ABSTRACT
Children with chronic tic disorders (CTD), including Tourette syndrome (TS), have significantly reduced serum 25-hydroxyvitamin D [25(OH)D]. While vitamin D3 supplementation (VDS) may reduce tic symptoms in these children, its mechanism is unclear. The study aim was to investigate the effects and mechanisms of vitamin D deficiency (VDD) and VDS on TS model behavior. Forty 5-week-old male Sprague-Dawley rats were randomly divided into (n = 10 each): control, TS model, TS model with VDD (TS + VDD), or TS model with VDS (TS + VDS; two intramuscular injections of 20,000 IU/200 g) groups. The VDD model was diet-induced (0 IU vitamin D/kg); the TS model was iminodipropionitrile (IDPN)-induced. All groups were tested for behavior, serum and striatal 25(OH)D and dopamine (DA), mRNA expressions of vitamin D receptor (VDR), glial cell line-derived neurotrophic factor (GDNF), protooncogene tyrosine-protein kinase receptor Ret (c-Ret), and DA D1 (DRD1) and D2 (DRD2) receptor genes in the striatum. TS + VDD had higher behavior activity scores throughout, and higher total behavior score at day 21 compared with TS model. In contrast, day 21 TS + VDS stereotyped behavior scores and total scores were lower than TS model. The serum 25(OH)D in TS + VDD was < 20 ng/mL, and lower than control. Striatal DA of TS was lower than control. Compared with TS model, striatal DA of TS + VDD was lower, while in TS + VDS it was higher than TS model. Furthermore, mRNA expression of VDR, GDNF, and c-Ret genes decreased in TS model, and GDNF expression decreased more in TS + VDD, while TS + VDS had higher GDNF and c-Ret expressions. VDD aggravates, and VDS ameliorates tic-like behavior in an IDPN-induced model. VDS may upregulate GDNF/c-Ret signaling activity through VDR, reversing the striatal DA decrease and alleviating tic-like behavior.
ABSTRACT
Ceramics, often exhibiting important functional properties like piezoelectricity, superconductivity, and magnetism, are usually mechanically brittle at room temperature and even more brittle at low temperature due to their ionic or covalent bonding nature. The brittleness in their working temperature range (mostly from room down to cryogenic temperatures) has been a limiting factor for the usefulness of these ceramics. In this Letter, we report a surprising "low-temperature toughening" phenomenon in a La-doped CaTiO_{3} perovskite ceramic, where a 2.5× increase of fracture toughness K_{IC} from 1.9 to 4.8 MPa m^{1/2} occurs when cooling from above room temperature (323 K) down to a cryogenic temperature of 123 K, the lowest temperature our experiment can reach. In situ microscopic observations in combination with macroscopic characterizations show that this desired but counterintuitive phenomenon stems from a reentrant strain-glass transition, during which nanosized orthorhombic ferroelastic domains gradually emerge from the existing tetragonal ferroelastic matrix. The temperature stability of this unique microstructure and its stress-induced transition into the macroscopic orthorhombic phase provide a low-temperature toughening mechanism over a wide temperature range and explain the observed phenomenon. Our finding may open a way to design tough ceramics with a wide temperature range and shed light on the nature of reentrant transitions in other ferroic systems.
ABSTRACT
BACKGROUND: To compare the effect of loteprednol suspension eye drops after corneal transplantation with the effect of prednisolone acetate eye drops. METHODS: A total of 234 patients (234 eyes) who underwent penetrating keratoplasty (PKP) and lamellar keratoplasty (LKP) were retrospectively included. Patients who received 1 % prednisolone acetate eye drops were defined as 1 % prednisolone acetate eye drop group (n = 96), and patients who received 0.5 % loteprednol suspension eye drops were defined as 0.5 % loteprednol suspension eye drop group (n = 138). RESULTS: 35 cases in 1 % prednisolone acetate eye drops group and 27 cases in 0.5 % loteprednol suspension eye drops group developed corticosteroid-induced ocular hypertension, and were defined as prednisolone acetate group and loteprednol group. No significant differences were observed in the average intraocular pressure (IOP) at 1 week, 1 month, 3 months or 12 months postoperatively. There were significant differences in the average IOP between the two groups at 6 months postoperatively (P = 0.001). There were no significant differences in the average best corrected visual acuity (BCVA) at 1, 3 and 12 months postoperatively between two groups. The average 6-month postoperative BCVA was significantly higher in the prednisolone acetate group than the loteprednol group (P < 0.05). There were no significant differences in the postoperative graft rejection rates between the two groups (P > 0.05). CONCLUSIONS: 0.5 % loteprednol suspension eye drops may be considered for long-term use after corneal transplantation.
