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Aim of the Study: To evaluate the outcome of prophylactic thyroidectomies (PT) in patients with MEN 2 syndrome in a tertiary center., Methods: A retrospective study was designed, including all patients with MEN 2 syndrome who underwent PT between 2000 and 2019. Demographics, gene mutation, postoperative complications and histopathological findings were registered., Main Results: 30 patients were included (29 MEN 2A and 1 MEN 2B) with a median age at surgery time of 7.0 ± 3.2 years. Familiar history was present in all but 3 patients. A therapeutic thyroidectomy was performed in 2 patients due to evidence of medullary thyroid carcinoma (MTC, both were late diagnosis), and in the other 28 cases, a PT was performed. 8 patients had a RET mutation ranked as Moderate Risk (American Thyroid Association): median age at surgery was 7.2 ± 4.2 years, and histological findings were C-cell hyperplasia (n = 6) and no alterations (n = 2). 16 patients had a high risk mutation; median age at surgery time was 6.9 ± 2.8 years and histological findings were normal thyroid gland (n = 1), C Cell Hyperplasia (n = 8), microcarcinoma (n = 6), and MTC (n = 1). The mean hospital stay was 1.4 ± 0.68 days. No intraoperative complications or recurrent laryngeal nerve injuries were registered. 7 patients presented a transient hypoparathyroidism and 1 patient had permanent hypoparathyroidism., Conclusions: Early PT in patients with MEN 2 syndrome is a safe procedure when performed by an experienced team of Pediatric Surgeons and with a multidisciplinary approach. Early genetic analysis and familial counselling is essential to prevent the development of a MTC., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021. Published by Elsevier Inc.)

AutoMeKin2021 is an updated version of tsscds2018, a program for the automated discovery of reaction mechanisms (J. Comput. Chem. 2018, 39, 1922). This release features a number of new capabilities: rare-event molecular dynamics simulations to enhance reaction discovery, extension of the original search algorithm to study van der Waals complexes, use of chemical knowledge, a new search algorithm based on bond-order time series analysis, statistics of the chemical reaction networks, a web application to submit jobs, and other features. The source code, manual, installation instructions and the website link are available at: https://rxnkin.usc.es/index.php/AutoMeKin., (© 2021 The Authors. Journal of Computational Chemistry published by Wiley Periodicals LLC.)

The real-time reverse transcription-polymerase chain reaction (real-time RT-qPCR) has become a leading technique for the detection and quantification of arboviruses, including Chikungunya, Dengue, and Zika viruses. In this study, an updated real-time RT-qPCR assay was designed and evaluated together with a synthetic positive-control chimeric RNA for the simultaneous detection and quantification of Chikungunya, Dengue, and Zika viruses. Amplification assays were performed to verify the construct integrity and optimal reaction/thermal cycling conditions. The analytical sensitivity of the assay was determined for each virus in single and multiplex reactions, as well as the performance in the detection and viral load quantification of experimental samples. The real-time RT-qPCR assay presented here allowed for the simultaneous detection and quantification of Chikungunya, Dengue, and Zika viruses and could be applied in several studies where the accurate quantification of viral genomes is required., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The Receptor-Binding Domain (RBD) of the Spike (S) protein from Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has glycosylation sites which can limit the production of reliable antigens expressed in prokaryotic platforms, due to glycan-mediated evasion of the host immune response. However, protein regions without glycosylated residues capable of inducing neutralizing antibodies could be useful for antigen production in systems that do not carry the glycosylation machinery. To test this hypothesis, the potential antigens NG06 and NG19, located within the non-glycosylated S-RBD region, were selected and expressed in Escherichia coli , purified by FPLC and employed to determine their immunogenic potential through detection of antibodies in serum from immunized rabbits, mice, and COVID-19 patients. IgG antibodies from sera of COVID-19-recovered patients detected the recombinant antigens NG06 and NG19 (A 450 nm = 0.80 ± 0.33; 1.13 ± 0.33; and 0.11 ± 0.08 for and negatives controls, respectively). Also, the purified antigens were able to raise polyclonal antibodies in animal models evoking a strong immune response with neutralizing activity in mice model. This research highlights the usefulness of antigens based on the non-N-glycosylated region of RBD from SARS-CoV-2 for candidate vaccine development.

Pediatric patients with sickle cell disease and thalassemia major present clinical characteristics that could lead to a higher incidence of central venous access devices-associated complications (CVAD-C). With the objective of analyzing the safety of the use of CVAD in these patients, a retrospective review including all pediatric patients with these pathologies who required the implantation of a CVAD between 2004 and 2019 was performed. In all, 54 patients with 100 CVAD (65 totally implantable venous access port with subcutaneous reservoir, 35 single-lumen or double-lumen partially tunneled catheter) were included. During 60,410 days at risk of suffering a CVAD-C, 55 complications (complication rate [CR]/1000 catheter-days at risk=0.91) were reported in 46 CVAD: 19 mechanicals (CR=0.32), 32 infectious (CR=0.53), and 4 thrombotic complications (CR=0.066). Incidence of mechanical and infectious complications was significantly higher in double-lumen partially tunneled catheter than in totally implantable venous access port with subcutaneous reservoir (P<0.001). Lower age at insertion was related with a higher incidence of any complication (odds ratio=0.88/y, P=0.02). Patients who required a stem cell transplantation (31 patients and 65 CVAD) had no significant higher incidences of CVAD-C. In conclusion, our study supports the safety of using CVAD in these patients, with a low incidence of infectious, thrombotic, and mechanical complications., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

We present a comprehensive study of the most relevant numerical aspects influencing frequencies and intensities in the infrared spectrum of isolated polycyclic aromatic hydrocarbons (PAHs) regarding the overestimate of the IR CH-stretching bands. We use naphthalene as benchmark and show the validity of our results to different members of the PAH family. Our analysis relies on widely employed density functional theory methods and second-order vibrational perturbational theory for the computation of vibrational eigenstates. We have focused on the elucidation of the origin of the systematic overestimate of the intensities in the CH-stretching region. To rule out nonfundamental numerical errors, we have initially considered the influence of the electronic basis set and various other parameters on the different stages of the vibrational analysis. In a second stage, we have benchmarked the results of different density functional theory functionals with respect to the aforementioned overestimate taken as the ratio between the most prominent features of the spectrum, the CH-bending and the CH-stretching bands. Our results unambiguously indicate that the long-range correction plays a major role in this spurious numerical issue. More specifically, this phenomenon is due to an incorrect description of the charge distribution (and hence dipole) within the symmetrically relevant CH bonds. Long-range correction specifically remedies this issue. It improves the description of the intensities in the stretching region while at the same time it does not perturb significantly the rest of the spectrum. With respect to the frequencies, we have observed an overall improvement when compared to noncorrected functionals., (© 2021 Wiley Periodicals LLC.)

