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PURPOSE: The outcomes of colorectal endoscopic submucosal dissection (ESD) in 15-19-mm tumors are unclear. This study compared the effectiveness and safety of colorectal ESD for 15-19-mm tumors and tumors exceeding that size. METHODS: From August 2018 to December 2020, 213 cases of colorectal tumors removed by colorectal ESD at a tertiary hospital were enrolled in this study. The cases were divided into two groups according to the pathologically measured size of the resected lesion: an intermediate group (15-19 mm, n = 62) and a large group (≥ 20 mm, n = 151). The en bloc resection rate, complete resection rate, and complications were investigated retrospectively. RESULTS: The en bloc resection rate was significantly higher in the intermediate than large group (100% vs. 94%, p = 0.049), and the mean total procedure time was shorter in the intermediate than large group (29.2 [Formula: see text] 12.6 vs. 48.4 [Formula: see text] 28.8 min, p < 0.001). However, the mean procedure speed was significantly lower in the intermediate than large group (0.25 [Formula: see text] 0.10 vs. 0.28 [Formula: see text] 0.11 cm2/min, p = 0.031). The complete resection rate, post-procedural bleeding, and perforation rate were not significantly different between the two groups. In multivariate analyses, the total procedure time and mean procedure speed were significantly associated with lesion size. CONCLUSION: Colorectal ESD of 15-19-mm lesions is effective, and has a shorter procedure time and higher en bloc resection rate than the same procedure for larger lesions.
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Neoplasias Colorretais , Ressecção Endoscópica de Mucosa , Humanos , Colonoscopia/métodos , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/patologia , Dissecação/métodos , Ressecção Endoscópica de Mucosa/efeitos adversos , Ressecção Endoscópica de Mucosa/métodos , Mucosa Intestinal/cirurgia , Mucosa Intestinal/patologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: Previous studies have demonstrated increased pore size and darkening skin color with total sleep deprivation. There are many studies of skin characteristics with short-term sleep restriction, but there are few studies on skin characteristics when sleep is restricted more than three consecutive days. This study evaluated skin changes with sleep limited to 4 hours per night for six nights. MATERIALS AND METHODS: The study included 32 Korean women in their 40s. Skin hydration, desquamation, barrier recovery, texture, gloss, transparency, elasticity, crow's feet, frown lines, and color were measured. Individual sleep time was monitored by smartwatches. Subjects slept 8 hours per night for six nights in week one and 4 hours per night for six nights in week two. RESULTS: Skin hydration was significantly reduced after 1 day of sleep deprivation, and it continued to decrease. Skin gloss, desquamation, transparency, elasticity, and wrinkles were significantly aggravated after 1 day of sleep deprivation. Skin texture was significantly aggravated on the fourth day of sleep restriction. Elasticity was most affected by reduced sleep, with a standardized coefficient of -.320, indicating a significant decrease over time as compared to other characteristics. CONCLUSION: Skin hydration was gradually decreased with sleep restriction. Skin texture did not change after only 1 day of sleep restriction. It is a new finding that elasticity decreases more than other skin characteristics with prolonged sleep restriction.
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Face/patologia , Pele/patologia , Privação do Sono/patologia , Adulto , Elasticidade/fisiologia , Face/diagnóstico por imagem , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Pessoa de Meia-Idade , Fotografação , República da Coreia , Pele/diagnóstico por imagem , Envelhecimento da Pele/fisiologia , Privação do Sono/diagnóstico por imagemRESUMO
Nocardiosis is a rare localized or systemic suppurative disease caused by the actinomycete Nocardia species. The respiratory tract is the most common site of infection, but primary cutaneous nocardiosis can also be induced by direct inoculation. Nocardiosis is usually reported in immunocompromised patients, such as those with human immunodeficiency virus (HIV) infection, chronic obstructive pulmonary disease, autoimmune diseases, cancer, or in those who have had organ transplantation or corticosteroid administration. However, it can also affect individuals with no serious underlying condition. We reported two cases of primary cutaneous nocardiosis in immunocompetent patients after intralesional injection of steroid.
