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1.
Materials (Basel) ; 16(16)2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37629929

ABSTRACT

Metal-oxide-semiconductor (MOS) capacitors with Al2O3 as a gate insulator are fabricated on cubic silicon carbide (3C-SiC). Al2O3 is deposited both by thermal and plasma-enhanced Atomic Layer Deposition (ALD) on a thermally grown 5 nm SiO2 interlayer to improve the ALD nucleation and guarantee a better band offset with the SiC. The deposited Al2O3/SiO2 stacks show lower negative shifts of the flat band voltage VFB (in the range of about -3 V) compared with the conventional single SiO2 layer (in the range of -9 V). This lower negative shift is due to the combined effect of the Al2O3 higher permittivity (ε = 8) and to the reduced amount of carbon defects generated during the short thermal oxidation process for the thin SiO2. Moreover, the comparison between thermal and plasma-enhanced ALD suggests that this latter approach produces Al2O3 layers possessing better insulating behavior in terms of distribution of the leakage current breakdown. In fact, despite both possessing a breakdown voltage of 26 V, the T-ALD Al2O3 sample is characterised by a higher current density starting from 15 V. This can be attributable to the slightly inferior quality (in terms of density and defects) of Al2O3 obtained by the thermal approach and, which also explains its non-uniform dC/dV distribution arising by SCM maps.

2.
Materials (Basel) ; 15(21)2022 Nov 04.
Article in English | MEDLINE | ID: mdl-36363379

ABSTRACT

Copper oxide thin films have been successfully synthesized through a metal-organic chemical vapor deposition (MOCVD) approach starting from the copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate), Cu(tmhd)2, complex. Operative conditions of fabrication strongly affect both the composition and morphologies of the copper oxide thin films. The deposition temperature has been accurately monitored in order to stabilize and to produce, selectively and reproducibly, the two phases of cuprite Cu2O and/or tenorite CuO. The present approach has the advantages of being industrially appealing, reliable, and fast for the production of thin films over large areas with fine control of both composition and surface uniformity. Moreover, the methylammonium lead iodide (MAPI) active layer has been successfully deposited on the ITO/Cu2O substrate by the Low Vacuum Proximity Space Effusion (LV-PSE) technique. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM) analyses have been used to characterize the deposited films. The optical band gap (Eg), ranging from 1.99 to 2.41 eV, has been determined through UV-vis analysis, while the electrical measurements allowed to establish the p-type conductivity behavior of the deposited Cu2O thin films with resistivities from 31 to 83 Ω cm and carrier concentration in the order of 1.5-2.8 × 1016 cm-3. These results pave the way for potential applications of the present system as a hole transporting layer combined with a perovskite active layer in emergent solar cell technologies.

3.
Nanomaterials (Basel) ; 12(8)2022 Apr 13.
Article in English | MEDLINE | ID: mdl-35458046

ABSTRACT

In this study, we deposit a Ge-rich Ge-Sb-Te alloy by physical vapor deposition (PVD) in the amorphous phase on silicon substrates. We study in-situ, by X-ray and ultraviolet photoemission spectroscopies (XPS and UPS), the electronic properties and carefully ascertain the alloy composition to be GST 29 20 28. Subsequently, Raman spectroscopy is employed to corroborate the results from the photoemission study. X-ray diffraction is used upon annealing to study the crystallization of such an alloy and identify the effects of phase separation and segregation of crystalline Ge with the formation of grains along the [111] direction, as expected for such Ge-rich Ge-Sb-Te alloys. In addition, we report on the electrical characterization of single memory cells containing the Ge-rich Ge-Sb-Te alloy, including I-V characteristic curves, programming curves, and SET and RESET operation performance, as well as upon annealing temperature. A fair alignment of the electrical parameters with the current state-of-the-art of conventional (GeTe)n-(Sb2Te3)m alloys, deposited by PVD, is found, but with enhanced thermal stability, which allows for data retention up to 230 °C.

