Optimization of dye adsorption capacity and mechanical strength of chitosan aerogels through crosslinking strategy and graphene oxide addition.

Chitosan (CS) aerogels were prepared by freeze-drying as potential adsorbents for water purification, and the effect of the strategy of crosslinking was investigated by varying the amount of crosslinker (glutaraldehyde) and the sequence of steps for the preparation of the aerogel. Two procedures were compared, in which the crosslinking step was carried out before or after the freeze-drying of the starting CS solution. When crosslinking was postponed after the freeze-drying step, the adsorption capacity towards an anionic dye, such as indigo carmine, considerably increased (up to +45%), reaching values as high as 534.4 ± 30.5 mg g-1. The same crosslinking strategy ensured a comparable improvement also in nanocomposite aerogels containing graphene oxide (GO), which was added to enhance the mechanical strength and provide adsorption capacity towards cationic dyes. Besides possessing good mechanical strength (compressive modulus higher than 1 MPa), the CS/GO aerogels were able to bind also cationic pollutants such as methylene blue. The maximum uptake capacity increased from 4.3 ± 1.6 to 168.6 ± 9.6 mg of cationic dye adsorbed per gram of adsorbent with respect to pristine CS aerogels.

Interfacial crowding of nanoplatelets in co-continuous polymer blends: assembly, elasticity and structure of the interfacial nanoparticle network.

The sequence of events which leads to the interfacial crowding of plate-like nanoparticles in co-continuous polymer blends is investigated through a combination of morphological and rheological analyses. Very low amounts (∼0.2 vol%) of organo-modified clay are sufficient to suppress phase coarsening in a co-continuous polystyrene/poly(methyl methacrylate) blend, while lower particle loading allows for a tuning of the characteristic size of the polymer phases at the µm-scale. In any case, an interfacial network of nanoparticles eventually forms, which is driven by the preferred polymer-polymer interface. The elastic features and stress-bearing ability of this peculiar nanoparticle assembly are studied in detail by means of a descriptive two-phase viscoelastic model, which allows isolation of the contribution of the filler network. The role of the co-continuous matrix in driving the space arrangement of the nanoparticles is emphasized by means of comparative analysis with systems based on the same polymers and nanoparticles, but in which the matrix is either a pure polymer or a blend with drop-in-matrix morphology. The relaxation dynamics of the interfacial network was found not to depend on the matrix microstructure, which instead substantially affects the assembly of the nanoplatelets. When the host medium is co-continuous, the particles align along the preferred polymer-polymer interface, percolating at a very low amount (∼0.17 vol%) and prevalently interacting edge-to-edge. The stress bearing ability of such a network is much higher than that in the case of matrix based on a homogeneous polymer or a drop-in-matrix blend, but its elasticity shows low sensitivity to the filler content.

Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the characterization of functionalized carbon nanotubes.

RATIONALE: Functionalization of carbon nanotubes (CNTs) generates complex systems that require the development of suitable characterization protocols. New techniques have been explored, and existing analytical and spectroscopic methods to characterize functionalized CNTs have been adapted. Presently, chemical characterization of functionalized CNTs (f-CNTs) remains a difficult task. METHODS: Matrix-assisted laser desorption/ionization (MALDI) analysis is performed on f-MWCNT samples prepared via grafting or absorption of anti-oxidant (AO) molecules on both MWCNT-COOH and MWCNT-OH. Covalently functionalized MWCNTs were subjected to thermal degradation and/or hydrolysis reaction before analysis, whereas MWCNTs with a physical adsorption of the functionalizing molecules were directly spotted in the target sample. Noteworthy, in our approach f-MWCNTs constitute at the same time analyte and MALDI matrix. RESULTS: The identification of functionalizing AO molecules is ascertained after degradation or hydrolysis reactions in both MWCNT-COOH and MWCNT-OH grafted samples. Absorbed AO molecules, as well as organic impurities derived from grafting reactions, are also revealed by MALDI MS without any preliminary cleavage reaction. CONCLUSIONS: A simple MALDI-TOF mass spectrometry method permits to obtain the unambiguous discrimination between grafted or adsorbed functionalized molecules onto the surface of MWCNTs.

Universal features of the melt elasticity of interacting polymer nanocomposites.

