Recent Progress and Prospects in Catalytic Water Treatment.

Presently, conventional technologies in water treatment are not efficient enough to completely mineralize refractory water contaminants. In this context, the implementation of catalytic processes could be an alternative. Despite the advantages provided in terms of kinetics of transformation, selectivity, and energy saving, numerous attempts have not yet led to implementation at an industrial scale. This review examines investigations at different scales for which controversies and limitations must be solved to bridge the gap between fundamentals and practical developments. Particular attention has been paid to the development of solar-driven catalytic technologies and some other emerging processes, such as microwave assisted catalysis, plasma-catalytic processes, or biocatalytic remediation, taking into account their specific advantages and the drawbacks. Challenges for which a better understanding related to the complexity of the systems and the coexistence of various solid-liquid-gas interfaces have been identified.

New MgFeAl-LDH Catalysts for Claisen-Schmidt Condensation.

A rapid, cheap and feasible new approach was used to synthesize the Mg0.375Fe0.375Al0.25-LDH in the presence of tetramethylammonium hydroxide (TMAH), as a nontraditional hydrolysis agent, applying both mechano-chemical (MC) and co-precipitation methods (CP). For comparison, these catalysts were also synthesized using traditional inorganic alkalis. The mechano-chemical method brings several advantages since the number of steps and the energy involved are smaller than in the co-precipitation method, while the use of organic alkalis eliminates the possibility of contaminating the final solid with alkaline cations. The memory effect was also investigated. XRD studies showed Fe3O4 as stable phase in all solids. Regardless of the alkalis and synthesis methods used, the basicity of catalysts followed the trend: mixed oxides > parent LDH > hydrated LDH. The catalytic activity of the catalysts in the Claisen−Schmidt condensation between benzaldehyde and cyclohexanone showed a linear dependence to the basicity values. After 2 h, the calcined sample cLDH-CO32−/OH−-CP provided a conversion value of 93% with a total selectivity toward 2,6-dibenzylidenecyclohexanone. The presence of these catalysts in the reaction media inhibited the oxidation of benzaldehyde to benzoic acid. Meanwhile, for the self-condensation of cyclohexanone, the conversions to mono- and di-condensed compounds did not exceed 3.8%.

DES-Based Biocatalysis as a Green Alternative for the l-menthyl Ester Production Based on l-menthol Acylation.

The deep eutectic solvent (DES)-based biocatalysis of l-menthol acylation was designed for the production of fatty acid l-menthyl ester (FME) using fatty acid methyl ester (FAME). The biocatalytic reaction was assisted by a lipase enzyme in the DES reaction medium. ւՒ-menthol and fatty acids (e.g., CA-caprylic acid; OA-oleic acid; LiA-linoleic acid; and LnA-linolenic acid) were combined in the binary mixture of DES. In this way, the DES provided a nonpolar environment for requested homogeneity of a biocatalytic system with reduced impact on the environment. The screening of lipase enzyme demonstrated better performance of immobilized lipase compared with powdered lipase. The performance of the biocatalytic system was evaluated for different DES compositions (type and concentration of the acid component). l-menthol:CA = 73:27 molar ratio allowed it to reach a maximum conversion of 95% methyl lauric ester (MLE) using a NV (Candida antarctica lipase B immobilized on acrylic resin) lipase biocatalyst. The recyclability of biocatalysts under optimum conditions of the system was also evaluated (more than 80% recovered biocatalytic activity was achieved for the tested biocatalysts after five reaction cycles). DES mixtures were characterized based on differential scanning calorimetry (DSC) and refractive index analysis.

Advances in porous and nanoscale catalysts for viable biomass conversion.

Heterogeneous catalysis is a promising technology for the valorization of renewable biomass to sustainable advanced fuels and fine chemicals. Porosity and nanostructure are the most versatile features of heterogeneous solid catalysts, which can greatly determine the accessibility of specific active sites, reaction mechanisms, and the selectivity of desirable products. Hence, the precise tuning of porosity and nanostructure has been a potential strategy towards developing novel solid catalysts with indispensable characteristics for efficient biomass valorization. Herein, we present a timely and comprehensive review of the recent advances in catalytic biomass conversions over microporous zeolites, mesoporous silicas, and nanostructured metals/metal oxides. This review covers the catalytic processing of both edible (lipids and starch) and non-edible (lignocellulose) biomass as well as their derived compounds, along with a systematic evaluation of catalyst reusability/kinetic/mechanistic aspects in the relevant processes. The key parameters essential for tailoring particle size, morphology, porosity, acid-base, and redox properties of solid catalysts are emphasized, while discussing the ensuing catalytic effects towards the selective conversion of biomass into desirable chemicals. Special attention has been drawn to understand the role of water in liquid phase biomass conversions as well as the hydrothermal stability and the deactivation of nanoporous catalysts. We believe this comprehensive review will provide new insights towards developing state-of-the-art solid catalysts with well-defined porosity and nanoscale properties for viable biomass conversion.