4.
Nanomaterials (Basel) ; 12(2)2022 Jan 06.
Article in English | MEDLINE | ID: mdl-35055201

ABSTRACT

In this paper, we report a multiscale investigation of the compositional, morphological, structural, electrical, and optical emission properties of 2H-MoS2 obtained by sulfurization at 800 °C of very thin MoO3 films (with thickness ranging from ~2.8 nm to ~4.2 nm) on a SiO2/Si substrate. XPS analyses confirmed that the sulfurization was very effective in the reduction of the oxide to MoS2, with only a small percentage of residual MoO3 present in the final film. High-resolution TEM/STEM analyses revealed the formation of few (i.e., 2-3 layers) of MoS2 nearly aligned with the SiO2 surface in the case of the thinnest (~2.8 nm) MoO3 film, whereas multilayers of MoS2 partially standing up with respect to the substrate were observed for the ~4.2 nm one. Such different configurations indicate the prevalence of different mechanisms (i.e., vapour-solid surface reaction or S diffusion within the film) as a function of the thickness. The uniform thickness distribution of the few-layer and multilayer MoS2 was confirmed by Raman mapping. Furthermore, the correlative plot of the characteristic A1g-E2g Raman modes revealed a compressive strain (ε ≈ -0.78 ± 0.18%) and the coexistence of n- and p-type doped areas in the few-layer MoS2 on SiO2, where the p-type doping is probably due to the presence of residual MoO3. Nanoscale resolution current mapping by C-AFM showed local inhomogeneities in the conductivity of the few-layer MoS2, which are well correlated to the lateral changes in the strain detected by Raman. Finally, characteristic spectroscopic signatures of the defects/disorder in MoS2 films produced by sulfurization were identified by a comparative analysis of Raman and photoluminescence (PL) spectra with CVD grown MoS2 flakes.

5.
Nanomaterials (Basel) ; 11(12)2021 Dec 07.
Article in English | MEDLINE | ID: mdl-34947665

ABSTRACT

This paper reports an investigation of the structural, chemical and electrical properties of ultra-thin (5 nm) aluminum nitride (AlN) films grown by plasma enhanced atomic layer deposition (PE-ALD) on gallium nitride (GaN). A uniform and conformal coverage of the GaN substrate was demonstrated by morphological analyses of as-deposited AlN films. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) analyses showed a sharp epitaxial interface with GaN for the first AlN atomic layers, while a deviation from the perfect wurtzite stacking and oxygen contamination were detected in the upper part of the film. This epitaxial interface resulted in the formation of a two-dimensional electron gas (2DEG) with a sheet charge density ns ≈ 1.45 × 1012 cm-2, revealed by Hg-probe capacitance-voltage (C-V) analyses. Nanoscale resolution current mapping and current-voltage (I-V) measurements by conductive atomic force microscopy (C-AFM) showed a highly homogeneous current transport through the 5 nm AlN barrier, while a uniform flat-band voltage (VFB ≈ 0.3 V) for the AlN/GaN heterostructure was demonstrated by scanning capacitance microscopy (SCM). Electron transport through the AlN film was shown to follow the Fowler-Nordheim (FN) tunneling mechanism with an average barrier height of <ΦB> = 2.08 eV, in good agreement with the expected AlN/GaN conduction band offset.

