Electrochemically anodized porous silicon: Towards simple and affordable anode material for Li-ion batteries.

Silicon is being increasingly studied as the next-generation anode material for Li-ion batteries because of its ten times higher gravimetric capacity compared with the widely-used graphite. While nanoparticles and other nanostructured silicon materials often exhibit good cyclability, their volumetric capacity tends to be worse or similar than that of graphite. Furthermore, these materials are commonly complicated and expensive to produce. An effortless way to produce nanostructured silicon is electrochemical anodization. However, there is no systematic study how various material properties affect its performance in LIBs. In the present study, the effects of particle size, surface passivation and boron doping degree were evaluated for the mesoporous silicon with relatively low porosity of 50%. This porosity value was estimated to be the lowest value for the silicon material that still can accommodate the substantial volume change during the charge/discharge cycling. The optimal particle size was between 10-20 µm, the carbide layer enhanced the rate capability by improving the lithiation kinetics, and higher levels of boron doping were beneficial for obtaining higher specific capacity at lower rates. Comparison of pristine and cycled electrodes revealed the loss of electrical contact and electrolyte decay to be the major contributors to the capacity decay.

Carotid intima-media thickness after pediatric renal or liver transplantation at high-resolution B-mode ultrasonography.

In a previous study, we observed a higher incidence of dyslipidemia in pediatric renal recipients compared with liver recipients. In the present study, we measured common carotid artery intima-media thickness (IMT) in 13 pediatric renal recipients, 9 liver recipients, and 26 control individuals with median age of 11.4, 10.8, and 12.0 years, respectively. The patients were studied from 0.2 to 10.8 years after renal transplantation (RTx) or liver transplantation (LTx). An experienced radiologist (T.K.) blinded to the status of the children measured the IMT using a high-resolution B-mode ultrasonography method. In patients who underwent RTx or LTx, serum fasting lipid profile, estimates of renal and liver function, and glucose metabolism were determined. Children undergoing RTx or LTx more often had hypertension compared with the control individuals (P = .004). Before transplantation, dyslipidemia was greater in patients undergoing RTx compared with those undergoing LTx (P < .05). Children who underwent RTx, compared with those who underwent LTx or control individuals, had thicker mean IMT at the 6 sites measured (mean [SD], 0.57 [0.07], 0.51 [0.05], and 0.53 [0.06] mm, respectively; P = .02]. As a result of linear regression in renal recipients, variability of glomerular filtration rate (<60 mL/min/1.73 m(2) vs normal) accounted for 43.3% of variability of the mean of maximal IMT (B = 8.9; SE = 3.1; P = .01). Variability of pre-RTx serum triglyceride concentration (B = 1.6; SE = 0.6; P = .03) and actual triglyceride concentration (B = 10.3; SE = 2.2; P = .002) accounted for 82.2% of variability of maximal IMT. Our findings support previous data on the importance of maintenance of good graft function with sufficient but not overly efficient immunosuppression after transplantation in prevention of future cardiovascular disease.

A critical evaluation of the binary and ternary solid-oil-water and solid-water-oil interaction.

When determining the surface energies of solids the most frequently utilised method is to measure contact angles for particular probe liquids. The measured contact angles (usually measured in air) are then combined with published values of surface- and interfacial tensions of the liquids to give the surface energy of the solid. It is, however, very seldom that sufficient attention is paid to the impurities, to the experimental (e.g. saturated vapour) conditions chosen and to the heterogeneities (chemical and structural) of the solid surface. In this study five typical probe liquids: octane, hexadecane, diiodomethane, alpha-bromonaphthalene and water have been used to establish the dispersion component of the surface energy of the solid and the hydrophobic interaction occurring at the interface of four solids: hydrophobic/hydrophilic SiO2 and hydrophobic/hydrophilic TiO2. Two (solid/liquid) and three (solid/liquid/liquid) component systems were investigated. The results are compared with previously published results when Alkenyl Succinic Anhydride (ASA) was brought into contact with SiO2 under water. The preferential surface vapour pressure and liquid spreading of the one liquid over the solids in the absence and presence of a saturated liquid vapour were evaluated as sources of errors.

