Influences of dielectric constant and scan rate on hysteresis effect in perovskite solar cell with simulation and experimental analyses.

In this work, perovskite solar cells (PSCs) with different transport layers were fabricated to understand the hysteresis phenomenon under a series of scan rates. The experimental results show that the hysteresis phenomenon would be affected by the dielectric constant of transport layers and scan rate significantly. To explain this, a modified Poisson and drift-diffusion solver coupled with a fully time-dependent ion migration model is developed to analyze how the ion migration affects the performance and hysteresis of PSCs. The modeling results show that the most crucial factor in the hysteresis behavior is the built-in electric field of the perovskite. The non-linear hysteresis curves are demonstrated under different scan rates, and the mechanism of the hysteresis behavior is explained. Additionally, other factors contributing to the degree of hysteresis are determined to be the degree of degradation in the perovskite material, the quality of the perovskite crystal, and the materials of the transport layer, which corresponds to the total ion density, carrier lifetime of perovskite, and the dielectric constant of the transport layer, respectively. Finally, it was found that the dielectric constant of the transport layer is a key factor affecting hysteresis in perovskite solar cells.

[Correlation between referred pain distribution and acupoint sensitization in patients with intestinal diseases].

OBJECTIVE: To observe the correlation between referred pain distribution and acupoint sensitization in patients with intestinal diseases. METHODS: In clinical research, 443 patients from 8 hospitals were recruited, including the outpatients and inpatients of Crohn's disease (n=143), ulcerative colitis (n=108), chronic appendicitis (n=87) and other intestinal diseases (n=105). The site with tenderness on the body surface and the morphological changes of local skin were observed and recorded in the patients. Using a sensory tenderness instrument, the pain threshold at the sensitization point was measured in 60 patients with ulcerative colitis. In animal experiment, SD rats were used and divided into a enteritis group (n=8), in which the enteritis model were established, and a control group (n=3), in which no any intervention was given. After the injection of Evans blue (EB) at caudal vein, the blue exudation points on the body surface were observed and the distribution rule was analyzed statistically. RESULTS: The referred pain on the body surface in the patients with intestinal diseases was mainly located in the lower abdomen (93.9%, 416/443), the lumbar region (70.9%, 314/443) and the lower legs (33.0%, 146/443). The diameter of tenderness region was 1.5 to 2.5 cm. Compared with the region without sensitization, the pain threshold of the sensitization point in the patients with ulcerative colitis was reduced significantly (P<0.001). The referred pain on the body surface in the patients with appendicitis was located in the right lower abdomen (97.7%, 85/87), the waist and back (54.0%, 47/87) and the right lower limbs on the medial side (71.3%, 62/87). The tenderness region was 1 to 2 cm in diameter and was irregular in form. After modeling of enteritis in the rats, the EB exudation points were visible from T12 to L2. CONCLUSION: Intestinal diseases induce referred pain on the body surface where is the same as or adjacent to the location of the spinal segment corresponding to the affected intestinal section. These sensitization regions are related to the locations of acupoints.

[Correlation Between Referred Pain Region and Sensitized Acupoints in Patients with Stable Angina Pectoris and Distribution of Sensitized Spots in Rats with Myocardial Ischemia].

OBJECTIVE: To observe the correlation between the referred pain regions of stable angina pectoris (SAP) and the acupoints in coronary heart disease (CHD) patients and to investigate the rule of regional sensitized point distribution in rats. METHODS: A total of 1 046 CHD patients with SAP from 8 hospitals in China were recruited in the present study. The tenderness was palpated along the left and right chest, back, shoulder, upper limb, etc. by a specially-assigned researcher in each hospital. Among them, 77 patients accepted pain threshold (PT) measurement by using a hand-held esthesiometer. In animal experiments, 14 SD rats were subjected to occlusion of the left anterior descending branch of the left coronary artery for 4 h for establishing myocardial ischemia (MI) model, and other 4 normal rats were used as the sham-operation control group. Four hours after MI, all the rats accepted tail venous injection of 5% Evans blue (50 mg/kg) for examining the distribution of the blue dye exudation spots at the body surface where the mechanical PT was also detected by a von Frey. RESULTS: In 1 046 CHD patients, 987 (94.36%) were found to have at least one tenderness spot. The tenderness spots were found at the left chest (87.47%), right chest (13.67%), left arm (ulnar side, 41.30%), right upper limb (4.68%), left shoulder back (30.21%), right shoulder back (7.07%), etc., accompanied with rash or pigmentation, subcutaneous induration, cord-like tissue contracture, skin sag, etc. The mechanical PT level was significantly lower at the tenderness spots of the left upper limb than at non-tender points of the right upper limb in CHD patients (P<0.001). Tenderness and cutaneous abnormal changes in angor pectoris patients distributed mostly on the left chest, back, shoulder and upper limb, and some also on the right. Tender points scattered on, near or outside acupoints. A similar distribution of the blue exudation spots and lower mechanical PT spots were found in MI rats, but not in sham-MI rats. CONCLUSION: In the case of MI, a regular "referred sensitization" response frequently occurs in the dermatomere area innervated by the corresponding segments (T 1－T 5) in both CHD patients and MI rats, which may be closely associated with the formation of acupoints in ancient China.

[Recent progress of study on imbalance of Th17/Treg cells in aplastic anemia].

Aplastic anemia (AA) is an autoimmune disease characterized by destruction of hematopoietic tissue resulting in hyperfunction of effector T-lymphocytes. Recent studies indicate that Th17 and Treg cells are functionally antagonistic each other, and the increase of Th17 cells and decrease of Treg cells are closely related with AA. In vivo experiments showed that both anti-IL-17 treatment and Treg cell infusion can protect against immune-mediated bone marrow failure in mouse with AA. This review summarizes the recent progress of study on imbalance of Th17/Treg cells in AA, so as to explore the pathogenesis of AA and provide approach to clinical treatment. The main problems that are discussed in this review include biological characteristics of Th17/Treg cells, the regulation of Th17/Treg cell balance and related cytokines, the relationship between Th17/Treg cells and AA.