Combined control algorithm based on synchronous reinforcement learning for a self-balancing bicycle robot

In this paper, balance control of a bicycle robot is studied without either a trail or a mechanical regulator when the robot moves in an approximately rectilinear motion. Based on the principle of moment balance, an input nonaffine nonlinear dynamics model of the bicycle robot is established. A driving velocity condition is proposed to maintain the robot balance. The nonaffine nonlinear system is transformed into an affine nonlinear system by defining the equivalent control. Subsequently, a feedback linearization controller is designed for the equivalent control. We design a combined control algorithm of synchronous policy iteration based on the actor-critic architecture. The actor neural network (NN) is designed based on the feedback linearization control law. Weight tuning laws for the critic and actor NNs are proposed. The system closed-loop stability and convergence of the NN weights are guaranteed based on the Lyapunov analysis. The optimality of the equivalent control policy is guaranteed. To satisfy the driving velocity condition, the values of the steering angle and driving velocity are determined based on the optimal equivalent control. The effectiveness of the proposed algorithm is verified through simulations and real experiments.

[Seroprevalence of the specific antibody against Toxoplasma gondii among patients with hematological diseases]

OBJECTIVE

To investigate the seroprevalence of Toxoplasma gondii infections among patients with hematological diseases, so as to provide insights into improving the prognosis and quality of life among patients with hematological diseases.

METHODS

A total of 240 patients with hematological diseases (including 170 patients with hematological tumors and 70 patients with non-tumor hematological diseases) admitted to The Affiliated Hospital of Putian University during the period from January 1, 2021 through October 10, 2023 and 500 healthy volunteers in the hospital during the same period were enrolled. Subjects' demographics and serum samples were collected, and serum specific IgG and IgM antibodies against T. gondii were detected using the chemiluminescence assay, with any of a positive IgG or IgM antibody defined as a positive T. gondii infection. The seroprevalence of specific IgG and IgM antibodies against T. gondii was compared between patients with hematological diseases and healthy volunteers.

RESULTS

The mean age (F = 2.034, P > 0.05) and gender distribution (χ2 = 0.462, P > 0.05) were comparable among patients with hematological tumors, patients with non-tumor hematological diseases and healthy volunteers, and there was no significant difference in the proportion of history of cat or dog contacts between patients with hematological diseases and healthy volunteers (χ2 = 0, P > 0.05). The seroprevalence of anti-T. gondii antibody was significantly higher among patients with hematological diseases than among healthy volunteers (15.8% vs. 0.6%; χ2 = 71.902, P < 0.01), and there was a significant difference in the seroprevalence of anti-T. gondii antibody among patients with hematological tumors (18.2%), patients with non-tumor hematological diseases (10.0%) and healthy volunteers (χ2 = 78.327, P < 0.01). The seroprevalence of anti-T. gondii antibody was significantly higher among patients with hematological tumors and non-tumor hematological diseases than among healthy volunteers (both P values < 0.05), while no significant difference was seen in the seroprevalence of anti-T. gondii antibody between patients with hematological tumors and non-tumor hematological diseases (P > 0.05). In addition, the proportion of history of cat or dog contacts was significantly higher among patients with hematological diseases that were positive for serum anti-T. gondii anti-body than among those negative for serum anti-T. gondii antibody (21.1% vs. 5.4%; χ2 = 8.653, P < 0.05).

CONCLUSIONS

There is a high seroprevalene rate of T. gondii infections among hematological diseases, which is significantly greater than that among healthy volunteers.

CHANGES OF WNT/B-CATENIN SIGNALING AND DIFFERENTIATION POTENTIAL OF BONE MARROW MESENCHYMAL STEM CELLS IN PROCESS OF BONE LOSS IN OVARIECTOMIZED RATS

Background

In vitro studies of the changes about osteoblastogenesis and adipogenesis potential of BMSCs were not clear. As it is the critical pathway for osteogenic differentiation and bone formation, whether or not Wnt/β-catenin signalling is involved in the changes of osteogenic and adipogenic potential of BMSCs and participates in bone content decrease of ovariectomized (OVX)osteoporosis rats has been rarely reported.