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Glucocorticoides/efeitos adversos , Nocardiose/induzido quimicamente , Pele/efeitos dos fármacos , Triancinolona/efeitos adversos , Adulto , Antibacterianos/uso terapêutico , Técnicas Bacteriológicas , Biópsia , Feminino , Glucocorticoides/administração & dosagem , Humanos , Injeções Intralesionais , Pessoa de Meia-Idade , Nocardiose/diagnóstico , Nocardiose/microbiologia , Nocardiose/transmissão , Fatores de Risco , Pele/microbiologia , Pele/patologia , Resultado do Tratamento , Triancinolona/administração & dosagemRESUMO
Plant-growth-promoting bacteria (PGPB) are beneficial microorganisms that can also protect against disease and environmental stress. Silicon (Si) is the second most abundant element in soil, and is known to increase plant growth, grain yield, resistance to biotic stress, and tolerance to abiotic stress. Combined treatment of PGPB and Si has been shown to further enhance plant growth and crop yield. To determine the global effects of the PGPB and Si on rice growth, we compared rice plants treated with Paenibacillus yonginensis DCY84T (DCY84T) and Si with untreated rice. To identify the genes that respond to DCY84T+Si treatment in rice, we performed an RNA-Seq transcriptome analysis by sampling treated and untreated roots on a weekly basis for three weeks. Overall, 576 genes were upregulated, and 394 genes were downregulated in treated roots, using threshold fold-changes of at least 2 (log2) and p-values < 0.05. Gene ontology analysis showed that phenylpropanoids and the L-phenylalanine metabolic process were prominent in the upregulated genes. In a metabolic overview analysis using the MapMan toolkit, pathways involving phenylpropanoids and ethylene were strongly associated with upregulated genes. The functions of seven upregulated genes were identified as being associated with drought stress through a literature search, and a stress experiment confirmed that plants treated with DCY84T+Si exhibited greater drought tolerance than the untreated control plants. Furthermore, the predicted protein-protein interaction network analysis associated with DCY84T+ Si suggests mechanisms underlying growth promotion and stress tolerance.
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Oryza/metabolismo , Plântula/metabolismo , Silício/metabolismo , Secas , Regulação da Expressão Gênica de Plantas/fisiologia , Paenibacillus/metabolismoRESUMO
OBJECTIVE: To investigate the correlations of leukemia inhibitory factor (LIF) and macrophage migration inhibitory factor (MIF) with endometrial carcinoma. MATERIALS AND METHODS: The study included 113 endometrial specimens from the Fourth Affiliated Hospital of Harbin Medical University, collected from May 2006 to October 2008, classified into normal endometrium, simple hyperplasia, complex hyperplasia, atypical hyperplasia, and endometrial carcinoma. The LIF and MIF expression of all 113 specimens was detected with immunohistochemistrical (IHC) method. RESULTS: The MIF expression in hyperplastic endometrium and endometrial carcinoma increased significantly as compared with that in normal endometrium (p < 0.05 and p < 0.001, respectively), and its expression in endometrial carcinoma was also remarkably higher than that in hyperplastic endometrium (p < 0.001). The expressions of LIF in atypical hyperplasia and endometrial carcinoma were also significantly higher than that in the normal endometrium (p < 0.05), but it is not obviously higher in simple hyperplasia and complex hyperplasia than in the normal endometrium (p > 0.05). Furthermore, the expression of LIF showed no statistical difference between hyperplastic endometrium and endometrial carcinoma. CONCLUSION: It could be speculated that MIF may be correlated with the occurrence of endometrial carcinoma. However, whether LIF also has a correlation with the occurrence of endometrial carcinoma still cannot be presumed.