The photodissociation channels of nitrosobenzene (PhNO) induced by a 255 nm photolytic wavelength have been studied using the complete active space self-consistent method and the multistate second-order multiconfigurational perturbation theory. It is found that there exists a triplet route for photodissociation of the molecule. The reaction mechanism consists of a complex cascade of nonadiabatic electronic transitions involving triple and double conical intersections as well as intersystem crossing. Several of the relevant states (S 2 , S 4 , and S 5 states) correspond to double excitations. It is worth noting that the last step of the photodissociation implies an internal conversion process. The experimentally observed velocity pattern of the NO fragment is a signature of such a conical intersection.

Objectives: Laparoscopic learning curves are slow, and there are no uniform surgical skill acquisition models. Therefore, our objective was to assess a laparoscopic skill learning program in individuals without any surgical experience, analyzing the learning curve by means of a certified custom-made simulator, and evaluating whether previous surgical experience had an impact on the learning curve., Material and Methods: A certified custom-made simulator and laparoscopic instruments were used to assess 20 university students who performed 10 repetitions of 3 exercises of growing difficulty (eye-hand coordination, hand-hand coordination, and cutting). Three parameters were analyzed: total time with each hand, total mistakes with each hand, and three items of the OSATS technical skill scale. The two first exercises were compared with a group of 14 experienced surgeons. Statistical analysis using repeated-measures Anova and Student's t-test was carried out (p < 0.05)., Results: Significant time improvement with each repetition was demonstrated in the three exercises. Curve stabilization was faster in surgeons (2-4 repetitions) than in students (8-9). Time reduction was noted in the first and second exercises in both groups, with 44.08% and 33.1% shorter times, respectively., Conclusions: Individuals without surgical experience acquired basic laparoscopic skills using a custom-made simulator, which allows simple surgical techniques to be carried out in an inexpensive, accessible fashion. Previous surgical experience was associated with a shorter learning curve. The custom-made simulator allowed individuals with and without surgical experience to be distinguished from each other.

Objective: Even though thyroid surgery is rare in pediatric patients, frequency has increased in the last years. The objective of this study was to analyze the causes and results of these procedures in a pediatric surgical facility., Patients and Methods: Retrospective study including all patients requiring thyroid surgery in our department from 2000 to 2019. Demographic data, diagnostic data, associated pathology, type of surgical procedure, pathological results, and intraoperative and postoperative complications were recorded., Results: 47 patients with a mean age of 8.9 ± 3.9 years at surgery were included. The most frequent diagnosis was MEN syndrome (n = 30, 29 MEN 2A and 1 MEN 2B), followed by thyroid papillary carcinoma (n = 5), follicular adenoma (n = 5), multinodular goiter (n = 4), follicular carcinoma (n = 1), thyroglossal duct papillary carcinoma (n = 1), and Graves-Basedow syndrome (n = 1). 38 total thyroidectomies (73.7% of which were prophylactic), 3 double hemithyroidectomies, 5 hemithyroidectomies, and 5 lymphadenectomies were performed. No intraoperative complications or recurrent laryngeal nerve lesions were noted. Mean postoperative hospital stay was 1.3 ± 0.6 days. 7 patients had transitory asymptomatic hypoparathyroidism, and 1 patient had persistent symptomatic hypoparathyroidism. Pathological results of prophylactic thyroidectomies were: 18 C cell hyperplasias, 7 microcarcinomas, and 3 cases without histopathological disorders., Conclusions: Thyroid surgery in pediatric patients is safe if performed by specialized personnel. Even though it remains rare, frequency has increased in the last years.

The sum-of-products finite-basis-representation (SOP-FBR) approach for the automated multidimensional fit of potential energy surfaces (PESs) is presented. In its current implementation, the method yields a PES in the so-called Tucker sum-of-products form, but it is not restricted to this specific ansatz. The novelty of our algorithm lies in the fact that the fit is performed in terms of a direct product of a Schmidt basis, also known as natural potentials. These encode in a non-trivial way all the physics of the problem and, hence, circumvent the usual extra ad hoc and a posteriori adjustments (e.g., damping functions) of the fitted PES. Moreover, we avoid the intermediate refitting stage common to other tensor-decomposition methods, typically used in the context of nuclear quantum dynamics. The resulting SOP-FBR PES is analytical and differentiable ad infinitum. Our ansatz is fully general and can be used in combination with most (molecular) dynamics codes. In particular, it has been interfaced and extensively tested with the Heidelberg implementation of the multiconfiguration time-dependent Hartree quantum dynamical software package.

Introduction: Anastomotic stricture is the most common complication following esophageal atresia (EA) surgical repair. The objective of this study was to evaluate Anastomotic Stricture Index (ASI: relationship between pouch and stricture diameters in the postoperative esophagram) as a predictor of the need for esophageal dilatation., Methods: A retrospective review of all patients undergoing EA repair in our healthcare facility from 2009 to 2017 was designed. Proximal pouch ASI (proximal ASI) and distal pouch ASI (distal ASI) in the first and second postoperative esophagram were calculated, and correlation with the number of esophageal dilatations required was studied. For statistical analysis purposes, Spearman's correlation test and ROC curves were used., Results: Of the 31 patients included, 21 (67.7%) required esophageal dilatation, and 11 (35.5%) required 3 or more dilatations. The relationship between ASIs in the first esophagram and the need for esophageal dilatation was not statistically significant (p >0.05). The relationship between proximal ASI (RHO = 0.84, p <0.05) and the number of dilatations in the second esophagram was statistically significant. None of the patients with <0.55 proximal ASI required dilatation; patients with 0.55-0.79 proximal ASI required less than 3 dilatations; and patients with >0.79 proximal ASI had a high risk of requiring 3 or more dilatations., Conclusion: According to our study, measuring ASI in the second esophagram proves useful in predicting EA patients' postoperative management, especially when it comes to identifying patients with lower risk of undergoing multiple dilatations.

Dengue is a mosquito-borne disease that is of major importance in public health. Although it has been extensively studied at the molecular level, sequencing of the 5' and 3' ends of the untranslated regions (UTR) commonly requires specific approaches for completion and corroboration. The present study aimed to characterize the 5' and 3' ends of dengue virus types 1 to 4. The 5' and 3' ends of twenty-nine dengue virus isolates from acute infections were amplified through a modified protocol of the rapid amplification cDNA ends approach. For the 5' end cDNA synthesis, specific anti-sense primers for each serotype were used, followed by polyadenylation of the cDNA using a terminal transferase and subsequent PCR amplification with oligo(dT) and internal specific reverse primer. At the 3' end of the positive-sense viral RNA, an adenine tail was directly synthetized using an Escherichia coli poly(A) polymerase, allowing subsequent hybridization of the oligo(dT) during cDNA synthesis. The incorporation of the poly(A) tail at the 5' and 3' ends of the dengue virus cDNA and RNA, respectively, allowed for successful primer hybridization, PCR amplification and direct sequencing. This approach can be used for completing dengue virus genomes obtained through direct and next-generation sequencing methods.

A Zika virus (ZIKV) strain was isolated from an acute febrile patient during the Zika epidemics in Colombia. The strain was intraperitoneally inoculated into BALB/c mice, and 7 days postinoculation, neurological manifestations and ZIKV infection in the brain were demonstrated. The reported genome sequence is highly related to strains circulating in the Americas., (Copyright © 2019 Laiton-Donato et al.)