Influence of film digitization on radiological interpretation.

Our objective was to evaluate the influence of changing from analogue to digital imaging on interobserver and intraobserver image interpretation. Three radiologists interpreted 96 three image series of occipitomental radiographs of paranasal sinuses from the films and from the corresponding digitized images from the screen. Images were classified according to degree of abnormality as either normal, with mucosal thickening of less than 5 mm, with mucosal thickening of 5 mm or more, total opacity, air-fluid level or polyp or cyst of maxillary sinuses. In the present study we found that there were more differences between two radiologist's interpretations with a single method than in a single radiologist's interpretations between the methods, although radiologists interpreted fewer pathological findings from the digitized images than from the corresponding films. Our data show that the results of image interpretation are preferentially dependent on the reader rather than on the method of reading.

Value of ultrasonography in acute renal failure: analysis of qualitative features in patients with nephropathia epidemica.

PURPOSE: To assess the value of renal ultrasonography (US) and the frequency of qualitative pathology in patients with nephropathia epidemica (NE) and to determine whether these features are related to the clinical course of NE. MATERIAL AND METHODS: Renal US was undertaken in 23 hospital-treated NE cases during the acute phase of the disease (first study). A second US study was performed 3-6 months later. Captured US images were used in the analysis. RESULTS: From acute to control phase the overall rating of kidney status improved in 20 patients, parenchymal swelling decreased and corticomedullary border differentiation improved in 21, echogenicity decreased in 18, and patchy pattern in parenchymal echo-texture decreased in 15. The severity of findings in US evinced some association with fluid volume overload, high blood pressure level and blood leukocyte count, and severe clinical renal insufficiency. The degree of parenchymal swelling had more statistically significant associations with clinical course than other US features. CONCLUSION: Qualitative US features are as sensitive as quantitative US parameters in assessment of NE patients' clinical course and recovery, assuming that a comparative study is available. US using only qualitative features is fairly limited in evaluating NE patients' clinical situation.

Effect of resin application time on bond strength of polymer substrate repaired with particulate filler composite.

Four different polymeric substrates were treated with unfilled intermediate resin (IMR) for various lengths of time (15 s, 3 min, 1 h, 24 h, and 2 weeks) to find out the effect of IMR treating time on shear bond strength between the substrate and a particulate filler composite. The IMR used in the study was a diacrylate monomer resin and the particulate filler composite was added on it. Two of the tested substrates were fiber-reinforced composites (FRCs). Two other substrates were cross-linked bisphenol-A-glycidyl dimethacrylate/triethyleneglycol dimethacrylate (BisGMA/TEGDMA) substrate and linear polymethylmethacrylate substrate. The bond strength of the particulate filler composite to the BisGMA/TEGDMA substrate was significantly higher compared to the other substrates (p<0.001). A correlation between increasing shear bond strength and longer treating time were found with the BisGMA/TEGDMA substrates (r=0.594, p<0.001) whereas no correlation was found with the other substrates. Prolonging of IMR treating time enhanced the BisGMA/TEGDMA substrate bond strength to the particulate filler composite but it had no clear effect on the bond strength of other substrates.

The bond strength of light-curing composite resin to finally polymerized and aged glass fiber-reinforced composite substrate.

