Resonant quantum transitions in trapped antihydrogen atoms.

The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and--by comparison with measurements on its antimatter counterpart, antihydrogen--the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave radiation to flip the spin of the positron in antihydrogen atoms that were magnetically trapped in the ALPHA apparatus. The spin flip causes trapped anti-atoms to be ejected from the trap. We look for evidence of resonant interaction by comparing the survival rate of trapped atoms irradiated with microwaves on-resonance to that of atoms subjected to microwaves that are off-resonance. In one variant of the experiment, we detect 23 atoms that survive in 110 trapping attempts with microwaves off-resonance (0.21 per attempt), and only two atoms that survive in 103 attempts with microwaves on-resonance (0.02 per attempt). We also describe the direct detection of the annihilation of antihydrogen atoms ejected by the microwaves.

Non-Fermi-liquid behavior in transport through Co-doped Au chains.

We calculate the conductance as a function of temperature G(T) through Au monatomic chains containing one Co atom as a magnetic impurity, and connected to two conducting leads with a fourfold symmetry axis. Using the information derived from ab initio calculations, we construct an effective model H(eff) that hybridizes a 3d(7) quadruplet at the Co site with two 3d(8) triplets through the hopping of 5d(xz) and 5d(yz) electrons of Au. The quadruplet is split by spin anisotropy due to spin-orbit coupling. Solving H(eff) with the numerical renormalization group we find that at low temperatures G(T)=a-b√[T] and the ground state impurity entropy is ln(2)/2, a behavior similar to the two-channel Kondo model. Stretching the chain leads to a non-Kondo phase, with the physics of the underscreened Kondo model at the quantum critical point.

Dendritic cells are recruited into the airway epithelium during the inflammatory response to a broad spectrum of stimuli.

A key rate-limiting step in the adaptive immune response at peripheral challenge sites is the transmission of antigen signals to T cells in regional lymph nodes. Recent evidence suggests that specialized dendritic cells (DC) fulfill this surveillance function in the resting state, but their relatively slow turnover in most peripheral tissues brings into question their effectiveness in signaling the arrival of highly pathogenic sources of antigen which require immediate mobilization of the full range of host defenses for maintenance of homeostasis. However, the present report demonstrates that recruitment of a wave of DC into the respiratory tract mucosa is a universal feature of the acute cellular response to local challenge with bacterial, viral, and soluble protein antigens. Consistent with this finding, we also demonstrate that freshly isolated respiratory mucosal DC respond in vitro to a variety of CC chemokines as well as complementary cleavage products and N-formyl-methionyl-leucine-phenylalanine. This suggests that rapid amplification of specific antigen surveillance at peripheral challenge sites is an integral feature of the innate immune response at mucosal surfaces, and serves as an "early warning system" to alert the adaptive immune system to incoming pathogens.

Correlated dynamics of water and amphiphilic molecules in thin Newton black films.

The dynamical properties of amphiphilics in Newton black films, as well as those of the water confined between the two charged hydrophilic surfaces, have been calculated via a series of molecular dynamic calculations in several films with different water contents. A charged semiflexible amphiphilic model and the TIP5P model of water are used in our simulations [Z. Gamba, J. Chem. Phys. 129, 164901 (2008)]. We calculate the diffusion coefficients, reorientational dynamics, and the atomic density profile of water molecules as a function of the number of water molecules per amphiphilic (n(w)). We also analyze the reorientational motion of the amphiphilics and determine a strong correlation between the dynamics of water molecules and the translational and reorientational dynamics of the amphiphilics, as well as a correlation between the reorientational dynamics of the amphiphilics belonging to the upper and lower halves of the studied thin films.

Rhombohedral R3c to orthorhombic Pnma phase transition induced by Y-doping in BiFeO3.