Background: Colombia was the second most affected country during the American Zika virus (ZIKV) epidemic, with over 109,000 reported cases. Despite the scale of the outbreak, limited genomic sequence data were available from Colombia. We sought to sequence additional samples and use genomic epidemiology to describe ZIKV dynamics in Colombia., Methods: We sequenced ZIKV genomes directly from clinical diagnostic specimens and infected Aedes aegypti samples selected to cover the temporal and geographic breadth of the Colombian outbreak. We performed phylogeographic analysis of these genomes, along with other publicly-available ZIKV genomes from the Americas, to estimate the frequency and timing of ZIKV introductions to Colombia., Results: We attempted PCR amplification on 184 samples; 19 samples amplified sufficiently to perform sequencing. Of these, 8 samples yielded sequences with at least 50% coverage. Our phylogeographic reconstruction indicates two separate introductions of ZIKV to Colombia, one of which was previously unrecognized. We find that ZIKV was first introduced to Colombia in February 2015 (95%CI: Jan 2015 - Apr 2015), corresponding to 5 to 8 months of cryptic ZIKV transmission prior to confirmation in September 2015. Despite the presence of multiple introductions, we find that the majority of Colombian ZIKV diversity descends from a single introduction. We find evidence for movement of ZIKV from Colombia into bordering countries, including Peru, Ecuador, Panama, and Venezuela., Conclusions: Similarly to genomic epidemiological studies of ZIKV dynamics in other countries, we find that ZIKV circulated cryptically in Colombia. More accurately dating when ZIKV was circulating refines our definition of the population at risk. Additionally, our finding that the majority of ZIKV transmission within Colombia was attributable to transmission between individuals, rather than repeated travel-related importations, indicates that improved detection and control might have succeeded in limiting the scale of the outbreak within Colombia.

Dengue virus (DENV) is the causative agent of one of the most important febrile illnesses worldwide. Four DENV serotypes are responsible for a broad clinical spectrum of the disease. Positive controls are costly and required for the validation of molecular test results of DENV serotyping. In this study, we describe the in silico design of the qDENV-Control plasmid with the target sequences to oligonucleotides and probes widely used for DENV serotyping, and the subsequent production of qDENV Control RNA by T7-driven run-off in vitro transcription. The qDENV Control RNA was successfully used to validate the positive and negative DENV serotyping results, allowing its incorporation in routine in-house protocols for virologic surveillance. This Control RNA allowed the absolute quantification of viral RNA copies from unknown samples as required in several fundamental studies., (Copyright © 2019 Elsevier B.V. All rights reserved.)

We present Specific Reaction Parameter Multigrid POTFIT (SRP-MGPF), an automated methodology for the generation of global potential energy surfaces (PES), molecular properties surfaces, e.g., dipole, polarizabilities, etc. using a single random geometry as input. The SRP-MGPF workflow integrates: (i) a fully automated procedure for the global topographical characterization of a (intermolecular) PES based on the Transition State Search Using Chemical Dynamical Simulations (TSSCDS) family of methods;i (ii) the global optimization of the parameters of a semiempirical Hamiltonian in order to reproduce a given level of electronic structure theory; and (iii) a tensor decomposition algorithm which turns the resulting SRP-PES into sum of products (Tucker) form with the Multigrid POTFIT algorithm. The latter is necessary for quantum dynamical studies within the Multiconfiguration Time-Dependent Hartree (MCTDH) quantum dynamics method. To demonstrate our approach, we have applied our methodology to the cis-trans isomerization reaction in HONO in full dimensionality (6D). The resulting SRP-PES has been validated through the computation of classical on-the-fly dynamical calculations as well as calculations of the lowest vibrational eigenstates of HONO as well as high-energy wavepacket propagations.

Chikungunya virus (CHIKV) is considered a public health problem due to its rapid spread and high morbidity. This study aimed to determine the genetic diversity and phylogenetic relationships of CHIKVs in Colombia. A descriptive and retrospective study was carried out using sera of patients infected with Chikungunya during the outbreak in Colombia. The whole genomes of CHIKV (n = 16) were sequenced with an Illumina Hi-seq 2500 and were assembled using the Iterative Virus Assembler software. A Bayesian inference phylogenetic analysis was carried out with 157 strains of worldwide origin. The Colombian CHIKV sequences were grouped in the Asian genotype; however, three independent phylogenetic subclades were observed, probably the result of three separate introductions from Panama, Nicaragua, and St. Barts. Each subclade showed several different non-synonymous mutations (nsP2-A153V; nsp2-Y543H; nsp2-G720A; nsP3-L458P; Capside R78Q), that may have functional consequences for CHIKV biology and pathogenesis. These same mutations may affect the efficacy of potential CHIKV vaccines.

Dengue is hyperendemic in Colombia, where a cyclic behavior of serotype replacement leading to periodic epidemics has been observed for decades. This level of endemicity favors accumulation of dengue virus genetic diversity and could be linked to disease outcome. To assess the genetic diversity of dengue virus type 2 in Colombia, we sequenced the envelope gene of 24 virus isolates from acute cases of dengue or severe dengue fever during the period 2013-2016. The phylogenetic analysis revealed the circulation of the Asian-American genotype of dengue virus type 2 in Colombia during that period, the intra-genotype variability leading to divergence in two recently circulating lineages with differential geographic distribution, as well as the presence of nonsynonymous substitutions accompanying their emergence and diversification.

Photochemistry of 3- and 4-methoxyphenyl azide at 266 nm has been studied by means of the complete active space self-consistent field (CASSCF) and multi-configurational second-order perturbation (MS-CASPT2) methods. Minima and interstate crossing points have been optimized using the CASSCF method. The calculations predict that the key step of the photolysis of both azides is a non-radiative process. However, an important difference is found when we compare the reactivity of both isomers of azide, deactivation of 3-methoxyphenyl azide (1) can occur via two reaction channels (internal conversion or intersystem crossing), which lead to formation of the dimer of 2H-azepine derivative (2a) and 3,3'-dimethoxyazobenzene (2b). In contrast, deactivation of 4-methoxyphenyl azide (3) takes place via a singlet to triplet intersystem crossing, which leads to formation of 4,4'-dimethoxyazobenzene (4). After initial deactivation, both isomers follow a cascade of surface crossings until they reach the final nitrenes, respectively. The reference active space for the two azides is 14 electrons in 13 orbitals and comprises the six π-type orbitals of the aromatic ring plus four σ-(N-N2) and five π-type orbitals of the -N3 moiety.

