Preparation of Cellulose Nanoparticles from Foliage by Bio-Enzyme Methods

There are vast reserves of foliage in nature, which is an inexhaustible precious resource. In this study, the chemical components of five foliage types (pine needles, black locust tree leaves, bamboo leaves, elm leaves and poplar leaves) were analyzed, including cellulose content, hemicellulose content, and lignin content. The bio-enzymatic method was then used to prepare cellulose nanoparticles (CNPs) from these five kinds of leaves, and the prepared CNPs were analyzed using TEM, FTIR, FESEM, and XRD. The results showed that the content of hemicellulose in bamboo leaves was the highest, and the lignin content in the other four leaves was the highest. The cellulose content in the five kinds of foliage was arranged from large to small as pine needles (20.5%), bamboo leaves (19.5%), black locust leaves (18.0%), elm leaves (17.6%), and poplar leaves (15.5%). TEM images showed that the CNPs prepared by the five kinds of foliage reached the nanometer level in width and the micrometer level in length; therefore, the CNPs prepared in this study belonged to cellulose nanofibers (CNFs). The results of FTIR and XRD showed that CNFs prepared by the enzyme treatment exhibited a typical crystalline structure of cellulose II. The degree of crystallinity (DOC) of CNFs prepared from pine needle, poplar leaves, and bamboo leaves are 78.46%, 77.39%, and 81.51%, respectively. FESEM results showed that the CNFs prepared from pine needles, poplar leaves and bamboo leaves by enzymatic method presents a three-dimensional (3D) network structure, and their widths are 31 nm, 36 nm, and 37 nm, respectively. This study provides a meaningful reference for broadening the use of foliage types and improving their added value.     

Foliage shedding in deciduous forests lifts up long-distance seed dispersal by wind

Seed terminal velocity and release height are recognized as key biotic determinants of long-distance dispersal (LDD) of seeds by wind. Yet, potential determinants at the ecosystem level, such as seasonal dynamics in foliage density characterizing many deciduous forests, have received much less attention. We integrated detailed field observations and experiments with a mechanistic wind dispersal model to assess how seasonal variation in foliage density, estimated by leaf-area index (LAI), affects LDD in deciduous forests. We found that the model, previously shown to accurately predict seed dispersal by wind, also reliably describes the effects of LAI variation on wind statistics for a wide range of canopy types. Sparser canopies are characterized by more organized vertical eddy motion that promotes LDD by uplifting seeds to higher elevations where winds are stronger. Yet, sparser canopies are also characterized by reduced mean windspeed aloft. We showed that former effect more than compensates for the latter, i.e., conditions of low LAI are favorable for LDD. This may account for the tendency of many temperate tree species to restrict seed release to either early spring or late fall, when LAI is relatively low. Sensitivity analysis reveals that the typical seasonal variation in LAI can be more important to LDD of seeds by wind than the natural variation in seed terminal velocity. Because our model accurately describes the effects of LAI variation for distinctly different sites, species, and life forms, we suggest that its results reflect a general association between LDD and foliage density dynamics.     

脑红蛋白与缺血缺氧性脑损伤

脑红蛋白(neuroglobin,Ngb)是携氧球蛋白家族成员之一,主要以单体形式存在于神经细胞中,与脑内氧供应密切相关.脑缺血缺氧能诱导Ngb高表达,并作为一种内源性神经保护因子保护神经元免受缺血缺氧性损害.文章对Ngb的分布、结构、功能及其在缺血缺氧性脑损伤中的保护作用和机制做了综述.     

老年脑出血与脑梗死心电图分析

目的观察不同部位脑出血及脑梗死老年患者的心电图异常表现及特征。方法回顾分析同期住院的126例老年脑出血患者（脑出血组）及151例老年脑梗死患者（脑梗死组）的心电图资料,分析其心电图表现及病因。结果两组患者心电图异常率间差异无显著性意义（P＞0．05）。两组患者窦性心动过速、左室肥大、室上性心动过速、窦性心动过缓并不齐、心律失常、肢体导联低电压、室性心动过速的发生率间差异均有非常显著性意义（P＜0．01）。结论脑出血组患者心动过速、左室肥大的发生率明显高于脑梗死组,而脑梗死组的窦性心动过缓并不齐、心律失常、肢体导联低电压的发生率明显高于脑出血组。脑出血、脑梗死的心电图异常与疾病的严重程度密切相关。     

Cerebral microangiopathies

Cerebral small vessels disease are characterized by lesions of the wall of the small cerebral arteries. They are responsible for 25 to 30% of strokes due to cerebral infarction or hemorrhage and/or cognitive impairment, dementia. Lipohyalinosis and cerebral amyloid angiopathy are the most common etiologies. They are associated with age, arterial hypertension, and diabetes. The localization of the lesions by MRI could help to differentiate both etiologies: deep localisation for lipohyalinosis and lobar (cortical) for cerebral amyloid angiopathy. Physiopathology of these diseases is not presently understood, and no specific treatment is available. Therefore, treatment of vascular risk factors (diabetes, arterial hypertension) is the only therapeutic measure available.     

脑微梗死

作为脑小血管病的一种表现形式,脑微梗死（cerebralmicroinfarct,CMI）是老年人一种非常常见的神经病理学改变,与认知功能下降和痴呆显著相关。文章对CMI的神经病理学、神经影像学和临床意义进行了综述。     

Cerebral palsy

Cerebral palsy, a range of non-progressive syndromes of posture and motor impairment, is a common cause of disability in childhood. The disorder results from various insults to different areas within the developing nervous system, which partly explains the variability of clinical findings. Management options include physiotherapy, occupational and speech therapy, orthotics, device-assisted modalities, pharmacological intervention, and orthopaedic and neurosurgical procedures. Since 1980, modification of spasticity by means of orally administered drugs, intramuscular chemodenervation agents (alcohol, phenol, botulinum toxin A), intrathecally administered drugs (baclofen), and surgery (neurectomy, rhizotomy) has become more frequent. Family-directed use of holistic approaches for their children with cerebral palsy includes the widespread adoption of complementary and alternative therapies; however, the prevalence of their use and the cost of these options are unknown. Traditional medical techniques (physiotherapy, bracing, and orthopaedic musculoskeletal surgery) remain the mainstay of treatment strategies at this time. This seminar addresses only the musculoskeletal issues associated with cerebral palsy and only indirectly discusses the cognitive, medical, and social issues associated with this diagnosis.