In this work we study, by means of ab initio calculations, the structural, electronic and magnetic properties of Y-doped BiFeO3 compounds. We determine that there is a morphotropic phase boundary at an yttrium concentration of [Formula: see text], where the structure changes from R3c to Pnma. This structural transition is driven by the chemical pressure induced by the dopant. By analyzing the evolution of the oxygen octahedral tilts we find an enhanced antiferrodistortive distortion when increasing the Y-doping, together with a reduction of the ferroelectric distorsion, that gives rise to a smaller value of the electric polarization. These cooperative effects should lead to a larger canting of the Fe magnetic moments and to a larger ferromagnetic response in the R3c phase, as it is observed in the experiments.

Consultas de demanda espontánea sobre trastornos del desarrollo en el Hospital Garrahan / Spontaneous consultations for developmental disorders at Garrahan Hospital

Introducción: Los trastornos del desarrollo (TD) constituyen un motivo de consulta muy frecuente en la práctica pediátrica. El Hospital Garrahan recibe por demanda espontánea al servicio de Mediano Riesgo (MR) consultas de cuidadores con preocupaciones sobre el desarrollo de los niños, niñas y adolescentes (NNyA). Allí son valorados por pediatras clínicos, quienes realizan la interconsulta al servicio de Clínicas Interdisciplinarias del Neurodesarrollo (CIND) según necesidad (representan el 10% del total de consultas en MR). El objetivo del trabajo es comparar las características de los pacientes de MR que fueron consultados al área de Maduración de CIND durante el bimestre marzo/abril de 2016, 2021 y 2022. Materiales y métodos: estudio retrospectivo, observacional y comparativo. Se revisaron las historias clínicas analizando las siguientes variables: edad, procedencia, contar con pediatra de cabecera, cobertura de salud, motivo de consulta y sospecha diagnóstica. Resultados: La cantidad de consultas aumentó por encima del 20%, con un descenso en la mediana de edad de alrededor de un año. Aproximadamente el 70% de los pacientes procedían del conurbano en los tres períodos. Observamos un descenso respecto al número de NNyA con seguimiento pediátrico y cobertura social. El lenguaje y la conducta fueron los motivos más frecuentes de consulta y la mayor sospecha diagnóstica fue el Trastorno del Espectro Autista (TEA). Conclusiones: Los datos observados pueden relacionarse con el impacto de la pandemia así como también con las condiciones socio-económicas de los últimos cinco años, con un mayor conocimiento acerca del desarrollo y un probable aumento de la prevalencia de los TD (AU)

Introduction: Developmental disorders (DD) are a frequent reason for consultation in pediatric practice. The Garrahan Hospital receives spontaneous consultations at the department of Intermediate Risk (IR) from caregivers with concerns about the development of children and adolescents. At the IR department, children and adolescents are evaluated by clinical pediatricians, who consult with specialists at the Interdisciplinary Neurodevelopmental Clinic (INDC) as needed (accounting for 10% of the total number of consultations at the IR department). The aim of this study was to compare the characteristics of IR patients who were consulted at the INDC during the bimonthly period March/April 2016, 2021, and 2022. Materials and methods: a retrospective, observational, and comparative study was conducted. Medical records were reviewed analyzing the following variables: age, provenance, having a primary care pediatrician, healthcare insurance, reason for consultation, and diagnostic suspicion. Results: The number of consultations increased by over 20%, with a decrease in median age of around one year. Approximately 70% of the patients came from Greater Buenos Aires in the three periods. A decrease in the number of children and adolescents with pediatric follow-up and a social health insurance was observed. Language and behavior disorders were the most frequent reasons for consultation and autism spectrum disorder (ASD) was most often suspected. Conclusions: The observed data may be related to the impact of the pandemic as well as socio-economic conditions over the last five years, together with increased knowledge about development and a probable increase in the prevalence of ASD (AU)

Evaluación funcional del neurodesarrollo a los 24-30 meses de edad, de niños que requirieron terapias complejas durante el período neonatal / Functional assessment of neurodevelopment at 24-30 months of life of children requiring complex interventions in the neonatal period