6.
Materials (Basel) ; 14(8)2021 Apr 14.
Article in English | MEDLINE | ID: mdl-33919896

ABSTRACT

In this study, 4H-SiC p-n junctions were irradiated with 700 keV He+ ions in the fluence range 1.0 × 1012 to 1.0 × 1015 ions/cm2. The effects of irradiation were investigated by current-voltage (I-V) and capacitance-voltage (C-V) measurements, while deep-level transient spectroscopy (DLTS) was used to study the traps introduced by irradiation defects. Modifications of the device's electrical performances were observed after irradiation, and two fluence regimes were identified. In the low fluence range (≤1013 ions/cm2), I-V characteristics evidenced an increase in series resistance, which can be associated with the decrease in the dopant concentration, as also denoted by C-V measurements. In addition, the pre-exponential parameter of junction generation current increased with fluence due to the increase in point defect concentration. The main produced defect states were the Z1/2, RD1/2, and EH6/7 centers, whose concentrations increased with fluence. At high fluence (>1013 ions/cm2), I-V curves showed a strong decrease in the generation current, while DLTS evidenced a rearrangement of defects. The detailed electrical characterization of the p-n junction performed at different temperatures highlights the existence of conduction paths with peculiar electrical properties introduced by high fluence irradiation. The results suggest the formation of localized highly resistive regions (realized by agglomeration of point defects) in parallel with the main junction.

7.
Materials (Basel) ; 15(1)2021 Dec 30.
Article in English | MEDLINE | ID: mdl-35009409

ABSTRACT

4H-SiC based p-n junction UV photo-detectors were irradiated with 600 keV He+ in the fluence range of 5 × 1011 ÷ 5 × 1014 ion/cm2 in order to investigate their radiation hardness. The effects of irradiation on the electro-optical performance were monitored in dark condition and in the UV (200 ÷ 400 nm) range, as well as in the visible region confirming the typical visible blindness of unirradiated and irradiated SiC photo-sensors. A decrease of UV optical responsivity occurred after irradiation and two fluence regimes were identified. At low fluence (<1013 ions/cm2), a considerable reduction of optical responsivity (of about 50%) was measured despite the absence of relevant dark current changes. The presence of irradiation induced point defects and then the reduction of photo-generated charge lifetime are responsible for a reduction of the charge collection efficiency and then of the relevant optical response reduction: point defects act as recombination centers for the photo-generated charges, which recombine during the drift/diffusion toward the electrodes. At higher irradiation fluence, the optical responsivity is strongly reduced due to the formation of complex defects. The threshold between low and high fluence is about 100 kGy, confirming the radiation hardness of SiC photo-sensors.

8.
Materials (Basel) ; 12(21)2019 Oct 23.
Article in English | MEDLINE | ID: mdl-31652698

ABSTRACT

This paper reports on the electrical activation and Ohmic contact properties on p-type Al-implanted silicon carbide (4H-SiC). In particular, the contacts were formed on 4H-SiC-implanted layers, subjected to three different post-implantation annealing processes, at 1675 °C, 1175 °C, and 1825 °C. Under these post-implantation annealing conditions, the electrical activation of the Al dopant species increased from 39% to 56%. The Ti/Al/Ni contacts showed an Ohmic behavior after annealing at 950 °C. The specific contact resistance ρc could be lowered by a factor of 2.6 with the increase of the post-implantation annealing temperature. The result can be useful for application in device fabrication. Moreover, the dependence of ρc on the active acceptor concentration followed the thermionic field emission model, with a barrier height of 0.63 eV.

9.
ACS Appl Mater Interfaces ; 9(27): 23164-23174, 2017 Jul 12.
Article in English | MEDLINE | ID: mdl-28603968

ABSTRACT

One of the main challenges to exploit molybdenum disulfide (MoS2) potentialities for the next-generation complementary metal oxide semiconductor (CMOS) technology is the realization of p-type or ambipolar field-effect transistors (FETs). Hole transport in MoS2 FETs is typically hampered by the high Schottky barrier height (SBH) for holes at source/drain contacts, due to the Fermi level pinning close to the conduction band. In this work, we show that the SBH of multilayer MoS2 surface can be tailored at nanoscale using soft O2 plasma treatments. The morphological, chemical, and electrical modifications of MoS2 surface under different plasma conditions were investigated by several microscopic and spectroscopic characterization techniques, including X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), conductive AFM (CAFM), aberration-corrected scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS). Nanoscale current-voltage mapping by CAFM showed that the SBH maps can be conveniently tuned starting from a narrow SBH distribution (from 0.2 to 0.3 eV) in the case of pristine MoS2 to a broader distribution (from 0.2 to 0.8 eV) after 600 s O2 plasma treatment, which allows both electron and hole injection. This lateral inhomogeneity in the electrical properties was associated with variations of the incorporated oxygen concentration in the MoS2 multilayer surface, as shown by STEM/EELS analyses and confirmed by ab initio density functional theory (DFT) calculations. Back-gated multilayer MoS2 FETs, fabricated by self-aligned deposition of source/drain contacts in the O2 plasma functionalized areas, exhibit ambipolar current transport with on/off current ratio Ion/Ioff ≈ 103 and field-effect mobilities of 11.5 and 7.2 cm2 V-1 s-1 for electrons and holes, respectively. The electrical behavior of these novel ambipolar devices is discussed in terms of the peculiar current injection mechanisms in the O2 plasma functionalized MoS2 surface.

