X-连锁肾上腺脑白质营养不良(X-linked adrenoleukodystrophy,X-ALD)是一种编码过氧化物酶体跨膜蛋白三磷酸腺苷结合盒亚家族D成员1(adenosine 5′-triphosphate binding cassette subfamily D member 1,ABCD1)基因突变的遗传病,其具有...X-连锁肾上腺脑白质营养不良(X-linked adrenoleukodystrophy,X-ALD)是一种编码过氧化物酶体跨膜蛋白三磷酸腺苷结合盒亚家族D成员1(adenosine 5′-triphosphate binding cassette subfamily D member 1,ABCD1)基因突变的遗传病,其具有多种临床表现,从首发症状到致死性炎性脱髓鞘的进展过程极其快速。因此,识别早期临床症状,早诊断、早治疗能有效阻止该疾病进展。本研究报道1例少见的以“皮肤色素沉着3年”为唯一临床表型的X-ALD患者的实验室检查及影像学特点,并采用高通量测序为患者及其父母进行ABCD1基因测序。实验室检查结果提示患者肾上腺皮质功能减退,血清极长链脂肪酸浓度增高;肾上腺及脑MRI显示未见明显异常信号影。患者基因检测结果显示ABCD1基因外显子1发生c.521A>C半合子突变,其母亲为同位点杂合突变,故诊断为“X-连锁肾上腺脑白质营养不良”。随访过程中,患者肾上腺皮质功能不全症状没有改善,颅脑MRI显示右侧放射冠、左侧顶叶脑白质见少许点状高flair信号影,提示可能出现脑损伤。仅有皮肤表现而无神经系统异常的X-ALD患者极易被忽视,早期诊断并给予早期干预是延缓该疾病进展的重要途径。因此,建议所有的男性儿童患者以皮肤色素沉着为唯一临床表现,继而诊断肾上腺皮质功能减退时,都应该进行基因检测,及早鉴别X-ALD。展开更多
Case histories have shown that the liquefaction-induced soil lateral spreading is one of the main causes of damage to pile foundations subjected to seismic loading. Post-liquefaction soil behaves similarly to a viscou...Case histories have shown that the liquefaction-induced soil lateral spreading is one of the main causes of damage to pile foundations subjected to seismic loading. Post-liquefaction soil behaves similarly to a viscous fluid. This study investigated the effect of soil lateral spreading on a single pile based on fluid mechanics in which the liquefied soils were treated as Newtonian fluids. A numerical simulation on a single pile embedded in a fully saturated sandy foundation was conducted and compared with shake table tests. The lateral flow effect and the effect of shear strain rate were discussed. After liquefaction, the acceleration of the foundation shows that there are no obvious spikes and finally reaches a stable state. The presented method can predict the pile response better than p-y curve method. A parametric study was performed to explore the effect of several influence factors on pile behaviors. The results show that the pile head displacement decreases and the maximum bending moment at pile bottom increases with the increase of bending stiffness. With the same pile bending stiffness, the displacement and bending moment of pile increase with the increase of soil viscosity and acceleration amplitude.展开更多
文摘X-连锁肾上腺脑白质营养不良(X-linked adrenoleukodystrophy,X-ALD)是一种编码过氧化物酶体跨膜蛋白三磷酸腺苷结合盒亚家族D成员1(adenosine 5′-triphosphate binding cassette subfamily D member 1,ABCD1)基因突变的遗传病,其具有多种临床表现,从首发症状到致死性炎性脱髓鞘的进展过程极其快速。因此,识别早期临床症状,早诊断、早治疗能有效阻止该疾病进展。本研究报道1例少见的以“皮肤色素沉着3年”为唯一临床表型的X-ALD患者的实验室检查及影像学特点,并采用高通量测序为患者及其父母进行ABCD1基因测序。实验室检查结果提示患者肾上腺皮质功能减退,血清极长链脂肪酸浓度增高;肾上腺及脑MRI显示未见明显异常信号影。患者基因检测结果显示ABCD1基因外显子1发生c.521A>C半合子突变,其母亲为同位点杂合突变,故诊断为“X-连锁肾上腺脑白质营养不良”。随访过程中,患者肾上腺皮质功能不全症状没有改善,颅脑MRI显示右侧放射冠、左侧顶叶脑白质见少许点状高flair信号影,提示可能出现脑损伤。仅有皮肤表现而无神经系统异常的X-ALD患者极易被忽视,早期诊断并给予早期干预是延缓该疾病进展的重要途径。因此,建议所有的男性儿童患者以皮肤色素沉着为唯一临床表现,继而诊断肾上腺皮质功能减退时,都应该进行基因检测,及早鉴别X-ALD。
文摘Case histories have shown that the liquefaction-induced soil lateral spreading is one of the main causes of damage to pile foundations subjected to seismic loading. Post-liquefaction soil behaves similarly to a viscous fluid. This study investigated the effect of soil lateral spreading on a single pile based on fluid mechanics in which the liquefied soils were treated as Newtonian fluids. A numerical simulation on a single pile embedded in a fully saturated sandy foundation was conducted and compared with shake table tests. The lateral flow effect and the effect of shear strain rate were discussed. After liquefaction, the acceleration of the foundation shows that there are no obvious spikes and finally reaches a stable state. The presented method can predict the pile response better than p-y curve method. A parametric study was performed to explore the effect of several influence factors on pile behaviors. The results show that the pile head displacement decreases and the maximum bending moment at pile bottom increases with the increase of bending stiffness. With the same pile bending stiffness, the displacement and bending moment of pile increase with the increase of soil viscosity and acceleration amplitude.