Introduction: Despite the availability of an effective vaccine and treatment to reduce the viral load and progressive hepatocellular injury, approximately 240 million people worldwide are chronically infected with the hepatitis B virus (HBV). In Colombia, the circulation of different viral genotypes has been confirmed. Mutations in the genome have been associated to antiviral therapy resistance, viral escape to neutralizing antibodies, occult infection and progression to hepatocellular carcinoma. Objective: To identify the genotypes and the presence of mutations in the coding region of the surface (S) antigen and the reverse transcriptase (RT) domain of the polymerase of HBV obtained from serum samples for hepatitis B diagnosis received by the Instituto Nacional de Salud during the period 2002-2014. Materials and methods: A total of 495 serum samples with previous HBsAg reactive result were used for molecular detection. A fragment of 1,591 nucleotides was sequenced, and the corresponding phylogenetic analysis was performed. Results: We detected the viral genome of HBV in 66 samples and 28 were successfully sequenced. The phylogenetic analysis allowed the identification of subgenotypes F3 and A2. The L180M and M204V resistance mutations were simultaneously identified in one sample, while the I169L resistance mutation was identified in another one. A single escape mutation, P120Q, was identified in one more. Two samples showed a deletion of 105 nucleotides in the preS1-preS2 region. Conclusions: The circulation of genotypes/subgenotypes F3 and A2 of HBV in Colombia was corroborated, as well as the presence of some resistance and escape mutations. The present study constitutes a contribution to the molecular epidemiology of HBV in Colombia.

The quantum photodynamics of a simple diatomic molecule with a permanent dipole immersed within an optical cavity containing a quantized radiation field is studied in detail. The chosen molecule under study, lithium fluoride (LiF), is characterized by the presence of an avoided crossing between the two lowest 1 Σ potential energy curves (covalent-ionic diabatic crossing). Without field, after prompt excitation from the ground state 1 1 Σ, the excited nuclear wave packet moves back and forth in the upper 2 1 Σ state, but in the proximity of the avoided crossing, the nonadiabatic coupling transfers part of the nuclear wave packet to the lower 1 1 Σ state, which eventually leads to dissociation. The quantized field of a cavity also induces an additional light crossing in the modified dressed potential energy curves with similar transfer properties. To understand the entangled photonic-nuclear dynamics, we solve the time-dependent Schrödinger equation by using the multiconfigurational time-dependent Hartree method (MCTDH). The single mode quantized field of the cavity is represented in the coordinate space instead of in the Fock space, which allows us to deal with the field as an additional vibrational mode within the MCTDH procedure on equal footing. We prepare the cavity with different quantum states of light, namely, Fock states, coherent states, and squeezed coherent states. Our results reveal pure quantum light effects on the molecular photodynamics and the dissociation yields of LiF, which are quite different from the light-undressed case and which cannot be described in general by a semiclassical approach using classical electromagnetic fields.

In electron dynamics calculations the interatomic Coulombic decay (ICD) process has recently been shown to take place in two vertically-aligned quantum dots (QDs). Energy emitted during the relaxation of one electron in one QD is converted into kinetic energy of another electron ejected from a neighboring QD. As the electronic structure of QDs can be controlled by their geometries, we prove here in thorough scans of the transversal and vertical QD confinement potentials' widths that geometries are likewise control parameters for ICD. Such a comprehensive investigation has been enabled by a significant development of the calculations in terms of speed achieved among others by optimization of the grid and Coulomb interaction operator representations. As key result of this study we propose two cigar-shaped singly-charged GaAs QDs vertically aligned in the direction of their long side for a most efficient QD ICD realization useful for an infrared photodetector. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Introduction: Since drinking water can be a vehicle for the transmission of pathogens, the detection of enteric viruses in these water samples is essential to establish the appropriate measures to control and prevent associated diseases. , Objective: To analyze the results obtained for enteric viruses in water samples for human consumption received at the Colombian Instituto Nacional de Salud and establish their association with the data on water quality in Colombian municipalities. , Materials and Methods: We conducted a descriptive-retrospective analysis of the results obtained in the detection of rotavirus, enterovirus, hepatitis A virus and adenovirus in water samples received for complementary studies of enteric hepatitis, acute diarrheal disease and foodborne diseases. Data were correlated with the results of water quality surveillance determined by the national human consumption water quality index (IRCA). , Results: Of the 288 samples processed from 102 Colombian municipalities, 50.7% were positive for viruses: 26.73% for hepatitis A virus, 20.48% for enterovirus and rotavirus and 18.05% for adenovirus. Viruses were detected in 48.26% of non-treated water samples and in 45.83% of treated water samples. The IRCA index showed no correlation with the presence of viruses. , Conclusions: The presence of viruses in water represents a public health risk and, therefore, the prevention of virus transmission through water requires appropriate policies to reinforce water supply systems and improve epidemiological surveillance.

Introduction: Hepatitis A virus (HAV) is an important pathogen, typically transmitted via the faecal-oral route. The epidemiology of the infection is directly related to drinking water access and adequate disposal of sewage water. , Objective: To determine the presence and identify the genotype of HAV in environmental samples from eight municipalities and two villages in Antioquia, northwestern Colombia. , Materials and Methods: Three serial samplings were done between December, 2012, and April, 2014. Water samples were obtained from drinking water plants prior to treatment, as well as from the main reserve of wastewater in each municipality included in the study. Viral concentrations for the two types of sample sources were determined by filtration/tangential ultrafiltration and polyethyleneglycol plus flocculation with skimmed milk, respectively. Total ARN was subsequently obtained from each sample and the VP3-VP1 region amplified for detection of the viral genome. The genotype was determined by amplification of the VP1-2B region. , Results: The HAV genome was detected in samples from drinking water plants at Puerto Berrío, Frontino and Nutibara, and in wastewater samples from the municipalities of Arboletes, Zaragoza and Venecia. HAV subgenotype IA was identified using phylogenetic analysis. , Conclusion: In this study, HAV was identified in 6.6% of the samples from drinking water plants and 13.3% of wastewater samples. This is the first report of HAV subgenotype IA circulating in environmental samples from Antioquia.

Introduction: Hepatitis E virus has emerged as a public health problem, particularly in developing countries. The four genotypes identified in mammals include the G3 found in indigenous hepatitis in countries and regions with high porcine population, and the G1, associated with maternal deaths. , Objective: To determine coinfection by hepatitis E virus and the circulating genotypes in Colombia in 1,097 samples using serological markers for hepatitis A, B and C. , Materials and Methods: Serum samples of 1,097 patients from different regions of Colombia stored at the Laboratorio de Virología of the Instituto Nacional de Salud were selected to detect IgG and IgM anti-hepatitis E virus antibodies. The viral genomes of positive samples were amplified by RT-PCR, and the products were sequenced and phylogenetically analyzed by comparing ORF2 sequences deposited in the GenBank. , Results: IgG anti-hepatitis E virus antibodies were found in 278 samples, IgM in 62, and both markers in 64. Hepatitis E virus and hepatitis A virus coinfection determined by IgG anti-hepatitis E virus was 33.6% and 16.1% by IgM; hepatitis E virus and hepatitis B virus coinfection was 23.4% and 8.1%, and hepatitis E virus and hepatitis C virus coinfection was 35.4% and 5.83%, respectively. Among the 52 positive samples by PCR nine were sequenced and grouped within genotype 3A of the American porcine strain. , Conclusions: The highest seropositivity was observed for hepatitis A and E. The incidence of hepatitis E virus coinfection with other hepatotropic viruses indicated that this pathogen is more frequent than expected. The circulation of genotype 3A implies that this disease may occur in outbreaks and as zoonosis in Colombia.

