武汉地区硅质磷片金藻的初步研究

1986年11月,在武汉植物所的3个池塘及东湖附近的池塘内采集的标本中,含有大量的具硅质磷片的金藻,共11种,分别隶属于Spiniferomonas,Paraphysomonas, Chrysosphaevella, Mallomonas和Synura 5个属。本文提供了这些藻的硅质磷片、刺及毛的电镜照片。这些藻在中国研究得很少,许多种都是第一次报道,它们中的大多数在世界上其它一些地区也是普遍出现的,有些则毫无疑问地属于世界性分布。     

Motor variability during a repetitive lifting task is impaired by wearing a passive back-support exoskeleton

PurposeEvaluate whether wearing a passive back-support exoskeleton during repetitive lifting impairs motor variability of erector spinae muscle and spine movement and whether this association is influenced by lifting style.Scope: Thirty-six healthy males performed ten lifts in four randomized conditions with exoskeleton (without, with) and lifting style (squat, stoop) as dependent variables. One lifting cycle contained four phases: bending/straighten without/with load. Erector spinae muscular activity, thoracic kyphosis and lumbar lordosis were measured with surface electromyography and gravimetric position sensors, respectively. Absolute and relative cycle-to-cycle variability were calculated. The effects of exoskeleton and exoskeleton × lifting style were assessed on outcomes during the complete lifting cycle and its four phases.ResultsFor the complete lifting cycle, muscular variability and thoracic kyphosis variability decreased whereas lumbar lordosis variability increased with exoskeleton. For lifting phases, effects of exoskeleton were mixed. Absolute and relative muscular variability showed a significant interaction effect for the phase straighten with load; variability decreased with exoskeleton during squat lifting.ConclusionUsing the exoskeleton impaired several motor variability parameters during lifting, supporting previous findings that exoskeletons may limit freedom of movement. The impact of this result on longer-term development of muscular fatigue or musculoskeletal disorders cannot yet be estimated.     

Pollen development in a submerged plant,Ottelia alismoides (L.) Pers. (Hydrocharitaceae)

Exine structure and its developmental program in a submerged plant,Ottella alismoides (L.) Per. were investigated with scanning and transmission electron microscopies. Verrucate protrusions initiate on microspore plasma membrane at early tetrad stage. The verrucate protrusions develop into spines during free microspore stage. A foot layer is formed by accumulation of lamellated structure. The pollen grains ofOttelia alismoides are inaperturate, not omniaperturate, because of the well-developed foot layer. The inaperturate pollen grains ofOttelia are characterized by the spinous protrusions and the granular foot layer.     

Continuous ambulatory hand force monitoring during manual materials handling using instrumented force shoes and an inertial motion capture suit

Hand forces (HFs) are commonly measured during biomechanical assessment of manual materials handling; however, it is often a challenge to directly measure HFs in field studies. Therefore, in a previous study we proposed a HF estimation method based on ground reaction forces (GRFs) and body segment accelerations and tested it with laboratory equipment: GFRs were measured with force plates (FPs) and segment accelerations were measured using optical motion capture (OMC). In the current study, we evaluated the HF estimation method based on an ambulatory measurement system, consisting of inertial motion capture (IMC) and instrumented force shoes (FSs).Sixteen participants lifted and carried a 10-kg crate from ground level while 3D full-body kinematics were measured using OMC and IMC, and 3D GRFs were measured using FPs and FSs. We estimated 3D hand force vectors based on: (1) FP+OMC, (2) FP+IMC and (3) FS+IMC. We calculated the root-mean-square differences (RMSDs) between the estimated HFs to reference HFs calculated based on crate kinematics and the GRFs of a FP that the crate was lifted from.Averaged over subjects and across 3D force directions, the HF RMSD ranged between 10-15N when using the laboratory equipment (FP + OMC), 11-18N when using the IMC instead of OMC data (FP+IMC), and 17-21N when using the FSs in combination with IMC (FS + IMC). This error is regarded acceptable for the assessment of spinal loading during manual lifting, as it would results in less than 5% error in peak moment estimates.     

The fin spine of a new holocephalan from the lower jurassic of Lyme Regis,Dorset, England

A fin spine previously described as ‘Myriacanthus paradoxus’ Agassiz from the Lower Lias (Lower Jurassic) of Lyme Regis, is allocated to the new genus and species Recurvacanthus uniserialis. The spine is unusual in possessing a single median row of four large, hook-like, downturned denticles on the distal part of the posterior wall. It is concluded that the unique specimen should be classified with the myriacanthoid chimaeriform holocephalans since it possesses a tubercular ornament on the lateral walls.     

