2,612 research outputs found

    Revisiting Multiplication Area Models for Whole Numbers

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    We argue that there are two conceptually different area models for whole number multiplication: area-to-area model and lengths-to-area model depending on how multiplication operation is conceived: action on / change of an initial quantity, or operation / coordination of two quantities. These models complement each other to promote students’ conceptual understanding of whole number multiplication and help students extend their understanding of whole number multiplication to fraction multiplication

    Revisiting Multiplication Area Models for Whole Numbers

    Get PDF
    We argue that there are two conceptually different area models for whole number multiplication: area-to-area model and lengths-to-area model depending on how multiplication operation is conceived: action on / change of an initial quantity, or operation / coordination of two quantities. These models complement each other to promote students’ conceptual understanding of whole number multiplication and help students extend their understanding of whole number multiplication to fraction multiplication

    Bilateral herpetic keratitis presenting with unilateral neurotrophic keratitis in pemphigus foliaceus: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We report a case of bilateral herpetic keratitis developing after rapid oral corticosteroid tapering in a patient with pemphigus foliaceus, which was followed by unilateral neurotrophic keratitis that was treated with amniotic membrane transplantation.</p> <p>Case presentation</p> <p>A 71-year-old Korean man developed bilateral herpetic keratitis one week after rapid tapering of systemic corticosteroid. He had been on high-dose oral corticosteroid and azathioprine therapy for six months for treatment of pemphigus foliaceus. Topical acyclovir ointment was prescribed. A week later, our patient's right eye had healed, but his left eye showed increased stromal edema with enlarged epithelial defects. He was prescribed oral acyclovir with topical broad-spectrum antibiotics applied to his left eye. The stromal edema cleared within a week but the epithelial defect remained unchanged. An amniotic membrane transplantation was performed on our patient's left eye, and his epithelial defect had totally healed three weeks later.</p> <p>Conclusions</p> <p>Patients with autoimmune disease or who are on immunosuppressive therapy have a higher chance of developing bilateral herpetic keratitis. Although rare, the condition may be followed by unilateral neurotrophic keratitis. Rapid corticosteroid tapering may act as a triggering factor for viral infection or reactivation of herpes.</p

    The effect of heating insufflation gas on acid-base alterations and core temperature during laparoscopic major abdominal surgery

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    BACKGROUND: Carbon dioxide (CO(2)) has different biophysical properties under different thermal conditions, which may affect its rate of absorption in the blood and the related adverse events. The present study was aimed to investigate the effects of heating of CO(2) on acid-base balance using Stewart's physiochemical approach, and body temperature during laparoscopy. METHODS: Thirty adult patients undergoing laparoscopic major abdominal surgery were randomized to receive either room temperature CO(2) (control group, n = 15) or heated CO(2) (heated group, n = 15). The acid-base parameters were measured 10 min after the induction of anesthesia (T1), 40 min after pneumoperitoneum (T2), at the end of surgery (T3) and 1 h after surgery (T4). Body temperature was measured at 15-min intervals until the end of the surgery. RESULTS: There were no significant differences in pH, PaCO(2), the apparent strong ion difference, the strong ion gap, bicarbonate ion, or lactate between two groups throughout the whole investigation period. At T2, pH was decreased whereas PaCO(2) was increased in both groups compared with T1 but these changes were not significantly different. Body temperatures in the heated group were significantly higher than those in the control group from 30 to 90 min after pneumoperitoneum. CONCLUSIONS: The heating of insufflating CO(2) did not affect changes in the acid-base status and PaCO(2) in patients undergoing laparoscopic abdominal surgery when the ventilator was set to maintain constant end-tidal CO(2). However, the heated CO(2) reduced the decrease in the core body temperature 30 min after the pneumoperitoneum.ope

    Screening for Early Gastric Cancer Using a Noninvasive Urine Metabolomics Approach

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    The early detection of gastric cancer (GC) could decrease its incidence and mortality. However, there are currently no accurate noninvasive markers for GC screening. Therefore, we developed a noninvasive diagnostic approach, employing urine nuclear magnetic resonance (NMR) metabolomics, to discover putative metabolic markers associated with GC. Changes in urine metabolite levels during oncogenesis were evaluated using samples from 103 patients with GC and 100 age- and sex-matched healthy controls. Approximately 70% of the patients with GC (n = 69) had stage I GC, with the majority (n = 56) having intramucosal cancer. A multivariate statistical analysis of the urine NMR data well discriminated between the patient and control groups and revealed nine metabolites, including alanine, citrate, creatine, creatinine, glycerol, hippurate, phenylalanine, taurine, and 3-hydroxybutyrate, that contributed to the difference. A diagnostic performance test with a separate validation set exhibited a sensitivity and specificity of more than 90%, even with the intramucosal cancer samples only. In conclusion, the NMR-based urine metabolomics approach may have potential as a convenient screening method for the early detection of GC and may facilitate consequent endoscopic examination through risk stratification

