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espanolObjetivo Valorar la utilidad de la 18F-DOPA PET/TC cerebral en el diagnostico diferencial de lesiones cerebrales con RM no concluyente. Material y metodos Se estudiaron 12 pacientes, con un total de 16 lesiones, sin diagnostico definitivo tras RM cerebral. Se adquirio estudio 18F-DOPA PET/TC cerebral con doble adquisicion a los 20 y 90 minutos. Se realizo valoracion visual y semicuantitativa con calculo del SUVmax de las lesiones y calculo del ratio T/S (tumor/estriado contralateral) y ratio T/N (tumor/parenquima sano contralateral) para cada uno de los tiempos. Resultados Con base en la escala de valoracion visual y utilizando los ratios T/S ≥ 1 y T/N ≥ 1,3 para determinar la positividad de un estudio, los valores de sensibilidad (S), especificidad (E) y valor predictivo positivo (VPP) han sido los siguientes: valoracion visual (S 100%, E 33,3%, VPP 71,4%), ratio T/S (S 90%, E 100%, VPP 100%) y ratio T/N (S 100%, E 16,6%, VPP 66,6%). Ninguna lesion mostro un aumento del SUVmax en la adquisicion tardia. La 18F- DOPA PET/TC modifico el comportamiento terapeutico en el 75% de los pacientes. Conclusion La 18F-DOPA PET/TC es una herramienta util para diferenciar la etiologia de lesiones cerebrales con RM no concluyente. La imagen tardia (dual point) no aporta un valor anadido al diagnostico final. Los estudios con F-DOPA tienen impacto en el manejo del paciente modificando la conducta terapeutica. EnglishAim To evaluate the utility of brain 18F-DOPA PET/CT in the differential diagnosis of brain lesions with inconclusive MRI. Material and methods Twelve patients were studied, with a total of 16 lesions, without definitive diagnosis after brain MRI. A double acquisition PET/CT brain scan was acquired at 20 and 90 minutes. Visual and semiquantitative assessment was performed with SUVmax calculation of the lesions and calculation of the T/S ratio (tumor/contralateral striatum) and T/N ratio (tumor/contralateral healthy parenchyma) for each time. Results Based on the visual assessment scale and using T/S ratio ≥ 1 and T/N ratio ≥ 1.3 to determine malignancy, the values of sensitivity (S), specificity (E) and positive predictive value (PPV) were: visual assessment (S 100%, E 33.3%, VPP 71.4%), T/S ratio (S 90%, E 100%, VPP 100%) and T/N ratio (S 100%, E 16.6%, VPP 66.6%). No lesion showed an increase in SUVmax in late acquisition. 18F-DOPA PET/CT modified treatment in 75% of the patients. Conclusion 18F-DOPA PET/CT is a useful tool in the study of brain lesions with inconclusive MRI. Late imaging (dual-point) has no added value in the final diagnosis. F-DOPA has an impact on patient management modifying therapeutic behavior.

Aim To evaluate the utility of brain 18F-DOPA PET/CT in the differential diagnosis of brain lesions with inconclusive MRI. Material and methods Twelve patients were studied, with a total of 16 lesions, without definitive diagnosis after brain MRI. A double acquisition PET/CT brain scan was acquired at 20 and 90 min. Visual and semiquantitative assessment was performed with SUVmax calculation of the lesions and calculation of the T/S Ratio (tumor/contralateral striatum) and T/N Ratio (contralateral healthy tumor/parenchyma) for each time. Results Based on the visual assessment scale and using T/S ratio ≥1 and T/N ratio ≥1.3 to determine malignancy, the values of sensitivity (S), specificity (E) and positive predictive value (PPV) were: visual assessment (S 100%, E 33.3%, VPP 71.4%), T/S Ratio (S 90%, E 100%, VPP 100%) and T/N Ratio (S 100%, E 16.6%, VPP 66.6 %). No lesion showed an increase in SUVmax in late acquisition. 18F-DOPA PET/CT modified treatment in 75% of the patients. Conclusion 18F-DOPA PET/CT is a useful tool in the study of brain lesions with inconclusive MRI. Late imaging (dual-point) has no added value in the final diagnosis. FDOPA has an impact on patient management modifying therapeutic behavior.