Vertebral morphology of Nacholapithecus kerioi based on KNM-BG 35250

This paper describes the morphology of the vertebral remains of the KNM-BG 35250 Nacholapithecus kerioi individual from the Middle Miocene of Kenya. Cervical vertebrae are generally large relative to presumed body mass, suggesting a heavy head with large jaws and well-developed neck muscles. The atlas retains the lateral and posterior bridges over the vertebral artery. The axis has a robust dens and a large angle formed by superior articular surfaces. The thoracic vertebral specimens include the diaphragmatic vertebra and one post-diaphragmatic vertebra. The thoracic vertebral bodies are much smaller that those of male Papio cynocephalus, whereas many of the dorsal elements are large and robust, exceeding those of male P. cynocephalus. Lumbar vertebral bodies are small relative to body mass, craniocaudally moderately long, and have a median ventral keel. The transverse process is craniocaudally long and arises from the widest part of the body cranially and the pedicle above the inferior vertebral notch caudally. Anapophyses are present in one of the preserved lumbar vertebrae. The postzygapophyses are thick dorsoventrally. These lumbar features are broadly shared with Proconsul. However, the base of the spinous process is longer and more caudally positioned in N. kerioi compared to Proconsul, and is more similar to the condition in Pongo. They are not dorsally (or moderately caudally) directed as is seen in P. nyanzae, Pan, and most other extant primates. A caudally directed spinous process does not permit a broad range of spinal dorsiflexion. The presumed stiff back in N. kerioi suggests a different locomotor repertoire than in Proconsul. Morotopithecus bishopi, although not possessing the same features, exhibits another morphological suite of characters for lumbar stiffness. Diverse functional adaptations of the lumbar spine were present in African hominoids during the Early to Middle Miocene.     

Brain-derived neurotrophic factor regulates AMPA receptor trafficking to post-synaptic densities via IP3R and TRPC calcium signaling

The change in the number of post-synaptic alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-type glutamatergic receptors (AMPARs) by neuronal activity is recognized as a molecular basis of synaptic plasticity. Here, we show that Ca(2+) transients evoked by brain-derived neurotrophic factor (BDNF) induce translocation of a subunit of AMPAR, GluR1, but not NMDAR, to the post-synaptic membrane in cultured cortical pyramidal neurons. Among BDNF-induced Ca(2+) transients, that dependent on IP3R was fully required, while store-operated calcium influx through the non-selective cation channel TRPC (transient receptor potential canonical) was partially required for the GluR1 up-regulation, suggesting that spatial and temporal calcium signaling regulate translocation of GluR1 to the polarized membrane domain.     

Dosimetric characterization of carbon fiber stabilization devices for post-operative particle therapy

PurposeThe aim of this study was to evaluate the dosimetric impact caused by recently introduced carbon fiber reinforced polyetheretherketone (CF/PEEK) stabilization devices, in comparison with conventional titanium (Ti) implants, for post-operative particle therapy (PT).MethodsAs a first step, protons and carbon ions Spread-Out Bragg Peaks (SOBPs) were delivered to CF/PEEK and Ti screws. Transversal dose profiles were acquired with EBT3 films to evaluate beam perturbation. Effects on image quality and reconstruction artifacts were then investigated. CT scans of CF/PEEK and Ti implants were acquired according to our clinical protocol and Hounsfield Unit (HU) mean values were evaluated in three regions of interest. Implants and artifacts were then contoured in the sample CT scans, together with a target volume to simulate a spine tumor. Dose calculation accuracy was assessed by comparing optimized dose distributions with Monte Carlo simulations. In the end, the treatment plans of nine real patients (seven with CF/PEEK and two with Ti stabilization devices) were retrospectively analyzed to evaluate the dosimetric impact potentially occurring if improper management of the spine implant was carried out.ResultsAs expected, CF/PEEK screw caused a very slight beam perturbation in comparison with Ti ones, leading to a lower degree of dose degradation in case of contouring and/or set-up uncertainties. Furthermore, CF/PEEK devices did not determine appreciable HU artifacts on CT images thus improving image quality and, as a final result, dose calculation accuracy.ConclusionsCF/PEEK spinal fixation devices resulted dosimetrically more suitable than commonly-used Ti implants for post-operative PT.     

Stem cells sources for intervertebral disc regeneration

Intervertebral disc regeneration field is rapidly growing since disc disorders represent a major health problem in industrialized countries with very few possible treatments.Indeed, current available therapies are symptomatic, and surgical procedures consist in disc removal and spinal fusion, which is not immune to regardable concerns about possible comorbidities, cost-effectiveness, secondary risks and long-lasting outcomes. This review paper aims to share recent advances in stem cell therapy for the treatment of intervertebral disc degeneration. In literature the potential use of different adult stem cells for intervertebral disc regeneration has already been reported. Bone marrow mesenchymal stromal/stem cells, adipose tissue derived stem cells, synovial stem cells, muscle-derived stem cells, olfactory neural stem cells, induced pluripotent stem cells, hematopoietic stem cells, disc stem cells, and embryonic stem cells have been studied for this purpose either in vitro or in vivo. Moreover, several engineered carriers(e.g., hydrogels), characterized by full biocompatibility and prompt biodegradation, have been designed and combined with different stem cell types in order to optimize the local and controlled delivery of cellular substrates in situ. The paper overviews the literature discussing the current status of our knowledge of the different stem cells types used as a cell-based therapy for disc regeneration.     

Androgen rapidly increases dendritic thorns of CA3 neurons in male rat hippocampus

Modulation of hippocampal synaptic plasticity by androgen has been attracting much attention. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. Here we demonstrated rapid effects of dihydrotestosterone (DHT) and testosterone (T) on the density of thorns, by imaging Lucifer Yellow-injected neurons in adult male rat hippocampal slices. The application of 10 nM DHT or T induced rapid increase in the density of thorns within 2 h. The androgen-mediated increase was suppressed by blocking several kinases, such as Erk MAPK, p38 MAPK, PKC, and CaMKII. On the other hand, PKA, PI3K were not involved in the signaling of thorn-genesis. The increase in the thorn density by androgen was also blocked by the inhibitor of classical androgen receptor. Almost no difference was observed between DHT and T in the effect on the thorn density. We observed that the androgen-induced thorn-genesis is opposite to estrogen-induced thorn-degeneration.