We study the structure and linear viscoelasticity of interacting polymer nanocomposites based on mixtures of poly(ethylene oxide) and fumed silica particles. The filler is dispersed within the polymer using two different techniques which lead to different dispersion states. The analysis of the dynamic response of our systems highlights the formation of a stress-bearing network above a critical volume fraction, Φ(c). Extending a two-phase model used to describe weakly interacting systems, we show that above Φ(c) the melt-state elasticity of the composites arises from the independent contributions of a polymer-particle network and a viscous matrix. We also find that, although Φ(c) depends on the initial state of dispersion, the network elasticity scales with volume fraction following a universal power-law, with an exponent ν ≈ 1.8. Such a scaling law has been recently predicted for the stress-bearing mechanism governed by polymer-mediated interactions.

Crura ultrastructural alterations in patients with hiatal hernia: a pilot study.

BACKGROUND: Laparoscopic fundoplication for gastroesophageal reflux disease (GERD) and hiatal hernia has been validated worldwide in the past decade. However, hiatal hernia recurrence still represents the most frequent long-term complication after primary repair. Different techniques for hiatal closure have been recommended, but the problem remains unsolved. The authors theorized that ultrastructural alterations may be implicated in hiatal hernia. Thus, this study was undertaken to investigate the presence of these alterations in patients with or without hiatal hernia. METHODS: Samples from Laimer-Bertelli connective membrane and muscular crura at the esophageal hiatus were collected from 19 patients with GERD and hiatal hernia (HH group), and from 7 patients without hiatal hernia enrolled as the control group (NHH group). Specimens were processed and analyzed by transmission electron microscopy. RESULTS: Muscle and connective samples from the NHH group did not present any ultrastructural alteration that could be detected by transmission electron microscopy. Similarly, connective samples from the HH group showed no ultrastructural alterations. In contrast, all muscle samples from the HH group exhibited sarcolemmal alterations, subsarcolemmal vacuolar degeneration, extended disruption of sarcotubular complexes, increased intermyofibrillar spaces, and sarcomere splitting. CONCLUSION: The evidence of ultrastructural alterations in all the patients in the HH group raises the suspicion that the long-term outcomes of antireflux surgery depend not only on the surgical technique, but also on the underlying muscular diaphragmatic illness.

Feasibility of primary inguinal hernia repair with a new mesh.

BACKGROUND: The purpose of this study was to evaluate the feasibility of primary inguinal repair with open tension-free and sutureless technique using a new polypropylene "patch and plug system" (Prolene 3D patch), and the quality of the treatment in terms of reduction of postoperative discomfort. METHODS: Fifty-six consecutive patients, mean age 54.5+/-11.2 years, with primary unilateral uncomplicated inguinal hernia, were treated in a day-surgery setting. Collected data included: pain scores at 24 hours, 72 hours, and 7, 15, and 30 days after operation, analgesic medications, return to work and to heavy house and/or moderate sporting activities, and quality of life as measured by Short Form 36 health survey questionnaire (SF-36) before the operation and at 6 months follow-up. RESULTS: Postoperative pain was low: the mean visual analog scale (VAS) scores were 2.8 at 24 h, 1.8 at 72 h, and 0.9, 0.3, and 0.04 at 7, 15, and 30 days, respectively. Analgesic drugs were not used by 66.0% (n=37) of the patients. The mean global time to return to work and to heavy activities was 9.9+/-4.6 and 14.6+/-7.0, days, respectively. Patient satisfaction showed a significant improvement in all SF-36 domain scores at 6 months follow-up (P<0.001). There were no major complications, recurrences, or mortality. CONCLUSIONS: The new mesh seems to satisfy all requirements of a feasible, reliable, and effective device for repairing primary inguinal hernia with high patient comfort.

New devices for inguinal hernia repair in elderly patients.

A recent meta-analysis concluded that there was a lower incidence of recurrences after mesh hernioplasty, as opposed to non-mesh open methods. Inguinal mesh and plug hernioplasties have been performed using prostheses of different sizes and shapes, either sutured or not to the tissues. However, hernia repair using mesh is sometimes associated with postoperative pain, more or less severe and/or persistent. As a consequence it may interfere with the time required to return to work and to normal daily activities. Finally, concerning the postoperative complications and recurrences, the data presented in our study confirm the very low rate for both aspects; then, as regards the time to return to work, our good results are similar to those of other studies available in literature. In conclusion the tension-free hernia repair described, based upon the use of Prolene 3D patch, is a safe operation, simple to be acquired, it can be performed on an outpatient basis, with a low complication rate, a low level of pain, and an excellent quality of life thereafter. The new device seems to satisfy all requisites of a feasible, reliable and effective system for repairing primary inguinal hernia, at low cost, high patient comfort, and with low risk of recurrences.

Radical excision of invasive thymoma with intracaval and intracardial extension: a successful case report.