    Hu.4-1BB-Fc fusion protein inhibits allergic inflammation and airway hyperresponsiveness in a murine model of asthma

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    Purpose4-1BB (CD 137) is a costimulatory molecule expressed on activated T-cells. Repression by 4-1BB is thought to attenuate Th2-mediated allergic reactions. The aim of this study was to investigate the effect of 4-1BB on allergic airway inflammation in a murine asthma model.MethodsBALB/c mice were sensitized to and challenged with ovalbumin (OVA). Hu.4-1BB-Fc was administered 1 day before the first OVA sensitization or 1 day after the second OVA sensitization. Following antigen challenge, airway responsiveness to methacholine was assessed and bronchoalveolar lavage (BAL) fluid was analyzed. Total immunoglobulin (Ig) E, OVA-specific IgE, IgG1, and IgG2a levels in sera were measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated.ResultsIn mice treated with Hu.4-1BB-Fc before the first OVA sensitization, there was a marked decrease in airway hyperresponsiveness, total cell count, and eosinophil count in the BAL fluid. In addition, Hu.4-1BB-Fc treatment decreased serum OVA-specific IgG1 levels and increased serum IgG2a level significantly compared with the corresponding levels in mice sensitized to and challenged with OVA. Hu.4-1BB-Fc-treated mice also showed suppressed peribronchial and perivascular inflammatory cell infiltration. In contrast, treatment with Hu.4-1BB-Fc 1 day after sensitization had no effect on airway hyperresponsiveness and showed less suppression of inflammation in lung tissue.ConclusionAdministration of Hu.4-1BB-Fc can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. In addition, administration before sensitization may be more effective. These findings suggest that 4-1BB may be a useful therapeutic molecule against asthma

    Protective Effects of Emodin and Chrysophanol Isolated from Marine Fungus Aspergillus sp. on Ethanol-Induced Toxicity in HepG2/CYP2E1 Cells

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    Alcohol-induced liver injury progresses from fatty infiltration followed by a harmful cause of inflammation leading to an irreversible damage. In this study, two compounds (emodin and chrysophanol) isolated from marine fungus Aspergillus sp. were examined for their protective effects against ethanol-induced toxicity in vitro. Ethanol-induced HepG2/CYP2E1 cells were treated with the compounds at various concentrations, and the results showed that there was a dose-dependent decrease of gamma-glutamyl transpeptidase (GGT) activity and increase of glutathione (GSH) in the culture media with an increase in cell viability. Furthermore, the protective effects of the compounds were evaluated by protein expression levels of GGT, GSH, and CYP2E1 using Western blot. Among the compounds, emodin addressed to the ethanol-induced cytotoxicity more effectively compared to the chrysophanol. It could be suggested that emodin isolated from this genus would be a potential candidate for attenuating ethanol induced liver damage for further industrial applications such as functional food and pharmaceutical developments

    Umbilical Arterial Blood Gas and Perinatal Outcome in the Second Twin according to the Planned Mode of Delivery

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    Purpose: To compare umbilical arterial gas parameters in the second twin of twin pregnancies according to the mode of deliver

    Combined Hepatocellular Carcinoma and Neuroendocrine Carcinoma with Ectopic Secretion of Parathyroid Hormone: A Case Report and Review of the Literature

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    Primary combined hepatocellular carcinoma (HCC) and neuroendocrine carcinoma is a rare entity, and so is hypercalcemia due to ectopic parathyroid hormone (PTH) secretion by tumor. A 44-year old man with hepatitis B virus associated chronic liver disease presented with a hepatic mass. Hemihepatectomy discovered the mass as combined HCC and poorly differentiated cholangiocarcinoma. During adjuvant chemoradiation therapy, he presented with nausea, and multiple systemic metastases were found. Laboratory tests revealed hypercalcemia with markedly elevated PTH and neuron specific enolase. Parathyroid scan showed normal uptake in parathyroid glands, suggestive of ectopic PTH secretion. Subsequently, immunohistochemistry of neuroendocrine marker was performed on the primary lesion, and confirmed the neuroendocrine differentiation in non-HCC component. The patient died 71 days after surgery. This report may suggest the possibility of ectopic PTH secretion by neuroendocrine carcinoma of hepatic origin causing hypercalcemia. Caution for neuroendocrine differentiation should be exercised when diagnosing poorly differentiated HCC
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