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In this work we performed a detailed numerical analysis to investigate the dynamic susceptibility of 1000 nm long Fe3O4 nanotubes by varying the diameter, the tube wall thickness and the magnitude of the external magnetic field applied along the tube axis. We found two well-defined modes, one of low frequency associated with the caps of the nanotubes, and another of high frequency associated with the central area of the nanotubes, which can be controlled by varying the geometry of the tubes or the external magnetic field to which they are subjected. These results allow us to suggest the use of these nanotubes in applications that require controlling the resonant frequency in the GHz range. [ABSTRACT FROM AUTHOR]

The restrictive measures required to face the recent outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may impact patterns of healthcare utilization. Our aim was to provide an insight into the change in the use of a pediatric emergency department (ED) during the SARS-CoV-2 pandemic. The medical records of the children seen in our pediatric ED during March and April 2020 were retrospectively reviewed. Consequently, these were compared to the medical records of 2018 and 2019 from the same time period and from other control periods (January–February 2019 and 2020, and July–August 2018 and 2019). The total number of ED visits declined by 73% from 2019 to 2020 (3051 vs 818). Significant variations were observed in the distribution of children between triage categories: the proportion of patients who was given a green-code showed a 0.59-fold decrease in comparison to 2019 (95% CI 0.5–0.69), while a relative increase in the proportion of yellow codes was observed (OR 1.46, 95% CI 1.2–1.78). Conclusion: Quarantine measures significantly impacted on the total number of patients and on the reasons for visiting them in our pediatric ED. This substantial decrease in pediatric care may either be due to lower rates of acute infections because of social distancing, or to parents' or caregivers' reticence to risk exposure to SARS-CoV-2 in a health-care setting. What is known: •A recent outbreak of a novel coronavirus responsible for a severe acute respiratory syndrome is spreading globally. •Restrictive measures may impact patterns of healthcare utilization, as observed in other previous outbreaks. What is new: •This study shows significant variations in the distribution of children among triage categories during the COVID-19 pandemic. •Discharge diagnosis was significantly different as well, in particular a relative increase in the proportion of children presenting with traumatic injuries and a decrease of viral infections were observed. [ABSTRACT FROM AUTHOR]

This work proposes a reliable and efficient two-stage driver solution for extra-high-current (EHC) chip-on-board (COB) light-emitting diode (LED) applications. An ac–dc boost converter operating in continuous conduction mode is employed to provide input power factor correction and regulated dc-link voltage. Considering that EHC COB LEDs often operate at higher current levels than those employed in conventional high-powered lighting applications, a dc–dc extended gain interleaved buck converter (EGIBC) is employed so that power control is achieved. The average state-space modeling of the EGIBC is derived, while a digital control system is also implemented for this purpose. A 500-W prototype of the proposed two-stage topology is implemented, which does not require electrolytic capacitors. The obtained results clearly demonstrate that the proposed driver complies with international power quality and flicker standards. Thus, it can be consolidated as a viable choice for practical applications involving outdoor floodlighting where high luminous flux is mandatory. [ABSTRACT FROM AUTHOR]