8 Figuras.- 4 Tablas, Pd and PdM (M = Fe or Co) nanostructured electrocatalysts were synthesized by the impregnation method and supported on carbon black Vulcan XC-72R for the formic acid oxidation reaction, FAOR, in acid medium. Nitrates or chlorides were used as Fe and Co precursors to study the counter ion role on the physicochemical features and electrochemical performance of the electrocatalysts. TEM analysis showed that PdM was deposited on the carbon material with a particle size around 2–3 nm. From XRD, peaks associated with the fcc palladium planes were observed along with evidence of PdM alloy formation, particularly when the nitrate salts were used as metal precursors. Furthermore, XPS analyses indicated that nitrates promote the metal oxide formation to a greater extent than chlorides, mainly for Pd. PdCo electrocatalyst obtained from nitrates exhibited the highest performance for FAOR with a steady state current density of 451 and 313 μA cm−2 at 200 and 400 mV respectively, which is in both cases, 3 times larger than that developed for a commercial Pd/C catalyst., LJM is grateful to CONACYT for the grant awarded for this research, as well as to the UAM-A and the ICB for the support provided. MGMY, MRR, MPP and AEM thank the SNI for the distinction of their membership and the stipend provided. MGMY is indebted to L'oreál-UNESCO-CONACyT-AMC for the grant Women in Science 2016. MJL and SPR gratefully acknowledge financial support given by Spanish MINECO (ENE2014-52158-C2-1-R).

Introduction Les effets indesirables secondaires a la double immunotherapie par ipilimumab + nivolumab sont souvent severes, multiples et atypiques. Nous rapportons le cas d’un patient presentant des vomissements incoercibles en rapport avec une achalasie oesophagienne immuno-induite. Observation Un homme de 33 ans suivi pour un melanome metastatique etait traite par double immunotherapie (ipilimumab 3 mg/kg et nivolumab 1 mg/kg), stoppee apres 3 cures pour une uveite severe. Devant l’amelioration oculaire sous corticoides, un relai par nivolumab seul etait decide. Quelques jours apres la perfusion apparaissaient des vomissements incoercibles avec intolerance digestive totale, engendrant une perte de 30 kg, et necessitant une nutrition parenterale. L’examen trouvait un vitiligo etendu, une mydriase bilaterale areactive predominant a droite, mais pas d’hypotension orthostatique ni d’autre deficit neurologique. La reevaluation du melanome par TEP retrouvait une remission complete. Le bilan digestif endoscopique (fibroscopie haute et coloscopie) etait normal, ainsi que l’IRM cerebrale et le bilan endocrinien. Le transit oesogastroduodenal montrait une stagnation du produit de contraste en amont du cardia evoquant un trouble sphincterien ; la manometrie œsophagienne montrait un aperistaltisme en faveur d’une achalasie de l’œsophage de type II. Le bilan neurologique trouvait une dysautonomie sur l’ENMG (alteration de la reponse cutanee sympathique) et le test de respiration ample ; la ponction lombaire et l’EEG etaient normaux. Parmi les anticorps anti-neuronaux recherches, les anti-GAD65 etaient eleves a 85 Ui/Ml (n Discussion Nous decrivons le premier cas d’achalasie de l’œsophage dans un contexte de polyneuropathie dysautonomique, associee a une pan-uveite et un vitiligo chez un patient traite pour melanome metastatique par double immunotherapie anti-PD1/CTLA4. L’achalasie de l’œsophage est un trouble primaire de la motilite resultant en un defaut de relaxation du sphincter inferieur de l’œsophage, lie a une perte selective de neurones inhibiteurs dans le plexus myenterique. Cette affection neurologique est liee a une dysimmunite avec souvent, comme chez notre patient, un taux eleve d’anticorps anti-GAD65. Ces anticorps sont aussi associes a des diabetes et a des encephalites limbiques, dont un cas a ete decrit sous anti-PD1. Cette complication neurologique grave doit etre evoquee en cas de vomissements inexpliques survenant sous immunotherapie.

