Wafer-scale graphene-ferroelectric HfO2/Ge-HfO2/HfO2 transistors acting as three-terminal memristors.

In this paper we report a set of experiments at the wafer level regarding field-effect transistors with a graphene monolayer channel transferred on the ferroelectric HfO2/Ge-HfO2/HfO2 three-layer structure. This kind of transistor has a switching ratio of 103 between on and off states due to the bandgap in graphene induced by the ferroelectric structure. Both top and back gates effectively control the carriers' charge flow in graphene. The transistor acts as a three-terminal memristor, termed a memtransistor, with applications in neuromorphic computation.

Efficacy of annealing and fabrication parameters on photo-response of SiGe in TiO2 matrix.

SiGe nanoparticles dispersed in a dielectric matrix exhibit properties different from those of bulk and have shown great potential in devices for application in advanced optoelectronics. Annealing is a common fabrication step used to increase crystallinity and to form nanoparticles in such a system. A frequent downside of such annealing treatment is the formation of insulating SiO2 layer at the matrix/SiGe interface, degrading the optical properties of the structure. An annealing process that could bypass this downside would therefore be of great interest. In this work, a short-time furnace annealing of a SiGe/TiO2 system is applied to obtain SiGe nanoparticles without formation of the undesired SiO2 layer between the dielectric matrix (TiO2) and SiGe. The structures were prepared by depositing alternate layers of TiO2 and SiGe films, using direct-current magnetron sputtering technique. A wide range spectral response with a response-threshold up to ∼1300 nm was obtained, accompanied with an increase in photo-response of more than two-orders of magnitude. Scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy and grazing incidence x-ray diffraction were used to analyze the morphological changes in respective structures. Photoconductive properties were studied by measuring photocurrent spectra using applied dc-voltages at various temperatures.

Orthorhombic HfO2 with embedded Ge nanoparticles in nonvolatile memories used for the detection of ionizing radiation.

Trilayer memory capacitors of control HfO2/floating gate of Ge nanoparticles in HfO2/tunnel HfO2/Si substrate deposited by magnetron sputtering and subsequently annealed are investigated for the first time for applications in radiation dosimetry. In the floating gate (FG), amorphous Ge nanoparticles (NPs) are arranged in two rows inside the HfO2 matrix. The HfO2 matrix is formed of orthorhombic/tetragonal nanocrystals (NCs). The adjacent thin films to the FG are also formed of orthorhombic/tetragonal HfO2 NCs. This phase is formed during annealing, in samples with thick control HfO2, in the presence of Ge, being induced by the stress. In the rest of the control oxide, HfO2 NCs are monoclinic. Orthorhombic HfO2 has ferroelectric properties and therefore enhances the memory window produced by charge storage in Ge NPs to above 6 V. The high sensitivity of 0.8 mV Gy-1 to α particle irradiation from a 241Am source was measured by monitoring the flatband potential during radiation exposure after electrical writing of the memory.

Single layer of Ge quantum dots in HfO2 for floating gate memory capacitors.

High performance trilayer memory capacitors with a floating gate of a single layer of Ge quantum dots (QDs) in HfO2 were fabricated using magnetron sputtering followed by rapid thermal annealing (RTA). The layer sequence of the capacitors is gate HfO 2/floating gate of single layer of Ge QDs in HfO 2/tunnel HfO 2/p-Si wafers. Both Ge and HfO2 are nanostructured by RTA at moderate temperatures of 600-700 °C. By nanostructuring at 600 °C, the formation of a single layer of well separated Ge QDs with diameters of 2-3 nm at a density of 4-5 × 1015 m-2 is achieved in the floating gate (intermediate layer). The Ge QDs inside the intermediate layer are arranged in a single layer and are separated from each other by HfO2 nanocrystals (NCs) about 8 nm in diameter with a tetragonal/orthorhombic structure. The Ge QDs in the single layer are located at the crossing of the HfO2 NCs boundaries. In the intermediate layer, besides Ge QDs, a part of the Ge atoms is segregated by RTA at the HfO2 NCs boundaries, while another part of the Ge atoms is present inside the HfO2 lattice stabilizing the tetragonal/orthorhombic structure. The fabricated capacitors show a memory window of 3.8 ± 0.5 V and a capacitance-time characteristic with 14% capacitance decay in the first 3000-4000 s followed by a very slow capacitance decrease extrapolated to 50% after 10 years. This high performance is mainly due to the floating gate of a single layer of well separated Ge QDs in HfO2, distanced from the Si substrate by the tunnel oxide layer with a precise thickness.