El objetivo de este trabajo fue la evaluación funcional del neurodesarrollo de niños que requirieron terapias complejas neonatales entre los 24 y 30 meses de vida. Se incluyeron 104 pacientes evaluados en el Servicio de Clínicas Interdisciplinarias del Neurodesarrollo del Hospital de Pediatría Juan P. Garrahan, mediante pruebas estandarizadas; cuestionarios auto administrados y datos extraídos del interrogatorio, el examen físico y la historia clínica. A partir de los mismos los pacientes fueron agrupados según el grado de compromiso de su funcionalidad en dos grupos: el primero sin compromiso o compromiso leve y el segundo con compromiso moderado o severo. La evaluación funcional intenta desde una perspectiva biopsicosocial evaluar las habilidades, las dificultades y las características del entorno, que pueden ser tanto facilitadores como barreras para el desarrollo de la persona. De esta manera, permite un abordaje holístico del paciente y muestra como gran fortaleza frente a los diagnósticos categórico y etiológico, la adecuación de los sistemas de apoyos necesarios para cada paciente particular. En concordancia con la bibliografía sobre el riesgo biológico aumentado de esta población, el 44.2% de los niños de la muestra se encontraron dentro del grupo con compromiso funcional moderado/severo. En el análisis univariado las variables que presentaron asociación significativa con el grado de severidad del funcionamiento fueron la prematurez extrema, la displasia broncopulmonar, las lesiones en las ecografías cerebrales neonatales, internaciones neonatales prolongadas y los síndromes genéticos. Entre los factores medio-ambientales, se encontró asociación con progenitor solo y necesidad básicas insatisfechas (AU)

The aim of this study was the functional assessment of the neurodevelopment of children who require complex neonatal interventions between 24 and 30 months of life. Overall, 104 patients were evaluated at the Department of Interdisciplinary Clinics of Neurodevelopment at Hospital de Pediatría Juan P. Garrahan, with standardized tests, self-administered questionnaires and data gleaned from the interview, physical examination, and clinical records. Based on these data, the patients were divided into two groups according to the degree of functional involvement: a first group without or with mild functional compromise and a second group with moderate or severe compromise. From a biopsychosocial perspective, the purpose of functional assessment is the evaluation of skills, difficulties, and environmental characteristics that may be either facilitators or barriers to personal development. Thereby the assessment allows for a holistic approach of the patient and, unlike categorical and etiologic diagnosis, may lead to the adequate selection of the necessary support systems for each individual patient. In agreement with the literature on the increased biological risk in this population, 44.2% of the children in this sample were in the moderate/severe functional compromise group. In univariate analysis, the variables that were statistically significantly associated with degree of severity of function were extreme prematurity, bronchopulmonary dysplasia, lesion on neonatal ultrasonography, prolonged neonatal hospitalization, and genetic syndromes. Among environmental factors a significant association was found with a single parent and unsatisfied basic needs (AU)

Primary lung cancer in young patients: a study of 82 surgically treated patients.

The aim of this study was to evaluate the prognosis for surgically treated young patients with primary lung cancer, a prognosis generally considered to be very poor. Eighty-two patients less than 40 years of age were operated on at Marie-Lannelongue Hospital between 1982 and 1990. There were 72 male and 10 female patients. Ten patients (12%) had never smoked, whereas 48 patients (59%) had smoked for more than 20 pack-years. The lung cancer was asymptomatic in 27 patients (33%) and symptomatic in the others. Adenocarcinoma was found in 42% of the patients, epidermoid carcinoma in 28%, mixed cell carcinoma in 16%, small cell carcinoma in 8.5%, and undifferentiated large cell carcinoma in 6%. Among the 69 resected tumors, 22 were stage I, ten were stage II, 32 were stage IIIa, and five were stage IIIb. The resection was considered complete and curative in 56 patients (68%) and noncurative in 26 (32%) either because of an incomplete resection (12 in stage IIIa; 1 in stage IIIb) or because of an exploratory thoracotomy only (13). The overall actuarial 5-year survival rate was 41%, and the actuarial 5-year survival for patients who had a complete resection was 56%. The actuarial 5-year survival rates were as follows: patients in stage I, 70%; stage II, 54%; stage IIIa, 28%; stage IIIb, 0%; and patients having exploratory thoracotomy only, 18%. These survival rates are similar to those of patients older than 40 years with similar stages of disease.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study of the anticancer efficacy of doxorubicin carrying microspheres and liposomes using a rat liver tumour model.