Material/Methods

BMSCs from femurs of ovariectomzed rats were isolated and cultured in vitro. The proliferation potential of BMSCs was analysed by CCK-8 assays . Osteoblastic and adipogenic differentiation potential of the BMSCs was assessed by ALP activity assay, Alizarin red S staining, Oil red O staining and RT-PCR analysis.

Results

The results demonstrated that BMSCs from bilateral ovariectomization rats were endowed with lower proliferation and osteoblastic differentiation potential but higher adipogenic potential than the control group in vitro. In addition, β-catenin was found to have been decreased in OVX BMSCs, indicating that Wnt/β-catenin signalling pathways were suppressed in OVX BMSCs .

Conclusions

Results suggested that changes in the Wnt canonical signalling pathway may be related to imbalances of osteogenic and adipogenic potential of BMSCs, and this may be an important factor related to bone content decrease in ovariectomized osteoporosis rats.

Muscle fatigue evaluation with EMG and Acceleration data: a case study

The design of effective rehabilitation protocols relies on the ability to accurately assess the physical condition and the rehabilitative needs of the patient. Monitoring muscle fatigue can increase the usability of rehabilitative and restorative devices as it helps avoiding premature tiring and injury of patients whose resistance is already compromised. In this study, we collected EMG and accelerometer data from one healthy subject during a 30-minute walk on treadmill to determine the variations of muscle activation, and gait acceleration patterns, which, however subtle, could be interpreted as early indicators of muscle fatigue. Results show an increasing Tibialis Anterior (TA) and decreasing Soleus (SOL) and Gastrocnemius (GASL, GASM) activation towards the end of the task as compared to the beginning, as well as increasing acceleration peaks during the middle swing phase. By following the approach outlined here we can assess the efficiency and reduction of metabolic cost achieved by an exoskeleton. Furthermore, muscle fatigue may be linked to the efficacy of gait rehabilitation, where decreased muscle fatigue across sessions possibly indicates longer retention of benefits after training and increased walking capacity. This methodology can be used to benchmark novel exoskeletons, monitor fatigue to avoid premature tiring of patients, and optimize rehabilitation therapies.

Compliant gripper design, prototyping, and modeling using screw theory formulation

This article investigates some aspects related to the design, modeling, prototyping, and testing of soft–rigid tendon-driven grippers. As a case study, we present the design and development of a two-finger soft gripper and exploit it as an example to demonstrate the application scenario of our mathematical model based on screw theory. A mathematical formulation based on screw theory is then presented to model gripper dynamics. The proposed formulation is the extension of a model previously introduced including the mechanical system dynamics. In this type of gripper, it is possible to achieve different behaviors, e.g., different fingertip trajectories, equivalent fingertip stiffness ellipsoids, etc., while keeping the same kinematic structure of the gripper and varying the properties of its passive deformable joints. These properties can be varied in the prototype by properly regulating some manufacturing parameters, such as percentage of printing infill density in a 3D printing process. We performed experiments with the prototype of the gripper and an optical tracking system to validate the proposed mathematical formulation, and to compare its results with other simplified formulations. We furthermore identified the main performance of the gripper in terms of payload and maximum horizontal resisted force, and verified the capabilities of the gripper to grasp objects with different shapes and weights.

Neuromorphic Vision Based Contact-Level Classification in Robotic Grasping Applications

In recent years, robotic sorting is widely used in the industry, which is driven by necessity and opportunity. In this paper, a novel neuromorphic vision-based tactile sensing approach for robotic sorting application is proposed. This approach has low latency and low power consumption when compared to conventional vision-based tactile sensing techniques. Two Machine Learning (ML) methods, namely, Support Vector Machine (SVM) and Dynamic Time Warping-K Nearest Neighbor (DTW-KNN), are developed to classify material hardness, object size, and grasping force. An Event-Based Object Grasping (EBOG) experimental setup is developed to acquire datasets, where 243 experiments are produced to train the proposed classifiers. Based on predictions of the classifiers, objects can be automatically sorted. If the prediction accuracy is below a certain threshold, the gripper re-adjusts and re-grasps until reaching a proper grasp. The proposed ML method achieves good prediction accuracy, which shows the effectiveness and the applicability of the proposed approach. The experimental results show that the developed SVM model outperforms the DTW-KNN model in term of accuracy and efficiency for real time contact-level classification.