OBJECTIVE: This study examines the shear bond strength of visible light-curing composite resin (VCR) to aged glass fiber-reinforced composite (FRC) substrate with multi-phase polymer matrix. METHODS: Linear polymethyl methacrylate and dimethacrylate monomer preimpregnated unidirectional glass fiber reinforcement was used as an adhesion substrate for low-viscosity diacrylate veneering composite resin and restorative composite resin. A total of 60 test specimens were divided into three groups according to the brand and the use of an intermediate monomer resin (IMR). The used IMRs were either BisGMA-HEMA-resin, BisGMA-TEGDMA resin or the controls were left without the IMR treatment. Dry- and water-stored FRC-substrates were used for adhering the VCR with or without the IMR. The shear bond strength of the VCR to the substrate was measured for dry and thermocycled specimens and the results were analyzed with multi-variate ANOVA. RESULTS: The highest mean shear bond strength (23.9 +/- 4.8 MPa) was achieved with FRC/BisGMA-HEMA/VCR combination when the FRC substrate was water stored and the test specimen was thermocycled. FRC/BisGMA-TEGDMA/VCR combination resulted in 15.7 +/- 6.0 MPa with the water-stored FRC substrate and after thermocycling of the test specimens. The lowest shear bond strength (1.0 +/- 0.5 MPa) was obtained with FRC/VCR combination with water-stored substrate and after thermocycling of the test specimens. Significant differences were found between the mean values of three groups according to the use of IMR (p<0.001). The storage conditions of the FRC substrate were related to brand of the IMR or the composite (p<0.001). High mean values of the shear bond strength after thermocycling fatigue were related to the type of IMR (p<0.001). SIGNIFICANCE: The results suggest that the IMRs used in this study greatly influence the mean shear bond strength values when the test specimens are thermocycled.

Renal ultrasound findings and their clinical associations in nephropathia epidemica. Analysis of quantitative parameters.

PURPOSE: To evaluate renal US findings in patients with nephropathia epidemica (NE) and to determine whether changes in these findings are related to the clinical course of NE. MATERIAL AND METHODS: Renal US was undertaken in 23 hospital-treated NE patients during the acute phase of their disease (first study). The second US study was performed 3-6 months later. RESULTS: The resistive index (RI) was abnormal in 12 patients and fluid collections (perirenal, pleural, pericardial, ascites) were found in 13 patients in the first study. Renal length decreased in every patient, cortical parenchymal thickness in 19 patients and RI in 18 patients from the first to the second studies. The mean change was significant in all parameters. Increased RI and presence of fluid collections in the first study as well as a greater change in length and RI between the first and the second studies were associated with high maximum daily urine excretion, substantial change in body weight between the anuric and polyuric phases, high maximum serum creatinine and urea concentration, high blood leukocyte count and low hematocrit value. CONCLUSION: Renal US changes occurred in every patient with NE. The severity of the findings was associated with fluid volume overload and degree of clinical renal insufficiency.

Hepatic subcapsular steatosis in diabetic CAPD patients treated with intraperitoneal insulin. Description of a typical pattern.

PURPOSE: To describe a specific imaging pattern of hepatic fatty change typical of diabetic patients on continuous ambulatory peritoneal dialysis (CAPD) treated with intraperitoneal (i.p.) insulin. MATERIAL AND METHODS: Liver ultrasound was applied in 16 CAPD patients with insulin-dependent diabetes mellitus. Presence of hepatic subcapsular steatosis and maximum thickness of the fatty layer were recorded. Liver MR examination was made of 1 patient found to have extensive subcapsular steatosis. RESULTS: Hepatic ultrasound revealed a typical pattern of subcapsular steatosis ("coating-of-fat") in 7/8 patients treated with i.p. insulin. None (0/8) of the diabetic CAPD patients treated with subcutaneous insulin had subcapsular steatosis. CONCLUSION: Hepatic subcapsular steatosis is specific to CAPD patients on i.p. insulin treatment. To our knowledge this is the first report to describe imaging findings in this particular form of hepatic fatty change.

Incidence of deep venous thrombosis after thoracotomy.

