BACKGROUND

The more wide spread laparoscopic technique to operate on the adrenal gland is transabdominal approach with a lateral flank adrenalectomy. However, the transabdominal anterior approach can be a sure and safe alternative in selected patients.

METHODS

From 1997 to 1999, 18 selected patients underwent laparoscopic anterior adrenalectomy. Mean age was 43 years (range 25-63) with a male/female ratio of 1:1. Indications were Conn's adenoma in 10 patients, pheochromocytoma in 3 cases, Cushing syndrome in 1 and incidentaloma in 4. All the procedures were carried out laparoscopically and only one patient required conversion to an open adrenalectomy for clear signs of malignancy. The mean time for adrenalectomy was 140 minutes and the shorter times were recorded in the right-sided procedures (mean time 84 minute). Estimated blood loss was minimal and no transfusion was done. There were no postoperative complications related to the surgical technique and the hospital stay was 4 days in average.

RESULTS

Our data confirm, according with other authors, that this method is feasible in selected patients. Longer times recorded for the left-sided lesions were due to the more difficult dissection required to gain the left adrenal gland.

CONCLUSIONS

Transabdominal adrenalectomy with patient in the supine position is feasible, but its use is restricted to the cases with suspect bilateral or multifocal pheochromocytoma, to patients with concomitant abdominal pathologies that can be operated on laparoscopically, to surgeons who prefer to have a frontal view of the operative field.

Adenocarcinoma arising from a recurrent fistula-in-ano

Anal fistulas are frequent events which often recur after an inadequate surgical treatment. Nevertheless their evolution into malignant diseases is infrequently observed. The authors report one case of mucinous adenocarcinoma arising out of a recurrent, long-lasting fistula-in-ano. As reported, abdomino-perineal resection combined with radiotherapy can be the choice treatment. The difficulty is to obtain a reliable differential diagnosis. No imaging technique nor histologic examination can establish a definitive reliable diagnosis; nevertheless, as the risk of adenocarcinoma developing from a long-lasting recurrent fistula-in-ano, although small, is real, authors believe that operative exploration and biopsy of recurrent abscesses and fistulas should be recommended.

[Perioperative changes in the plasma levels of fibrinogen and D-dimer during laparoscopic cholecystectomy: the preliminary results of a prospective randomized clinical study]

AIM

Considering that laparoscopic procedure is associated with increased resistance to lower-limb venous return and subsequent stasis, with possible implications in terms of thromboembolic complications, the aim of our study was to investigate prospectively the coagulative-fibrinolytic profile, in laparoscopic and open cholecystectomy, in patients randomly alloted to receive or not preoperative heparin.

METHODS

We prospectively analyzed 36 patients (20 laparoscopic and 16 open) and we randomly divided the patients in two groups: Group-A (28 patients--16 laparoscopic and 12 open) didn't take any preoperative thromboprophylaxis, Group-B (8 patients--4 laparoscopic and 4 open) took preoperative subcutaneous heparin. We took blood venous samples before surgery, at time 0 and + 30 min., at the end and 1 and 24 hours postoperatively. The following parameters were assessed: prothrombin time, partial thromboplastin time, fibrinogen and D-dimer. We statistically analyzed the differences by ANOVA test.

RESULTS

In Group A, fibrinogen and D-dimer were significantly higher (p < 0.0001 and p = 0.0266) in open group as compared with laparoscopic one and we observed significant time-depending changes of fibrinogen's concentration (p = 0.0168). In Group B we obtained a higher fibrinogen's value in laparoscopic group than in conventional one, with a significant difference (p = 0.0283); also, the sampling-time affected the result in a very significant meaning (p = 0.0041). Comparing fibrinogen levels between Groups A and B, we observed lower values in heparin-treated group than in the other one (p < 0.0001), while in laparoscopic surgery there was not a significant difference between two groups of treatment.

CONCLUSIONS

Our preliminary data suggest that, perioperatively (besides a smaller laparoscopic acute-phase response) the coagulative-fibrinolytic changes are lower in laparoscopic cholecystectomy than in open one and heparin treatment significantly reduces these changes in open surgery but doesn't seem to affect laparoscopic group. Our results seem to show another possible advantage of the laparoscopic surgical procedures over the traditional ones.

[Perihepatic packing combined with wrapping in the treatment of major bi-lobar hepatic trauma]

After the spleen the liver is the most exposed organ to injury in abdominal blunt trauma. The improvement in imaging techniques and in anesthesia and intensive care have contributed to a fallen in mortality rate and an enhanced possibility in non-operative management. In unstable patients the packing may be used to defer the definitive operation. The Authors report a case of liver injury of two lobes where the packing was followed by liver wrapping with an absorbable mesh. The patient, a female aged 67, resulted to have a bilobar liver injury of IV degree in the injury severity score. The delay of reoperation was 15 days. The procedure was complicated by a subphrenic abscess, successfully managed with non-operative procedures. Wrapping after liver packing may be considered a good option in unstable patient affected, by severe liver injuries after blunt abdominal traumas.

[Choledochojejunostomy using a mechanical stapler]

Authors performed the mechanical termino-lateral bilio-digestive anastomosis, adopting a circular 21 mm stapler device. The patient was affected by non neoplastic papillary stenosis producing a common biliary tract dilatation so large to allow the stapler's head introduction. A 12 month follow-up was performed using ultrasonography and MRI cholangiopancreatography, that obtained a good demonstration of both biliary tract and bilio-digestive anastomosis.

The effect of a carbohydrate loading on running performance during a 25-km treadmill time trial by level of aerobic capacity in athletes

The aim of the present study was to examine the influence of a high carbohydrate diet and the level of aerobic capacity on running performance during a 25-km treadmill time trial. The study used a 2*2 design with the factors being training and diet composition. We divided the athletes in 4 groups: 1. Trained athletes with carbohydrate loading (CHO1); 2. Trained athletes without carbohydrate loading (C1); 3. Untrained athletes with carbohydrate loading (CHO2); 4. Untrained athletes without carbohydrate loading (C2). The carbohydrate loading was effected with confectionery. Performance time, running speed, blood glucose and blood lactate concentrations were evaluated during two 25-km treadmill time trial (trial 1 and trial 2) separated by 7 days in which two groups (CHO1 and CHO2) had a carbohydrate loading. The results showed that the athletes with lower level of aerobic capacity had better performance time after carbohydrate loading. They ran faster and had a higher glucose and lactate concentrations in the last 5 km during trial 2. There were no significant differences in the other groups. In conclusion, we can assert that dietary carbohydrate loading can improve running performance and that confectionery can be used as an effective means of supplementing the normal carbohydrate intake in preparation for endurance competitions. But the improvement depends on some factors such as the distance and the level of aerobic capacity.

[Study of circadian variations of plasma renin activity in the normal human in the supine position]

A study of circadian variations of plasma renin activity in normal supine man.--The cosinor analysis has detected circadian rhythm of PRA in fifteen normal supine men, aged 21-28, studied over a 24-hour span. The acrophase occurs at 05.55 and it is consistent with the findings of the other authors.