Due to low efficacy of chemotherapy in the treatment of liver cancer, several methods of drug targeting have been investigated. Liposomes designed to carry cytotoxic drugs to the liver are currently under clinical evaluation. While experimental evidence shows promise, this method of drug delivery has several disadvantages that include short shelf life and poor drug delivery into tumour tissue. An alternative strategy for targeted drug delivery involving use of ion exchange microspheres may overcome these limitations while still reducing systemic toxicity and maintaining therapeutic efficacy. The purpose of this study was to determine the relative antitumour efficacy of these two drugs carrying systems in the treatment of liver cancer. Compared to controls, DOX treatment with free drug, liposomes or microspheres significantly reduced tumour growth by 56% (P < 0.001), 51% (P < 0.01) and 79% (P < 0.001) respectively. Furthermore, the DOX-microsphere treatment was significantly better than either of the other DOX treatments (53%, P < 0.05) or the sham-microsphere treated group (64%, P < 0.05). Thus, drug microspheres can increase the anti-tumour efficacy compared to either free or liposomal drug while simultaneously reducing systemic toxicity.

Elective laparoscopic cholecystectomy.

BACKGROUND: Gallbladder stones are very common in patients with sickle cell disease and are the cause of recurrent abdominal pain. Their management has been highly controversial, especially for children. Nonoperated patients and those treated on an emergency basis have a very high rate of morbidity (>50%). METHODS: We performed a retrospective review of a series of 29 homozygous SS sickle cell children who underwent laparoscopic cholecystectomy between 1991 and April 1998. RESULTS: Only in one case a conversion was necessary (early in the series). Exploration of the common bile duct was done via intraoperative cholangiography. There were no mortalities. The morbidity rate was 17%; (however, of the five patients concerned, four suffered from hyperthermia for 2 days. All of the children were improved and enjoyed resolution of their abdominal pain. CONCLUSIONS: We believe that elective laparoscopic cholecystectomy at the earliest time possible, along with correct perioperative management, is the treatment of choice for cholelithiasis in children with sickle cell disease.

Evaluation of ion-exchange microspheres as carriers for the anticancer drug doxorubicin: in-vitro studies.

A comparison study of doxorubicin loading, release characteristics and stability within sodium and hydrogen forms of ion-exchange resin microspheres has been performed. It was demonstrated that resins in the Na+ form, although having lower drug loading capacity, showed similar release profiles to resins in the H+ form but still maintain all the drug activity. Resins in the H+ form, despite having high drug loading capacity, caused drug degradation within microspheres due to their strong acidic nature. Therefore, in comparison with the H+ form, resins in the Na+ form can be considered as better carriers for doxorubicin in terms of sustaining the release of drug and maintaining drug activity. Other factors such as the degree of resin cross-linkage and drug/resin mixing time have also been examined in relation to drug loading and release characteristics. Overall, this study demonstrated the significance of the characteristics of matrix materials and their influence on the drug activity and microsphere performance in-vitro.

[Renal involvement in multiple myeloma. Physiopathology and therapy]. / Patologia renale nel mieloma multiplo. Fisiopatologia e terapia.