BACKGROUND: Incidence of deep venous thrombosis (DVT) after thoracotomy has not been widely studied. DVT is a frequent complication in major surgery involving abdominal and pelvic areas and lower extremities. The aim of the present study was to evaluate the rate of postoperative DVTs after surgery of the lung. METHODS: In this prospective study with 25 patients undergoing thoracotomy both legs were studied with venous duplex imaging (VDI) preoperatively and on the second postoperative day. Clinically manifest thromboembolic events during one-month postoperative period were reviewed from the patients' records. DVT prophylaxis included compression stockings and early mobilization without low-molecular weight heparin. RESULTS: Frequency of postoperative DVTs was 4%. There were no clinically manifest thromboembolic events during one-month postoperative period. In 8% of the patients an old DVT was found preoperatively. CONCLUSIONS: Based on this material, incidence of DVT is low after thoracotomy. Early mobilization and the use of compression stockings may be a sufficient form of prophylaxis in these patients. The relatively small sample size and the use of ultrasound as a screening method should be noted in judging the results.

Bonding of restorative and veneering composite resin to some polymeric composites.

OBJECTIVES: The aim of the study was to determine bond strengths between different fiber-reinforced composites (FRC) and visible light-curing composites (VCR). METHODS: A total of 180 specimens comprising eight types of FRC substrates and four types of VCR substrates were fabricated and divided in 36 different groups. Substrate surfaces were ground with 1200-grit silicon carbide paper before adding a repair composite (RC). The shear bond strength was determined for specimens without the use of an intermediate resin (IMR), for specimens with the IMR and for specimens with the IMR and thermocycling. Surface roughness of the substrate was measured with a profilometer before adding RC on the substrate. RESULTS: The univariate analyses of variance (ANOVA) revealed significant differences (p<0.001) related to the type of the substrate, the IMR and the thermocycling. The highest shear bond strength for FRC substrates was achieved with StickNet/Z-100 combination and for VCR substrates with Sinfony/Sinfony combination. Surface roughness (R(a)) varied from 0.10 microm of Targis VCR to 0.50 microm for Vectris Pontic FRC. SIGNIFICANCE: Surface roughness seemed not to influence shear bond strengths of RC to FRC and VCR substrates. High shear bond strengths were related to specific materials and IMRs used. In some cases materials performed better without the use of the accessory IMR.

Validity of ultrasonography in diagnosis of acute maxillary sinusitis.

BACKGROUND: Accurate diagnosis of maxillary sinusitis is difficult on the basis of clinical examination only because the signs and symptoms of sinusitis are nonspecific. A simple, rapid, and readily available method for diagnosing maxillary sinusitis in primary care would increase the accuracy of the diagnoses and thus reduce unnecessary antibiotic treatment. OBJECTIVE: To investigate the validity of ultrasonography compared with radiography and magnetic resonance imaging (MRI) in detection of maxillary sinusitis. DESIGN: Ultrasonography and plain-film radiography of the paranasal sinuses were performed on all patients and MRI was performed on 40 randomly selected patients on day 7 of the study. SETTING: Study office at the Department of Pediatrics of Turku University Hospital, Turku, Finland. PATIENTS: One hundred ninety-seven young adults who contacted the study office within 48 hours of the onset of symptoms of the common cold. MAIN OUTCOME MEASURES: Detection rates of maxillary sinusitis by ultrasonography, radiography, and MRI. RESULTS: Acute maxillary sinusitis was diagnosed in 24% of the sinuses by radiography and in 28% by MRI. Compared with MRI findings, the sensitivity of ultrasonography for detection of maxillary sinusitis was 64% (specificity, 95%). Using a 2-step diagnostic approach in which radiological findings were additionally considered in cases of negative ultrasound findings, a sensitivity of 86% (specificity, 95%) was observed. CONCLUSIONS: The high specificity of ultrasonography indicates that a positive ultrasound finding can be regarded as evidence of maxillary sinusitis. The addition of plain-film radiography in cases of negative ultrasound findings increases the diagnostic sensitivity to clinically acceptable levels without loss in specificity. Active use of ultrasonography would substantially decrease the need for radiological imaging of the sinuses and also help reduce unnecessary antibiotic treatment in primary care. Arch Otolaryngol Head Neck Surg. 2000;126:1482-1486

The occurrence of the post-thrombotic changes after an acute deep venous thrombosis. A prospective two-year follow-up study.