Wound infections with multi-drug resistant bacteria.

INTRODUCTION: Wound infections remain a public health problem, despite the progress made on improving surgical techniques and antibiotic prophylaxis application. Misuse of antibiotics to prevent bacterial infections leads to increased bacterial resistance and their dissemination. MATERIAL AND METHODS: The study refers to 470 samples taken from wound infections of which only multi-drug resistant strains were selected for study, using two special culture mediums (Metistaph-2 for methicillin-resistant staphylococci and ESBLs-Agar for extended-spectrum betalactamases secreting bacteria). Sensitivity of these strains was tested using the diffusion method. RESULTS: Of all studied samples, a rate of 27.6 bacterial strains showed multi-drug resistance. Among them stood primarily Staphylococcus aureus; both MRSA strains and ESBL Gram negative bacteria studied showed high resistance to aminoglycosides, quinolones, third generation cephalosporins and low to fourth generation cephalosporins. No vancomycin resitant nor vancomycin-intermediate Staphylococcus aureus strains were isolated. CONCLUSIONS: Knowing the antibiotic resistance is very useful in antibiotic "cycling"application, avoiding this way the emergence of increased resistant strains.

Pure pectus carinatum (not associated with pectus excavatum) solved by MIRPC (minimally invasive repair of pectus carinatum) associated with bilateral mamarian hypoplasia solved by bilateral breast implants.

We present the case of a young 24-year-old woman with an important but symmetrical pectus carinatum, not associated with pectus excavatum, without cardiorespiratory symptoms but with significant psychosocial implications for the patient, solved by the minimally invasive technique described by Abramson(reversed Nuss procedure) - MIRPC (Minimally invasive Repair of Pectus carinatum). The sternal malformation was associated with bilateral mammary hypoplasia, solved by bilateral breast implants 10 months later. The evolution was favorable and the aesthetic result was satisfactory for the patient.

Locally recurrent colorectal cancer: results of surgical therapy.

PURPOSE: Up to 20 % of colorectal cancer patients develop recurrent disease despite standardized surgical techniques and multimodal treatment strategies. Radical resection is the central component of curative therapy in these cases. The aim of this study was to evaluate treatment results in patients with locoregionally recurrent colorectal cancer. METHODS: From January 1995 to December 2007, surgery was performed for recurrent colorectal cancer in 82 patients who had undergone curative (R0) resection of their primary tumor. Assessment included patient, tumor and treatment characteristics, postoperative complications, and time without re-recurrence; recurrence-free and overall survival rates were calculated according to the Kaplan-Meier method. RESULTS: Resection was performed in 60 of the 82 patients (73 %), repeat R0 resection in 52 % (31/60). Patients had a postoperative morbidity of 39 % (31/82), a relaparotomy rate of 13 % (11/82), and a lethality of 7 % (6/82). Forty-eight percent of all surgically-treated patients received a permanent stoma. Re-recurrence was seen in 52 % (16/31). R0 resection was associated with a 5-year survival rate of 35 % (11/31). CONCLUSIONS: Extensive reinterventions often enable repeat R0 resection. Despite relevant morbidity, the lethality appears to be acceptable. Decisive for the prognosis is re-recurrence.

[Surgical management of Meckel's diverticulum in adults--retrospective analyses of 62 cases]. / Atitudinea chirurgicala fata de diverticulul Meckel la adult--analiza retrospectiva a unui lot de 62 de cazuri.

Meckel's diverticulum (MD) is the most common congenital anomaly of the small intestine. We searched and analyzed the records of 62 cases with MD admitted in University Emergency Hospital Bucharest between 2001-2009. Sex ratio was M:F 3:1, with 74% male and 26% female. 51.6% (n = 32) of this where symptomatic and 48.4% (n = 30) asymptomatic, discovered during laparotomy for other reasons. The analysis highlights an increased frequency of symptomatic diverticulum at early ages, with a medium age of about 39.2 years comparing to asymptomatic group with a medium age of about 54.2 years. The diverticulum complication generated: occlusion--43.7% (n = 15), inflammation--37.5% (n = 12), bleeding, two cases of diverticulum tumor, an intussusception case and a perforation case with unknown object. 25% of the diverticulectomies were followed by postsurgery complications, the parietal suppuration being the most frequent (50%). Three patients died independent of the diverticulum or its resection, all three having an asymptomatic diverticulum. The difficult diagnosis and the seriousness of diverticulum complications force us to take into consideration DM in all cases of severe or chronic abdominal pain. The diverticulum has to be surgically removed to all patients under 50 years, especially men.