10.
Beilstein J Nanotechnol ; 8: 254-263, 2017.
Article in English | MEDLINE | ID: mdl-28243564

ABSTRACT

Molybdenum disulphide (MoS2) is currently regarded as a promising material for the next generation of electronic and optoelectronic devices. However, several issues need to be addressed to fully exploit its potential for field effect transistor (FET) applications. In this context, the contact resistance, RC, associated with the Schottky barrier between source/drain metals and MoS2 currently represents one of the main limiting factors for suitable device performance. Furthermore, to gain a deeper understanding of MoS2 FETs under practical operating conditions, it is necessary to investigate the temperature dependence of the main electrical parameters, such as the field effect mobility (µ) and the threshold voltage (Vth). This paper reports a detailed electrical characterization of back-gated multilayer MoS2 transistors with Ni source/drain contacts at temperatures from T = 298 to 373 K, i.e., the expected range for transistor operation in circuits/systems, considering heating effects due to inefficient power dissipation. From the analysis of the transfer characteristics (ID-VG) in the subthreshold regime, the Schottky barrier height (ΦB ≈ 0.18 eV) associated with the Ni/MoS2 contact was evaluated. The resulting contact resistance in the on-state (electron accumulation in the channel) was also determined and it was found to increase with T as RC proportional to T3.1. The contribution of RC to the extraction of µ and Vth was evaluated, showing a more than 10% underestimation of µ when the effect of RC is neglected, whereas the effect on Vth is less significant. The temperature dependence of µ and Vth was also investigated. A decrease of µ proportional to 1/Tα with α = 1.4 ± 0.3 was found, indicating scattering by optical phonons as the main limiting mechanism for mobility above room temperature. The value of Vth showed a large negative shift (about 6 V) increasing the temperature from 298 to 373 K, which was explained in terms of electron trapping at MoS2/SiO2 interface states.

11.
Beilstein J Nanotechnol ; 8: 467-474, 2017.
Article in English | MEDLINE | ID: mdl-28326237

ABSTRACT

Graphene is an ideal candidate for next generation applications as a transparent electrode for electronics on plastic due to its flexibility and the conservation of electrical properties upon deformation. More importantly, its field-effect tunable carrier density, high mobility and saturation velocity make it an appealing choice as a channel material for field-effect transistors (FETs) for several potential applications. As an example, properly designed and scaled graphene FETs (Gr-FETs) can be used for flexible high frequency (RF) electronics or for high sensitivity chemical sensors. Miniaturized and flexible Gr-FET sensors would be highly advantageous for current sensors technology for in vivo and in situ applications. In this paper, we report a wafer-scale processing strategy to fabricate arrays of back-gated Gr-FETs on poly(ethylene naphthalate) (PEN) substrates. These devices present a large-area graphene channel fully exposed to the external environment, in order to be suitable for sensing applications, and the channel conductivity is efficiently modulated by a buried gate contact under a thin Al2O3 insulating film. In order to be compatible with the use of the PEN substrate, optimized deposition conditions of the Al2O3 film by plasma-enhanced atomic layer deposition (PE-ALD) at a low temperature (100 °C) have been developed without any relevant degradation of the final dielectric performance.