Dynamic-Vision-Based Force Measurements Using Convolutional Recurrent Neural Networks

In this paper, a novel dynamic Vision-Based Measurement method is proposed to measure contact force independent of the object sizes. A neuromorphic camera (Dynamic Vision Sensor) is utilizused to observe intensity changes within the silicone membrane where the object is in contact. Three deep Long Short-Term Memory neural networks combined with convolutional layers are developed and implemented to estimate the contact force from intensity changes over time. Thirty-five experiments are conducted using three objects with different sizes to validate the proposed approach. We demonstrate that the networks with memory gates are robust against variable contact sizes as the networks learn object sizes in the early stage of a grasp. Moreover, spatial and temporal features enable the sensor to estimate the contact force every 10 ms accurately. The results are promising with Mean Squared Error of less than 0.1 N for grasping and holding contact force using leave-one-out cross-validation method.

Diagnostic potential of urinary monocyte chemoattractant protein-1 for Alzheimer's disease and amnestic mild cognitive impairment

BACKGROUND AND PURPOSE

The chemokine monocyte chemoattractant protein-1 (MCP-1) is involved in the pathogenesis of Alzheimer's disease (AD). This study aimed to investigate whether urinary MCP-1 can distinguish patients with AD, patients with amnestic mild cognitive impairment (aMCI) and cognitively normal (CN) subjects.

METHODS

A total of 754 participants, including 97 patients with AD, 50 patients with aMCI and 84 age- and sex-matched CN controls as well as a cohort of 523 CN subjects of different ages, were enrolled from five hospitals located in different areas of China. Urinary MCP-1 levels were determined using enzyme-linked immunosorbent assays. The correlations between urinary MCP-1 levels and cognition test scores or age were analysed. The optimal diagnostic sensitivity and specificity were determined using receiver operating characteristic curve analysis.

RESULTS

In the cohort of CN subjects of different ages, urinary MCP-1 levels increased with ageing and were correlated with age. The urinary MCP-1 levels were higher in females than in males. In the cohort composed of patients with AD, aMCI and age- and sex-matched CN controls, urinary MCP-1 levels were significantly higher in patients with AD and aMCI than in CN controls. There were no differences in urine MCP-1 levels between the AD group and the aMCI group. The urinary MCP-1 levels were correlated with the Mini-Mental State Examination scores and age, and were able to differentiate patients with AD and aMCI from CN subjects.

CONCLUSIONS

Urinary MCP-1 is a potential biomarker for the diagnosis of AD and aMCI.

Design and prototyping soft–rigid tendon-driven modular grippers using interpenetrating phase composites materials

Advances in soft robotics and material science have enabled rapid progress in soft grippers. The ability to 3D print materials with softer, more elastic materials properties is a recent development and a key enabling technology for the rapid development of soft robots. However, obtaining the desired mechanical properties (e.g., stiffness) of the soft joints and information about the parameters to select in 3D printers is often not straightforward. In this article, we propose the use of interpenetrating phase composites (IPCs) materials with mathematically generated topologies based on triply periodic minimal surfaces for the development of soft grippers with desired mechanical properties. The flexible joints of the gripper can be realized through two or more phases that are topologically interconnected such that each phase represents a standalone cellular structure. As a case study, we present the design and development of a two-finger soft gripper as an example to demonstrate the application scenario of our approach. The flexible parts with desired stiffness values are realized by using IPCs materials in which the reinforcement distribution can be regulated on the basis of mathematical models. We characterized the properties of the material through a set of quantitative experiments on IPCs material specimens, and then we realized qualitative grasping tests with the gripper and a set of objects with different shapes and sizes. We showed that by properly regulating the properties of IPCs material it is possible to design modular grippers with the same structure, but different closure motions. Grippers can be customized for different tasks by easily assembling and disassembling fingers.