BACKGROUND: The aim of the study is to investigate the development of subjective and objective findings during the first two years after DVT (deep venous thrombosis). METHODS: This prospective two-year follow-up study was established in Tampere University Hospital in Finland. Twenty-six patients with a two-year follow-up after a phlebographically confirmed DVT were followed. Patients were treated conventionally with heparin and warfarin. Phlebography was repeated 7 months after DVT. Color-flow duplex imaging (CFDI) was performed in both legs 7 and 20 months after DVT. The subjective symptoms in both legs were recorded at the beginning and at the end of the follow-up. The development of venous reflux, obstruction and subjective symptoms after DVT were studied. RESULTS: 50% of the legs with DVT had a pathological (deep reflux or obstructive change) CFDI-finding in the popliteal segment after a 20-month follow-up. The pathological findings in the control legs were rare. The rate of recanalisation was high. There was no difference between calf and more proximal DVTs. Pain (62%), oedema (46%) and pigmentation (35%) were common and only 27% of the legs with DVT were asymptomatic. CONCLUSIONS: The development of the post-thrombotic syndrome begins quite early. The frequency of the subjective symptoms is high. Calf DVT may lead to postthrombotic sequelae in the popliteal segment.

Imaging end-stage kidney disease in adults. Low-field MR imaging with magnetization transfer vs. ultrasonography.

PURPOSE: To 1) assess the potential of magnetization transfer (MT)-weighted MR imaging to improve the often poor visibility of native kidneys in patients with a renal transplant; and 2) compare low-field MR imaging and ultrasonography (US) for imaging these fibrotic kidney remnants. MATERIAL AND METHODS: Seventy-two native kidneys of 36 patients were prospectively evaluated with US and MR. In low-field (0.1 T) MR imaging, T1-, T2- and MT-weighted sequences were used. MT-weighted images were compared with T2-weighted images in their ability to delineate the kidneys from their surroundings whereas US and MR were compared for detection of renal cysts and possible solid tumors. RESULTS: MT-weighted images proved superior to conventional T2-weighted images in producing contrast between the kidney remnants and their fatty surroundings. Although US revealed a few small renal cysts that were not seen at MR images, no statistical difference was found between the two modalities in this respect. CONCLUSION: MT imaging, due to its unique protein-specific signal depression, offers significantly improved visualization and delineation of end-stage kidneys. US, because its better availability and cost-benefit ratio, remains the method-of-choice compared to low-field MR imaging in detecting cysts in multicystic kidneys. MR investigation is helpful in selected patients and may be used as an alternative.

High peritoneal permeability predisposes to hepatic steatosis in diabetic continuous ambulatory peritoneal dialysis patients receiving intraperitoneal insulin.

OBJECTIVE: To evaluate hepatic fat accumulation in diabetic patients taking intraperitoneal or subcutaneous insulin treatment during continuous ambulatory peritoneal dialysis (CAPD). DESIGN: Cross-sectional study. SETTING: Tertiary-care university hospital. PATIENTS: We studied 16 patients with diabetic end-stage renal disease currently treated with CAPD. Median age was 42 years (range: 34-70 years), duration of diabetes was 27.5 years (range: 17-39 years), and duration of CAPD was 16.5 months (range: 2-59 months). OUTCOME MEASURES: Ultrasound measures of liver steatotic area and thickness, peritoneal equilibration test (PET), weekly Kt/V urea, protein catabolic rate (PCR), hemoglobin A1c (HbA1c), lipoproteins, alanine aminotransferase, alkaline phosphatase, insulin dose, and dialysate glucose load. RESULTS: Focal hepatic fat accumulation was found. The location of steatosis was subcapsular; a negligible amount was periportal. Hepatic subcapsular steatosis was present in 7 of 8 patients taking insulin intraperitoneally and in 0 of 8 patients taking insulin subcutaneously. The maximal thickness of subcapsular steatosis correlated directly with peritoneal transport rate (2-hour dialysate-to-plasma creatinine ratio in PET, r = 0.80, p < 0.05) and inversely with PCR (r = -0.82, p < 0.05). The area of the lesions correlated directly with body weight (r = 0.80, p < 0.05) and inversely with weekly Kt/V urea (r = -0.90, p < 0.01). CONCLUSIONS: Intraperitoneal insulin, together with glucose-based peritoneal dialysate, induces hepatic subcapsular steatosis. The amount of hepatic subcapsular steatosis increases when peritoneal transfer rate and body weight are high.