12.
ACS Appl Mater Interfaces ; 9(8): 7761-7771, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-28135063

ABSTRACT

High-quality thin insulating films on graphene (Gr) are essential for field-effect transistors (FETs) and other electronics applications of this material. Atomic layer deposition (ALD) is the method of choice to deposit high-κ dielectrics with excellent thickness uniformity and conformal coverage. However, to start the growth on the sp2 Gr surface, a chemical prefunctionalization or the physical deposition of a seed layer are required, which can effect, to some extent, the electrical properties of Gr. In this paper, we report a detailed morphological, structural, and electrical investigation of Al2O3 thin films grown by a two-steps ALD process on a large area Gr membrane residing on an Al2O3-Si substrate. This process consists of the H2O-activated deposition of a Al2O3 seed layer a few nanometers in thickness, performed in situ at 100 °C, followed by ALD thermal growth of Al2O3 at 250 °C. The optimization of the low-temperature seed layer allowed us to obtain a uniform, conformal, and pinhole-free Al2O3 film on Gr by the second ALD step. Nanoscale-resolution mapping of the current through the dielectric by conductive atomic force microscopy (CAFM) demonstrated an excellent laterally uniformity of the film. Raman spectroscopy measurements indicated that the ALD process does not introduce defects in Gr, whereas it produces a partial compensation of Gr unintentional p-type doping, as confirmed by the increase of Gr sheet resistance (from ∼300 Ω/sq in pristine Gr to ∼1100 Ω/sq after Al2O3 deposition). Analysis of the transfer characteristics of Gr field-effect transistors (GFETs) allowed us to evaluate the relative dielectric permittivity (ε = 7.45) and the breakdown electric field (EBD = 7.4 MV/cm) of the Al2O3 film as well as the transconductance and the holes field-effect mobility (∼1200 cm2 V-1 s-1). A special focus has been given to the electrical characterization of the Al2O3-Gr interface by the analysis of high frequency capacitance-voltage measurements, which allowed us to elucidate the charge trapping and detrapping phenomena due to near-interface and interface oxide traps.

13.
Nanotechnology ; 27(31): 315701, 2016 Aug 05.
Article in English | MEDLINE | ID: mdl-27324844

ABSTRACT

In this paper, nanoscale resolution scanning capacitance microscopy (SCM) and local capacitance-voltage measurements were used to probe the interfacial donor concentration in SiO2/4H-SiC systems annealed in N2O. Such nitrogen-based annealings are commonly employed to passivate SiO2/SiC interface traps, and result both in the incorporation of N-related donors in SiC and in the increase of the mobility in the inversion layer in 4H-SiC MOS-devices. From our SCM measurements, a spatially inhomogeneous donor distribution was observed in the SiO2/4H-SiC system subjected to N2O annealing. Hence, the effect of a phosphorus implantation before the oxide deposition and N2O annealing was also evaluated. In this case, besides an increased average donor concentration, an improvement of the lateral homogeneity of the active doping was also detected. The possible implications of such a pre-implantation doping of the near-interface region on 4H-SiC MOS-devices are discussed.

14.
Beilstein J Nanotechnol ; 4: 234-42, 2013.
Article in English | MEDLINE | ID: mdl-23616943

ABSTRACT

Chemical vapour deposition (CVD) on catalytic metals is one of main approaches for high-quality graphene growth over large areas. However, a subsequent transfer step to an insulating substrate is required in order to use the graphene for electronic applications. This step can severely affect both the structural integrity and the electronic properties of the graphene membrane. In this paper, we investigated the morphological and electrical properties of CVD graphene transferred onto SiO2 and on a polymeric substrate (poly(ethylene-2,6-naphthalene dicarboxylate), briefly PEN), suitable for microelectronics and flexible electronics applications, respectively. The electrical properties (sheet resistance, mobility, carrier density) of the transferred graphene as well as the specific contact resistance of metal contacts onto graphene were investigated by using properly designed test patterns. While a sheet resistance R sh ≈ 1.7 kΩ/sq and a specific contact resistance ρc ≈ 15 kΩ·µm have been measured for graphene transferred onto SiO2, about 2.3× higher R sh and about 8× higher ρc values were obtained for graphene on PEN. High-resolution current mapping by torsion resonant conductive atomic force microscopy (TRCAFM) provided an insight into the nanoscale mechanisms responsible for the very high ρc in the case of graphene on PEN, showing a ca. 10× smaller "effective" area for current injection than in the case of graphene on SiO2.