[Complicated Meckel's diverticulum in adult pathology]. / Diverticulul Meckel complicat în patologia adultului.

Meckel's diverticulum is the most prevalent abnormality of the gastrointestinal tract seen in approximately 2% of the population. Diagnosing complicated diverticulum is difficult, for its capacity to mime multiple disorders such as appendicitis, ulcer disease, enterocolitis, Chron disease, sigmoid diverticulitis, cholecystitis, and it should be considered in all patients with unexplained chronic abdominal pain, nausea, vomiting, gastrointestinal bleeding, unexpected cause of intestinal obstruction or acute abdomen. Herewith we provide an illustrative presentation, emphasizing the difficulties in preoperative diagnosis of complicated Meckel's diverticulum and underlining the nonspecific nature of the subjective and objective findings. Both cases were admitted to our clinic with acute abdomen diagnoses--first case as a intestinal obstruction and in second case was acute appendicitis. Laparatomy ascertain that the cause of symptoms was the complicated Meckel's diverticulum.

[Late pancreatic metastasis from primary Grawitz tumor--surgical management]. / Metastaza cefalo-pancreatica tardiva dupa tumora Grawitz operata--atitudine chirurgicala.

Renal cell carcinoma (Grawitz tumor) is an epithelial tumor able, to develop, in some cases, very late metastases. The most frequent localization are: lung, bones and liver. Pancreatic metastasis are rare and appear late, sometime even after 12 years from primary renal tumor. In this cases the differential diagnosis must be made with primary pancreatic tumors. We present a case report of pancreatic metastatic tumor developed 5 years after right nephrectomy for renal cell carcinoma. We decide to perform cephalic duodenopancreatectomy (Wipple type).

Effects of Platelet Rich Fibrin on Full Thickness Skin Grafts in the Rat Model-Planimetry Results.

Platelets play a crucial role in wound healing as they are reservoirs of growth factors and cytokines which play a fundamental role in homeostasis and tissue remodeling. Recently, fields such as dermatology and plastic and reconstructive surgery have become interested in the tissue regenerative properties of these compounds, especially since it promotes wound healing, improves scar outcomes and has rejuvenating effects on the skin and other tissues. We evaluated the effects of Platelet Rich Fibrin (PRF) in full thickness skin graft healing. Our study included 40 male Wistar rats. Skin grafts were assessed macroscopically using planimetry. The full thickness skin grafts in the test group, displayed a lower necrosis rate compared to the control group. Our study displays the potential benefits of using Platelet Rich compounds to facilitate wound healing and integration of full thickness skin grafts.

Palatal Reconstruction after Major Surgical Excision.

Oncological excision surgery in the oral and maxillofacial area amputates important structures or open cavities (sinus, nose, mouth) which are usually "closed". The disappearance of an eye, tongue, soft palate or cheek, raises serious issues regarding the resumption of partial or total functions of that region, in terms of social reintegration of the patient. In the cephalic extremity, the reconstruction material is limited, so specialists resort to resources located away from the defect to achieve closure. The temporal flap isn't used very often, although this procedure has the advantages of a shorter time for surgery and for healing.

A Novel Method of Obtaining Platelet Rich Fibrin from Rats and Quantifying Platelet Count.

BACKGROUND AND OBJECTIVES: Rat experimentation is the first line of research by which a medical hypothesis is usually tested. Platelet Rich Fibrin (PRF) is a relatively new bio-material that has shown promise to enhance healing in the field of bone research and tissue engineering. In order to perform PRF based experiments on rats, a proper protocol of obtaining PRF from rats needs to be established. MATERIALS AND METHODS: 35 Wistar rats were used to obtain PRF by using cardiac puncture blood draw and quick subsequent centrifugation. The PRF samples wereanalyzed and compared to standard literature PRF composition. RESULTS: PRF samples analysis showed persistent results pertaining to known PRF composition. CONCLUSIONS: Our experiment has shown that our protocol of obtaining PRF is capable of providing high quality PRF from rats.

