Elastocapillarity-driven 2D nano-switches enable zeptoliter-scale liquid encapsulation.

Biological nanostructures change their shape and function in response to external stimuli, and significant efforts have been made to design artificial biomimicking devices operating on similar principles. In this work we demonstrate a programmable nanofluidic switch, driven by elastocapillarity, and based on nanochannels built from layered two-dimensional nanomaterials possessing atomically smooth surfaces and exceptional mechanical properties. We explore operational modes of the nanoswitch and develop a theoretical framework to explain the phenomenon. By predicting the switching-reversibility phase diagram-based on material, interfacial and wetting properties, as well as the geometry of the nanofluidic circuit-we rationally design switchable nano-capsules capable of enclosing zeptoliter volumes of liquid, as small as the volumes enclosed in viruses. The nanoswitch will find useful application as an active element in integrated nanofluidic circuitry and could be used to explore nanoconfined chemistry and biochemistry, or be incorporated into shape-programmable materials.

Tuning ferromagnetism at room temperature by visible light.

Most digital information today is encoded in the magnetization of ferromagnetic domains. The demand for ever-increasing storage space fuels continuous research for energy-efficient manipulation of magnetism at smaller and smaller length scales. Writing a bit is usually achieved by rotating the magnetization of domains of the magnetic medium, which relies on effective magnetic fields. An alternative approach is to change the magnetic state directly by acting on the interaction between magnetic moments. Correlated oxides are ideal materials for this because the effects of a small external control parameter are amplified by the electronic correlations. Here, we present a radical method for reversible, light-induced tuning of ferromagnetism at room temperature using a halide perovskite/oxide perovskite heterostructure. We demonstrate that photoinduced charge carriers from the [Formula: see text] photovoltaic perovskite efficiently dope the thin [Formula: see text] film and decrease the magnetization of the ferromagnetic state, allowing rapid rewriting of the magnetic bit. This manipulation could be accomplished at room temperature; hence this opens avenues for magnetooptical memory devices.

HMGB1 as a new biomarker of celiac disease in children: A multicenter study.

OBJECTIVE: Despite the availability of specific sierology and point-of-care tests, the phenotypic heterogeneity and the symptoms fluctuation as well as the "open-window" existing among the late and silent forms cause often a delayed celiac disease (CD) diagnosis. Recently, it has been reported that high mobility group box 1 (HMGB1) mediates inflammation and gastrointestinal barrier failure. The aim of this study was to detect serum HMGB1 levels at CD diagnosis and to evaluate the relationship between serum HMGB1 levels and clinical and histologic phenotypes. METHODS: 49 CD children and 44 healthy children were enrolled. Specific antitissue transglutaminase type 2, antideaminated form of gliadin antibodies, serum HMGB1 levels, and typical histopathological changes in duodenal mucosa were performed in all patients. Mucosal lesions were classified according to Marsh classification. In relation to clinical presentation, we classified patients into: typical, atypical and silent forms. RESULTS: Serum HMGB1 levels were significantly higher in those with CD than those in the healthy control group (P < 0.001). Significant differences in serum HMGB1 levels were detected in children with typical CD form compared to both children with atypical CD form (P < 0.001) and children with silent CD form (P < 0.001). By using the Marsh classification, significant differences were found between subjects with grade 3 B-B1 and 3 C-B2 and villous atrophy, respectively (P < 0.05). On the contrary, no significant differences in serum HMGB1 levels in subgroups of children with grade 3 A compared to grade 3 B-B1 were detected. CONCLUSIONS: HMGB1 is upregulated at diagnosis in all CD children, especially in typical form, and reflecting the histologic severity of disease.

Photodiode Response in a CH3NH3PbI3/CH3NH3SnI3 Heterojunction.

Here we report another surprising feature of the methylammonium metal halide material family, the phototunability of the diode response of a heterojunction made of CH3NH3PbI3 and its close relative, CH3NH3SnI3. In the dark state the device behaves as a diode, with the Sn homologue acting as the "p" side. The junction is extremely sensitive to illumination. A complete reversal of the diode polarity, the first observation of its kind, is seen when the junction is exposed to red laser light of 25 mW/cm2 or larger power density. This finding opens up the possibility for a novel class of optoelectronic devices.

CH3NH3PbI3: precise structural consequences of water absorption at ambient conditions.

The crystal structure of the pristine (I) and aged (II) crystals of CH3NH3PbI3 (hereafter MAPbI3) hybrid organic-inorganic lead iodide has been studied at 293 K with high-precision single-crystal X-ray diffraction using a synchrotron light source. We show that (I) and (II) are characterized by an identical tetragonal unit cell but different space groups: I422 for (I) and P42212 for (II). Both space groups are subgroups of I4/mcm, which is widely used for MAPbI3. The main difference between (I) and (II) comes from the difference in hydrogen bonds between the MA+ cation and the PbI3 framework which is the direct consequence of H2O insertion in the aged crystal (II).