A recent outbreak of a novel Coronavirus responsible for a Severe Acute Respiratory Syndrome (SARS-CoV-2) is spreading globally. The aim of this study was to systematically review main clinical characteristics and outcomes of SARS-CoV-2 infections in pediatric age. An electronic search was conducted in PubMed database. Papers published between 1 January and 1 May 2020 including children aged 0-18 years were selected. Sixty-two studies and three reviews were included, with a total sample size of 7480 children (2428/4660 males, 52.1%; weighted mean age 7.6 years). Patients showed mainly mild (608/1432, 42.5%) and moderate (567/1432, 39.6%) signs of the infection. About 2% of children were admitted to the pediatric intensive care unit. The most commonly described symptoms were fever (51.6%) and cough (47.3%). Laboratory findings were often unremarkable. Children underwent a chest CT scan in 73.9% of all cases, and 32.7% resulted normal. Overall, the estimated mortality was 0.08%. A higher proportion of newborns was severely ill (12%) and dyspnea was the most common reported sign (40%).Conclusion: SARS-CoV-2 affects children less severely than adults. Laboratory and radiology findings are mainly nonspecific. Larger epidemiological and clinical cohort studies are needed to better understand possible implications of COVID-19 infection in children.What is Known:• A novel Coronavirus has been recently identified as responsible for a new Severe Acute Respiratory Syndrome (SARS-CoV-2) spreading globally.• There is limited evidence on SARS-CoV2 infection in children.What is New:• Systematically reviewed available evidence showed that children with SARS-CoV-2 infection may have a less severe pattern of disease in comparison to adults.• Blood tests and radiology findings are mainly nonspecific in children but may help to identify those who are severely ill. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to describe the symptoms and signs of central nervous system (CNS) tumors in a pediatric population and to assess the time interval between the onset of the disease and the time of the diagnosis. Methods: A retrospective observational study was conducted at our Oncology Pediatric Unit between January 2000 and November 2011. We included 75 children between 5 months and 16 years (mean age of 7.8 ± 4.7 years), with male to female ratio of 3:2. The tumor localization was supratentorial in 51% of cases, and the most frequent histological type was low-grade astrocytoma (48%). Results: Presenting symptoms were headache (31%), vomiting (31%), seizures (21%), and behavioral change (11%). The most common symptoms at diagnosis were headache (51%), vomiting (51%), visual difficulties (37%), seizures (24%), and behavioral change (21%). By the time of diagnosis, neurologic examination was altered in 68% of our patients. Vomiting (44%) and behavioral change (44%) were the most frequent symptoms in children under 4 years of age, headache (61%) and vomiting (54%) in children older than 4 years. The median interval between symptoms' onset and diagnosis was 4 weeks (range 0 to 314 weeks). A longer symptom interval was associated with younger age, infratentorial localization and low-grade tumors. The differences in symptom intervals between the different age, location, and grade groups were not statistically significant. Survival probability was influenced by tumor grade but not by diagnostic delay or age of the child. Conclusions: Headache and vomiting are the earliest and commonest symptoms in children with brain tumors. Visual symptoms and signs and behavioral change are often present. Abnormalities in neurological examination are reported in most of the children. Intracranial hypertension symptoms suggest the need for a neurological clinical examination and an ophthalmological assessment. [ABSTRACT FROM AUTHOR]

We describe a very rare case of chronic peritonitis with secondary adhesive intestinal obstruction caused by Sphingomonas paucimobilis in a healthy 28-year-old Chinese man. This bacillus has not been described as a cause of spontaneous peritonitis in healthy people. It was an asymptomatic, generalized, and slow-growing peritonitis causing peritoneal adherens and at the end intestinal occlusion that needed surgical adhesiolysis. [ABSTRACT FROM AUTHOR]

A new method to improve the signal to noise ratios in multi-pulse nuclear quadrupole resonance (NQR) sequences was developed. In this method, called TONROF, the transmitter frequency is set on-resonance, while the receiver frequency is offset. Experimental results of using TONROF in conjunction with the SSFP sequence with RDX sample are presented. Elevated signal levels were obtained without losses in transmission efficiency. The results are compared with those obtained with the typically used off-resonance version of SSFP, called strong off-resonance comb (SORC) sequence. [ABSTRACT FROM AUTHOR]

