The crystal structure and thermal expansion of novel substitutionally disordered Ca10TM0.5(VO4)7 (TM = Co, Cu) orthovanadates.

The whitlockite-related materials have attracted researchers' attention because of their potential application in various fields, especially in optoelectronics. In the present work, the structure of novel whitlockite-related oxides Ca10TM0.5(VO4)7 (TM = Co, Cu) is studied at room and high temperatures, using X-ray powder diffraction. These compounds form by fractional substitution of divalent transition metal atoms into the Ca3(VO4)2 lattice. Rietveld refinements provided the structural details. The lattice parameters are a = 10.78074(6) Å, c = 37.8196(2) Å, and V = 3806.67(4) Å3 for Ca10Co0.5(VO4)7 and a = 10.78710(7) Å, c = 37.8997(3) Å, and V = 3819.23(4) Å3 for Ca10Cu0.5(VO4)7. Structure refinement results show that among the five available sites (M1-M5), the M2+ ions select the M5 site. This finding is confirmed by analysis of interatomic distances: due to the difference in size between TM and Ca ions sharing the M5 site, the M5-O distance shortens by about 5.0% for Ca10Co0.5(VO4)7 and 2.7% for Ca10Cu0.5(VO4)7 with respect to the unsubstituted parent compound, Ca3(VO4)2. The observed trends in the crystallographic properties of the studied crystals are in line with those of previously reported structurally related phosphates, Ca10.5-xMx(PO4)7 (M = Mg or divalent transition metal). Moreover, the observed tendency for occupation of M5 by small divalent ions follows the earlier theoretical results. For cobalt and copper substituted orthovanadate and orthophosphate whitlockite related materials, a linear variation in the unit cell size is demonstrated. The common equation for evaluation of volume is applicable to the substitution of the two transition metals in orthovanadate and orthophosphate whitlockite related materials. Thermal expansion is investigated for both compounds. The variations of the lattice parameters and the thermal expansion coefficient with temperature are determined in the 300-810 K range. The lattice parameter, a, expands by 0.80% for Ca10Co0.5(VO4)7 and 0.74% for Ca10Cu0.5(VO4)7 in this range. The lattice parameter, c, enlarges by about 0.70% for both samples. In the studied temperature range, the volume thermal expansion coefficient of Ca10Co0.5(VO4)7 increases from 37.2 to 44.8 MK-1 and for Ca10Cu0.5(VO4)7, it increases from 35.1 to 45.2 MK-1; the observed expansion anisotropy is smaller than those of other related compounds.

Note: Size effects on the tensile response of top-down fabricated Si nanobeams.

The tensile response of top-down fabricated sc-Si nanobeams is inferred from the fitting of stress-strain data obtained under tensile loading conditions over a large range of deformation. The testing is performed using MEMS structures consisting of two connected beams; a highly stressed silicon-nitride (SiN) beam connected to a sc-Si specimen beam. The high tensile stress component present upon the deposition of the SiN loads the sc-Si beam once the entire structure is released. The strain and stress values are extracted independently, respectively, by scanning electron microscopy inspection and vibration frequency measurement of the released tensile MEMS structures. The tensile tests are undertaken for six thicknesses to determine the dependence of the elastic response on dimensions. The Young's modulus shows a variation of 40% for thicknesses ranging from 200 to 30 nm.

Lipopolysaccharide hyporesponsiveness as a risk factor for intensive care unit hospitalization in infants with respiratory syncitial virus bronchiolitis.

Factors such as genetic heterogeneity in the immune response contribute to respiratory syncytial virus (RSV) bronchiolitis severity. Such heterogeneity may manifest by an aberrant proliferation of phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) in response to lipopolysaccharide (LPS). The proliferation of PBMC was analysed in 52 infants: 21 ambulatory infants with mild RSV bronchiolitis (group I), 26 hospitalized infants with RSV bronchiolitis on ward (group II) and five intensive care unit (ICU) hospitalized infants (group III). Proliferation was analysed in response to negative control, PHA (LPS) and LPS/PHA. The TLR4 mutations were genotyped using reverse-transcriptase-polymerase chain reaction. The optical density (OD) post-LPS/PHA of group II (1.27 +/- 0.63) was significantly higher than group II (0.65 +/- 0.38, P = 0.005) or group I (0.63 +/- 0.33, P = 0.003), suggesting hyporesponsiveness to the LPS attenuation effect. None of the ICU hospitalized infants demonstrated OD readings post-LPS/PHA under the 0.75 threshold as opposed to group I (67% under 0.75) and group II (69%) (P < 0.05). The responses to negative-control, LPS and PHA stimulation alone were similar across groups. The presence of TLR4 mutations (Asp299Gly and Thr399Ile) were associated with severe RSV bronchiolitis and were significantly over-represented in groups II and III. These findings suggest that impairments of PBMC function manifested by hyporesponsiveness to LPS as well as the presence of TLR4 mutations are associated with an increased risk for more severe RSV bronchiolitis in previously healthy infants. A certain threshold of LPS hyporesponsiveness may have a very high negative predictive value for ICU hospitalization, even better than the determination of known TLR4 mutations for this purpose.