Background: Multiple approaches to the treatment of simple and complicated (gangrenous or perforated) appendicitis in children have been promoted. Our goal is to develop a new protocol for these patients that allows shorter hospital stays without increasing complications rates., Methods: Prospective collected data of patients undergoing appendicitis treated according to the new protocol for a period of 7 months were reviewed. This protocol consists on antibiotic prophylaxis in all cases continued with triple antibiotic regimen in complicated appendicitis. Antibiotics were stopped when specific clinical and laboratory criteria were met. Outcomes are compared to a historical group of patients treated under standard protocol (antibiotic prophylaxis followed by 48 hours of dual antibiotic therapy in simple appendicitis or 5 day-course of triple antibiotic therapy in complicated as postooperative antibiotic regimen)., Results: A total of 196 patients (96 current group and 100 historical group) were reviewed. In simple appendicitis average length of postoperative hospitalization was significantly lower in the current group (no statistical difference). 52.9% of complicated appendicitis in the current group were discharged home before 5th day without increasing the complication rate. When a wound infection or intraabdominal abscess occurs thrombocytosis (52%) and prolonged vomiting are the most frequent symptoms., Conclusion: No further postoperative treatment is needed in simple appendicitis. In complicated appendictis a short course of antibiotics according to clinical and laboratory criteria allows early discharge without major morbidity. Prolonged postoperative vomiting and thrombocytosis suggest infectious complications.

Background: Noniatrogenic traumatic injuries of the esophagus are rare and are associated with considerable morbidity and mortality. This result is influenced by the time elapsed, severity of injury and concomitant organ damage. Current management is controversial. Different treatment options exist; however, choice should be individualized to obtain the best result., Objective: To discuss the current management of esophageal trauma., Clinical Case: We report the case of a 19 year-old male with a grade V esophageal injury caused by shotgun and treated by esophagectomy and immediate gastric reconstruction., Conclusion: Current treatment of traumatic iatrogenic esophageal injury should be individualized for a better clinical outcome.

Background: Laparoscopic cholecystectomy (LC) is a very usual procedure within adult population, but not as frequent in childhood. The aim of this study was to assess the outcome of LC in children compared with those performed in adulthood., Materials and Methods: We reviewed 39 consecutive patients who underwent LC between 2003 and 2013 at our Department and a similar sample of patients from 18 to 40 years of age from the General Surgery Department., Results: 39 children and 40 adults fulfilled criteria to be included in the study. The most frequent indication was cholelithiasis in both groups. The mean operating time was significantly higher among children (127 min, adults 71 min, p < 0.01) but we didn't find differences neither in conversion nor in complication rates (children 5% and 7.7%, adults 2.5% and 15% respectively). In regard to preoperative factors, only male gender was correlated to a higher complication rate (p 0.037). On the other hand we found out that, in absence of complications, both the average length of stay (children 2.1 days, adults 0.5 days) and mean time to first feeding (children 21 hours, adults 8 hours) were significantly higher among children (p < 0.01)., Conclusions: 1) LC in childhood is a safe procedure that does not imply more morbidity than the same intervention in adults, even though a more prolonged operating time. 2) We believe that our longer hospital stay is due to certain lack of confidence with the technique and, in the future, the trend should be bent on encouraging a shorter time to first feeding and an earlier discharge.

Introduction: Hepatitis E virus (HEV) is an emergent virus of global importance; it is the etiological agent of sporadic cases and outbreaks of hepatitis. The epidemiology of this infection in Colombia is unknown., Objective: To determine the seropositivity for hepatitis E virus in Colombia in cases with clinical diagnosis of viral hepatitis., Materials and Methods: Serum samples from patients that were sent to the Instituto Nacional de Salud during the period 2005-2010 (group 1) and samples sent to the Laboratorio Departamental de Salud Pública de Antioquia during the 2008-2009 period were included in this study (group 2). Serum samples were analyzed by immunoassay with commercial kits., Results: From the 344 analyzed samples, 8.7% were positive for anti-HEV; the frequency of anti-HEV IgM was 1.74% (6/344) and the frequency of anti-HEV IgG was 7.5% (26/344). A difference in frequency of anti-HEV between group 1 (6.3%) and group 2 (1.3%) was observed. The cases were identified in nine departments of Colombia., Conclusions: This is the first study of hepatitis E virus infection in patients with diagnosis of hepatitis in Colombia. The frequency of anti-HEV described in this population of patients in Colombia is similar to that described in other Latin American countries like Brazil, Perú and Uruguay. Considering the results of this study, it could be necessary to include hepatitis E virus infection serological markers in the differential diagnosis of viral hepatitis in Colombia.

The study of excited triplet states of a molecular system is a difficult task because accessing them involves forbidden transitions from the singlet ground state. Nevertheless, absorption spectra of many molecules present, at low energies, the weak fingerprint of these triplet states. At higher energies this information is usually masked by the intense signal of the singlet states. Here we show, for the specific case of the sulphur dioxide molecule, that the combined use of polarized light and molecular alignment can enhance the triplet part of the spectrum, even making it the only absorption process.

Strain monitoring for emergence of novel strains after the introduction of rotavirus vaccine is an integral component of routine rotavirus immunization programs. Using a laboratory based strain surveillance system between 2008 and 2012, a wide variation in strain pattern in Colombia was founded both before and after the introduction of a monovalent rotavirus vaccine in 2009. G2P[4], a strain fully heterotypic to the vaccine was predominant before vaccine introduction in 2008 (47%) and after vaccine introduction in 2010 (54%), 2011 (86%), and 2012 (32%). The presence of this strain before the introduction of vaccine and decreasing prevalence during the most recent surveillance year suggests secular variation rather than vaccine pressure as a cause for this fluctuation. While strain monitoring can be valuable after vaccine introduction, these surveillance data alone without information on disease incidence or strain specific vaccine effectiveness can be prone to misinterpretation with regard to the role of vaccine pressure on emergence of new or persistent strains., (© 2014 Wiley Periodicals, Inc.)

In this study, we present a full-dimensional (9D) quantum dynamical analysis of the lowest vibrational eigenstates of H3O2(-). We have made use of the Multiconfiguration Time-Dependent Hartree method in conjunction with both an analytical and a numerical representation of the Kinetic Energy Operator and the newly developed Multigrid POTFIT [D. Peláez, H.-D. Meyer, J. Chem. Phys. 138 (2013) 014108], an algorithm which performs the transformation of a high-dimensional (up to ~12D) Potential Energy tensor into product form. Many sets of top-down Multigrid POTFIT expansions, differing in the system coordinate definition (valence and Jacobi), as well as in the number of terms in the expansion, have been analyzed. Relaxations for the computation of the ground states energies have been carried out on these potentials, obtaining an excellent overall agreement with accurate previous Diffusion Monte Carlo (DMC) calculations, irrespective of the coordinate choice. The 24 lowest excited vibrational states of H3O2(-) have been computed by Block Relaxation and assigned for the first time. This has been carried out in two different pictures, namely: a 7D reduced dimensional one, in which the OH distances have been frozen at the Potential Energy Surface minimum, and a 9D full-dimensional one. The agreement between both descriptions is remarkable. The following fundamental modes have been characterized: OH torsion, OO stretching, OH wagging, OH rocking, and the elusive bridging H stretching. In particular, we provide a very accurate description of the latter in perfect agreement with experiment., (Copyright © 2013 Elsevier B.V. All rights reserved.)

