Mixture of Graphene Oxide/Phosphoric Acid/Melamine as Coating for Improved Fire Protective Performance and Enhancement of Surface Electrical Properties on Wood Chipboard

Looking for multifunctional materials, an assessment of the performances both as fire retardant and generator of electrically conductive surfaces for a three component mixture of graphene oxide, phosphoric acid and melamine applied on wood chipboard was performed. A simple approach was used to investigate the intumescent char formation and quantify the loss mass during vertical burning tests, in which the prepared samples were exposed for a certain time interval to a flame generated by an ethanol lamp in ambient conditions. Moreover, mass loss evolution and structural changes that occur during the burning process were more comprehensive investigated by differential thermal and thermogravimetric (DTA/TGA) techniques. By comparing the performances between the wood chipboard samples without any coverage and those covered with one or multiple component mixture, an increase of protection against the fire action was noticed when the three component mixture was used. Also, an improvement of the electrical properties was observed, after flame exposure of the samples covered with multiple layers (i.e., two and three), when the three component mixture was used. Morphological and structural investigations by microscopy (optical and electronic-SEMEDX), X-ray diffraction (XRD) and spectral (Raman, FTIR) methods are described. An assessment of market potential is also discussed.

Vibrational and Photoluminescence Properties of Composites Based on Double-Walled Carbon Nanotubes, Poly(o-phenylenediamine) and Poly(ethylene oxide)

Chemical polymerization of o-phenylenediamine (OPD) in the presence of poly(ethylene oxide), double-wall carbon nanotubes (DWNTs) and ferric chloride is carried out in order to obtain composites based on the poly(o-phenylenediamine)-poly(ethylene oxide) (POPD-PEO) fibres covered and interconnected with DWNTs. Vibrational and photoluminescence properties of these composite materials as well as their morphologies are shown by infrared (IR) spectroscopy, Raman scattering, photoluminescence (PL) and scanning electron microscopy (SEM). An adsorption of DWNTs onto the POPD rods surface in the absence and in the presence of PEO is highlighted by SEM. The vibrational changes reported by Raman scattering and IR spectroscopy prove a covalent functionalization of DWNTs with the macromolecular compound POPD which is doped with FeCl^-₄ ions. New hydrogen bonds are generated between POPD covalently functionalized DWNTs and hydroxyl groups of PEO according to IR spectroscopic studies. The two macromolecular compounds, POPD and POPD-PEO, show a complex emission band with maxima at 572 and 566 nm, having a shoulder at 667 nm. A significant change in the profile of the PL bands of POPD and POPD-PEO is induced in the DWNTs presence. We show that DWNTs induce (i) a diminution in the POPD PL band intensity peaked between 525-600 nm simultaneous with the increase in the intensity of the PL band situated in the 600-800 nm spectral range and (ii) an enhancement process of the emission band localized in the 475-800 nm spectral range in the case of POPD-PEO.

Azathioprine Electrochemical Adsorption onto the Reduced Graphene Oxide Sheets in Absence and in the Presence of Polyaniline

The azathioprine (AZA) electrochemical adsorption onto the screen-printed carbon electrodes (SPCE) modified with the reduced graphene oxide (RGO) sheets in the absence and in the presence of polyaniline-emeraldine salt (PANI-ES) is reported in this work. Using cyclic voltammetry (CV), in the case of the SPCE modified with the RGO sheets non-functionalized and functionalized with PANI-ES, respectively, an irreversible process at the electrode/electrolyte interface is highlighted to take place. In the case of the SPCE modified with the non-functionalized RGO sheets (SPCERGO), the oxidation-reduction processes induce an up-shift of the AZA Raman lines from 856 and 1011 cm^-1 to 863 and 1020 cm^-1, respectively. These variations indicate an AZA adsorption onto the surface of the SPCE modified with the RGO sheets that takes place throught the imidazole and pyrimidine cycles of mercaptopurine, when the generation of the π-π^* bonds between the mercaptopurine structure and hexagonal carbon cycles of RGO occurs. The electrochemical functionalization of the RGO sheets with PANI-ES is proved by the appearance of the Raman lines at 1165, 1332-1371, 1496 and 1585 and 1616 cm^-1. The oxidation-reduction processes induced at the interface of the SPCE modified with PANI-ES functionalized RGO sheets and the electrolyte consisting into a phosphate buffer (PB) and AZA lead to the generation of new positive charges onto the PANI macromolecular chain and the adsorption of the drug on the working electrode surface that takes place via the π-π^* bonds established between the benzene/quinoide rings of PANI and the imidazole/ purine cycles of AZA. These results indicate that the SPCE modified with the PANI-ES functionalized RGO sheets shows potential applications in the field of sensors for AZA detection.