Modeling, Control, and Numerical Simulations of a Novel Binary-Controlled Variable Stiffness Actuator (BcVSA)

This research work aims at realizing a new compliant robotic actuator for safe human-robotic interaction. In this paper, we present the modeling, control, and numerical simulations of a novel Binary-Controlled Variable Stiffness Actuator (BcVSA) aiming to be used for the development of a novel compliant robotic manipulator. BcVSA is the proof of concept of the active revolute joint with the variable recruitment of series-parallel elastic elements. We briefly recall the basic design principle which is based on a stiffness varying mechanism consisting of a motor, three inline clutches, and three torsional springs with stiffness values ( K 0 , 2 K 0 , 4 K 0 ) connected to the load shaft and the motor shaft through two planetary sun gear trains with ratios (4:1, 4:1 respectively). We present the design concept, stiffness and dynamic modeling, and control of our BcVSA. We implemented three kinds of Multiple Model Predictive Control (MPC) to control our actuator. The main motivation of choosing this controller lies in the fact that working principle of multiple MPC and multiple states space representation (stiffness level) of our actuator share similar interests. In particular, we implemented Multiple MPC, Multiple Explicit MPC, and Approximated Multiple Explicit MPC. Numerical simulations are performed in order to evaluate their effectiveness for the future experiments on the prototype of our actuator. The simulation results showed that the Multiple MPC, and the Multiple Explicit MPC have similar results from the robustness point of view. On the other hand, the robustness performance of Approximated Multiple Explicit MPC is not good as compared to other controllers but it works in the offline framework while having the capability to compute the sub-optimal results. We also performed the comparison of MPC based controllers with the Computed Torque Control (CTC), and Linear Quadratic Regulator (LQR). In future, we are planning to test the presented approach on the hardware prototype of our actuator.

Dynamics and control of separable coupled rigid body systems

This paper explores the dynamics of separable coupled rigid body systems, a special class of constrained rigid body systems. These are defined as two systems that interact with each other by forces of contact, resulting in a reduction in dimensionality and complexity. The mechanics and consequences of this reduction are investigated here. The basic hypothesis and an example of the reduction in two successive steps are formulated. A simple mechanical biped model is developed and analyzed in some details by both system theoretical concepts and simulations. The main contribution of this work is the novel extension to the known dynamics of constrained rigid bodies. The modular, versatile and systematic formulation presented here is computationally efficient and has many applications in the studies of the human neuro-musculoskeletal system, robotic systems and humanoids, as well as clinical and sports biomechanics applications. Computer simulations are provided to demonstrate the feasibility and effectiveness of the methodology.

Wetting behavior of water on silicon carbide polar surfaces

Technically important wide band-gap semiconductors such as GaN, AlN, ZnO and SiC are crystallized in polar structures.

The effect of N-acetyl-glucosamine on stratum corneum desquamation and water content in human skin

Alpha-hydroxy acids have been used topically to treat skin for both dermatological and cosmetic problems for many years. Though there are many known benefits of the use of alpha-hydroxy acids on skin, there have been recent reports that topical treatments with alpha-hydroxy acids increase skin damage resulting from UVB. Additionally, high concentrations of alpha-hydroxy acids by themselves have also been found to cause skin irritation. In order to find alternatives to alpha-hydroxy acids, we investigated a variety of amino sugar compounds that were previously reported to inhibit the reaggregation of dissociated corneocytes by modulating cellular adhesion. In vivo, we observed that topical treatments with a formulation containing N-acetyl-glucosamine (NAG) led to an increase in skin moisturization, a decrease in skin flakiness, and the normalization of stratum corneum exfoliation. In vitro, we observed an upregulation of differentiation markers, keratin 10 and involucrin, in keratinocytes treated with NAG. CD44 is a lectin cell adhesion molecule that is also expressed in keratinocytes. Amino sugars such as NAG may competitively bind to CD44, modulating keratinocyte cellular adhesion. We hypothesize that these amino sugars modulate keratinocyte cellular adhesion and differentiation, leading to the normalization of stratum corneum exfoliation. We propose the use of amino sugars such as NAG as alternative compounds to replace the use of alpha-hydroxy acids in skin care.