A new device designed for both volumetric and surface NQR detection of substances spatially located in several positions, and in the presence of environmental interference, is described. The device consists of two probe coils, placed on the same detection plane, for excitation and detection of NQR signals. Experimental results obtained using Strong Off Resonance Comb (SORC) pulse sequences, for the excitation of the ν- transition in samples of Sodium Nitrite ( NaNO 2), are presented. It is shown that, when the total signals induced in each coil are properly combined, the interference commonly detected in both coils is attenuated relative to the NQR signal detected by either one or both probe coils. NQR signal can be detected by either one or both coils, but in both cases the noise induced by distant environmental sources is attenuated. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: To evaluate the nutritional status of vitamin D in urban populations of healthy elderly people living at home, in different regions of Argentina. DESIGN:: Cross-sectional study. SUBJECTS:: In total, 386 ambulatory subjects over 65?y of age from seven cities (between latitude 26°S and 55°S) were asked to participate between the end of winter and the beginning of spring. Of these, 369 accepted, 30 were excluded because of medical history or abnormal biochemical determinations. Finally, 339 subjects (226 women and 113 men) (X±s.d.) (71.3± 5.2?y) were included. RESULTS:: Serum 25OHD levels were lowest in the South (latitude range: 41°S-55°S): 14.2±5.6?ng/ml (P<0.0001vs North and Mid regions); highest in the North (26°S-27°S): 20.7±7.4?ng/ml (P<0.03 vs Mid, P<0.0001vs South); and intermediate in the Mid region (33°S-34°S) 17.9±8.2?ng/ml. Serum mid-molecule PTH (mmPTH) and 25OHD were inversely related: (r=-0.24, P<0.001). A cutoff level of 25OHD at which serum mmPTH levels began to increase was established at 27?ng/ml. A high prevalence (87-52%) of subjects with 25OHD levels in the deficiency-insufficiency range (25OHD levels <20?ng/ml) was detected. CONCLUSION:: This study shows that vitamin D deficiency/insufficiency in the elderly is a worldwide problem. Correction of this deficit would have a positive impact on bone health of elderly people. SPONSORSHIP:: Asociación Argentina de Osteología y Metabolismo Mineral (AAOMM).European Journal of Clinical Nutrition (2004) 58, 337-342. doi:10.1038/sj.ejcn.1601786 [ABSTRACT FROM AUTHOR]

We describe a field-cycling magnetic resonance experiment aimed to study the nuclear spinlattice relaxation in the simultaneous presence of an oscillating magnetic field and a magnetomechanically induced perturbation across the sample volume. The studied system is a gelatine doped with surfacted nanosize ferromagnetic particles. The spin system relaxes in coexistence with the magnetic interaction between the dopants and a weak external alternating magnetic field. Due to the interaction between the alternating field and the high magnetic moment of the dopants, a mechanical shaking of the particles becomes effective at low evolution fields. In this way, the particles act as local sonic sources, thus transmitting the vibrations to the gelic matrix where they are trapped. The impact produced on the molecular dynamics is observed through a magnetic resonance relaxation experiment. Saturation of the proton magnetization produced by the alternating magnetic field is also discussed. Results are compared with the direct effects produced by a pure sonic perturbation at the same frequency, introduced by coupling a piezoelectric transducer in direct contact with the sample. [ABSTRACT FROM AUTHOR]

The first experimental evidence of director fluctuations in a micellar lyotropic liquid crystal, studied by 1H spin-lattice relaxation rate, is reported. The system is constituted by the ternary mixture: potassium laurate/1-decanol/water. With the aim to test the slow dynamics, the experiment has been performed over a broad range of Larmor frequencies (2 × 103− 6.6 × 106 Hz), using fast field-cycling NMR relaxometry. The results evidence that in the nematic and isotropic mesophases and the poliphasyc region, director fluctuations are responsible for the spin-lattice relaxation dispersion in the low Larmor frequency range (<105 Hz). By increasing the intermicellar water content, a crossover was found between a quasi-isotropic 3D director fluctuations behavior to a 2D pseudo-lamellar undulation fluctuations. In order to explain the higher frequency range (>105 Hz), two relaxation mechanisms are assigned: i) molecular reorientation by translational diffusion on the micellar surface, and ii) molecular exchange between the micelle and the bulk. [ABSTRACT FROM AUTHOR]