In this article, a new method, multigrid POTFIT (MGPF), is presented. MGPF is a grid-based algorithm which transforms a general potential energy surface into product form, that is, a sum of products of one-dimensional functions. This form is necessary to profit from the computationally advantageous multiconfiguration time-dependent Hartree method for quantum dynamics. MGPF circumvents the dimensionality related issues present in POTFIT [A. Jäckle and H.-D. Meyer, J. Chem. Phys. 104, 7974 (1996)], allowing quantum dynamical studies of systems up to about 12 dimensions. MGPF requires the definition of a fine grid and a coarse grid, the latter being a subset of the former. The MGPF approximation relies on a series of underlying POTFIT calculations on grids which are smaller than the fine one and larger than or equal to the coarse one. This aspect makes MGPF a bit less accurate than POTFIT but orders of magnitude faster and orders of magnitude less memory demanding than POTFIT. Moreover, like POTFIT, MGPF is variational and provides an efficient error control.

Introduction: Minimally Invasive Surgery (MIS) is getting more and more important in our specialty. However, the formation of the residents on MIS is, in many cases, irregular. The purpose of this study is to assess the state of training in MIS among the residents of Pediatric Surgery and their potential weaknesses., Material and Methods: An electronic survey was distributed among 71 residents of Pediatric Surgery from 17 national hospitals., Results: The response rate was 70.2%.100% of the residents are interested in a broadening of training activities in MIS. The main areas of interest are gastrointestinal (92%) and thoracic (47%) surgery. Only 57% have access to training facilities and less than half of them attend to courses and conferences. 80% believe that they are not given adequate attention from specialized associations. 52% think they should do rotations at referral centers, 86% that courses and seminars should be enhanced, and 44% that the responsibility of the resident in surgery should be increased. The main defects encountered in their training are scarce volume of patients, lack of financial support and overcoming the learning curve of surgeons in their services., Conclusions: Despite the advance of the MIS, resident's training in this discipline still has shortcomings, as expressed in their views. Knowledge of the current state of training should be the starting point for designing a training strategy that ensures adequate skills.

Introduction. Vascular endothelial growth factor (VEGF), an angiogenic factor secreted by type II pneumocytes, could play a role in congenital diaphragmatic hernia (CDH) pathogenesis. Animal studies suggest that VEGF accelerates lung growth. Aim. To quantify VEGF on fetal lungs in a nitrofen rat model for CDH and to analyze the effect of tracheal occlusion (TO) in VEGF in fetal lung rats after nitrofen and in control rats not exposed to nitrofen. Methods. Pregnant rats received nitrofen on day 9.5 of gestation. Fetuses were divided into 2 groups: those that underwent TO on day 20 and those that did not. On day 21, fetuses were delivered, and the lungs were dissected for subsequent VEGF quantification. Results. CDH was detected in 43% of the fetuses that received nitrofen. Fetuses with CDH showed significantly reduced lung weight/fetal weight ratio and lower VEGF levels than the remainder. A higher VEGF value was observed after TO. Conclusions. VEGF protein was significantly lower in fetuses with CDH. TO induced a significant increase in VEGF compared to the fetuses that did not undergo TO. Although not statistically significant, we observed higher VEGF levels in fetuses with CDH and TO compared to fetuses with CDH and no further intervention.

Introduction: Anal prolapse is a common postoperative complication related to anorectal malformations (MAR) surgery, which is sometimes considered to be insignificant and/or not worthy of further intervention. We analysed the causes of this complication and our current surgical protocols., Material and Methods: Since 1995, 26 patients with anal prolapse have been operated secondary to surgical correction of an anorectal pathology. The most common MAR in girls (12) was cloaca (10), and in boys (14) was anorectal atresia with prostate fistula (8). The symptoms were anal pain and bleeding associated with alterations in bowel control alterations. The diagnosis in most patients was made in the first months after surgery, during the period of anal dilatations period. The surgical procedure involves prolapse resection of the prolapse and a new anoplasty. In 18 patients (69%) the prolapse was corrected before the colostomy closure on an outpatient basis. The other 8 patients (31%) underwent prolapse surgery after colostomy closure, requiring hospitalisation., Results: There were no immediate postoperative complications, improving continence and aesthetic anus appearance. In 4 patients the prolapse recurred, requiring further surgical correction., Conclusions: Anal prolapse is a possible minor complication after anorectal correction. MAR type, the quality of the perineal musculature and defects in surgical technique are the main factors determining ia prolapse will appearance. The anal prolapse surgery indication has been recently increased (including small unilateral prolapses) as long as they are done before the colostomy closure, due to good aesthetic and functional results, requiring only outpatient surgery.

Unlabelled: The incidence of surgical wound infections in neonates is high and it has an associated morbidity which extends hospital stay and gets a worse prognosis. The purpose of this study is to analyze the risk factors associated with the development of surgical wound infection and to identify susceptible patients with modifiable factors., Material and Methods: Case-control study of 90 surgical procedures underwent in newborns. We analyze pre-, intra- and postoperative risk factors., Main Results: There are statically significant differences in terms of wound infection in dirty and contaminated surgery, reoperation, lavage of abdominal cavity, preoperative hospital stay longer than 8 days and wound closure with reabsorbable material. Furthermore, the surgical site infection is more likely in preterms patients, with a previous positive culture infection and the use of invasive devices as mechanical ventilation or central venous access. We found no relationship between wound infection and surgical time, bleeding during surgery and preoperative skin preparation with antiseptics., Conclusions: Reoperative patients, in which dirty and contaminated surgery is performed, absorbable material for skin is used and who have a preoperative hospital stay longer than 8 days, are in risk of developping wound infection and they will require an aggressive antibiotic treatment and special postsurgical care.

Long-term indwelling central venous access devices are frequently used in pediatric patients. Their main complication is infection, that can even mean their removal. We try to identify the risk factors really involved in this complication and in their removal. We have made a retrospective review of 120 oncologic pediatric patients who received a central venous device between 2003 and 2009. We searched for epidemiologic, clinic, microbiologic and surgical risk factors. We made a comparative data analysis among: GROUP A, children who suffered device infection, GROUP B the others. Group A was divided into early infection (first month after implantation)/late infection, removed/not removed. Data were analized with statistical program SPSS. 29 suffered from leukemia, 19 from lymphoma and the main part, 72, from solid tumour. 31% experienced infection (GROUP A), being early in the 36% of them. 16% had to be withdrawn. Data analysis revealed statistical association with the age (p=0.015) and with the reception of chemiotherapic treatment the week before the surgical insertion. The rest of the studied factors did not revealed a real association, but could be guess a relationship among infection and leukemia, subclavian catheters, those patients whose deviced was introduced using a guide over a previous catheter and also transplanted. Related to early infection the only associateon founded was with the subclavian access (p=0.018). In conclusion, in our serie long-term central venous access infection was more frequent in the younger patients and also in those who had received chemotherapy the week before the catheter implantation. The tendency towards infection in leukemia, transplanted and subclavian carriers has to be studied in a prospective way with a larger number of oncologic children.