15.
Int J Surg Case Rep ; 2(6): 150-3, 2011.
Article in English | MEDLINE | ID: mdl-22096711

ABSTRACT

Endometriosis within a perineal scar after a Miles' procedure has not been previously reported in literature. We report a case of a 35-year-old-female who was treated 10 years before at the same institution for a low rectal cancer that presents with two discrete subcutaneous bulges within her perineal wound. Since the patient was asymptomatic and the complete work up for recurrent disease showed no evidence of malignancy, first line therapy was conservative. After two pregnancies and a caesarean section, the patient presented at our observation with enlarged and tender perineal nodules. The patient was treated with a wide excision of the perineal scar en-bloc with the nodules. Final pathology report was consistent with scar endometriosis.

17.
Nanoscale Res Lett ; 6(1): 158, 2011 Feb 21.
Article in English | MEDLINE | ID: mdl-21711667

ABSTRACT

This work reports a nanoscale electro-structural characterisation of Ti/Al ohmic contacts formed on p-type Al-implanted silicon carbide (4H-SiC). The morphological and the electrical properties of the Al-implanted layer, annealed at 1700°C with or without a protective capping layer, and of the ohmic contacts were studied using atomic force microscopy [AFM], transmission line model measurements and local current measurements performed with conductive AFM.The characteristics of the contacts were significantly affected by the roughness of the underlying SiC. In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing. This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions. The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

18.
Lung Cancer ; 64(1): 92-7, 2009 Apr.
Article in English | MEDLINE | ID: mdl-18804892

ABSTRACT

OBJECTIVES: The presence of circulating DNA in plasma of patients with malignant neoplasm has been a known fact for over 30 years. Since then, the concentration of free circulating plasma DNA has been studied as well as the genetic alterations and epigenetic alterations of tumour DNA of patients that suffer from various types of tumours. The analysis of circulating plasma DNA may be a useful marker to get an early diagnosis on malignant neoplasms. This study has been specifically designed to validate the quantification of circulating DNA in order to design a test useful for the early identification of non-small cell lung cancer patients and the monitoring of lung cancer progression. A second aim of this work is the sensibility and specificity evaluation of such method for future applications. METHODS: The quantity of plasma DNA was determined using quantitative Real-Time PCR with amplification of the human telomerase reverse transcriptase (hTERT) gene in 151 patients that suffer from lung cancer and 79 healthy controls. The performance of the test was evaluated with a ROC curve. The relationship between the DNA concentration and main demographic, clinical and pathological variables was examined with logistic regression models as well as multiple linear regression models. RESULTS: The concentration of circulating plasma DNA was about four times higher in patients with lung cancer with respect to the controls (12.8 vs 2.9 ng/mL). The area under the ROC curve was 0.79 (95% CI, 0.710-0.83). The concentration of circulating DNA proved to be an important risk factor for the presence of the illness and a prognostic index in the follow-up. CONCLUSIONS: The use of quantitative Real-Time PCR revealed that higher values of circulating DNA can be found in patients with lung neoplasm compared to the healthy controls. This could have practical implications such as the use in screening programs and a possible prognostic significance in the follow-up.