Normal human keratinocytes pretreated with damaged mRNA are resistant to UVB damage and exhibit increased DNA repair

Treatment of normal human keratinocytes with UVC-irradiated rabbit globin mRNA 24 h before and after UVB exposure increased the survival of the human keratinocytes. We also observed that UVC-damaged mRNA reduced the formation of sunburn cells in skin models. We next tested the effects of UVC-damaged mRNA on cellular repair of DNA. DNA repair was evaluated using 2 assay methods. The first method used a damaged plasmid that is transfected back into the cell where it is repaired by the host cell repair mechanism. In these experiments, we observed that externally added UVC-damaged rabbit globin mRNA enhanced the repair of a plasmid transfected into the host keratinocyte cells. The second method used to determine the effects on DNA repair was direct immunostaining for thymidine-thymidine dimers (TT dimers) in histological sections of the skin models. Skin models were irradiated with UVB and then fixed immediately or after 24 h and stained for TT dimers. UVB irradiation immediately caused an increase in the number of stained keratinocytes in the skin. The number of stained cells decreased in skin fixed 24 h after UVB. This is due to repair of the TT dimers and their removal. Sections of skin models pretreated with UV-damaged mRNA exhibit greater removal of these TT dimers after 24 h. The above evidence suggests that damaged mRNA can trigger a host cell DNA repair pathway.

Temperature-jump investigations of the kinetics of hydrogel nanoparticle volume phase transitions

The dynamics of the deswelling and swelling processes in thermoresponsive poly-N-isopropylacrylamide (pNIPAm) hydrogel nanoparticles have been studied by using time-resolved transmittance measurements, in combination with a nanosecond laser-induced temperature-jump (T-jump) technique. A decrease in the solution transmittance associated with deswelling of the particles has been observed as the solution temperature traverses the volume phase transition temperature of the particles. Upon inducing the T-jump, the deswelling transition only occurs in a small percentage (<10%) of the particle volume, which was found to be a thin periphery layer of the particles. The particle deswelling occurs on the microsecond time scale, and as shown previously, the collapse time can be tuned via adding small amounts of hydrophobic component to the particle shell. In contrast, the reswelling of the particles was thermodynamically controlled by bath equilibration, and only small differences in particle reswelling kinetics were found due to sluggish heat dissipation (millisecond time scale) from the sample cell.

Human keratinocytes respond to osmotic stress by p38 map kinase regulated induction of HSP70 and HSP27

Human skin is exposed to an environment that varies in humidity from 100 to 0%, leading to seasonal variations in the condition of the skin. Exposure to a low humidity environment creates an osmotic gradient across the stratum corneum, which is known to modulate cutaneous barrier function. Heat shock proteins protect against stress-induced destabilization of proteins. We investigated whether osmotic shock (sorbitol) induced a heat shock protein response in normal human keratinocytes, and used heat shock as a positive control. Both heat shock and osmotic stress (200 and 300 mM sorbitol) clearly induced heat shock proteins 70 and 27 mRNA levels. The induction of heat shock protein 70 mRNA levels by osmotic stress peaked at 16 h and persisted until 24 h, whereas upregulation of heat shock protein 70 mRNA levels by heat peaked at 2 h and returned to baseline levels by 6 h. Sorbitol also increased heat shock protein 70 levels in a concentration-dependent manner. The kinetics of heat shock protein 27 mRNA induction by osmotic stress and heat were similar with peak induction at 6 h. The mitogen activated protein kinase family of proteins plays an important part in the coordination of gene responses to various stress conditions. We have demonstrated that the p38 mitogen activated protein kinase was strongly activated by 200 mM and 300 mM sorbitol. The specific p38 mitogen activated protein kinase inhibitor PD169316 almost completely blocked heat shock protein 70 mRNA induction by 200 mM and 300 mM sorbitol and completely suppressed heat shock protein 27 mRNA induction with 200 mM sorbitol. PD169316 also counteracted upregulation of heat shock protein 70 levels by sorbitol. These data indicate that keratinocytes respond to osmotic stress by p38 mitogen activated protein kinase regulated induction of heat shock proteins. This molecular pathway may be relevant for the mechanisms regulating the response of human skin to variations in environmental humidity.