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Fator Inibidor de Leucemia/análise , Fatores Inibidores da Migração de Macrófagos/análise , Hiperplasia Endometrial/metabolismo , Neoplasias do Endométrio , Endométrio/química , Feminino , Humanos , Imuno-HistoquímicaRESUMO
Human leukocyte antigen (HLA)-B27 is closely associated with ankylosing spondylitis (AS). However, the exact correlation between HLA-B27 subtypes and AS manifestations remains unknown. This study aimed to investigate the correlation between HLA-B27 polymorphism and the clinical features of AS. This study included 846 patients with AS and 959 healthy controls. Direct sequencing was used to identify the HLA-B27 genotype. Clinical parameters, including age, age of onset, family history, low back pain, peripheral arthritis, hip joint involvement, dactylitis, uveitis, and sex ratio, were compared among patients with various HLA-B27 subtypes. In total, 741 AS patients (87.6%) and 39 healthy controls (4%) were HLA-B27-positive. The most prevalent subtypes were HLA-B*2704 (88%) and HLA-B*2705 (10.1%) in patients with AS. Compared with HLA-B*2704-positive patients, HLA-B*2705-positive patients demonstrated a significant increase in the incidence of uveitis (16% vs 6.13%, P = 0.002) and dactylitis (9.3% vs 3.8%, P = 0.028) and they had an older age of onset (22.9 ± 8.0 vs 20.7 ± 6.7 years, P = 0.028). Binary logistic regression analysis revealed that presence of uveitis was significantly associated with HLA-B*2705 (P = 0.008; odds ratio, 2.63; 95% confidence interval, 1.283-5.393). There were no significant differences in family history, low back pain, peripheral arthritis, or hip joint involvement among HLA-B27 subtypes. Specific HLA-B27 subtypes were positively associated with particular clinical features of AS. AS patients with HLA-B*2705 demonstrated an older age of onset and had a higher risk of uveitis and dactylitis than did AS patients with HLA-B*2704.
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Dedos , Antígeno HLA-B27/genética , Espondilite Anquilosante/epidemiologia , Espondilite Anquilosante/genética , Dedos do Pé , Uveíte/genética , Adulto , Idade de Início , China , Progressão da Doença , Feminino , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Haplótipos , Teste de Histocompatibilidade , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Risco , Espondilite Anquilosante/imunologia , Uveíte/imunologia , Adulto JovemRESUMO
The aim of the study was to investigate and compare the clinical manifestations between HLA-B27(+) and HLA-B27(-) ankylosing spondylitis (AS) patients in order to obtain knowledge of the impact of HLA-B27 status on AS, and to inform clinical treatment. A nationwide epidemiological investigation was performed from November 2008 to October 2010. The demographic data and clinical characteristics, and the status of HLA-B27 were collected using questionnaires and laboratory assay, respectively. A total of 2144 patients (78.5% males and 78.4% HLA-B27(+) AS patients) participated in this study. The percentages of males, patients with family history, and involvement of lumbar spine, thoracic spine and hip joints, were observed to be significantly higher in the HLA-B27(+) AS patients than in their HLA-B27(-) AS peers.
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Povo Asiático/genética , Predisposição Genética para Doença , Antígeno HLA-B27/genética , Espondilite Anquilosante/epidemiologia , Espondilite Anquilosante/genética , Adolescente , Adulto , China/epidemiologia , Demografia , Etnicidade/genética , Feminino , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Plasma iron circulates bound to transferrin (Trf), which solubilizes the ferric ion and attenuates its reactivity. Diferric Trf interacts with cell-surface Trf receptor (Trfr) to undergo receptor-mediated endocytosis into specialized endosomes. Endosomal acidification leads to iron release, and iron is transported out of the endosome through the activity of divalent metal transporter 1 (DMT1, formerly Nramp2), a transmembrane iron transporter that functions only at low pH. Trf and Trfr then return to the cell surface for reuse, completing a highly efficient cycle. Although the Trf cycle is assumed to be the general mechanism for cellular iron uptake, this has not been validated experimentally. Mice with hypotransferrinaemia (hpx) have little or no plasma Trf. They have severe anaemia, indicating that the Trf cycle is essential for iron uptake by erythroid cells. Other hpx tissues, however, are generally normal, and there is a paradoxical increase in intestinal iron absorption and iron storage. To test the hypothesis that the Trf cycle has unique importance for erythropoiesis, we disrupted the Trfr gene in mice. This results in elimination of the Trf cycle, but leaves other Trf functions intact. Mice lacking Trfr have a more severe phenotype than hpx mice, affecting both erythropoiesis and neurologic development. Furthermore, haploinsufficiency for Trfr results in impaired erythroid development and abnormal iron homeostasis.