[General principles of abdominal wall reconstruction--20 years of experience]. / Principii generale ale protezarii herniilor incizionale--20 de ani de experienta.

After 20 years of reconstructive abdominal wall surgery and almost five thousand surgical interventions for this pathology, most of them resolved with prosthesis, authors present a retrospective study concerning to increased biocompatibility, world dynamics of alloplastic solution and also the technical surgical problems that appears in incisional hernia repair. There are underlined two concepts: first--the maximal transversal diameter--that define the size of musculo-aponeurosis defect and the span of alloplastic substitution, in opposition to the old idea that allude to the size of hernia sack; the second concept--receptor prosthetic layer--define the interface between abdominal viscera and prosthetic material. This is not just a mechanical divider, being also a conjunctive and vascular support, helping prosthetic tissue integration.

A Rare Case of Upper Calf Swelling and Necrosis - The Morel-Lavallée Lesion.

A 31-year-old patient presented in the Emergency Department with a tibial fracture following a car accident that crushed the lower third of his thigh and the proximal and median part of his calf. Tibial fracture fixation with an intramedullary rod, was complicated by a Morel-Lavallée lesion. Sequential debridement procedures were performed with partially successful granulation tissue proliferation under NPWT (Negative-Pressure Wound Therapy). To further promote the already delaying granulation, plastic surgeons opted for PRP/PRF (Platelet Rich Plasma/Platelet Rich Fibrin) which allowed appropriate skin grafting. In our opinion, PRP/PRF should be considered as a viable adjuvant therapy to promote granulation.

Dense Ge nanocrystals embedded in TiO2 with exponentially increased photoconduction by field effect.

Si and Ge nanocrystals in oxides are of a large interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in nanocrystals. In this work, dense Ge nanocrystals suitable for enhanced photoconduction were fabricated from 60% Ge in TiO2 amorphous layers by low temperature rapid thermal annealing at 550 °C. An exponential increase of the photocurrent with the applied voltage was observed in coplanar structure of Ge nanocrystals composite films deposited on oxidized Si wafers. The behaviour was explained by field effect control of the Fermi level at the Ge nanocrystals-TiO2 layer/substrate interfaces. The blue-shift of the absorption gap from bulk Ge value to 1.14 eV was evidenced in both photocurrent spectra and optical reflection-transmission experiments, in good agreement with quantum confinement induced bandgap broadening in Ge nanocrystal with sizes of about 5 nm as found from HRTEM and XRD investigations. A nonmonotonic spectral dependence of the refractive index is associated to the Ge nanocrystals formation. The nanocrystal morphology is also in good agreement with the Coulomb gap hopping mechanism of T-1/2 -type explaining the temperature dependence of the dark conduction.

Case Presentation of Soft Tissue Defect after Bimalleolar Fracture Osteosynthesis.

A 59-year-old patient presented in the ER with wound dehiscence and skin necrosis on the right ankle, with osteosynthesis implant visible, after open reduction and fixation with plate and screws, performed abroad, 16 days prior to the presentation, for a bimalleolar fracture. The patient was admitted to the plastic surgery department, where surgical debridement of the necrotic tissue was initially performed. Postoperatively, the patient was treated with Negative-pressure wound therapy (VAC dressing) and Platelet rich plasma (PRP) therapy. Upon obtaining granulation tissue without signs of infection, a sural fasciocutaneous flap was performed to cover the skin defect. Proper graft integration and healing was observed.

[External biliary fistulas selectively managed by endoscopic retrograde cholangiography with sphincterotomy and/or stent placement]. / Rolul tratamentului individualizat prin colangiografie endoscopica retrograda cu sfincterotomie si/sau plasare de proteze in fistulele biliare externe.