Optimized Nb-Based Zeolites as Catalysts for the Synthesis of Succinic Acid and FDCA.

Nb(0.05 moles%)-zeolites prepared via a post synthesis methodology (BEA, Y, ZSM-5), or a direct sol-gel method (Silicalite-1) were investigated in the hydroxymethylfurfural (HMF) oxidation by both molecular oxygen, in aqueous phase, and organic peroxides, in acetonitrile. The catalysts prepared through the post synthesis methodology (i.e., Nb-Y5, Nb-ZSM25, Nb-Y30, Nb-BEA12, and Nb-BEA18) displayed a mono-modal mesoporosity and contain residual framework Al-acid sites, extra framework isolated Nb(V)O-H and Nb2O5 pore-encapsulated clusters, while Nb-Sil-1, prepared through a direct synthesis procedure, displayed a bimodal micro-mesoporosity and contains only -Nb=O species. These modified zeolites behave as efficient catalysts in both HMF/glucose wet oxidation to succinic acid (SA) and HMF oxidation with organic peroxides to the 2,5-furandicarboxylic acid (FDCA). The catalytic behavior of these catalysts, in terms of conversion and especially the selectivity, mainly depended on the base/acid sites ratio. Thus, the HMF/glucose wet oxidation occurred with a total conversion and a selectivity to SA of 37.7% (from HMF) or 69.1% (from glucose) on the Nb-Y5 catalyst, i.e., the one with the lowest base/acid sites ratio. On the contrary, the catalysts with the highest base/acid sites ratio, i.e., Nb-ZSM25 and Nb-Sil-1, afforded a high catalytic efficiency in HMF oxidation with organic peroxides, in which FDCA was produced with selectivities of 61.3-63.8% for an HMF conversion of 96.7-99.0%.

Unbiased Measurement of Phosphate and Phosphorus Speciation in Surface Waters.

Trace-level phosphate analysis and phosphorus speciation in surface water remained challenging due to adsorption and phosphate uptake by microorganisms. In this study a two-dimensional ion chromatography separation coupled to electrospray ionization high-resolution mass spectrometry (2D-IC-ESI-MS) allowed isotope dilution quantitation of phosphate with simultaneous analysis of 11 phosphate-containing metabolites and two inorganic condensed phosphates. Samples were collected from Lake St. Clair, Lake Ontario, and Georgian Bay (ON, Canada). Comparative experiments showed lower phosphate results for samples not immediately spiked and for external calibration quantitation. Field spiking with 18O-labeled phosphate combined with isotope dilution quantitation allows measurement of the phosphate levels existent at the collection time instead of the phosphate concentrations remaining in the samples at the analysis time. This is a significant advantage against the traditional colorimetric and ion chromatographic (IC) analysis methods, which are unable to compensate for the adsorption loss occurring in standards and samples, especially when phosphate is present at levels below 20 µg L-1 as P (61 µg L-1 as PO43-). Two phosphate-containing metabolites, adenosine 5'-monophosphate (AMP) and d-glucose 6-phosphate (Glucose-P), were detected in a subset of samples collected from Lake St. Clair, with no statistically significant correlation between them and the simultaneously measured phosphate. Directly bioavailable P (phosphate), indirectly bioavailable P (phosphatase-hydrolyzed P) and nonbioavailable P (nonhydrolizable P) fractions were quantified by measuring phosphate, phosphate after phosphatase addition and total phosphorus. The proposed 2D-IC-ESI-MS method developed for a QExactive MS instrument with field spiking of the internal standard provides accurate phosphate results and eliminates quantitation errors caused by phosphate adsorption. This setup allows simultaneous collection of targeted and nontargeted analysis data and thus the detection of trace polar organic phosphorus metabolites as well.