Reversible fulminant lactic acidosis and liver failure in an infant with hepatic cytochrome-c oxidase deficiency.

Cytochrome-c oxidase (COX) is the most common respiratory chain complex involved in liver failure, either as a single enzyme deficiency or as part of multiple enzyme deficiencies. We describe an infant who presented with fulminant lactic acidosis in the neonatal period. The lactic acidosis resolved spontaneously but liver and pancreatic insufficiency ensued. Isolated cytochrome-c oxidase deficiency was found in liver but not in muscle and fibroblasts. mtDNA rearrangements or depletion were ruled out. By the age of one year, liver and pancreatic functions have normalized completely and neurodevelopment is normal.

Save a child's heart: we can and we should.

BACKGROUND: Congenital heart disease (CHD) causes the death of thousands of children in developing countries. At the Wolfson Medical Center (WMC), a prototype program has been developed to address this issue. METHODS: Since 1996, indigent children have been referred to the program, with the cooperation of partners in developing countries. The project's aims are to (a) train their medical personnel at WMC, (b) travel to participating countries to teach, evaluate patients, operate, and promote the development of local centers, and (c) treat children with CHD, at WMC, who lack a local option for care either due to prohibitive costs or unavailability. The project's personnel are state employees who volunteer to treat additional patients within the framework of their salaries, and community volunteers. RESULTS: The program has seven partner sites in six countries, including two provinces in China (Hebei and Gansu), Ethiopia, Moldova, Nigeria, the Palestinian Authority, and Tanzania. Five physicians and 10 nurses have been trained from five participating countries. Over the past 4 years, 11 teaching trips have been made abroad, and operations have been performed at four partner sites. A total of 386 patients have been operated on-360 at WMC and 26 at other sites. There have been 17 (4.3%) acute deaths. Follow-up is 92% complete with 3 late deaths reported. CONCLUSIONS: Hospital-based regional centers can be created to promote the care of children with CHD in developing countries. Good results and follow-up care can be provided with appropriate planning.

Is nebulized aerosol treatment necessary in the pediatric emergency department?

BACKGROUND: Infants and small children admitted to the pediatric emergency department (PED) with acute wheezing episodes (AWE) are currently treated with nebulized wet aerosol (NWA). OBJECTIVE: To determine the efficacy of MDI with Nebuchamber (Astra AB; Lund, Sweden), a nonelectrostatic spacer device (NESD), as compared to NWA in the treatment of an unselected population of babies and small children with AWE. DESIGN: Randomized, double-blind, placebo-controlled trial. Forty-two children referred to the PED (median age +/- SD, 16 +/- 15 months) with AWE received either placebo MDI through a NESD (four puffs) and salbutamol 0.5 mL (2.5 mg) as a NWA (group I, n = 19), or salbutamol MDI and 0.5 mL of saline solution administered in the same manner as above (group II, n = 23). This treatment was repeated three times every 20 min. RESULTS: The respiratory rates (RRs) at baseline were as follows: group I, 45 +/- 11.2 breaths/min; and group II, 52.3 +/- 11.3 breaths/min (p = not significant [NS]). After the first, second, and third interventions, the percent fall from baseline of the RR were as follows: group I, 8.9, 13.1, and 17.9%, respectively; group II, 8. 6, 14.6, and 18.6%, respectively. There was no significant difference at any time in the results between the two groups. The clinical scores (CSs) at baseline were as follows: group I, 6.6 +/- 1.3; group II, 6.8 +/- 1.49 (p = NS). After the first, second, and third interventions, the percent fall from baseline of the CS were as follows: group I, 9.1, 17.9, and 23.2%, respectively; group II, 8. 6, 18.9, and 24.7%, respectively. These results, also, did not differ significantly at any time between the two groups. Hospitalization rate and side effects did not differ between the two groups. CONCLUSIONS: We conclude that even in the group of unselected very young children (mean age < 2 years) with AWE, the use of MDI with NESD is at least as effective as the use of NWA. As opposed to data from an adult population, no plateau was reached in the dose-response curve using the above doses over time.

The pivotal role of deep vein thrombophlebitis in the development of acute disseminated staphylococcal disease in children.

Deep vein thrombophlebitis (DVT) and septic pulmonary emboli (PE) are rare in children. The association of DVT and acute disseminated staphylococcal disease (DSD) during childhood has not been previously reported. We report 3 children who developed a triad of DVT, septic PE, and acute osteomyelitis with Staphylococcus aureus cultured from blood and bone. One child succumbed, while 2 survived following prolonged, morbid hospitalizations. The rapid clinical deterioration observed in these patients might be caused by the aggressiveness of staphylococcal infection combined with an ongoing showering of septic emboli from the ileo-femoral DVT. We suggest that infected DVT with septic PE had a pivotal role in the development of DSD in these children. The presence of this triad should prompt aggressive treatment with the appropriate antibiotics, anticoagulation, surgical drainage, and assisted ventilation when indicated.