An encoding procedure for two-dimensional rotating-frame imaging and positional spectroscopy in quadrupole systems with spin I > 3/2 is reported. The technique consists of a two-frequency irradiation pulse sequence: The population of a pair of spin states is changed by a radiofrequency pulse with a linear gradient and a second transition, which involves one of the two affected states, is excited with a second pulse with a gradient perpendicular to the first one. The spatial-spin distribution in the plane defined by the orthogonal radiofrequency gradients is recorded on Cartesian coordinates. The theoretical description of the technique and experimental results demonstrating its applicability to a powder sample containing I = 7/2 nucleus are given. [ABSTRACT FROM AUTHOR]

A correction to this paper has been published: https://doi.org/10.1007/s00431-021-03961-z [ABSTRACT FROM AUTHOR]

Lienal vein aneurysms are a very unusual pathology. Usually they are extremely rare incidental findings, associated with many diseases as hepatic cirrhosis, portal hypertension and other conditions as pregnancy. We report here the case of death of a mother and her fetus at the third trimester of her third pregnancy due to haemoperytoneum for rupture of aneurysm. The autoptic examination revealed the presence of three fusiform and saccular aneurysms of the lineal vein. The histopathological features of aneurysms’ wall are described. The aetiopathogenetic hypothesis of the lesion is discussed. To our knowledge this is the first case report describing the sudden death of pregnant woman and fetus from a rupture of maternal lineal vein aneurysm, complication of multiple aneurysms. [ABSTRACT FROM AUTHOR]

Unlabelled: Rituximab is a chimeric monoclonal antibody directed against normal and malignant mature B-lymphocytes and results in prolonged and severe B-cell depletion. Recently, rituximab has been successfully used in adult and paediatric disorders of B-lymphocytes such as autoimmune haemolytic anaemia and Werlhof disease. We report on two children with chronic immune thrombocytopenic purpura (ITP) refractory to steroids and immunoglobulins who achieved complete normalisation of their platelet counts after treatment with rituximab, 375 mg/m2 given weekly in four doses. In both cases the B-lymphocyte count dropped to zero after the second dose of rituximab and an unsupported platelet count > 100 x 10(9)/l was achieved during treatment. Six and 12 months after treatment, both patients remain well with normal platelet counts.Conclusion: This report supports the concept that rituximab may also be a valuable therapeutic option in children with chronic immune thrombocytopenic purpura refractory to standard treatment. Controlled clinical trials are needed to evaluate the efficacy and long-term side-effects of rituximab in this group of patients. [ABSTRACT FROM AUTHOR]

Endocrine disruptors are chemical substances that can interfere with the endocrine system. They include pesticides, metals, additives or contaminants in food, and personal care products. Pesticides are the only substances intentionally released into our environment to kill living things (herbicides, insecticides, fungicides, rodenticides). There is scientific evidence that exposure to pesticides produces a growing number of human pathological conditions; among these, stillbirth is an emerging issue. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 58-year-old male patient who was diagnosed with dedifferentiated liposarcoma that was arisen from the fat tissue of the endothoracic fascia. It mentions that a voluminous inhomogeneous mass adjacent to the apical segment of the inferior left lobe was found following compute tomography of chest.

We describe the first report of plexiform lipoleiomyoma with amyloid stroma. A 57-year-old woman underwent an abdominal hysterectomy for methrorragia. The hysterectomy specimen exhibited a soft, rubbery, encapsulated 11 cm ovoid mass with aciniform, white cut surface on the right edge of the uterus. The histology was distinctive and typical of plexiform lipoleiomyoma: long cords, strands and small nests of cells embedded in a collagenous matrix. The neoplastic cells showed eosinophilic cytoplasm, crumpled, bland nuclei. Scattered islands of mature adipocytes were distributed throughout the leiomyomatous proliferation. Immunohistochemistry showed positivity for smooth muscle actin in the plexiform component, and for S100 in the adipocytes. Histogenesis and origin of the cellular neoplastic component are discussed. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "A primary atypical solitary fibrous tumour of the sella mimicking non-functional pituitary adenoma: a case report," by Yin W. and colleagues published in the June 2010 issue.