Functionalised heterogeneous catalysts for sustainable biomass valorisation.

Efficient transformation of biomass to value-added chemicals and high-energy density fuels is pivotal for a more sustainable economy and carbon-neutral society. In this framework, developing potential cascade chemical processes using functionalised heterogeneous catalysts is essential because of their versatile roles towards viable biomass valorisation. Advances in materials science and catalysis have provided several innovative strategies for the design of new appealing catalytic materials with well-defined structures and special characteristics. Promising catalytic materials that have paved the way for exciting scientific breakthroughs in biomass upgrading are carbon materials, metal-organic frameworks, solid phase ionic liquids, and magnetic iron oxides. These fascinating catalysts offer unique possibilities to accommodate adequate amounts of acid-base and redox functional species, hence enabling various biomass conversion reactions in a one-pot way. This review therefore aims to provide a comprehensive account of the most significant advances in the development of functionalised heterogeneous catalysts for efficient biomass upgrading. In addition, this review highlights important progress ensued in tailoring the immobilisation of desirable functional groups on particular sites of the above-listed materials, while critically discussing the role of consequent properties on cascade reactions as well as on other vital processes within the bio-refinery. Current challenges and future opportunities towards a rational design of novel functionalised heterogeneous catalysts for sustainable biomass valorisation are also emphasized.

Impact of SCILL catalysts for the S-S coupling of thiols to disulfides.

This study reports the behaviour of SCILL based catalysts in the oxidative S-S coupling of aliphatic and aromatic thiols, namely 1-butanethiol and thiophenol, to dibutyl disulfide and diphenyl disulfide. A range of ionic liquids (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide) and metal supported catalysts (5% Pt/SiO2; 5% Ru/SiO2; 5% Ru/C; 5% Pt/OMS-2) were used to prepare the SCILL catalysts and all were found to be active for the reaction following the trend 5% Pt-OMS-2 > 5% Pt/SiO2 > 5% Ru/C > 5% Ru/SiO2. The presence of SCILL catalysts afforded high selectivity to the disulfide, and the activity of the SCILL catalyst was dependent on the ionic liquid used. A significant increase in the stability of all the supported metal catalysts was found in the presence of the ionic liquid, and there was no change in the selectivity towards disulfides. This demonstrated that the ionic liquids protect the active sites of the catalyst against sulfation, thus providing more stable and active catalysts.

Anthropogenic Perchlorate Increases since 1980 in the Canadian High Arctic.

An ice core of 15.5 m retrieved from Agassiz Ice Cap (Nunavut, Canada) in April 2009 was analyzed for perchlorate to obtain a temporal trend in the recent decades and to better understand the factors affecting High Arctic deposition. The continuous record dated from 1936 to 2007, covers the periods prior to and during the major atmospheric releases of organic chlorine species that affected the stratospheric ozone levels. Concentrations and yearly fluxes of perchlorate and chloride showed a significant correlation for the 1940-1959 period, suggesting a predominant tropospheric formation by lightning. While concentration of chloride remained unchanged from 1940s until 2009, elevated levels of perchlorate were observed after 1979. A lack of significant increases in either sulfate or chloride between 1980 and 2001 suggests that the effect of volcanic activities on the perchlorate at the study site during this period could be insignificant. Therefore, the elevated perchlorate in the ice could most likely be attributed to anthropogenic activities that influenced perchlorate sources and formation mechanisms after 1979. Our results show that anthropogenic contribution could be responsible for 66% of perchlorate found in the ice. Although with some differences in trends and amounts, deposition rate found in this study is similar to those observed at Devon Island (Nunavut, Canada), Eclipse Icefield (Yukon, Canada) and Summit Station (Greenland). Methyl chloroform, a chlorinated solvent largely used after 1976, peaked in the atmosphere in 1990 and has a much shorter atmospheric life than chlorofluorocarbons (CFCs). This study proposes methyl chloroform (CH3CCl3) as the significant anthropogenic source of perchlorate in the Canadian High Arctic between 1980 and 2000, with HCFC-141b (Cl2FC-CH3), a relatively short-lived CFC probably responsible for a slower decrease in perchlorate deposition after the late 1990s. The presence of aerosols in the stratosphere appears to suppress perchlorate production after 1974. As both methyl chloroform and HCFC-141b had no new significant emissions after 2003, deposition of perchlorate in High Arctic is expected to remain at pre-1980 levels.

Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose.

The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%)-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V) and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA) which, further, suffers an oxidation process to succinic acid (SA). After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.

Human mannose-binding lectin inhibitor prevents Shiga toxin-induced renal injury.

Hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC HUS) is a worldwide endemic problem, and its pathophysiology is not fully elucidated. Here we tested whether the mannose-binding lectin (MBL2), an initiating factor of lectin complement pathway activation, plays a crucial role in STEC HUS. Using novel human MBL2-expressing mice (MBL2 KI) that lack murine Mbls (MBL2(+/+)Mbl1(-/-)Mbl2(-/-)), a novel STEC HUS model consisted of an intraperitoneal injection with Shiga toxin-2 (Stx-2) with or without anti-MBL2 antibody (3F8, intraperitoneal). Stx-2 induced weight loss, anemia, and thrombocytopenia and increased serum creatinine, free serum hemoglobin, and cystatin C levels, but a significantly decreased glomerular filtration rate compared with control/sham mice. Immunohistochemical staining revealed renal C3d deposition and fibrin deposition in glomeruli in Stx-2-injected mice. Treatment with 3F8 completely inhibited serum MBL2 levels and significantly attenuated Stx-2 induced-renal injury, free serum hemoglobin levels, renal C3d, and fibrin deposition and preserved the glomerular filtration rate. Thus, MBL2 inhibition significantly protected against complement activation and renal injury induced by Stx-2. This novel mouse model can be used to study the role of complement, particularly lectin pathway-mediated complement activation, in Stx-2-induced renal injury.

Human mannose-binding lectin inhibitor prevents myocardial injury and arterial thrombogenesis in a novel animal model.

Myocardial infarction and coagulation disorders are leading causes of disability and death in the world. An important role of the lectin complement pathway in myocardial infarction and coagulation has been demonstrated in mice genetically deficient in lectin complement pathway proteins. However, these studies are limited to comparisons between wild-type and deficient mice and lack the ability to examine reversal/inhibition of injury after disease establishment. We developed a novel mouse that expresses functional human mannose-binding lectin (MBL) 2 under the control of Mbl1 promoter. Serum MBL2 concentrations averaged approximately 3 µg/mL in MBL2(+/+)Mbl1(-/-)Mbl2(-/-) [MBL2 knock in (KI)] mice. Serum MBL2 level in MBL2 KI mice significantly increased after 7 (8 µg/mL) or 14 (9 µg/mL) days of hyperglycemia compared to normoglycemic mice (P < 0.001). Monoclonal antibody 3F8 inhibited C3 deposition on mannan-coated plates in MBL2 KI, but not wild-type, mice. Myocardial ischemia/reperfusion in MBL2 KI mice revealed that 3F8 preserved cardiac function and decreased infarct size and fibrin deposition in a time-dependent manner. Furthermore, 3F8 prevented ferric chloride-induced occlusive arterial thrombogenesis in vivo. MBL2 KI mice represent a novel animal model that can be used to study the lectin complement pathway in acute and chronic models of human disease. Furthermore, these novel mice demonstrate the therapeutic window for MBL2 inhibition for effective treatment of disease and its complications.

One-Step Pyrolysis Preparation of 1.1.1 Oriented Gold Nanoplatelets Supported on Graphene and Six Orders of Magnitude Enhancement of the Resulting Catalytic Activity.

Pyrolysis of chitosan films containing Au(3+) renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3-4 nm height) on a few layers of N-doped graphene (Au/fl-G), while the lateral sides were 0.0.1 oriented. Comparison of the catalytic activity of Au/fl-G films with powders of unoriented Au NPs supported on graphene showed that Au/fl-G films exhibit six orders of magnitude enhancement for three gold-catalyzed reactions, namely, Ullmann-like homocoupling, C-N cross coupling, and the oxidative coupling of benzene to benzoic acid. This enhancement is the result of the defined morphology, facet orientation of Au nanocrystals, and strong gold-graphene interaction.

Mannose-binding lectin-associated serine protease-1 is a significant contributor to coagulation in a murine model of occlusive thrombosis.