Crystallization kinetics mechanism investigation of sol–gel-derived NaYF4:(Yb,Er) up-converting phosphors

The crystallization mechanism of sol–gel-derived NaYF₄:(Yb,Er) up-converting phosphors has been studied by differential scanning calorimetry analysis using both model-free and model fitting approaches.

Technical aspects of biliary reconstruction correlated with biliary complications in 46 consecutive right lobe liver transplantations from living donors

INTRODUCTION

Biliary complications contribute to a high morbidity rate in patients with right lobe liver transplant from a living donor. We retrospectively evaluated biliary reconstructions and complications in a number of recipients with liver transplant from a living donor, in a single center.

PATIENTS AND METHODS

A number of 46 patients (23 males and 23 females aged 9-63) received a right lobe liver graft between 2009 and 2013, with the following types of biliary reconstruction:duct-to-duct choledochocholedochal anastomosis (n=24)or Roux-en-Y hepaticojejunoanastomosis, with or without an external transanastomotic biliary stent.

RESULTS

The rate of biliary complications (leakage 15.21%,anastomotic stenosis 4.34%, overall 17.39%) was not statistically significantly influenced by the demographics of the studied lot, by the etiology of the liver disease or by the characteristics of the biliary reconstruction; the only risk factor which showed a statistically significant influence in terms of biliary complications was MELD.

CONCLUSION

The type and technique of the biliary reconstruction in LDLT should be adapted depending on the anatomy of the biliary tree of both the donor and recipient, as well as the clinical and laboratory findings of the recipient.

Living donor liver transplantation with dual grafts -- a case report

BACKGROUND

Living donor liver transplantation (LDLT) exposes to risks both the donor, due to a potential small residual liver volume, and the recipient, who faces the risk of small-for-size graft syndrome. In order to overcome these drawbacks, liver grafts from two different donors can be used. This paper presents a case of dual graft LDLT using a right hemiliver and a left lateral section from related donors.

CASE PRESENTATION

A 14-year old female diagnosed with chronic hepatic failure due to Wilson's disease with Model-for-End- Stage-Liver-Disease score of 25, underwent a dual graft LDLT, receiving a right hemiliver with a reconstructed middle hepatic vein from her sister, and a left lateral section from her mother. None of the grafts complied with a satisfactory graft-to-recipient weight ratio (GRWR), if they would have been independently transplanted. The combined GRWR was 1.10. The donors and the recipient have been followed-up for over 1 year.

RESULTS

The donors had no postoperative complications. The donors and the recipient were discharged 8 and 19 days after surgery, respectively. After 12-month follow-up, both donors and the recipient were alive, with normal graft function.

CONCLUSION

Dual graft LDLT can be a feasible solution to overcome the risk of small-for-size graft syndrome.

ABBREVIATIONS

BSA = body surface area, GRWR = graft-to-recipient weight ratio, GV SLV = recipient standard liver volume, HA = hepatic artery, HD = hepatic duct, HV = hepatic vein, LDLT = Living donor liver transplantation, LL = left lobe, LLS = left lateral section, MELD = Model for End-Stage Liver Disease, POD = postoperative day, PV = portal vein, RL = right lobe, SFS = small-for-size graft, SLV = standard liver volume, WD = Wilson's disease.