Immune response to hepatitis B virus vaccine in celiac subjects at diagnosis.

AIM: To evaluate hepatitis B virus (HBV) vaccine response and correlation with human leukocyte antigens (HLA) and/or gluten intake in celiac patients at diagnosis. METHODS: Fifty-one patients affected by celiac disease, diagnosed at the Department of Pediatrics of the University of Catania (Italy), were recruited. All patients were tested at admission for immunization against HBV, according to findings from analysis of quantitative HBV surface antibody (anti-HBs). The anti-HBs titer was measured by enzyme-linked immunosorbent assay. Following the international standards, subjects with antibody titer < 10 IU/L were defined as non-responders. The prevalence of responders and non-responders among celiac subjects and the distribution of immunization for age were examined. In addition, the prevalence of responders and non-responders was assessed for correlation to HLA and clinical features at diagnosis of celiac disease. RESULTS: The entire study population was divided into three groups according to age: 24 patients aged between 0 to 5.5 years (48.9%, group A); 16 aged between 5.5 and 9.5 years (30.61%, group B); 9 aged between 9.5 and 17 years (18.75%, group C). Comparison of the percentage of responders and non-responders between the youngest and the oldest age group showed no significant difference between the two groups (P > 0.05). With regard to the HLA haplotype, comparison of the distribution of vaccination response showed no statistically significant difference between the different genotypes (homozygosity for the HLADQ2 haplotype compared with HLADQ2/DQ8 heterozygosity or other haplotypes; P > 0.05). Moreover, distribution of the responders according to clinical features of celiac disease showed no statistically significant differences (P > 0.05). CONCLUSION: This prospective study confirmed the lower percentage of response to HBV vaccine in celiac subjects. However, the underlying mechanism remains unclear and further studies are needed.

Controlled growth of CH3NH3PbI3 nanowires in arrays of open nanofluidic channels.

Spatial positioning of nanocrystal building blocks on a solid surface is a prerequisite for assembling individual nanoparticles into functional devices. Here, we report on the graphoepitaxial liquid-solid growth of nanowires of the photovoltaic compound CH3NH3PbI3 in open nanofluidic channels. The guided growth, visualized in real-time with a simple optical microscope, undergoes through a metastable solvatomorph formation in polar aprotic solvents. The presently discovered crystallization leads to the fabrication of mm(2)-sized surfaces composed of perovskite nanowires having controlled sizes, cross-sectional shapes, aspect ratios and orientation which have not been achieved thus far by other deposition methods. The automation of this general strategy paves the way towards fabrication of wafer-scale perovskite nanowire thin films well-suited for various optoelectronic devices, e.g. solar cells, lasers, light-emitting diodes and photodetectors.

Health hazards of methylammonium lead iodide based perovskites: cytotoxicity studies.

New technologies launch novel materials; besides their performances in products, their health hazards must be tested. This applies to the lead halide perovskite CH3NH3PbI3 as well, which offers fulgurate applications in photovoltaic devices. We report the effects of CH3NH3PbI3 photovoltaic perovskites in human lung adenocarcinoma epithelial cells (A549), human dopaminergic neuroblastoma cells (SH-SY5Y) and murine primary hippocampal neurons by using multiple assays and electron microscopy studies. In cell culture media the major part of the dissolved CH3NH3PbI3 has a strong cell-type dependent effect. Hippocampal primary neurons and neuroblastoma cells suffer a massive apoptotic cell death, whereas exposure to lung epithelial cells dramatically alters the kinetics of proliferation, metabolic activity and cellular morphology without inducing noticeable cell death. Our findings underscore the critical importance of conducting further studies to investigate the effect of short and long-term exposure to CH3NH3PbI3 on health and environment.

Nanowires of methylammonium lead iodide (CH3NH3PbI3) prepared by low temperature solution-mediated crystallization.

We report the synthesis of Methylammonium Lead Iodide (CH(3)NH(3)PbI(3)) nanowires by a low temperature solution processed crystallization using a simple slip-coating method. The anisotropic particle shape exhibits advantages over nanoparticles in terms of charge transport under illumination. These results provide a basis for solvent-mediated tailoring of structural properties like the crystallite size and orientation in trihalide perovskite thin films, which, once implemented into a device, may ultimately result in an enhanced charge carrier extraction.

Ultra-Low Thermal Conductivity in Organic-Inorganic Hybrid Perovskite CH3NH3PbI3.