Choline chloride based-deep eutectic solvents (DES), namely: choline chloride (ChCl): urea (U), reline, ChCl: glycerol (G), and ChCl: ethylene glycol (EG), ethaline, were used as leaching media for the cathode powder of spent Ni-MH batteries. It is shown that the best metal extraction was obtained with the reline DES. The resulting solution was used as electrolytic bath for the electrochemical deposition of a Ni–Co alloy onto a glassy carbon electrode (GCE). A theoretical model that involves the simultaneous presence of two contributions, to the total current density, namely: three-dimensional nucleation and diffusion-controlled growth of the bimetallic phases, and the residual water reduction on the growing surfaces of the bimetallic (Ni–Co) nuclei, was implemented for the analysis of the potentiostatic current density transients. From this analysis, the potential dependence of kinetic parameters was obtained. SEM images of the GCE, after the potentiostatic electrodeposition, showed the formation of nuclei distributed all over the substrate surface. From EDX and XRD analysis it is shown that these nuclei were composed by Ni, Co and oxygen.

The present work studies the influence of the surface chemistry of carbon supports on the electrochemical behaviour of Pd and Au–Pd core–shell (CS) nanoparticles. Vulcan XC-72R was chemically modified by different acid treatments, inducing changes in the volume of the mesopores and surface density of oxygenated species. The CS nanostructures featuring 19 nm Au cores and 10 nm Pd shells were synthesized by colloidal methods and subsequently incorporated to the carbons supports. Pd nanoparticles were prepared by impregnating a Pd precursor into the modified carbons followed by reduction with sodium borohydride. The use of different preparation methods allowed the independent study of the effect of the support on the morphology/distribution of the nanoparticles and on the reactivity of the nanoparticles, through their interaction with organic molecules. The electrocatalysts were characterised by XRD, EDX, Raman spectroscopy and contact angle measurements. CO and formic acid (HCOOH) electro-oxidation were studied using cyclic voltammetry and chronoamperometry. The effect of the carbon support on the electrocatalytic activity was highly dependent on the method of preparation. Pd nanoparticles obtained by impregnation showed higher HCOOH oxidation currents when supported on the highly oxidised Vulcan support. This is due to the generation of smaller particle sizes (2.3 nm) as a result of the high density of oxygenated functional groups. On the other hand, the CS nanostructures are significantly less active in highly oxidised Vulcan as a results of specific chemical interactions which may be related to the formation of oxides. The implication of these findings towards rationalising particle–substrate interactions are briefly discussed.

The grafting of natural halloysite nanotubes (HNT) with aminosilanes exhibiting two (DAS) and three (TAS) amino groups has been investigated and compared to the physisorption of both silanes on halloysite nanotubes. Halloysite nanotubes were used as solid support for the heterogeneous Atom Transfer Polymerization of methyl methacrylate (MMA) into poly(methylmethacrylate) (PMMA) using CuBr as catalyst. Silane grafted on the nanoclay acts both as a ligand that bonds to CuBr and as a catalyst for the heterogeneous MMA polymerization. Grafting of halloysite nanotubes with DAS produced a polymer with polydispersities similar to those produced by the physically adsorbed diaminosilane catalyst, but conversion percentages were lower and a poorer control over the polymerization reaction was achieved. Grafting of halloysite nanotubes with TAS had a detrimental effect on the control of the polymerization reaction and a loss of catalytic activity due to the immobilization of the copper catalyst. The best control over the polymerization of methyl methacrylate is achieved when the catalyst is not immobilized by covalent bond on the surface of halloysite nanotubes. Therefore, physysorption of the CuBr/aminosilane complex on the halloysite nanotubes provided better control on the polymerization reaction compared to the grafting of the aminosilanes on the halloysite nanotubes.