A case of invasive thymoma with intracaval and intracardiac extension is reported. The use of cardiopulmonary bypass was necessary to achieve a radical excision of the tumor thus avoiding early death due to cardiovascular complications. This highly unusual mode of tumor presentation makes this particular case worth reporting.

[Care and rehabilitation of colostomized patients]. / L'assistenza e la riabilitazione del colostomizzato.

The enterostomies represent the result of a surgical operation that we have been carrying out more frequently in the last few years both on account of the neoplastic and inflammatory pathology of the large bowel; in fact about 40,000 colostomies are effectuated in Italy every year. On the basis of what has been said, the problem of assistance and of rehabilitation of the patients with colostomy assumes great importance. Therefore the authors have examined the various phases of the assistance (pre, intra and post-operatory) and they have underlined the rehabilitation of such patients. They conclude by affirming that it is indispensable to have a multidisciplinary collaboration to insure a correct assistance and rehabilitation, which involves the surgeon, the radiotherapist, the enterostomist, the psychologist and the oncologist; only in this way will they be able to restore to society these patients capable of living the rest of their lives if not happy at least serenely.

[Prostaglandins and gastric cancer: a preliminary study]. / Prostaglandine e cancro gastrico: studio preliminare.

As high levels of Prostaglandins E2 were observed in several gastric diseases, the Authors determined the PGE2 levels in gastric cancer patients without recurrences, in pre and post-operative period. PGE levels were correlated with cancer progression and their significance as tumoral markers was also assessed.

[Diagnostic and therapeutic considerations in early gastric cancer]. / Considerazioni diagnostiche e terapeutiche sull'early gastric cancer.

A ten-year series of early gastric cancer is reported, stress being laid on the diagnostic and therapeutic problems associated with the condition. The importance of intensified mass screening programmes, particularly in populations at risk, is underlined to enable these potentially dangerous conditions to be treated in time.

[Clinico-therapeutic considerations on primary gastric lymphoma]. / Considerazioni clinico-terapeutiche sul linfoma gastrico primitivo.

The Authors report four cases of primary gastric lymphomas. They stress the anatomopathological, clinical and therapeutic problems related to this disease because, at present, they are still discussed.

[The inguinal hernia today. Technical notes]. / L'ernia inguinale oggi. Note di tecnica.

Following a short introduction on Bassini's operation, alternative surgical techniques are discussed: Postempski, Halsted, Mugnai-Ferrari, Anson-McVay, Marcy, Ferguson, Shouldice with their indications, advantages and disadvantages. Personal experience in the surgical treatment of 516 patients suffering from inguinal hernia is then reported and stress is laid on the need for precise anatomic knowledge of the inguinal region and skill in one technique in particular to limit the risk of recurrences.

[Retroperitoneal neurilemmoma (anatomo-pathologic and clinical considerations)]. / Il neurilemmoma retroperitoneale (considerazioni anatomo-patologiche e cliniche).

After extensively reviewing the literature on primary retroperitoneal tumours, the authors present a case of retroperitoneal neurilemmoma. They stress the rareness of this disease and go on to discuss the related epidemiological, histogenetic and anatomo-pathological problems. Finally, they deal at some length with the symptoms of the disease and the diagnostic strategy they adopt, emphasizing the usefulness of CT and ultrasonic tomography in the study of the retroperitoneal region.

Prevention of childhood poisoning: efficacy of an educational program carried out in an emergency clinic.

For many inner-city families, the emergency clinic is the most frequent and sometimes the only point of contact with medical services. We hypothesized that this setting could serve as an opportunity to direct a health promotion at a population that might not receive such a message elsewhere. The objectives of the program were (1) to remind parents of the telephone number of the Massachusetts Poison Center, (2) to ensure that parents have ipecac for use in an emergency, and (3) to counsel parents on how to use ipecac. Of 403 families recruited from the emergency clinic and divided randomly into intervention and nonintervention groups, 262 families completed the follow-up interview 6 months later (65%). Results showed that 68% of intervention families compared with 42% of control families reported ipecac storage at follow-up (chi 2 = 7.65, P = .005) and that 40% of intervention families v 25% of control families reported familiarity with the use of ipecac (chi 2 = 4.04, P = .04). Accessibility to the poison center's telephone number was reported by 62% of intervention families and by 49% of control families (chi 2 = 4.60, P = .13). Finally, 42% of intervention families v 25% of control families reported that they had a sticker on their phone with the number of the poison center on it (chi 2 = 4.60, P = .03). Our results suggest that a brief intervention, even in an emergency clinic, can introduce the topic of poisoning prevention to families and can encourage the storage of syrup of ipecac in the home.