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Eritrócitos/fisiologia , Sistema Nervoso/embriologia , Receptores da Transferrina/genética , Anemia/genética , Anemia/patologia , Animais , Embrião de Mamíferos/química , Embrião de Mamíferos/patologia , Eritropoese/genética , Homeostase , Homozigoto , Absorção Intestinal , Ferro/sangue , Ferro/metabolismo , Camundongos , Camundongos Endogâmicos , Camundongos Mutantes , Reticulócitos/metabolismo , Transferrina/deficiência , Transferrina/genéticaRESUMO
The cryoprotection of carboxylated h-poly-L-lysine (COOH-PLL) was investigated on fibroblasts [L-929 cells and human dermal fibroblasts (HDFs)] during multiple freeze/thaw cycles. COOH-PLL was not toxic to two fibroblast cell types even at 25% (w/v) concentration, whereas dimethylsulphoxide (DMSO) was highly toxic over 3.13% (v/v). When L-929 cells were subjected to 5 freeze/thaw cycles, the media containing 7.5% (w/v) COOH-PLL maintained cell morphology and significantly suppressed growth inhibition as well as cell detachment (P < 0.05). The result was comparable to the media containing 10% (v/v) DMSO. For HDFs, COOH-PLL could effectively retain cell viability and proliferation against 3 freeze/thaw cycles. Cell viability of HDFs was decreased after 5 freeze/thaw cycles, but COOH-PLL exerted better cryoprotection. The cell type might account for the difference in the observations. The data demonstrated that COOH-PLL is a good cryoprotectant for mammalian cells against repeated freeze/thaw cycles, and may be used for cell preservation in fields of cell transplantation, tissue engineering and regenerative medicine.
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Criopreservação/métodos , Crioprotetores/metabolismo , Fibroblastos/citologia , Lisina/análogos & derivados , Lisina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , Crioprotetores/toxicidade , Derme/citologia , Dimetil Sulfóxido/metabolismo , Dimetil Sulfóxido/toxicidade , Fibroblastos/efeitos dos fármacos , Congelamento , Humanos , Recém-Nascido , Lisina/toxicidade , CamundongosRESUMO
The photocatalytic oxidation and generation/regeneration of amines to imines and leucodopaminechrome (LDC)/NADH are subjects of intense interest in contemporary research. Imines serve as crucial intermediates for the synthesis of solar fuels, fine chemicals, agricultural chemicals, and pharmaceuticals. While significant progress has been made in developing efficient processes for the oxidation and generation/regeneration of secondary amines, the oxidation of primary amines has received comparatively less attention until recently. This discrepancy can be attributed to the high reactivity of imines generated from primary amines, which are prone to dehydrogenation into nitriles. In this study, we present the synthesis and characterization of a novel polymer-based photocatalyst, denoted as PMMA-DNH, designed for solar light-harvesting applications. PMMA-DNH incorporates the light-harvesting molecule dinitrophenyl hydrazine (DNH) at varying concentrations (5%, 10%, 20%, 30%, and 40%). Leveraging its high molar extinction coefficient and slow charge recombination, the 30% DNH-incorporated PMMA photocatalyst proves to be particularly efficient. This photocatalytic system demonstrates exceptional yields (96.5%) in imine production and high generation/regeneration rates for LDC/NADH (65.27%/78.77%). The research presented herein emphasizes the development and application of a newly engineered polymer-based photocatalyst, which holds significant promise for direct solar-assisted chemical synthesis in diverse commercial applications.
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To replace porous basalt, the mechanical properties of concrete with recycled resources and durability improvement were analyzed in this study. The analysis was based on the quality improvement of recycled aggregate, use of fly ash, and changes in curing conditions. Basalt aggregate (BA) with a 3% water absorption, raw recycled aggregate and basalt (RRA), and improved recycled aggregate and basalt (PRA) were the main experimental variables. As PRA was applied to concrete, the compressive strength was lower than that of the specimen comprising BA in the normal strength region, but the modulus of elasticity (22.9 GPa) was equivalent or higher. The initial drying shrinkage increased because of the use of basalt-based recycled aggregate (B-RA). The drying shrinkage of PRA was similar to that of BA with an average difference of <7% as the age increased. The specimens subjected to steam curing exhibited the lowest drying shrinkage. These results showed that pores in the old paste of recycled aggregate increased freeze−thaw resistance because of the increase in the spacing factor. Although the PRA did not satisfy the quality criteria, the efficient use of recycled aggregate achieved an equivalent or higher performance than that of concrete comprising BA and improved durability.