A parent activated carbon (C-0) was subjected to four different treatments: (i) heat treatment at 1273 K in Ar (C-1); (ii) heat treatment at 473 K in air (C-2); (iii) oxidation with H 2 O 2 (C-3) and, (iv) oxidation with HNO 3 (C-4). These materials were evaluated as supports of CuBr–[1,1,4,7,10,10-hexamethyltriethylenetetramine] (Cu I Br–HMTETA), a catalyst for the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate (MMA) using methyl-α-bromophenylacetate (MBP) as radical initiator. The supported catalysts showed an adequate control of polymerization, evidenced by polydispersity indexes (PDI) falling in the range 1.13–1.55. The best performance was achieved when activated carbon was treated with nitric acid (C-4) and with air at 473 K (C-2). Some copper leaching was always detected. The catalysts were reused and an adequate polymerization control was obtained in subsequent runs.

Resumen Introduccion Los hematomas retroclivales postrau-maticos son extremadamente infrecuentes y casi exclusivos de la edad pediatrica. Unicamente se ha documentado en la literatura un caso de hematoma subdural retroclival postraumatico. Caso clinico Varon de 8 anos de edad que tras accidente de bicicleta sufre traumatismo craneo-encefalico con hiperextension cervical. A su ingreso presento Glasgow inicial de 13 y diplopia por paresia del VI par derecho. En la TAC y RM craneo-cervical se objetivo un hematoma subdural retroclival. Se realizo manejo conservador con colocacion de collarin rigido. Se observo recuperacion espontanea del VI par a los 6 dias presentando unicamente cervicalgia al alta. Presento resolucion clinica y radiologica a los 3 meses del accidente. Conclusion Las lesiones hemorragicas retroclivales postraumaticas son tipicas de la edad pediatrica por la inmadurez de la union craneo-cervical que presentan. El tratamiento de eleccion es la colocacion de un collarin rigido aunque si existe progresion clinica puede ser necesaria la evacuacion quirurgica.

Three activated carbons exhibiting different textural characteristics were considered as support for CuBr–HMTETA catalyst in the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate. The pore distribution of the activated carbons played an important role in the control of the polymerization reaction: polydispersity index always failed in the range 1.1–1.3. However, the accessibility of the catalyst to pores in the activated carbon was limited by pore size and growing polymer size. Catalyst located within the micropores of spherical carbon was isolated from the growing polymer chains during the polymerization reaction, which took place at the mesopores. Mesoporous structure of LMA F-12 carbon enhanced polymerization rate but control over the molecular weight distribution was decreased. A carbon with an adequate distribution of micro- and mesoporosity (RGC-30) provided a suitable balance between activation and deactivation processes involving Cu (I) and Cu (II) catalytic species, which resulted in the appropriate control of the molecular weight during the methyl methacrylate polymerization reaction.

The aim of this work is to analyze the mechanisms involved on hematite floatability using tetradecylammonium chloride as collector agent. The emphasis of the study is focused on mineral/collector interactions with the aim of optimizing the mineral recovery. In order to obtain better hematite floatability, the tetradecylammonium chloride concentration is relatively high in comparison with its corresponding critical micelle concentration (CMC) value, widely reported in the literature. The optimum was found when surfactant monolayer coverage was attained. Furthermore, if the zeta potential is close to zero or shifts to positive values the mineral recovery is enhanced, possibly due to the counter ions chemically adsorbed on the mineral surface.