Interfacial nonradiative energy transfer in responsive core-shell hydrogel nanoparticles

Fluorescently labeled core-shell latex particles composed mainly of the thermoresponsive polymer poly-N-isopropylacrylamide (p-NIPAm) have been synthesized such that an energy transfer donor (phenanthrene) and an energy transfer acceptor (anthracene) are covalently localized in the core and shell, respectively. When the thermally induced particle deswelling is interrogated by photon correlation spectroscopy (PCS), a continuous (non-first order) phase transition is observed. Conversely, when the nonradiative energy transfer (NRET) efficiency is used to probe the collapse of these same particles, the phase transition event is observed to occur over a much smaller temperature range and approaches first-order (discontinuous) behavior. Furthermore, core-shell particles with differing shell thicknesses display identical phase transition temperatures when PCS is used to monitor the transition, while NRET measurements show a clear increase in collapse temperature as the shell thickness is increased. These apparently contradictory results are discussed in terms of a radial phase coexistence that exists in the microgel particles, which arises from a similarly radial inhomogeneity in the cross-linker concentration. The prospects for the NRET technique as a molecular-scale probe of nanostructured microgels are also discussed.

Tunable swelling kinetics in core--shell hydrogel nanoparticles

Thermoresponsive, core--shell poly-N-isopropylacrylamide (p-NIPAm) nanoparticles (microgels) have been synthesized by seed and feed precipitation polymerization, and the influence of chemical differentiation between the core and shell polymers on the phase transition kinetics and thermodynamics has been examined. The results suggest that the core--shell architecture is a powerful one for the design of colloidal "smart gels" with tunable properties. To examine these materials, differential scanning calorimetry (DSC), (1)H NMR, and temperature-programmed photon correlation spectroscopy (TP-PCS) have been employed. These measurements show that the addition of small concentrations of a hydrophobic monomer (butyl methacrylate, BMA) into the particle shell produces large decreases in the rate of thermo-induced particle collapse. Conversely, these low levels of hydrophobic modification do not perturb the thermodynamics of the particle phase transition. When these results are examined in light of previous studies of macroscopic hydrogels, they suggest that the formation of a thin, stable skin layer at the particle exterior during the early stages of particle collapse is the rate limiting factor in particle deswelling. Finally, the hydrophobicity (BMA content) of the shell determines the magnitude of the hydrogel collapse rate, while the thickness of the BMA containing region does not impact the observed kinetics. Together, these results suggest that control over the kinetics of microgel deswelling events can be accomplished simply by modification of the particle periphery, and therefore do not require homogeneous modification of the entire polymer structure.

Successful separation of apoptosis and necrosis pathways in HaCaT keratinocyte cells induced by UVB irradiation

UVB irradiation can induce apoptotic, necrotic, and differentiation pathways in normal human keratinocytes. The present study was undertaken to determine at what dose of UVB each of these pathways is induced and whether these pathways are distinct or overlapping. We have observed that UVB induces fragmentation of DNA in human HaCaT keratinocytes, in a bimodal manner. Low doses of UVB, 5-20 mJ/cm2, increase the levels of apoptosis as shown by increased levels of fragmented DNA, Fas, PARP, and FasL protein, and the number of apoptotic cells as assessed by FACS analysis. At higher doses of UVB (20 and 30 mJ/cm2) the number of apoptotic cells becomes reduced, as does the amount of Fas, PARP, and FasL protein. At these higher doses, cell viability is decreased as measured by DNA synthesis (BrdU labeling) neutral red uptake, which represents an increasing necrotic phenotype. Expression of markers of keratinocyte differentiation, involucrin, keratin K1, and keratin K10, are also observed to decrease with increasing UVB dose. These changes are accompanied by a further increase in DNA fragmentation. We conclude that low doses of UVB (5-20 mJ/cm2) induced an apoptotic pathway, whereas increasing doses (greater than 20 mJ/cm2) of UVB produce a direct necrotic effect and inhibit terminal differentiation.