We report on the temperature dependence of thermal conductivity of single crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The comparable absolute values and temperature dependence of the two samples' morphologies indicate the minor role of the grain boundaries on the heat transport. Theoretical modeling demonstrates the importance of the resonant scattering in both specimens. The interaction between phonon waves and rotational degrees of freedom of CH3NH3(+) sublattice emerges as the dominant mechanism for attenuation of heat transport and for ultralow thermal conductivity of 0.5 W/(Km) at room temperature.

Lactobacillus reuteri in children with functional abdominal pain (FAP).

AIM: Functional abdominal pain (FAP) is a frequent condition affecting 10-20% of children and can be considered within the classification of functional gastrointestinal disorders (FGID). The objective of this study was to determine the effect of daily supplementation with the probiotic Lactobacillus reuteri DSM 17938 in children with FAP. METHODS: The children (aged 6-16 years) were screened for FAP as defined in the Rome III criteria and 60 patients were recruited in this double-blind, randomised, placebo-controlled trial. The children were randomly allocated to receive either L. reuteri (2×10(8) CFU/day) or identical placebo for 4 weeks followed by a 4-week follow-up period without supplementation. Frequency and intensity of pain was self-recorded by the subjects. RESULTS: The L. reuteri-supplemented children had significantly lower pain intensity compared with the placebo controls. CONCLUSIONS: Supplementation with L. reuteri reduced perceived abdominal pain intensity, which may encourage clinicians to use this probiotic in children with FAP.

The importance of disease prevalence in assessing the diagnostic value of a test: endoscopic markers in celiac disease.

BACKGROUND/AIMS: We evaluated the diagnostic variability and reproducibility of endoscopic signs in two populations with a different pretest likelihood of celiac disease (CD). METHODS: We recruited 289 CD patients (both adults and children) in a multicenter prospective study. Group 1 (high risk) included 111 patients referred for positive serology. Group 2 (low risk) included 178 unselected patients. Mosaic pattern, reduction/loss of Kerckring's folds, scalloping of the valvulae conniventes and a nodular pattern were the endoscopic findings looked for in the duodenum. RESULTS: In group 1, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of endoscopic findings were 100, 84.6, 94.2 and 100% in adults, and 86.8, 9.1, 82.1 and 12.5% in children. In group 2, the sensitivity, specificity, PPV and NPV of endoscopic findings were 33.3, 91.4, 7.7 and 98.5% in adults, and noncalculable, 78.3, 0.0 and 100% in children. Comparing group 1 and group 2, there was a statistically significant difference in sensitivity and PPV in adults, and in specificity, PPV and NPV in children. Concerning the reproducibility of endoscopic findings, a wide variability of κ values was found. CONCLUSION: Endoscopic signs have low reproducibility for CD, and their diagnostic value in selecting patients for multiple intestinal biopsies is unacceptable, especially in populations with low disease prevalence.

Intramuscular vs intradermal route for hepatitis B booster vaccine in celiac children.

AIM: To compare intradermal (ID) and intramuscular (IM) booster doses, which have been used in healthy and high risk subjects, such as healthcare workers, haemodialysis patients, human immunodeficiency virus patients, and renal transplant recipients unresponsive to initial hepatitis B vaccination, in celiac individuals. METHODS: We conducted our study on 58 celiac patients, vaccinated in the first year of life, whose blood analysis had showed the absence of protective hepatitis B virus (HBV) antibodies. All patients had received the last vaccine injection at least one year before study enrolment and they had been on a gluten free diet for at least 1 year. In all patients we randomly performed an HBV vaccine booster dose by ID or IM route. Thirty celiac patients were revaccinated with recombinant hepatitis B vaccine (Engerix B) 2 µg by the ID route, while 28 celiac patients were revaccinated with Engerix B 10 µg by the IM route. Four weeks after every booster dose, the anti-hepatitis B surface (HBs) antibody titer was measured by an enzyme-linked immune-adsorbent assay. We performed a maximum of three booster doses in patients with no anti-HBs antibodies after the first or the second vaccine dose. The cut off value for a negative anti-HBs antibody titer was 10 IU/L. Patients with values between 10 and 100 IU/L were considered "low responders" while patients with an antibody titer higher than 1000 IU/L were considered "high responders". RESULTS: No significant difference in age, gender, duration of illness, and years of gluten intake was found between the two groups. We found a high percentage of "responders" after the first booster dose (ID = 76.7%, IM = 78.6%) and a greater increase after the third dose (ID = 90%, IM = 96.4%) of vaccine in both groups. Moreover we found a significantly higher number of high responders (with an anti-HBs antibody titer > 1000 IU/L) in the ID (40%) than in the IM (7.1%) group, and this difference was evident after the first booster dose of vaccination (P < 0.01). No side effects were recorded in performing delivery of the vaccine by either the ID or IM route. CONCLUSION: Our study suggests that both ID and IM routes are effective and safe options to administer a booster dose of HBV vaccine in celiac patients. However the ID route seems to achieve a greater number of high responders and to have a better cost/benefit ratio.