Introduction: Peritoneal drainage is one of the options for treatment in necrotizing enterocolitis (NEC). Currently its role is controversial as an alternative to laparotomy in low birthweight and mortality associated with both procedures is high (35-55%)., Material and Methods: We reviewed 30 low-weight premature (< 1000 g) with NEC treated surgically. We evaluate the hemodynamic, respiratory and metabolic status of the patients, as well as multi-organ involvement and the need for inotropic drugs. These data were analyzed previos to surgery and at 6 and 12 hours. We divided the sample into two groups: those who underwent peritoneal drainage (PD) input or laparotomy (LAP)., Results: In the series the average birth weight was 754 +/- 156 g and gestational age was 26.1 +/- 2.1 weeks. We carry on 10 peritoneal drainage and 20 laparotomies. The DP group before the intervention showed increased heart rate, FiO2 and acidosis (p < 0.05). The needs of dopamine were similar in both groups. Following the peritoneal drainage, we found breathing improvement (adequate ventilation and oxygenation, decreased FiO2) and hemodynamic improvement (blood pressure maintained, reduced heart rate, reduced requirements for dopamine) at 6 and 12 h. DP was not the definitive treatment in any of the patiens, and all survivors (80%) of this group required further laparotomy. 62% of them died. Overall mortality was 47% (70% DP and 35% LAP, p = 0.07)., Conclusions: Peritoneal drainage allowed the stabilization of low-weight premature in critical condition. The hemodynamic and respiratory stabilization was transient and did not prevent the definitive surgical treatment, although it improved the conditions for doing so. In our series, the peritoneal drainage did not improve long-term survival, questioning its role as an alternative to surgery for NEC.

Introduction: The indication of surgery in necrotizing enterocolitis (NEC) can be difficult in the absence of pneumoperitoneum or peritonitis. We propose laparoscopy for early diagnosis of intestinal perforation or necrosis in order to avoid unneccessary laparotomies., Material and Methods: A new protocol was proposed which included diagnostic and therapeutic laparoscopy in cases of uncertain surgical ECN indication. Subsequently, a prospective study of the 7 patients who underwent laparoscopy was performed, analyzing pathophysiological effects in the premature, technical difficulties of the procedure, and postoperative diagnostic consistency., Results: The mean gestational age at birth was 27 weeks (range 25 to 31) with an average weight of 1.147 kg (range 0.900 to 1.600) two trocars were placed as the focal oriented scanning or radiography, using a pneumoperitoneum 6-10 mmHg for an average of 17 min. Laparoscopy avoided laparotomy in a patient who did well after washing and drainage and magnified lesions in one patient who did not require laparotomy after intestinal bypass. In other cases, laparoscopy was followed by minilaparotomy oriented to the lesions and stoma formation. There were no surgical complications attributable to the procedure, which was well tolerated in all cases., Conclusions: Laparoscopy can be a useful tool for evaluation of lesions of NEC in cases of uncertain surgical indications. In our experience, it is well tolerated in neonates of low weight, allowing oriented minilaparotomies or even to avoid laparotomy.

Introduction: Phimosis is perhaps one of the most frequent consultation on pediatric surgery clinics throught the world. The aim of this study is to compare the two procedures more frequently performed in our hospital: dorsal slit and circumcision. PATIENTS Y METHODS: Retrospective study of 1698 patients who were admitted for elective surgical treatment of phimosis between 2003 and 2009. We analyzed age, surgical and anesthethic times, surgical technique and complications. We also did transversal descriptive study through telephonic survey on parents and patients older than 16 years old., Results: There was 76.6% of dorsal slit (n = 1300) and 23.4% (n= 398) of circumcisions. Mean age was 7.15 years y mean time of follow up was 42.3 months. Surgical time was significantly higher in circumcision (p < 0.0001). There were 3% (n = 51) of reoperations, no differences between groups. We didn't find differences in postoperative stenosis, but bleeding was more frequent in circumcision group (1.7%; p = 0.03). There were no differences on parental appreciation of postoperative pain, or functional and esthetic satisfaction between groups., Conclusions: We didn't find differences on subjective satisfaction between groups. Even if there are differences n postoperative bleeding, global incidence is very low. In our experience both techniques are valid and safe, so surgeon and parents must jointly make the decision.

Introduction: Percutaneus gastrostomy placement is a procedure widely performed in children with failure to thrive or intolerance to oral feeding. At the moment of making the indication, the need of an antir-reflux surgery in the same procedure comes to question. The aim of this study was to analyse which preoperative factors are associated with a higher risk of a posterior fundoplication., Material and Methods: We realized a retrospective review of 67 patients divided in 2 groups (cases and controls) in which a percutaneus gastrostomy (PEG) had been made by our service in the period of 1997 to 2008. We compared these two groups: Group A (n=11) - patients with severe gastroesophageal reflux who required a Nissen procedure afterwards; Group B (n=56) - patients who kept without reflux after PEG. We analyzed the different preoperative factors that could have been in association to severe reflux after gastrostomy., Results: Mean age at the moment of undergoing PEG was 15 months. Mean time of follow up was 3,5 years. Only neurological impairment and documented reflux pregastrostomy were associated with the need of an antirreflux surgery after PEG., Conclusions: Neurological impairment and documented pregastrosotmy GER could be an indication of concurrent antirreflux surgery at the time of gastrostomy.

Introduction: Enteric viruses have been implicated in acute diarrheal disease, food-borne disease, hepatitis A and meningitis outbreaks, in which water was the vehicle of transmission., Objective: A concentration method was standardized for the detection of enteric viruses in drinking water., Materials and Methods: Twenty liters of water were concentrated to 6 ml by filtration and tangential ultrafiltration. Viral solutions of 20 L each were prepared at 1, 10, 50 and 100 TCID50 of Sabin poliovirus type 1 as positive controls. Viral particles were recovered by tissue culture and detected by conventional polymerase chain reaction (PCR), according to the international standards recommended by the Enterovirus Laboratory at the Centers for Disease Control and Prevention, Atlanta, GA., Results: All positive controls showed cytopathic effect on L20B and RD cells and were amplified by conventional PCR directly from samples. Negative controls did not show any amplification or viral cytopathic effect., Conclusions: Tangential ultrafiltration for concentrating viruses proved to be a fast, efficient recovery and reproducible. It has the advantage of allowing the detection (at the 1 TCID50 level) and identification of viruses by RT-PCR and the demonstration of viral infectivity by tissue culture.