Inverted left atrial appendage presenting as a left atrial mass after cardiac surgery.

Inversion of the left atrial appendage can masquerade as a new left atrial mass. Failure to be aware of this entity can result in unnecessary diagnostic and therapeutic procedures. If the entity is diagnosed intraoperatively, treatment is simple with external reduction and ligation.

Salbutamol metered-dose inhaler with spacer for hyperkalemia: how fast? How safe?

OBJECTIVE: To determine the efficacy of inhaled salbutamol (rapidly delivered, using a metered-dose inhaler with a spacer device [MDI-S]) in lowering the serum potassium levels in patients with hyperkalemia. DESIGN: A randomized, double-blind, placebo-controlled trial. PATIENTS: Seventeen chronic renal failure patients referred to the Nephrology Unit between October 1, 1997 and March 31, 1998 for hemodialysis were randomized. INTERVENTION AND RESULTS: Group 1 received salbutamol followed by a placebo. Group 2 received a placebo followed by salbutamol. Each patient inhaled 1,200 microg salbutamol or a placebo through an MDI-S within 2 min. Blood samples were obtained repeatedly before inhalation and after 1, 3, 5, 10, and 60 min. The pulse rate and blood pressure were repeatedly measured. Insulin levels were examined in a subset of patients (n = 10) before, and 1 and 5 min following inhalation. Salbutamol's known side effects, palpitation, tachycardia tremor, and headache, were recorded. Potassium levels rose after 1 min following the completion of treatment and then decreased steadily thereafter. A rise of > or = 0.1 mEq/L was seen in 10 of 17 patients (59%) during the treatment period and there was no change (0%) seen during the placebo period (p < 0.0001). Within 3 min after inhalation of salbutamol, potassium levels declined as a function of time. Potassium levels in those patients taking the placebo did not change as a function of time (p < 0.001). The difference between the placebo and the salbutamol-treated periods reached significance after 5 min (p < 0.05). The serum glucose levels rose following inhalation of salbutamol, with a significant rise after 3 min. The heart rate rose significantly within the first 5 min following inhalation. Serum insulin levels remained unchanged 1 min after inhalation; however, after 5 min, a significant elevation was detected. CONCLUSION: Salbutamol inhalation of 1,200 microg, using an MDI-S, has a relatively rapid onset of action that induces a consistent reduction in serum potassium levels, starting 3 to 5 min following delivery. Unexpectedly, a paradoxical elevation was detected in serum potassium levels in the first minutes following inhalation. This effect, although minor (0.15 mEq/L above baseline), may cast some doubt on the role of salbutamol inhalation as the first treatment for excessive hyperkalemia.

Effect of airway pressure on inferior vena cava pressure as a measure of central venous pressure in children.

We evaluated the effect of elevated airway pressure on the validity of intravascular pressure obtained in the distal inferior vena cava (IVC) as a measure of central venous pressure (CVP) in a group of children receiving mechanical ventilation. The IVC pressure correlated well with CVP in the patients without abdominal distention, but the disparity was wider in those with abdominal distention. Elevated mean airway pressure or positive end-expiratory pressure had no effect on the relationship of IVC to CVP.

Type of acidosis and clinical outcome in infantile gastroenteritis.

To explore different types of metabolic acidosis in acute gastroenteritis of infancy, and to correlate it with nutritional status and clinical outcome, we examined prospectively 27 consecutive infants admitted with moderate to severe dehydration and arterial blood pH less than or equal to 7.20. Serum anion gap, creatinine, divalent cations (Ca, Mg), and the anionic contribution of total protein, lactate, and phosphate as well as ketones and urine pH, were determined on admission and compared with age-matched controls. Twenty infants (Group A) presented with normal anion gap (13.1 +/- 2.7) associated with hyperchloremia (115.8 +/- 4.2 mmol/L, p less than 0.01) and diminished bicarbonate (9.7 +/- 2.4 mmol/L, p less than 0.01), compared with controls. The other seven infants (group B) demonstrated an increased anion gap (26.7 +/- 3.2, p less than 0.01), associated with significant elevations of lactate (3.4 +/- 0.7 mmol/L, p less than 0.001), total protein (93.4 +/- 12.3 g/L, p less than 0.01), as well as phosphate (2.3 +/- 0.2 mmol/L, p less than 0.01) and creatinine (164.9 +/- 45.1 mumol/L, p less than 0.001), compared with controls. No significant deviations of blood divalent cations or ketones were noted in both groups. Urine pH was less than or equal to 5.5 in all subjects. Analysis of nutritional status and clinical outcome in both groups revealed significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)