Bleeding disorders and thrombotic complications constitute a major cause of death and disability worldwide. Although it is known that the complement and coagulation systems interact, no studies have investigated the specific role or mechanisms of lectin-mediated coagulation in vivo. FeCl(3) treatment resulted in intra-arterial occlusive thrombogenesis within 10 min in wild-type (WT) and C2/factor B-null mice. In contrast, mannose-binding lectin (MBL)-null and MBL-associated serine protease (MASP)-1/-3 knockout (KO) mice had significantly decreased FeCl(3)-induced thrombogenesis. Reconstitution with recombinant human (rh) MBL restored FeCl(3)-induced thrombogenesis in MBL-null mice to levels comparable to WT mice, suggesting a significant role of the MBL/MASP complex for in vivo coagulation. Additionally, whole blood aggregation demonstrated increased MBL/MASP complex-dependent platelet aggregation. In vitro, MBL/MASP complexes were captured on mannan-coated plates, and cleavage of a chromogenic thrombin substrate (S2238) was measured. We observed no significant differences in S2238 cleavage between WT, C2/factor B-null, MBL-A(-/-), or MBL-C(-/-) sera; however, MBL-null or MASP-1/-3 KO mouse sera demonstrated significantly decreased S2238 cleavage. rhMBL alone failed to cleave S2238, but cleavage was restored when rMASP-1 was added to either MASP-1/-3 KO sera or rhMBL. Taken together, these findings indicate that MBL/MASP complexes, and specifically MASP-1, play a key role in thrombus formation in vitro and in vivo.

Highly Efficient Ru-Based Catalysts for Lactic Acid Conversion to Alanine.

The primary objective of this research was to develop efficient solid catalysts that can directly convert the lactic acid (LA) obtained from lignocellulosic biomass into alanine (AL) through a reductive amination process. To achieve this, various catalysts based on ruthenium were synthesized using different carriers such as multi-walled carbon nanotubes (MWCNTs), beta-zeolite, and magnetic nanoparticles (MNPs). Among these catalysts, Ru/MNP demonstrated a remarkable yield of 74.0% for alanine at a temperature of 200 °C. This yield was found to be superior not only to the Ru/CNT (55.7%) and Ru/BEA (6.6%) catalysts but also to most of the previously reported catalysts. The characterization of the catalysts and their catalytic results revealed that metallic ruthenium nanoparticles, which were highly dispersed on the external surface of the magnetic carrier, significantly enhanced the catalyst's ability for dehydrogenation. Additionally, the -NH2 basic sites on the catalyst further facilitated the formation of alanine by promoting the adsorption of acidic reactants. Furthermore, the catalyst could be easily separated using an external magnetic field and exhibited the potential for multiple reuses without any significant loss in its catalytic performance. These practical advantages further enhance its appeal for applications in the reductive amination of lactic acid to alanine.

Endogenous and natural complement inhibitor attenuates myocardial injury and arterial thrombogenesis.

BACKGROUND: Coagulation disorders and reperfusion of ischemic myocardium are major causes of morbidity and mortality. Lectin pathway initiation complexes are composed of multimolecular carbohydrate recognition subcomponents and 3 lectin pathway-specific serine proteases. We have recently shown that the lectin pathway-specific carbohydrate recognition subcomponent mannose-binding lectin plays an essential role in the pathophysiology of thrombosis and ischemia/reperfusion injury. Thus, we hypothesized that the endogenous mannose-binding lectin (MBL)/ficolin-associated protein-1 (MAP-1) that inhibits complement activation in vitro also could be an in vivo regulator by attenuating myocardial schema/reperfusion injury and thrombogenesis when used at pharmacological doses in wild-type mice. METHODS AND RESULTS: In 2 mouse models, MAP-1 preserves cardiac function, decreases infarct size, decreases C3 deposition, inhibits MBL deposition, and prevents thrombogenesis. Furthermore, we demonstrate that MAP-1 displaces MBL/ficolin-associated serine protease (MASP)-1, MASP-2, and MASP-3 from the MBL complex. CONCLUSIONS: Our results suggest that the natural, endogenous inhibitor MAP-1 effectively inhibits lectin pathway activation in vivo. MAP-1 at pharmacological doses represents a novel therapeutic approach for human diseases involving the lectin pathway and its associated MASPs.

Targeting mannose-binding lectin confers long-lasting protection with a surprisingly wide therapeutic window in cerebral ischemia.