The photodissociation reactions of methyl nitrate CH(3)ONO(2) starting at the 193 and 248 nm photolytic wavelengths have been studied with the second-order multiconfigurational perturbation theory (CASPT2) by computation of numerical energy gradients for stationary points. In addition, energy profiles of reaction paths and vertical excitations have been investigated with the multistate extension of the multiconfigurational second-order perturbation theory (MS-CASPT2). It is found that excitation at 193 nm yields three reaction paths: (i) the so-called slow channel CH(3)ONO(2)--> CH(3)O + NO(2)--> CH(3)O + NO + O; (ii) the fast channel CH(3)ONO(2)--> CH(3)O + NO(2); and (iii) CH(3)ONO(2)--> CH(3)ONO + O. The slow channel starts at the S(4) surface, in contrast, the population of the S(3) state can lead to the fast channel or to direct atomic oxygen extrusion. The rather high relative yield of the channel leading to oxygen extrusion from methyl nitrate is explained on the basis of an S(3)/S(2) conical intersection that transfers the initial excitation localized in the npi* S(3) state to the sigmapi* S(2) state with a consequent weakening of the N-O bond. With respect to photolysis at 248 nm, it was not possible to unambiguously distinguish between S(1) and S(2) as the populated state, however, the S(2) state is suggested as mainly responsible for dissociation at this excitation energy.

Surface-enhanced Raman scattering (SERS) of hydroxybenzoic acids has been studied on silver sols in H(2)O and D(2)O solutions. The adsorption behavior of 4-hydroxybenzoic acid (4HBA) is different from that of salicylic (2HBA) and 3-hydroxybenzoic (3HBA) acids. It was concluded that 4HBA is adsorbed on silver nanoparticles (Ag(n)) as either oxidobenzoate (A(2-)) or hydroxybenzoate (A(-)), depending on the pH of the solution, given rise to a flat orientation. Both 2HBA and 3HBA acids are always adsorbed as hydroxybenzoates anions (A(-)) at pH >or=5 and link to the metal through the carboxylate group (Ag(n)--A(-)), standing more or less perpendicular to the metal surface. In the case of these monoanions, the selective enhancement of the bands is due mainly to a resonant electron or charge transfer process (ET or CT) from the metallic nanoparticles to the adsorbates, yielding the transient formation of the respective radical dianions (Ag(+)(n)--A(2-)). It is found that the enhanced bands, and especially the mode 8a;nu(ring), are related to the difference between the equilibrium structures of the adsorbate in its ground (A(-)) and CT-excited (A(2-)) states. In the SERS spectrum of 4HBA dianion, the contribution of CT mechanism is not observed.

The photochemical behavior of the protonated simplest nitrosamine [NH2NO-H](+) has been addressed by means of the CASPT2//CASSCF methodology in conjunction with the ANO-L basis sets. The relative stability of the different tautomers, namely, (1) NH2NOH(+), (2) NH3NO(+), and (3) NH2NHO(+), has been considered, and the corresponding tautomerization transition states have been characterized. With respect to the most chemically relevant species, it has been found that NH2NOH(+) corresponds to a bound structure, while NH3NO(+) corresponds to an adduct between NH3 and NO(+) at both CASSCF and CASPT2 levels of theory. Vertical transition calculations and linear interpolations on the homolytic dissociation of NH3NO(+) in combination with previous results on neutral nitrosamine [J. Chem. Phys. 2006, 125, 164311] and neutral N,N-dimethylnitrosamine [J. Org. Chem. 2007, 72, 4741] indicate that, in acidic diluted solutions, the protonation of nitrosamine takes place on the excited surface. The N-N dissociation channels have been studied both in ground and first excited singlet state. An S1/S0 conical intersection is found to be responsible for the photostability of NH2NOH(+). On the contrary, NH3NO(+) is photochemically unstable as its first excited state is purely dissociative. The latter species is characterized by a twofold reactivity: the formation of nitrosyl cation (NO(+)) in the ground state and the photorelease of physiologically relevant nitric oxide radical (NO) in its first excited state.

We report quantum wave packet calculations of state-to-state reaction probabilities and cross sections for the reaction H+H(2)(v(0)=0,j(0)=0)-->H(2)(v,j)+H, at total energies up to 4.5 eV above the ground state potential minimum. The calculations are repeated using (i) the ground electronic state only, (ii) the ground state plus the diagonal non-Born-Oppenheimer correction, (iii) the ground state, diagonal non-Born-Oppenheimer correction and geometric phase (GP), and (iv) both electronic states including all nonadiabatic couplings, using the diabatic potential approach of Mahapatra et al. [J. Phys. Chem. A 105, 2321 (2001)]. The results for calculations (iii) and (iv) are in very close agreement, showing that the upper electronic state makes only a very small contribution to the state-to-state dynamics, even at energies much higher than the conical intersection minimum (at 2.74 eV). At total energies above 3.5 eV, many of the state-to-state reaction probabilities show strong GP effects, indicating that they are dominated by interference between one- and two-transition-state (1-TS and 2-TS) reaction paths. These effects survive the coherent sum over partial waves to produce features in the state-to-state differential cross sections which could be detected in an experiment with an angular resolution of approximately 20 degrees . Efficient dephasing of the interference between the 1-TS and 2-TS contributions causes almost complete cancellation of the GP in the integral cross sections, thus continuing a trend observed at lower energies in earlier work.

Unlabelled: Oesophageal Stricture (ES) is one of the most frequent complications of oesophageal atresia repair surgery. The treatment consists of dilatation of the stricture. Mostly more than one procedure is necessary for its correction., Aim: Present our experience in balloon dilatation in the treatment of ES post-correction of oesophageal atresia., Patients and Methods: A retrospective study of 34 children diagnosed and treated of oesophageal atresia was done. In all cases the surgical repair included a termino-terminal oesophageal anastomosis. Prevalence of ES (requiring dilatation), number of necessary dilatations, time between the correcting atresia surgery and the first dilatation, time between the first and the last dilatation and complications were analyzed. Dilatations were done under direct radioscopic control with general anesthesia using balloons of 6 to 20 mm diameter. Afterwards esophageal lumen was checked by oral endoscopy., Results: Thirty-four patients were studied (19 male, 16 female) with a medium weight of 2474 g (rango 1800 to 3300 g). Twenty-nine patients had a type III oesophageal atresia (Vogt classification) which was corrected in their first 24-48 hours of life, five patients had a type I oesophageal atresia and repair surgery was done with a medium age of five months. All patients received medical treatment for the gastroesophageal reflux and 11 patients needed a surgical antireflux surgery. Sixty-eight endoscopic procedures were done. Seventy-nine % of the children required some endoscopic dilatation (27 patients) and received an average of 2.5 dilatations (1 to 8 dilatations): 55.5% between 1 and 2 dilatations, 37% between 3 and 4, and 7.5% more than 5. The first dilatation took place in the average of 49.4 days post-correction surgery (15 days to 1 year). The medium time interval between the first dilatation and the last one was 131 days, although in more than 50% of the cases it did not reach 2 months. Only 2 oesophageal perforations were observed (2.3% of the dilatations), one of which had a favourable outcome with conservative management and the second one required surgery. All patients except for one are alive at this time and in more than 90% of the cases they have a complete and normal oral intake., Conclusions: Es requiring dilatations after oesophageal atresia repair are a frequent problem, appearing generally in an early period. Balloon dilatation under radioscopic control is an efficient and safe procedure for its treatment. Usually more than 1 dilatation is needed being the time period between two dilatations small. We think that associated medical antirreflux treatment is necessary in all cases, but only in specific cases surgical management of the gastroesophageal reflux.