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This study investigated recycled aggregates of Jeju Island-where porous basalt exists as a natural aggregate-and is a study aimed at verifying the applicability of the basalt-based recycled aggregate in the field. To this end, the application properties of concrete were analyzed using the quality improvement of the recycled aggregate (PRA), the type of fine aggregate received in the region, and the cement content as variables. In an experiment using concrete in which 50% of the PRA was replaced with basalt (BA), the air content of the fresh concrete decreased due to the increasing solid content of the aggregate when PRA and fine aggregates (with an even particle size distribution) were used. Regarding the properties of the hardened concrete, when the PRA and fine aggregate (with a high fineness modulus) were used, the compressive strength was 33.6 MPa and the modulus of elasticity was 23.1 GPa, which are higher than those of the BA specimen. The resistance to carbonation increased due to the improved quality of the PRA specimen. Pores that are 0.3 mm in size or larger decreased when the PRA and fine aggregates of even particle sizes were used. This form of pore reduction was found to have a direct correlation with the improvement of mechanical properties.
RESUMO
Recycled aggregate is essential to protect Jeju Island's natural environment, but waste concrete, including porous basalt, is a factor that lowers the quality of recycled aggregate. Therefore, an experiment was conducted to analyze the properties of concrete application of basalt-based recycled aggregate (B-RA) through quality improvement. The absorption of the B-RA ranged from 3-5%; restricting its absorption to less than 3% was challenging owing to its porosity and irregular shape. However, the increase in the solid volume percentage of the concrete when replacing 25 or 50% of fresh basalt aggregate with recycled basalt aggregate improved the mechanical performance of the concrete, especially at 25%, for which a compressive strength of 55.9 MPa and modulus of elasticity of 25.9 GPa exceeded those of concrete with fresh basalt aggregate. Moreover, increasing the replacement ratio of the fresh basalt with recycled aggregate reduced the slump and decreased the air content, consequently increasing the concrete drying shrinkage. However, the replacement of fresh basalt aggregate with recycled basalt aggregate unaltered the mechanical performance of the concrete. The results indicate that efficient use of recycled aggregates can yield superior performance to that of fresh basalt, irrespective of aggregate quality.
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Shoe dermatitis is a type of contact dermatitis precipitated by allergens or irritants found in shoes. Potassium dichromate, commonly used in leather processing, is one of the most prevalent agents responsible for shoe dermatitis; however, it is not the only one. Shoe dermatitis caused by an allergen or an irritant may affect a person of any age, sex, or ethnicity. Numerous treatments exist for shoe dermatitis, the most simple yet important being avoidance of causative agents. Pharmaceutical agents commonly used are emollients, humectants, and topical corticosteroids. In more severe cases, topical calcineurin inhibitors and phototherapy may be used.
Assuntos
Dermatite Alérgica de Contato , Dermatoses do Pé , Alérgenos , Dermatoses do Pé/diagnóstico , Dermatoses do Pé/etiologia , Dermatoses do Pé/terapia , Humanos , Testes do Emplastro , SapatosRESUMO
In this study, the sensitivity of the apparent response of trabecular bone to different constitutive models at the tissue level was investigated using finite element (FE) modeling based on micro-computed tomography (micro-CT). Trabecular bone specimens from porcine femurs were loaded under a uniaxial compression experimentally and computationally. The apparent behaviors computed using von Mises, Drucker-Prager, and Cast Iron plasticity models were compared. Secondly, the effect of bone volume fraction was studied by changing the bone volume fraction of a trabecular bone sample while keeping the same basic architecture. Also, constitutive models' parameters of the tissue were calibrated for porcine bone, and the effects of different parameters on resulting apparent response were investigated through a parametric study. The calibrated effective tissue elastic modulus of porcine trabecular bone was 10±1.2 GPa, which is in the lower range of modulus values reported in the literature for human and bovine trabecular bones (4-23.8 GPa). It was also observed that, unlike elastic modulus, yield properties of tissue could not be uniquely calibrated by fitting an apparent response from simulations to experiments under a uniaxial compression. Our results demonstrated that using these 3 tissue constitutive models had only a slight effect on the apparent response. As expected, there was a significant change in the apparent response with varying bone volume fraction. Also, both apparent modulus and maximum stress had a linear relation with bone volume fraction.