The MX80 bentonite (bentonite of Wyoming) contains about 85% of montmorillonite and 15% of accessory minerals. The dominant presence of montmorillonite in this clay mineral could cause it to perform exceptionally well as an engineered barrier for a radioactive waste repository because of its swelling properties. In the current study the MX80 bentonite was mechanically compacted by a uniaxial system at four different pressures (21, 35, 49, and 63 MPa) in order to obtain four different physical densities. Then each sample was submitted to a hydration/dehydration cycle into an environmental scanning electron microscopy (ESEM) chamber in order to observe in situ the structural modifications after one hydration/dehydration cycle. This instrument allows the possibility to observe geological samples in their natural state without preliminary preparation or modification. In addition, the classical methods (BET measurements, SEM, Hg-porosimetry and isothermal adsorption of water vapour) were carried out to characterize the texture of compacted samples before hydration/dehydration in the ESEM. ESEM observations clearly show that the mechanical compaction influences the textural behavior when the bentonite MX80 is submitted to a hydration/dehydration cycle. In general, the inter-aggregate pores are open during hydration stage and sometimes there is an aggregate cracking. This phenomenon is more significant when mechanical compaction increases since the cohesion force of inter-aggregates at high mechanical compaction “49 and 63 MPa” limits the free swelling of MX80 bentonite. In addition, Hg-porosimetry shows that only the macro-porosity (porous size >50 nm) and eventually the meso-porosity (porous size between 2 and 50 nm) are affected by the mechanical compaction. In fact, the total porosity decreases when the mechanical compaction increases. On other hand, BET measurements and adsorption isotherms of water vapour show a non-significant impact on the microporosity.

Bentonites have been proposed as buffer materials for barriers in geological disposal systems for radioactive waste. In these conditions the bentonite barriers may be submitted to changes of humidity, temperature variation, fluid interaction, mass transport, etc. This could modify the physico-chemical performance of the barrier, mainly on the interface with the steel container and with the geological barrier. The engineered barrier development necessitates thus the study of the physicochemical stability of its mineral constituents as a function of time under the conditions of the repository in the long term. The aim of this paper is to simulate the chemical transformations of the engineered barrier and chemical-elements diffusion impact resulting from the temperature increase (disintegration reactions of wastes), the presence of fluids coming from the geological barrier, and from the liberation of iron (degradation of the containers). The current study was based on the laboratory experiments and mineral characterization achieved by LEM and GREGU research laboratories. The simulations to predict the chemical transformations of argillaceous barrier (MX80 bentonite) and chemical-elements diffusion impact (water-saturated medium) were carried out by using a thermo-kinetic hydrochemical code (KIRMAT: Kinetic Reactions and Mass Transport). This code considers a 1D multisolute mass transport system. Here, all simulations were made in reducing initial conditions (PO2 i0; Eh=� 200 mV) and the reaction temperature was considered as constant at 100 8C during 1000 years. The results show that the more significant chemicals transformations were (1) the Na/Ca–montmorillonite-to-Ca– montmorillonite conversion, (2) the montmorillonite-to-chlorite conversion and (3) the dissolution/precipitation of accessory minerals. The first chemical transformation represents about 22% in the worst case, i.e., near of the engineered barrier interfaces while the second chemical transformation only represents about 3% (near the container), i.e., a high concentration of iron favours the chlorite–FeAl precipitation. Concerning the dissolution/precipitation of accessory minerals, in general, it was observed that the quartz, microcline and albite were re-precipitated in the system; the calcite and biotite were partially dissolved, and the pyrite was kept inactive. D 2005 Elsevier B.V. All rights reserved.

The ATPase inhibitor protein (IP) of mitochondria was detected in the plasma membrane of living endothelial cells by flow cytometry, competition assays, and confocal microscopy of cells exposed to IP antibodies. The plasma membranes of endothelial cells also possess beta-subunits of the mitochondrial ATPase. Plasma membranes have the capacity to bind exogenous IP. TNF-alpha decreases the level of beta-subunits and increases the amount of IP, indicating that the ratio of IP to beta-subunit exhibits significant variations. Therefore, it is probable that the function of IP in the plasma membrane of endothelial cells is not limited to regulation of catalysis.