External bile duct fistulas are inherent postoperative complications that usually appear after biliary tract surgery, traumatic bile duct injuries and liver surgery for hepatic hydatid disease or liver transplant. The management is highly individualized, while the success and long-term results of endoscopic and surgical techniques are conflicting. The study included 32 cases with external bile duct fistulas managed by endoscopic retrograde cholangiography (ERC) with sphincterotomy and/or stent placement, including "rendez-vous" procedures in 2 cases. The causes of the external fistula were represented by cholecystectomy with/without retained common bile duct stones or strictures (22 cases), cholecystectomy and drainage of a subphrenic abscess caused by severe acute pancreatitis (1 case) and surgical interventions for hepatic hydatid disease (9 cases). Due to the prospective protocol of the study we were able to apply an individualized endoscopic treatment: sphincterotomy with proper relief of the bile duct obstruction (stone extraction) or sphincterotomy with large-size (10 Fr) stent placement for large-sized bile duct defects. The results consisted in closure of the fistula in 3.5 +/- 1.7 days for the subgroup of patients with sphincterotomy alone. Among the patients with stent insertion, fistulas healed slower in 14 +/- 3.5 days. There were no complications after endoscopic treatment; however the stent could not be passed in one patient that required subsequent surgery. In conclusion, endoscopic intervention is the treatment of choice for small external biliary fistulas complicating biliary tract surgery or liver surgery for hepatic hydatid disease. When the fistula is large, the placement of a 10 Fr endoprosthesis becomes necessary, while failure of endoscopic treatment leads to surgery with hepatico-jejunal anastomosis.

[Postoperative biliary peritonitis--diagnosis and treatment difficulties]. / Peritonitele biliare postoperatorii--dificultati de diagnostic si tratament.

AIM: To point out the severity of the postoperative biliary peritonitis (PBP) and to established the most proper ways of diagnosis and treatment. MATERIAL AND METHODS: 14 PBP (6 males and 8 females, age between 42 and 76 years) admitted in the last 14 years were analyzed. The PBP occurred after biliary surgery in 13 cases and after gastro-duodenal surgery in 1 case. The delay between the first operation and the establishing of the diagnosis and reoperation varied between 24 hours and more than 3 days. All the patients were operated on; the operation had to fulfill 2 main objectives: the treatment of the peritonitis and to solve the biliary lesions. RESULTS: 6 patients had a fair evolution. We registered 8 complications with a morbidity rate of 57,14% and 2 deaths with a mortality rate of 14,3%. CONCLUSIONS: 1. Postoperative biliary peritonitis is one of the most severe complications of the biliary and gastro-duodenal surgery, due to preoperative unrecognized biliary lesions or occurring as postoperative accidents or complications. 2. The clinical picture, deeply modified by the complex postoperative treatment makes the early diagnosis very difficult and leads to a delay of the re-operation. 3. The treatment is exclusively a surgical one, with two main objectives: the biliary lesion repair and the treatment of the peritonitis. 4. The postoperative biliary peritonitis are charged by a high postoperative morbidity and mortality rate, the delay of the diagnosis and the time of reoperation being the main risk factor.

[Severe acute pancreatitis--diagnostic and therapeutic strategy]. / Pancretitele acute severe--strategie diagnostica si terapeutica.

To establish the optimal diagnosis and therapeutical strategy in severe acute pancreatitis. 94 (56.9%) severe acute pancreatitis (79 males and 15 females, aged between 26 and 81), selected from 165 acute pancreatitis admitted in the last 5 years (2000-2004) were analyzed. The disease was assigned as severe when one or more of the following criteria were present: Ranson score >3 on admission or at 48 hours, APACHE II score >8, visceral failures, Balthazar CT score C, D or E and local complications (infected necrosis, pseudocyst or pancreatic abscess). Medical treatment (aggressive supportive intensive care therapy, minimizing pancreatic secretion and antibiotic therapy) was the first therapeutical step in all cases. 49 (52.1%) patients were operated on: 20 as early surgery imposed by biliary sepsis (16 cases) or by an acute abdomen with uncertain etiology and unfavourable evolution, and 22 as late surgery (at least 12 days after onset), imposed by the presence of the infected pancreatic necrosis, visceral failures or other local complications, the necrosectomy being the main surgical procedure for infected necrosis. 77 (81.9%) cases had a fair evolution. The conservative treatment led to a complete recovery in 37 (37.2%) cases. We registered an overall mortality rate of 12.7% and postoperative mortality rate of 14%; we also registered 5 (10.2%) postoperative complications: 4 pancreatic and 1 colonic fistulae. (1) The treatment of the severe acute pancreatitis must be performed only in the specialized multidisciplinary well equipped centers with very well trained staff. (2) Medical conservative treatment (aggressive supportive intensive care therapy and antibiotic therapy) is the main therapeutical method within the acute phase (first two weeks). (3) Very restrictive surgical indications within the acute phase. (4) Necrosectomy is the main surgical procedure for the infected necrosis.