Subject(s)
Biomarkers, Tumor/blood , Carcinoma, Non-Small-Cell Lung/blood , DNA, Neoplasm/blood , Lung Neoplasms/blood , Neoplastic Cells, Circulating/metabolism , Aged , Biomarkers, Tumor/genetics , Carcinoma, Non-Small-Cell Lung/diagnosis , Case-Control Studies , Female , Humans , Lung Neoplasms/diagnosis , Male , Middle Aged , Neoplasm Staging , Polymerase Chain Reaction , Prognosis , ROC Curve , Sensitivity and Specificity , Telomerase/blood , Telomerase/genetics
19.
Ann Ital Chir ; 78(6): 525-7, 2007.
Article in English | MEDLINE | ID: mdl-18510035

ABSTRACT

OBJECTIVE: The aim of this manuscript is to verify the impact that some recanalization procedures for intestinal continuity could have in bowel function and quality of life. STUDY MATERIAL: We describe a clinical case of a rectal cancer patient who underwent anterior resection of the rectum with colo-anal anastomosis, colo-plasty and diverting ileostomy. RESULTS: After the diverting ileostomy closure, suffered of severe bowel function problems. The establishment of a colo-plasty caused a syndrome of such severe obstructed defecation to necessitate the reestablishment of a diverting ileostomy. DISCUSSION: Anterior resection with total mesorectal excision and colo-anal anastomosis is the gold standard surgical treatment of rectal carcinoma. The so called "anterior resection syndrome" is well known after such surgical procedures. The establishment of a reservoir such as the J-pouch and more recently the transverse pouch (colo-plasty) are procedures used to improve the quality of life after anterior resection of the rectum. CONCLUSIONS: The presence of bowel obstruction without mechanical causes makes us consider the colo-plasty as its cause with a Hirschprung like mechanism or similar to the "obstructed defecation". The peristalsis stops at the colo-plasty level impeding the progression of feces. The colo-plasty or the pouch do not function as a reservoir to accommodate feces, but because they stop the peristalsis.


Subject(s)
Colectomy/adverse effects , Constipation/etiology , Intestinal Obstruction/surgery , Postoperative Complications/surgery , Rectal Neoplasms , Rectum/surgery , Aged , Anastomosis, Surgical , Colectomy/methods , Defecation , Humans , Ileostomy , Intestinal Obstruction/etiology , Male , Postoperative Complications/etiology , Proctocolectomy, Restorative/methods , Quality of Life , Rectal Neoplasms/surgery , Treatment Outcome
20.
World J Emerg Surg ; 1: 30, 2006 Oct 05.
Article in English | MEDLINE | ID: mdl-17022807

ABSTRACT

BACKGROUND: Penetrating chest injuries account for 1-13% of thoracic trauma hospital admissions and most of these are managed with a conservative approach. Nevertheless, 18-30% of cases managed only with tube thoracostomy have residual clotted blood, considered the major risk factor for the development of fibrothorax and empyema. In addition, 4-23% of chest injury patients present persistent pneumothorax and 15-59% present an injury to the diaphragm, which is missed in 30% of cases. In order to make a correct diagnosis, reduce the number of missed injuries, chronic sequelae and late mortality we propose performing surgical exploration of all patients with a penetrating injury of the pleural cavity. METHODS: 1270 patients who sustained thoracic trauma were admitted to our hospital between 1994 and 2004. Of these, 16 patients had penetrating injuries: thirteen were surgically explored by means of Video Assisted Thoracic Surgery (VATS), and 3 with thoracotomy due to hemodynamic instability or suspected lesion of the heart or great vessels. RESULTS: In the 13 patients who underwent VATS, 5 injuries to the diaphragm, 3 lesions to an intercostal artery, and 1 lesion to the diaphragmatic artery were detected. In 12 of these patients a laceration of the pulmonary parenchyma was also present. A conversion to thoracotomy was necessary due to a broad laceration of the diaphragm and due to hemostasis of an intercostal artery. In all but one case, which was later converted, diagnostic imaging missed the diagnosis of laceration of the diaphragm. There was no intra- or postoperative mortality, and average hospital stay was five days. CONCLUSION: VATS is a safe and effective way to diagnose and manage penetrating thoracic injuries, and its extensive use leads to a reduction in the number of missed, potentially fatal lesions as well as in chronic sequelae.

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