Renal failure (RF) is a common accompaniment of multiple myeloma and is identified in over half of patients at presentation. RF is usually related to the presence of Bence-Jones protein (immunoglobulin light chain) which damages all the compartments of the kidney: glomerule, tubulo-interstitium and vasculature. The most common renal lesion is cast nephropathy, named "myeloma kidney": Cast are produced by two mechanisms: proximal tubule damage and intratubular cast formation. The predominant pathophysiologic mechanism of tubule damage appears to be a precipitation of Bence-Jones protein and Tamm-Horsfall glycoprotein produced by cells of ascending limb of Henle's loop in the tubule lumen. The therapeutic maneuvers to reduce renal damage and preserve renal function are reduction of plasma concentration of light chain with chemotherapy, elimination of factors which favour coprecipitation of Tamm-Horsfall protein with light chain (hypercalcemia, acid urine, radiocontrast material, furosemide, oliguria). At last, colchicine (1.2 mg/day) will also be efficacious in the acute management of patients with cast nephropathy.

[Warfarin fetopathy]. / Foetopathie coumarinique.

UNLABELLED: We report a case of warfarin embryopathy. This disease affects more than 6% of fetuses exposed in utero to a vitamin K antagonist. OBSERVATION: A child whose mother was treated with acenocoumarol because of a mechanical heart valve presented with signs of warfarin embryopathy. He showed chondrodysplasia punctata with telebrachydactyly, facial dysmorphism with nasal hypoplasia, a cataract, and a bilateral pyeloureteral junction syndrome. COMMENTS: Characteristics of this drug induced embryopathy are reminded, while bearing in mind the conflict of interests between the mother and the fetus. The mechanisms of this embryopathy are debated in light of the recent knowledge concerning fetal metabolism of vitamin K.

[Intramural cyst of the esophagus. Apropos of a surgical case]. / Kyste intramural de l'oesophage. A propos d'un cas opéré.

Surgical excision of a benign cyst of esophagus was justified by the presence of dysphagia, totally relieved by the operation. Esophageal cysts are exceptional findings, their histology often resembling that of bronchogenic cysts as in the case reported.

[Dyspneic bronchopathy and asthma: hospital admission between 1979 and 1994]. / Broncopatia dispneizzante e asma: l'andamento dei ricoveri dal 1979 al 1994.

4,618 children, hospital admitted between 1979 and 1994 for wheezy bronchitis or asthma, have been investigated. the patients were distributed in two groups, according to mean age of 19 months or 8 year. An increasing incidence of asthma, an earlier onset or respiratory symptoms, more frequent hospitalisation in children aging less than 2 years, in recent years were observed. In elder children however, less frequent hospitalisation occurred.

Effect of magnetism and light sp-dopants on chain creation in Ir and Pt break junctions.

Applying the generalization of the model for chain formation in break-junctions (Di Napoli et al 2012 J. Phys.: Condens. Matter 24 135501), we study the effect of light impurities on the energetics and elongation properties of Pt and Ir chains. Our model enables us to develop a tool ideal for detailed analysis of impurity-assisted chain formation, in which zigzag bonds play an important role. In particular we focus on H (s-like) and O (p-like) impurities and assume, for simplicity, that the presence of impurity atoms in experiments results in a ..M-X-M-X-... (M: metal, X: impurity) chain structure in between the metallic leads. Feeding our model with material-specific parameters from systematic full-potential first-principles calculations, we find that the presence of such impurities strongly affects the binding properties of the chains. We find that, while both types of impurities enhance the probability of chains being elongated, the s-like impurities lower the chain's stability. We also analyze the effect of magnetism and spin-orbit interaction on the growth properties of the chains.