BACKGROUND: The involvement of the complement system in brain injury has been scarcely investigated. Here, we document the pivotal role of mannose-binding lectin (MBL), one of the recognition molecules of the lectin complement pathway, in brain ischemic injury. METHODS AND RESULTS: Focal cerebral ischemia was induced in mice (by permanent or transient middle cerebral artery occlusion) and rats (by 3-vessel occlusion). We first observed that MBL is deposited on ischemic vessels up to 48 hours after injury and that functional MBL/MBL-associated serine protease 2 complexes are increased. Next, we demonstrated that (1) MBL(-/-) mice are protected from both transient and permanent ischemic injury; (2) Polyman2, the newly synthesized mannosylated molecule selected for its binding to MBL, improves neurological deficits and infarct volume when given up to 24 hours after ischemia in mice; (3) anti-MBL-A antibody improves neurological deficits and infarct volume when given up to 18 hours after ischemia, as assessed after 28 days in rats. CONCLUSIONS: Our data show an important role for MBL in the pathogenesis of brain ischemic injury and provide a strong support to the concept that MBL inhibition may be a relevant therapeutic target in humans, one with a wide therapeutic window of application.

Absence of mannose-binding lectin prevents hyperglycemic cardiovascular complications.

Diabetes, stress, pharmaceuticals, surgery, and physical trauma can lead to hyperglycemic conditions. A consistent relationship has been found between chronic inflammation and the cardiovascular complications of hyperglycemia. We hypothesized that cardiomyopathy and vasculopathy resulting from acute hyperglycemia are dependent on mannose-binding lectin (MBL) and lectin complement pathway activation. Hyperglycemia was induced in wild-type (WT) C57BL/6 and MBL-null mice after streptozotocin administration. Echocardiographic data and tissue samples were collected after 4, 7, or 14 days of acute hyperglycemia. Hyperglycemic WT mice demonstrated dilated cardiomyopathy with significantly increased short and long axis area measurements during systole and diastole compared to hyperglycemic MBL-null mice. The EC(50) for acetylcholine-induced relaxation of mesenteric arterioles in WT mice after 4 days of hyperglycemia demonstrated a significant loss of nitric oxide-mediated relaxation compared to normoglycemic WT or hyperglycemic MBL-null mice. Myocardial histochemistry and Western blot analysis revealed a significant influx of macrophages, altered morphology, and increased elastin and collagen deposition in hyperglycemic WT hearts compared to MBL-null hearts. Serum transforming growth factor-ß1 levels were significantly lower in hyperglycemic MBL-null compared to WT mice, suggesting decreased profibrotic signaling. Together, these data suggest that MBL and the lectin complement pathway play a significant role in vascular dysfunction and cardiomyopathy after acute hyperglycemia.

Local surgical treatment with curative intent in rectal cancer.

The surgical treatment of rectal cancer includes radical resection techniques and local excision procedures. Radical resection techniques are still the golden standard in the management of rectal cancer, but the increased postoperative morbidity and mortality led to the idea that less traumatizing procedures of local excision may have the same oncologic results, in selected cases. Yet, the significantly higher local recurrence rate after local excision in comparison to radical resection has been certified by most studies; that points out the need of clearly defined guidelines for local excision. In the present review the following aspects were taken into consideration, when considering local surgical excision as a radical procedure for rectal cancer: the clinico-pathological features of the tumours, the various types of surgical techniques used in local excision, the need for an adjuvant or neoadjuvant oncological treatment, the variety of results obtained in a large number of studies, making this particular issue a topic that is currently subject to debate.

Problems of diagnosis and treatment caused by ingested foreign bodies.

An ingested foreign body often passes the gastrointestinal tract without any complications. Foreign bodies, such as fish bones, chicken bones and toothpicks, have been known to cause perforation of the gastrointestinal tract. We present 4 cases: the first 2 of a 27-year-old male and a 48-years-old female respectively, with acute abdomen, diffuse purulent peritonitis, with ileum perforation, both caused by accidentally ingesting a wire, 1 case of a 64-year-old male with sigmoid perforation, caused by accidentally ingesting a toothpick and 1 case of a 52-year-old female presented with left buttock painful swelling for 1 week associated with fever,physical examination revealed an ischiorectal abscess.During incision and drainage a 3 cm chicken bone was found inside the abscess cavity. Evolution was favorable in all 4 cases.