The MELD score exception for polycystic liver disease

Polycystic Liver Disease (PLD) is a rare progressive disease characterized by increased liver volume due to many cysts, with symptoms related mainly to the size of the liver and the compression on adjacent organs. Most patients who have PLD require no medical or surgical intervention. On the other hand, massive hepatomegaly with severe symptoms which cannot be managed conservatively requires surgical procedures.Liver transplantation (LT) offers the only curative option for the relief of symptoms arising from cyst enlargement and compression of abdominal structures. We presented a rare case of a young man with highly symptomatic isolated PLD due to liver volume - 23,200 cm3, which provokes severe physical and social handicaps and we considered that only total hepatectomy and LT provides a chance of definitive treatment.To our knowledge this is the largest specimen from a PLD patient who was transplanted.

[The role of the middle hepatic vein in the living donor liver transplantation with right hemiliver]

BACKGROUND

Living donor liver transplantation has appeared and developed as a consequence to the shortage of organs. In case of right hemiliver procurement, the role of the middle hepatic vein is crucial for the prevention of right anterior section congestion and the promotion of liver regeneration.

MATERIAL AND METHOD

We performed a retrospective study on a group of 36 adult patients who underwent living donor liver transplantation with right hemiliver in Fundeni Clinical Institute, having as a major indication liver cirrhosis. Concerning the middle hepatic vein, this was procured in 10 cases, not procured nor reconstructed in another 10 cases, and reconstructed on the bench in 16 cases.

RESULTS

The immediate postoperative survival was roughly 91%, with 7 cases of "small for size syndrome", 2 cases being retransplanted.

CONCLUSIONS

In case of living donor liver transplantation with the right hemiliver, the reconstruction of the middle hepatic vein helps the liver regeneration and prevent the "small for size" syndrome.

[Biliary complications following liver transplantation]

The biliary complications (BC) were always considered the "Achilles heel" of liver transplantation, being one of the leading causes of postoperative morbidity. The technique of the biliary reconstruction depends on the surgical procedure and it has a major impact on the patients and the graft evolution. The most frequent types of BC were stenoses, leaks, bilomas, cholangitis, etc. As an incidence, there is a peak of BC in the first 6 months after the transplant, a third of them appearing in the first month. Among the major BC risk factors, the most important are: hepatic artery pathology, the use of partial liver graft, bilioplasty and the number of biliary ducts and anastomoses. The BC management can be conservative, interventional or surgical depending on the type of BC. Along with the improvement of the interventional radiological and endoscopic methods, a large number of BCs are successfully treated non-surgically. There are still a few circumstances in which surgery is mandatory such as important persistent biliary leaks, even more when a partial liver graft was used or in association with hepatic artery pathology when re-transplantation is required. Multiple or serial biliary stenoses can lead to surgical revision. Although BC plays an important role in the patients postoperative morbidity, by early diagnosis and through numerous therapeutic methods promptly applied, there is no major impact on mortality.

[Liver transplantation--indications, surgical technique, results--the analysis of a clinical series of 200 cases]

INTRODUCTION

Initially considered experimental, liver transplantation (LT) has become the treatment of choice for the patients with end-stage liver diseases.

MATERIAL AND METHODS

Between April 2000 and October 2009, 200 LTs (10 reLTs) were performed in 190 patients, this study being retrospective. There were transplanted 110 men and 80 women, 159 adults and 31 children with the age between 1 and 64 years old (mean age--39.9). The main indication in the adult group was represented by viral cirrhosis, while the pediatric series the etiology was mainly glycogenosis and biliary atresia. There were performed 143 whole graft LTs, 46 living donor LTs, 6 split LTs, 4 reduced LTs and one domino LT RESULTS: The postoperative survival was 90% (170 patients). The patient and graft one-year and five-year survivals were 76.9%, 73.6% and 71%, 68.2%, respectively. The early complications occurred in 127 patients (67%). The late complications were recorded in 71 patients (37.3%). The intraoperative and early postoperative mortality rate was 9.5% (18 patients).