Bentonites have been proposed as buffer material for barriers in geological disposal facilities for radioactive waste. This material is expected to fill up by swelling the void between the canisters containing the waste and the surrounding ground. However, the bentonite barriers may be submitted to changes of humidity, temperature variation, fluid interaction, mass transport, etc. This could modify the physico-chemical performance of the barrier, mainly on the interface with the steel container and with the geological barrier. The engineered barrier development necessitates thus the study of the physico-chemical stability of its mineral component as a function of time under the conditions of the repository in the long-term. The aim of this paper is to apply a simplified method (volume balance in a saturated medium) to evaluate the swelling capacity evolution of a bentonite barrier because of their geochemical transformations by using a thermo-kinetic hydrochemical code (KIRMAT: Kinetic Reactions and Mass Transport “1D”). The system modelled here consists of 1 m thick zone of water-saturated engineered barrier. This non-equilibrated system is placed in contact with a geological fluid on one side, which is then allowed to diffuse into the barrier, while the other side is kept in contact with iron-charged solution (0.001 mol/kg H2O). The initial reducing conditions ( P O 2 ≅ 0 ; Eh = −200 mV) and a constant reaction temperature (100 °C) were considered. In the current study the decay of swelling capacity was considered directly proportional on the volume of transformed montmorillonite (cation exchange + geochemical transformation), taking into account that it may be partially compensated by the volume of neo-formed swelling-clays. The results showed that the swelling capacity of the engineered barrier is not drastically affected after about 3000 years of reaction and transport because the volume of neo-formed swelling clays is almost directly proportional on the volume of transformed montmorillonite. In fact, a graphical method predicted that the decay of swelling capacity of the engineered barrier lies between 11% and 14% when the montmorillonite is completely transformed (cation exchange + minimal geochemical transformation) in the system.

Sugarcane (Saccharum spp.) is rather unusual among field crops in that it is not the seed that is of economic value, but rather the stalk. Sucrose is extracted from the large stalks that are produced by sugarcane plants. Considering their economic value, it is rather surprisingly that there is very little information concerning the development and size of the individual internodes over the length of sugarcane stalks. The objective of this study was to document internode volume over the sugarcane stalk of four cultivars and to observe changes in individual internode volume later in the growing season and in response to lodging. When harvested in August, the size of the internodes varied in a continuous manner along the stalk with the largest internode occurring at the bottom of the plant at approximately internode #15. One cultivar (CP80-1743) had much less of a decrease in internode volume below internode #15 than the other cultivars, indicating that growth was more concentrated in the lower internodes of this cultivar. Since the internode volume diminished as the apex was approached, much of the harvested material was concentrated in the bottom nodes. Comparison of a mid-season harvest (August) and a final harvest (January) indicated both that additional internodes were added to the stalk and that the size of all internodes increased. That is, plant growth was distributed all along the stalk and not focused on one particular zone. Similarly, the negative impact of plant lodging was uniformly distributed over the entire stalk, although there appeared to be differences in cultivars in the extent to which the growth of the stalk was decreased.

Leaf area development is critical in the establishment of a full leaf canopy to maximize interception of solar radiation and achieve high crop productivity. In sugarcane, leaf area development is especially important because the rate of leaf area increase is relatively slow. Previous studies have highlighted the fact that the rate of emergence of individual leaves is highly dependent on temperature. These previous studies have been limited, however, to only very few cultivars, and these cultivars were adapted for production in environments different from the climate of the continental USA. Hence, there is little information for cultivars selected for production in other environments and little basis for resolving which variable contributing to leaf area development has the greatest impact on canopy leaf area. The objective of this 2-year field study was to examine the contribution of rate of leaf emergence, leaf shape, and individual leaf area to the development of plant leaf area. Four cultivars developed for the subtropical climate of Florida were compared. The dependence of leaf emergence as a function of temperature was confirmed in this study and the leaf appearance rate of CP88-1762 was significantly greater than CP72-2086. Leaf shape was found to be nearly uniform among the four cultivars although the shape factor (0.72) was different from that previously reported for sugarcane. Cultivars differed in the area of successive emerged leaves on the stalk. Leaves produced early in development were found to be larger for one cultivar (CP88-1762) as compared to the other cultivars. These results indicated that area of earliest leaves produced by sugarcane cultivars might be a variant that could be exploited to achieve more rapid development of crop leaf area.

