4D printing of biodegradable elastomers with tailorable thermal response at physiological temperature.

4D printing has a great potential for the manufacturing of soft robotics and medical devices. The alliance of digital light processing (DLP) 3D printing and novel shape-memory photopolymers allows for the fabrication of smart 4D-printed medical devices in high resolution and with tailorable functionalities. However, most of the reported 4D-printed materials are nondegradable, which limits their clinical applications. On the other hand, 4D printing of biodegradable shape-memory elastomers is highly challenging, especially when transition points close to physiological temperature and shape fixation under ambient conditions are required. Here, we report the 4D printing of biodegradable shape-memory elastomers with tailorable transition points covering physiological temperature, by using poly(D,L-lactide-co-trimethylene carbonate) methacrylates at various monomer feed ratios. After the programming step, the high-resolution DLP printed stents preserved their folded shape at room temperature, and showed efficient shape recovery at 37 °C. The materials were cytocompatible and readily degradable under physiological conditions. Furthermore, drug-loaded devices with tuneable release kinetics were realized by DLP-printing with resins containing polymers and levofloxacin or nintedanib. This study offers a new perspective for the development of next-generation 4D-printed medical devices.

Ischemic heart disease and early diagnosis. Study on the predictive value of 2D strain.

INTRODUCTION: Two-dimensional strain echocardiography (2D-SE) quantifies left ventricular global longitudinal strain (GLS) and global circumferential strain (GCS). Our aim was to test 2D-SE during dipyridamole stress echocardiography (Dipy-Stress) in patients with non-diagnostic result, checking by way of coronary CT angiography (CCTA) the possible presence of coronary artery disease (CAD). METHODS: Over twenty-four months 65 consecutive patients with non-diagnostic Dipy-Stress were studied by 2D-SE and by CCTA. GCS and GLS at rest and after stress were compared according to data derived from CCTA. CAD was graded as significant (stenosis ≥50%), mild (stenosis between 15 and 50%) or absent (stenosis <15%). CCTA was defined as "positive" in presence of mild CAD and "negative" in absence of stenoses. Furthermore, Δ strain was defined as follows: [(stressS-restS)/restS]×100. RESULTS: GCS at rest and after stress was similar in CCTA-positive (26±5% and 27±5% respectively) and CCTA-negative groups (27±3% and 28±3% respectively). GLS at rest was significantly reduced (P<0.0001) in CCTA-positive (23±3%) compared to CCTA-negative group (25±2%). GLS after stress was lower (P<0.0001) in CCTA-positive group (20±3%) than CCTA-negative one (26±2%). A significant reduction (P<0.0001) of GLS at rest versus after stress was found in positive-CCTA group. ΔGLS showed a significant decrease (P<0.0001) in CCTA-positive (-10±8%) compared to CCTA-negative (4.4±5.8%) group. ROC analysis of ΔGLS showed high accuracy (area under the ROC curve 0.916, 95% CI: 0.820-0.970) in distinguishing positive and negative CCTA groups. CONCLUSIONS: 2D-SE during Dipy-Stress allows, in case of non-diagnostic test, identification of mild-CAD with high sensitivity and specificity.

Superparamagnetism in iron-doped CeO2-y nanocrystals.

We have measured the magnetization of undoped and Fe(2+/3+) doped CeO(2-y) nanocrystals at various temperatures and magnetic fields. The Stoner condition N(0)I > 1 is multiply fulfilled in the case of nano-CeO(2-y), favoring the band ferromagnetism approach. In the case of Fe-doped samples, the magnetization versus magnetic field dependence is well fitted with a weighted Langevin function. A blocking temperature of about 20 K is obtained both from the ZFC/FC curves and from the coercive field against temperature dependence. The temperature and field dependence of the magnetization clearly shows the presence of nanosized particles which exhibit superparamagnetic behavior.

Cognitive-behavior therapy vs exposure therapy in the treatment of PTSD in refugees.

The present study investigated the efficacy of cognitive-behavior therapy (CBT) and exposure therapy (E) in the treatment of post-traumatic stress disorder (PTSD) in refugees. Sixteen outpatients fulfilling the DSM-IV criteria for PTSD were randomized to one of the two treatments. Assessor and self-report measures of PTSD-symptoms, generalized anxiety, depression, quality of life and cognitive schemas were administered before and after treatment, and at a 6-month follow-up. The patients were treated individually for 16-20 weekly sessions. The results showed that both treatments resulted in large improvements on all the measures, which were maintained at the follow-up. There was no difference between E and CBT on any measure. E and CBT led to a 48 and 53% reduction on PTSD-symptoms, respectively, a 49 and 50% reduction on generalized anxiety, and a 54 and 57% reduction on depression. The results were maintained at the 6-month follow-up. The conclusion that can be drawn is that both E and CBT can be effective treatments for PTSD in refugees.

Exposure counterconditioning (EC) as a treatment for severe PTSD and depression with an illustrative case.

Cognitive behavioral therapies have strong empirical support as the treatments of choice for PTSD. Still, a significant proportion of the patients retain distressing PTSD symptoms after treatment. A treatment named Exposure Counterconditioning (EC), based on Wolpe's (1995, Theories of behaviour therapy (pp. 23-57). Washington, DC: American Psychological Association) reciprocal inhibition theory and Pavlovian conditioning mechanisms (Baldwin & Baldwin, 1986, Behavior principles in everyday life (pp. 41-42). New Jersey: Prentice-Hall) is presented. The EC treatment is proposed as an addition to the established treatments for PTSD. A case study from which the EC treatment was first developed is illustrated. The patient suffered from severe PTSD and depression. The EC treatment was effective in eliminating the patient's PTSD and depression. Also, the patient's severe anger, guilt and dissociation were eliminated. The results and important clinical observations are discussed within an counterconditioning framework.