Estudio de riesgo de recurrencia de trastorno del espectro autista (TEA) en hermanos de niños con diagnóstico TEA / Study on recurrence risk of autism spectrum disorders (ASD) in siblings of children diagnosed with ASD

El trastorno del espectro autista (TEA) es un trastorno del desarrollo, común de la niñez, con una fuerte predisposición genética y alta heredabilidad. El riesgo de recurrencia en hermanos oscila entre 10-20% y en caso de familias con dos o más niños afectados el riesgo de recurrencia aumenta hasta un 35%. Dentro de las pruebas complementarias para el diagnóstico, el gold standard es la escala ADOS, existe además una prueba de pesquisa, el M-CHAT. Objetivo: evaluar riesgo de recurrencia de TEA en hermanos menores de niños con diagnóstico de TEA. Materiales y Métodos: se realizó un estudio de tipo transversal, observacional y descriptivo. Fueron estudiados niños entre 18-36 meses, hermanos de pacientes con diagnóstico de TEA. La evaluación del desarrollo se realizó utilizando: Escalas CAT/CLAMS, M-CHAT y ADOS 2. Resultados: se estudiaron 39 hermanos. 25 fueron varones y 14 fueron mujeres. Se identificaron 5 niños con diagnóstico de TEA, por lo que el riesgo de recurrencia en la población estudiada fue de 13%, con una relación varón/mujer de 4/1. Del resto de la población estudiada, 13% reunieron criterios para fenotipo ampliado del autismo (Broader Autism Phenotype ­BAP­ en su sigla en inglés), 31% presentaron retraso del lenguaje(RL) y 7%retraso global del desarrollo (RGD). Solo el 36% presentó desarrollo típico. Conclusión: Los hermanos de niños afectados representan un grupo de riesgo para problemas del desarrollo, que debe ser tenido en cuenta por los profesionales de la salud que siguen longitudinalmente a niños con diagnóstico confirmado de TEA (AU)

Autism spectrum disorder (ASD) is a developmental disorder that is common in childhood with a strong genetic predisposition and high heritability. The risk of recurrence in siblings is found to be between 10-20% and in families with two or more affected children recurrence risk is as high as 35%. Among the complementary diagnostic tests, the gold standard is the ADOS scale, and additionally the M-CHAT screening test. Objective: To evaluate the recurrence risk of ASD in younger siblings of children diagnosed with ASD. Material and Methods: A cross-sectional, observational, descriptive study was conducted. Children between 18- 36 months of age, siblings of children diagnosed with ASD were studied. Development was assessed using the CAT/CLAMS, MCHAT, and ADOS 2 scales. Results: 39 siblings were studied; 25 were male and 14 female. Five children with ASD were identified, accounting for a recurrence risk of 13% in the study population and a male/female ratio of 4/1. Of the remaining children, 13% met the criteria for the broader autism phenotype (BAP), 31% had language delay (LD), and 7% global developmental delay (GDD). Only 36% had normal development. Conclusion: Siblings of affected children are at risk for developmental disorders that should be taken into account by health professionals that ongitudinally follow children with a confirmed diagnosis of ASD (AU)

An experimental limit on the charge of antihydrogen.

The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects.

Autoresonant-spectrometric determination of the residual gas composition in the ALPHA experiment apparatus.

Knowledge of the residual gas composition in the ALPHA experiment apparatus is important in our studies of antihydrogen and nonneutral plasmas. A technique based on autoresonant ion extraction from an electrostatic potential well has been developed that enables the study of the vacuum in our trap. Computer simulations allow an interpretation of our measurements and provide the residual gas composition under operating conditions typical of those used in experiments to produce, trap, and study antihydrogen. The methods developed may also be applicable in a range of atomic and molecular trap experiments where Penning-Malmberg traps are used and where access is limited.

Description and first application of a new technique to measure the gravitational mass of antihydrogen.

Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe a novel direct test methodology; we search for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap. In the absence of systematic errors, we can reject ratios of the gravitational to inertial mass of antihydrogen >75 at a statistical significance level of 5%; worst-case systematic errors increase the minimum rejection ratio to 110. A similar search places somewhat tighter bounds on a negative gravitational mass, that is, on antigravity. This methodology, coupled with ongoing experimental improvements, should allow us to bound the ratio within the more interesting near equivalence regime.