The clay materials are widely used in industrial processes. One significant application is as a solid desiccant agent or as a dehydrator of gases. In this case, it is fundamental to investigate on the sorption kinetics of water vapour. The main aim of the current study has been to present an experimental–theoretical study on the sorption kinetics of water vapour, using as reference material MX80 bentonite. This clay mineral was submitted at different physical, chemical and mechanical conditions. Then 0.5 g of the modified-sample previously dried for 24 h at 110 °C was placed in plastic desiccators (2 l) under isothermal conditions and atmospheric pressure, here the relative humidity was controlled by a supersaturated salt solution. This instrumental system allowed us to study the sorption kinetics of water vapour of MX80 bentonite where the control parameters were the interlayer cation (bentonite exchanged with Na, Li, K, Mg, Ca), mechanical compaction (uni-axial system at 21, 35 and 63 MPa), drying temperature of sample (110, 150, 250 and 500 °C), relative humidity (61, 75, 87 and 95%) and the amount of the sample (0.5, 1, 2, 3, 4 and 5 g). Thanks to a kinetic model of second order it was possible to estimate that the sorption kinetic of water vapour of MX80 bentonite depends directly on the relative humidity, the interlayer cation and amount of the sample. In contrast, the sorption kinetics of water vapour was lightly affected by the mechanical compaction. Finally, the sorption kinetics of water vapour was modified by the drying temperature of sample exclusively when this is very high (for example, 500 °C).

The swelling–shrinkage kinetic of an industrial Bentonite (MX80) was investigated using a new technique of environmental scanning electron microscopy (ESEM) coupled with a digital image analysis (DIA) program (Visilog). This expansive clay was characterized by several analytic tools (ICP-AES, SEM, STEM, XRD, etc.), before applying the new ESEM technique. The swelling–shrinkage was directly observed at high magnification and at different relative humidity states in an ESEM. Nine wetting/drying cycles were performed on the sample. Each cycle was performed at different relative humidities (55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%). A DIA program was used to determine swelling–shrinkage. This method consists of estimating the percent augmentation of the surface as a function of time. Finally, a swelling–shrinkage kinetic model was tested, based on a first-order linear kinetic equation. The results show that the coupled ESEM and DIA can be a powerful method of estimating the swelling/shrinkage potential of expansive clays. The exponential model fits well with the experimental data. D 2003 Elsevier Science B.V. All rights reserved.

Background/Purpose: Functional constipation with associated fecal incontinence responds poorly to medical management once megarectum has developed. The authors describe resecting the dilated rectum and inserting a cecostomy button for antegrade enemas in this difficult condition. Methods: Four children, ages 9 to 15 years, with a history of unremitting constipation and fecal incontinence were referred for evaluation after not responding to medical management. All patients had exhibited normal lumbosacral magnetic resonance images (MRI) and open rectal biopsies; however, all 4 patients had a megarectum on contrast enema. In addition, anorectal manometry was consistent with functional fecal retention. The dilated rectum was resected by anastamosing the nondilated sigmoid colon to the distal rectum, and a standard gastrostomy button was inserted into the cecum for antegrade enemas. Mean follow-up was 35 months (range, 8 to 60 months). Results: Constipation and incontinence resolved within 6 months in all patients, and all children remained continent without the aid of cathartic agents. There were no postoperative episodes of fecal impaction. The only complication was antibiotic-associated diarrhea in 1 patient. Cecostomy buttons were removed at 1 year postplacement in all 4 patients with continued success. Three patients underwent repeat anorectal manometry; all 3 had normal rectal sensory threshold volumes and anorectal inhibitory reflexes. Barium studies also were obtained in the 3 patients without evidence of recurrent rectal dilation. Conclusions: Refractory constipation and incontinence associated with megarectum may be amenable to surgical intervention in selected patients. The authors' limited experience suggests that proctectomy and button cecostomy is an effective treatment option that improves the quality of life in these patients. Furthermore, proctectomy alone may be curative. J Pediatr Surg 37:76-79. This is a US government work. There are no restrictions on its use.

Mitochondria have been found in invaginations, most of which were very deep and were normally situated near the periphery of chloroplasts in the bundle sheath of Zea mays and in Hyptis suaveolens mesophyll. They were present only in plants grown under low light intensities (0.16 and