CONCLUSIONS

The Romanian liver transplantation program from Fundeni includes all types of current surgical techniques and the results are comparable with those from other international centers.

Gallbladder adenoma with focal adenocarcinoma

The majority of polypoid lesions of the gallbladder are cholesterolosis pseudopolyps. True neoplastic GB polyps are represented mainly by adenomas. The case of a 52-year old male patient with an adenomatous polyp of the GB with focal adenocarcinoma is presented.

Combined liver and islet transplantation using steroid-free immunosuppression

Due to a vicious circle in which HCV favors insulin resistance and, alternatively, insulin resistance facilitates the persistence of HCV, HCV patients have often diabetes associated with liver cirrhosis. We present the case of combined liver and pancreatic islets transplantation performed in a patient with HCV liver cirrhosis associated with insulin-dependent diabetes. This is also the first case of islet allotransplantation in Romania. A 40-year-old male diagnosed with liver cirrhosis due to HCV infection and insulin dependent diabetes underwent combined liver and islet transplantation. Our therapeutic design was based on data provided by both the use of Edmonton immunosuppressive steroid-free protocol in islets cell transplantation and the findings of international studies on the effects of this protocol in liver transplantation for patients with HCV infection. Good metabolic control of the diabetes was obtained. The absence of anti beta cell autoimmunity could explain also the good tolerance for the transplanted islets, proved by the rapid and durable decrease of the insulin need, from 64 U/day to 20 U/day at one month post-transplantation, dose that was maintained for 16 months when the patient died due to recurrent HCV hepatitis. Islet transplantation can be associated to liver transplantation in order to improve the associated diabetes in cirrhotic patients.

Battery powered BION FES network

The Alfred Mann Foundation is completing development of a coordinated network of BION microstimulator/sensor (hereinafter implant) that has broad stimulating, sensing and communication capabilities. The network consists of a master control unit (MCU) in communication with a group of BION implants. Each implant is powered by a custom lithium-ion rechargeable 10 mW-hr battery. The charging, discharging, safety, stimulating, sensing, and communication circuits are designed to be highly efficient to minimize energy use and maximize battery life and time between charges. The stimulator can be programmed to deliver pulses in any value in the following range: 5 microA to 20 mA in 3.3% constant current steps, 7 micros to 2000 micros in 7 micros pulse width steps, and 1 to 4000 Hz in frequency. The preamp voltage sensor covers the range 10 microV to 1.0 V with bandpass filtering and several forms of data analysis. The implant also contains sensors that can read out pressure, temperature, DC magnetic field, and distance (via a low frequency magnetic field) up to 20 cm between any two BION implants. The MCU contains a microprocessor, user interface, two-way communication system, and a rechargeable battery. The MCU can command and interrogate in excess of 800 BlON implants every 10 ms, i.e., 100 times a second.

[Human pancreas procurement for pancreas and islet transplantation]

Insulin-dependent diabetes mellitus is a disease characterized by a deficiency of insulin secretion by beta islet cells. Integral pancreatic transplantation and islet cell transplantation represent two possibilities of replacing the beta islet cells. The aim of this paper is to analyze the main aspects of selection criteria of the pancreas donor and surgical methods of preservation for integral pancreas or islet cell transplantation. There are described the pancreas procurements realized by the Center of General Surgery and Liver Transplantation team from Fundeni Clinical Institute between December 2005-December 2006 and correlation between the donor's and pancreas features and the quality of islet cell isolation. The selection of pancreas donor and the accomplishment of pancreas procurement represent important factors in the post-transplantation course of the graft. The data from pancreas/islet cell transplantation centers suggest that the factors that influence positively the course of graft are: the donor's age, body mass index, cold ischemia time.