Compliant gluten-free children with celiac disease: an evaluation of psychological distress.

BACKGROUND: Children with chronic illnesses are known to have increased risks for emotional and behavioral problems. In the present study, children and adolescent suffering from celiac disease (CD) were compared with healthy controls to assess differences in the psychological profile. METHODS: A total of 100 well-treated and compliant CD patients (65 females/35 males; age mean ± SD: 10.38 ± 2.71) were compared to 100 normal controls (58 females/42 males; age mean ± SD: 11.47 ± 2.61). Emotional and behavioral problems were assessed by the Child Behavior Checklist (CBCL), the Children's Depression Inventory (CDI) and the Multidimensional Anxiety Scale for Children (MASC). RESULTS: Subjects with CD self-reported an increased rate of anxiety and depression symptoms and showed higher scores in "harm avoidance" and "somatic complaints", in the CBCL parent-report questionnaire, as compared to healthy control subjects. Furthermore, gender differences could be observed in the group of CD patients, with males displaying significantly higher CBCL externalizing scores, in social, thought and attention problems, as compared to female, who in turns showed more prominent internalizing symptoms such as depression. CONCLUSIONS: The increased rate of emotional and behavioral problems in children and adolescent with CD emphasizes the importance of an early detection of mental health problems in these children.

Headache in pediatric patients with celiac disease and its prevalence as a diagnostic clue.

OBJECTIVES: To establish the prevalence of headache in children with celiac disease (CD), the response to a gluten-free diet, and the prevalence of CD in children affected by headache. METHODS: This hospital-based study included 2 steps. In the retrospective part, 354 children with CD answered a questionnaire investigating the presence of headache before and after the gluten-free diet. The same questionnaire was administered to 200 healthy children matched for sex and age. In the prospective part, 79 children affected by headache were screened for CD by antitransglutaminase IgA. Diagnosis of CD was confirmed by duodenal biopsy; before starting a gluten-free diet patients underwent a brain positron emission tomography study. After 6 months of follow-up children were reevaluated for the presence of headache. RESULTS: Overall, 88 patients with CD complained of headaches before the diagnosis of CD as compared with 16 in the control group (24.8% vs 8%, P < 0.001). After the institution of a gluten-free diet, the headaches significantly improved in 68 children (77.3%), of whom 24 (27.3%) were headache-free during the study period. Four of 79 (5%) headache patients were found to have CD compared with 0.6% of the general population (P = 0.005). The brain positron emission tomography studies did not show any anomalies. During the follow-up, headaches improved in all 4 children with CD. CONCLUSIONS: We recorded -- in our geographical area -- a high frequency of headaches in patients with CD and vice versa with a beneficial effect of a gluten-free diet. Screening for CD could be advised in the diagnostic work-up of patients with headache.

Low prevalence of neurologic and psychiatric manifestations in children with gluten sensitivity.

OBJECTIVE: To determine the frequency of neurologic manifestations in children with gluten sensitivity (GS) and the frequency of GS in children with neurologic disease. STUDY DESIGN: A total of 835 children with GS (based on positive titers for serum anti-gliadin antibody [AGA], anti-endomysial antibody [EMA], and anti-tissue transglutamine [tTG] antibody and a positive gut biopsy), representing the local childhood GS population in the town of Catania, Italy, were recruited, prospectively followed up, and screened for neurologic and psychiatric disturbances between 1991 and 2004. Serum AGA, EMA, and anti-tTG antibody titers were estimated in a prevalence sample of 630 consecutive children with neurologic disorders of unknown cause despite full investigation, 300 children with known neurologic syndromes, and 300 healthy children who served as controls. Statistical significance was assessed by the chi(2) test and Yates' chi(2) test. RESULTS: Neurologic or psychiatric problems were noted in 15 of 835 children with GS (1.79%) with previously diagnosed GS enteropathy (GSE). In 7 of 630 children (1.1%) with a cryptogenic neurologic disorder, GS was identified based on GS autoantibody screening. These 22 children had febrile seizures, epilepsy, headache, mental retardation, neuropathy, and bipolar disorder; no children had ataxia or cerebellar disturbances. The HLAs were DQ2 (n = 16), DQ8 (n = 4), and DQ2/DQ8 (n = 2). Two of the 300 healthy controls (0.66%) had GS. CONCLUSIONS: Based on our findings, the prevalence of neurologic/psychiatric manifestations in this group of children with GS was low but slightly higher than that in the controls (P = .041). Children with known (P = .772) and cryptogenic (P = 1.0) neurologic disorders did not exhibit a higher prevalence of GS.