Assuntos
Osso Esponjoso/anatomia & histologia , Osso Esponjoso/diagnóstico por imagem , Análise de Elementos Finitos , Dinâmica não Linear , Microtomografia por Raio-X , Animais , Calibragem , Simulação por Computador , Tamanho do Órgão , Estresse Mecânico , Sus scrofaRESUMO
BACKGROUND: Various kinds of functional cosmetics are on the market, although there are a variety of opinions concerning the actual effect. Transdermal microneedle patch has been introduced as a newly developed device for drug delivery through the skin. OBJECTIVE: This study was conducted to verify the face skin improvement effect and safety of a novel cosmetic microneedle patch. METHODS: A total of 84 Korean females finished this prospective clinical trial. The subjects were divided into 3 groups: (1) soluble hyaluronic acid (HA) microneedle patch alone, (2) soluble HA microneedle patch plus adenosine wrinkle cream, and (3) adenosine wrinkle cream alone. The treatments were applied to the crow's feet and nasolabial fold wrinkle for 12 weeks. The test areas were measured before treatment and at 4, 8, and 12 weeks after use of the test product. At the completion of the testing period of the trial, the global assessment of efficacy and product preferences were surveyed from the subjects. RESULTS: Combination treatment with wrinkle cream and microneedle patch significantly improved Merz scale for crow's feet and nasolabial folds, compared to the sole application of wrinkle cream or patch. Measurement on the crow's feet showed an overall improvement in all 3 groups, yielding no significant differences among the groups. No serious adverse effects were observed during the follow-up period. CONCLUSION: Combination application of a soluble microneedle patch and wrinkle cream was an effective treatment in improving facial wrinkles, thus enhancing skin rejuvenation.
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Preenchedores Dérmicos/uso terapêutico , Ácido Hialurônico/uso terapêutico , Envelhecimento da Pele , Adesivo Transdérmico , Adenosina/uso terapêutico , Idoso , Preenchedores Dérmicos/administração & dosagem , Fármacos Dermatológicos/uso terapêutico , Quimioterapia Combinada , Elasticidade/efeitos dos fármacos , Olho , Face , Feminino , Humanos , Ácido Hialurônico/administração & dosagem , Pessoa de Meia-Idade , Sulco Nasogeniano , Agulhas/efeitos adversos , Estudos Prospectivos , Rejuvenescimento , Método Simples-Cego , Creme para a Pele/uso terapêutico , Fenômenos Fisiológicos da Pele/efeitos dos fármacos , Adesivo Transdérmico/efeitos adversosRESUMO
The free volume properties of phospholipid bilayers have been determined using a new assay that applies the photochromic and solvatochromic properties of merocyanines. The orientation and embedding depth of the merocyanines in the bilayer are controlled using substitution on the merocyanine indole moiety. The free volume changes at the aqueous interface (region 1), the phospholipid headgroup (region 2), and the aliphatic interior (region 3) of the bilayer are compared by analyzing the rate constants for the merocyanine ring-closing reaction. Free volume variations during the P(beta)(')(gel) <--> L(alpha)(liquid) phase transition are observed in region 1, in accordance with large structural rearrangements between the gel and the liquid phases in this region. The largest free volume is found in region 3, and the smallest is found in region 2. This distribution of free volume in the bilayer agrees with computational studies of these systems. Comparison of the free volume in region 2 of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipids shows that this method is sensitive to small structural differences between lipids. In region 2, the free volume is found to be approximately 2 times larger in DPPC bilayers, which could be related to different merocyanine interactions with the two phosphatidylcholines. Free volume properties determined on picosecond and second time scales are compared based on an analysis of merocyanine formation and decoloration reactions.