[A method of preparing the section of eye tissue for transmission electron microscopy]

A method of preparing the section of eye tissue for transmission electron microscopy (TEM) is recommended. The tissue was prefixed with a mixed solution of 4% paraformaldehyde and 2.5% glutaraldehyde and followed by softening in 3% EDTA solution for 20 minutes, then the tissue was fixed in 1% osmium tetroxide, dehydrated in series acetone, infiltrated in Epox 812 for a longer, and embeded. Ultrathin sections were cut with glass knives or diamond knife, stained with uranyl acetate and lead citrate and examined with H600-IV. The advantage of this method is that the ultrastructures of tissues are well preserved without any damage and distortion. The main points of the procedure of preparation have been discussed.

[The standardized techniques for preparing samples used in pathologic diagnostic transmission electron microscopy]

Transmission electron microscopy (TEM) has been used widespreadly in the field of diagnostic pathology. Based on the practical domestic condition and aimed at fully satisfying the needs of the pathologic diagnostic TEM, a set of standardized techniques were established for preparing different kinds of samples. The techniques included the preparation and storage of fixatives and embedding media, the requirement of sampling, the 5 h and 24 h embedding procedures for fresh specimens, the embedding procedure for suspension specimens and specimens collected from fine needle aspiration biopsy, as well as the procedures for preparing samples taken from paraffin embedded blocks or paraffin sections. In practical use, we found that the advantage of these techniques was that the ultrastructures of the tissues and cells were well preserved and they perfectly met the needs for diagnosis of tumors, kidney diseases, et al. The main points of the standardized techniques have been discussed in detail in this paper.

[Effects of smoking on interleukin-2 and its receptor system in human peripheral blood]

42 healthy male smokers and 42 healthy male nonsmokers matched in age and life style were strictly chosen into the study from Beijing urban and rural areas. Peripheral blood mononuclear cells(PBMCs) were separated and then stimulated by PHA under 37 degrees C, 5% CO2 condition. Immunochemical methods were applied in testing the synthesis of interleukin 2(IL-2) and the expression of its membrane receptor (mIL-2R) and the level of soluble receptor (sIL-2R) in serum. The results showed that when compared with nonsmokers, stimulated PBMC from smokers had significant higher percentage of mIL-2R positive cells (P < 0.05) in vitro. Levels of sIL-2R in serum of smokers were also significantly higher than those of nonsmokers (P < 0.05). The percentage of IL-2 secrete cells of smokers had higher tendency (P = 0.08). These data indicated that the immune function of smokers and nonsmokers are different concerning the IL-2 and its receptor system.

[Ultrastructural observation of SC1001-sodium on brain neurons kindled seizures by coriaria lactone in rabbits]

The ultrastructural changes of hippocampus and cerebral cortex neurons were derived from the rabbits kindled by coriaria lactone and from the kindled rabbits after treatment with SC1001 Na. The results of experiment showed that the hippocampus and cerebral cortex neurons in the kindled group had some degenerative changes, such as the swelling mitochondria, dilated rough endoplasmic reticulum and Golgi complexes when the injuries of neurons were not serious, but the seriously injured neurons were subjected to rupture of the cell membrane and solution of most organella, with only a small amount of degenerative organella. In the group treated with SC1001 Na, the ultrastructure of brain neurons demonstrated a tendency of recreation to normal which showed that SC1001 Na had cured many of the degenerative brain cells. This suggested that active treatment is very important for the epileptic patients.

[Observation of monoclonal antibody E4B7D5 inhibitory effect on leptospiral adherence using scanning electron microscope]

BALB/c mice were immunized intraperitoneally with outer envelopes of serogroup icterohaemorrhagiae lai serovar strain 017 leptospires. Monoclonal antibody (McAb) E4B7D5 against outer envelopes (IgG1, agglutinating titre 1:25,600) was produced by hybridoma technique. Passive immunoprotection experiments have demonstrated the immunoprotection of McAb E4B7D5 against strain 017 leptospires. Effect of McAb E4B7D5 on leptospiral adherence to the surface of normal human pulmonary embryonic fibroblasts was observed by using scanning electron microscope. The results indicated that the leptospiral adherence noted in various agglutinating titre McAb E4B7D5 groups was less frequent than that in the three control groups. It was concluded that the inhibitory effect of McAb E4B7D5 on leptospiral adherence may play a role in the immunoprotection.