Sinusitis in the common cold.

BACKGROUND: Acute community-acquired sinusitis is considered a bacterial complication of the common cold. Radiologic abnormalities in sinuses occur, however, in most patients with upper respiratory virus infections. OBJECTIVE: Assessment of the occurrence, clinical profile, laboratory findings, and outcome of radiologically confirmed sinusitis was carried out as part of a common cold study in young adults. METHODS: Clinical examinations and radiography of the paranasal sinuses were carried out on days 1, 7, and 21 in 197 patients with the common cold. The symptoms were recorded on diary cards on days 1 to 20. Ten viruses and 5 bacteria were studied as etiologic agents of common cold as reported earlier. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and total white blood cell counts with differentials were determined in 40 randomized subjects on day 7. The effect of 6 days of intranasal fluticasone propionate treatment of the common cold in the prevention of sinusitis was analyzed. RESULTS: On day 7, 39% of patients with the common cold in the placebo group (n = 98) had sinusitis, which we would prefer to call viral sinusitis. The symptoms of patients with sinusitis and those without it were not clinically distinguishable. Viral infection was detected in 81.6% of patients with sinusitis. No significantly increased levels of antibodies to bacteria were detected. Serum C reactive protein concentrations, erythrocyte sedimentation rates, and white blood cell counts were low in patients with sinusitis. All patients made a clinical recovery within 21 days without antibiotic treatment. Fluticasone propionate treatment tended to prevent paranasal sinusitis, especially in rhinovirus-positive subjects. CONCLUSION: Viral sinusitis frequently occurs in the early days of the common cold, but it is a self-limited illness. The sinuses should not be imaged in patients with the common cold if the signs and symptoms of illness gradually become less severe and no specific signs suggestive of bacterial sinusitis occur.

Effect of fasting and food intake on magnetization transfer of human liver tissue.

Magnetization transfer (MT) technique is a promising method in differential diagnosis of diseases in parenchymal tissues. Basic knowledge about circumstances and elementary factors that influence MT and its parameters is still insufficient, however. Having a meal before the magnetic resonance (MR) examination could change liver MT parameters compared to fasting state through alteration in liver perfusion, blood flow, and content of portal blood (proteins and other derivates from a meal). If MT parameters can be altered by a meal, then MR liver studies should always be performed after fasting. Before MRI examinations we examined three healthy volunteers after a high-fat meal with Doppler ultrasound technique to find out duration and magnitude of changes in portal blood flow. Duration of > or = 50% increased peak-flow value compared to fasting state in portal vein was > 90 min, which is enough for our MR examination. With a low-field 0.1-T MR imager we examined 10 healthy volunteers after a short (range from 3 h 45 min to 17 h 30 min) fast and also immediately after a high-fat meal. Magnetization transfer parameters, magnetization transfer ratio (MTR) and magnetization transfer rate Rwm of liver tissue were determined. MTR changed significantly (Student paired two-tailed t-test, p = .0044) after a meal, but Rwm did not (p = .0952). We recommend a 4 h fast before MR examination that aims to determine the MTR of liver tissue.