Assuntos
Corantes Fluorescentes/química , Bicamadas Lipídicas/química , Fosfolipídeos/química , Pirimidinonas/química , 1,2-Dipalmitoilfosfatidilcolina/química , Dimiristoilfosfatidilcolina/química , Cinética , Modelos Biológicos , Modelos Químicos , TermodinâmicaRESUMO
A simple imaging setup based on the principle of coherence-based contrast X-ray imaging with unmonochromatized synchrotron radiation was used for studying mammographic phantom and human breast specimens. The use of unmonochromatized synchrotron radiation simplifies the instrumentation, decreases the cost and makes the procedure simpler and potentially more suitable for clinical applications. The imaging systems consisted of changeable silicon wafer attenuators, a tungsten slit system, a CdWO4 scintillator screen, a CCD (Charge Coupled Device) camera coupled to optical magnification lenses, and a personal computer. In preliminary studies, a spatial resolution test pattern and glass capillary filled with air bubbles were imaged to evaluate the resOolution characteristics and coherence-based contrast enhancement. Both the spatial resolution and image quality of the proposed system were compared with those of a conventional mammography system in order to establish the characteristic advantages of this approach. The images obtained with the proposed system showed a resolution of at least 25 microm on the test pattern with much better contrast, while the images of the capillary filled with air bubbles revealed coherence-based edge enhancement. This result shows that the coherence-based contrast imaging system, which emphasizes the refraction effect from the edge of materials of different refractive indexes, is applicable to imaging studies in fundamental medicine and biology, although further research works will be required before it can be used for clinical applications.
Assuntos
Doenças Mamárias/diagnóstico por imagem , Mamografia/instrumentação , Mamografia/métodos , Imagens de Fantasmas , Síncrotrons , Feminino , Humanos , Projetos Piloto , Raios XRESUMO
This paper presents the vibration characteristics of the radial mode in spherical piezoelectric transducers. The differential equations of piezoelectric radial motion have been derived in terms of radial displacement and electric potential. Applying mechanical and electrical boundary conditions yielded a characteristic equation for radial vibration. Theoretical calculations of the fundamental natural frequency have been compared with numerical and experimental results for transducers of several sizes, and have shown a good agreement. This paper discusses the dependence of natural frequencies on the radius and thickness of the piezoelectric spheres and the difference between piezoelectric and elastic resonances. From the results it has been concluded that the natural frequency was not affected for the first radial mode but was reduced by the piezoelectric phenomenon. It has also been concluded that the natural frequency of the first radial mode depended mostly on the radius rather than on the thickness of the sphere whereas the natural frequency of the second radial mode depended mostly on the thickness rather than the radius.
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Patterning the developing nervous system in the mouse has been proposed to depend on two separate sources of signals, the anterior visceral endoderm (AVE) and the node or organizer. Mutation of the winged-helix gene HNF3beta leads to loss of the node and its derivatives, while mutation of the homeobox gene Otx2 results in loss of head structures, apparently at least partially because of defects in the AVE. To investigate the potential genetic interactions between the two signaling centers, we crossed Otx2+/- and HNF3beta+/- mice and found that very few Otx2+/-;HNF3beta+/- double heterozygous mutants survived to weaning. Normal Mendelian ratios of genotypes were observed during gestation, but more than half the double heterozygotes displayed a severe anterior patterning phenotype that would be incompatible with postnatal survival. The phenotype was characterized by varying degrees of holoprosencephaly, cyclopia with proboscis-like structures, and anterior forebrain truncations. Regional marker analysis revealed that ventral forebrain structures of Otx2+/-;HNF3beta+/- mutant embryos were most severely affected. Shh expression was completely absent in the anterior region of Otx2+/-;HNF3beta+/- embryos, suggesting that Otx2 and HNF3beta genetically interact, directly or indirectly, to regulate Shh expression in the anterior midline. In addition, the forebrain truncations suggest an involvement of both genes in anterior patterning, through their overlapping expression domains in either the AVE and/or the prechordal mesoderm.