The purpose of the study was to assess the effect of autologous activated platelet-rich plasma on healing of a bone substitute - tricalcium phosphate hydroxyapatite in experimental long bone defects using an animal model.

The experiment involved an animal model of femoral defect. 24 Termond white rabbits were used in the study. We evaluated the effect of autologous platelet-rich plasma on tricalcium phos- phate using classical radiology, micro-CT studies, strength tests and histological evaluation.

Radiological and histological assessment did not show a beneficial effect of PRP together with a bone substitute in comparison to filling the defects only with bone replacement material. The only benefit of adding platelet-rich plasma to a bone substitute was shown in microCT imaging.

Autologous, activated platelet-rich plasma combined with hydroxyapatite tricalcium phos- phate has a positive effect on the remodeling of the newly formed bone tissue, increasing its density.

Introduction: Platelet-rich plasma (PRP) preparations can be used in bone tissue healing but there are numerous doubts among clinical orthopedists about effectiveness of this method.

Materials and methods: The studies were carried out in 12 rabbits of white termond breed. In operating room we operationally generated cylindrical, unicortical defects of the diameter of 4 mm in the middle of the shafts of both femurs. The defects in the left bones were left without filling and served as controls, and 0.7 ml of the ready-to-use PRP was administered to the defects in the right bones (experimental group). We evaluated the usefulness of the diagnostic methods applied: biomechanical tests, micro-CT tests, densitometry, typical radiology, macroscopic measurements, histopathological examinations.

Results: The macroscopic measurements showed a statistically significant increase in the dimension in the area of the right defect filled with PRP in relation to the control group. In experimented group, the assessment of the X-ray images showed the formation of a callus cuff around the defects. Densitometric examinations showed no statistically significant differences between defects in the experimental and control group. The analysis of the micro-CT examina- tions showed an increase in the total volume of the tissue examined (Vb) and the low density tissue fraction (Vb2) in the experimental group. The biomechanical examinations revealed signi- ficant decrease in the maximum breaking force (F max) necessary to break the bone in the experi- mental group in relation to the control group.

Conclusions: Platelet-rich plasma (PRP) stimulates bone formation in the area of bone defects and may accelerate bone regeneration.

We conducted pre-registered replications of 15 effects in the field of judgment and decision making (JDM). We aimed to test the generalizability of different classical and modern JDM effects, including, among others: less-is- better, anchoring, and framing to different languages, cultures, or current situations (COVID-19 pandemic). Replicated studies were selected and conducted by undergraduate psychology students enrolled in a decision-making course. Two hundred and two adult volunteers completed an online battery of replicated studies. With a classical significance criterion (p < .05), seven effects were successfully replicated (47%), five partially replicated (33%), and three did not replicate (20%). Even though research materials differed from the originals in several ways, the replication rate in our project is slightly above earlier reported findings in similar replication projects. We discuss factors that may underlie replication results (success vs. failure). We also stress the role of open science practices such as open data, open research materials, pre-registration, and registered reports in improving the replicability of results in the JDM field.