Radical Polymers as Anodic Charge Extraction Layers in Small Molecule Organic Photovoltaic Devices

Organic photovoltaic (OPV) devices based on the copper (II) phthalocyanine(CuPc)/ fullerene(C60) system are an innovative photovoltaic technology optimal for situations requiring low-cost, transparent, and flexible devices. Furthermore, the high degree of reproducibility of this system allows for the ready study of new OPV technologies. Here, we have used this system to elucidate systematic structure-property-performance relationships for a new OPV anode modifier. The addition of interfacial modifier materials between the organic CuPc/C60 layers and the metallic anode drastically can improve efficiency. Radical polymers are a class of polymers with aliphatic backbones and pendent stabilized radical groups. Here, we utilize poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) (PTMA) to examine the feasibility of radical polymers as anode modifiers. OPV devices utilizing a PTMA thin film deposited onto an ITO substrate (anode) with subsequent CuPc and C60 active layers followed by a BCP cathode modifier and an aluminum layer (cathode) were fabricated using thermal evaporation. Device performance was evaluated by measuring current density as a function of voltage during simulated solar radiation. Addition of a thin layer of PTMA between the ITO and CuPc layers increased device power conversion efficiency to approximately 0.95% from a control of 0.57%, likely due to enhancement of the crystal structure of the CuPc layer. The addition of interfacial modifiers significantly increases the overall efficiency, and consequently, viability of CuPc/C60 OPV devices, and this logic should be extendable to a myriad of other polymer based solar cell designs

Keuzestress!?

In de media en de sociologie wordt steeds vaker de indruk gewekt dat hedendaagse individuen aan stress en frustratie ten onder gaan vanwege hun schijnbaar onbeperkte keuzevrijheid. Maar is dat zo? Mensen blijken keuzestress bij hun alledaagse keuzes op drie manieren te ondervangen

Spontaneous externalization of a ventriculoperitoneal shunt tip through the navel

The authors describe spontaneous externalization of a ventriculo-peritoneal shunt through the navel

Tradeoff between User Experience and BCI Classification Accuracy with Frequency Modulated Steady-State Visual Evoked Potentials

Steady-state visual evoked potentials (SSVEPs) have been widely employed for the control of brain-computer interfaces (BCIs) because they are very robust, lead to high performance, and allow for a high number of commands. However, such flickering stimuli often also cause user discomfort and fatigue, especially when several light sources are used simultaneously. Different variations of SSVEP driving signals have been proposed to increase user comfort. Here, we investigate the suitability of frequency modulation of a high frequency carrier for SSVEP-BCIs. We compared BCI performance and user experience between frequency modulated (FM) and traditional sinusoidal (SIN) SSVEPs in an offline classification paradigm with four independently flickering light-emitting diodes which were overtly attended (fixated). While classification performance was slightly reduced with the FM stimuli, the user comfort was significantly increased. Comparing the SSVEPs for covert attention to the stimuli (without fixation) was not possible, as no reliable SSVEPs were evoked. Our results reveal that several, simultaneously flickering, light emitting diodes can be used to generate FM-SSVEPs with different frequencies and the resulting occipital electroencephalography (EEG) signals can be classified with high accuracy. While the performance we report could be further improved with adjusted stimuli and algorithms, we argue that the increased comfort is an important result and suggest the use of FM stimuli for future SSVEP-BCI applications

The COPE-Trial-Communicating prognosis to parents in the neonatal ICU: Optimistic vs. PEssimistic: study protocol for a randomized controlled crossover trial using two different scripted video vignettes to explore communication preferences of parents of preterm infants.

BACKGROUND One of the numerous challenges preterm birth poses for parents and physicians is prognostic disclosure. Prognoses are based on scientific evidence and medical experience. They are subject to individual assessment and will generally remain uncertain with regard to the individual. This can result in differences in prognostic framing and thus affect the recipients' perception. In neonatology, data on the effects of prognostic framing are scarce. In particular, it is unclear whether parents prefer a more optimistic or a more pessimistic prognostic framing. OBJECTIVE To explore parents' preferences concerning prognostic framing and its effects on parent-reported outcomes and experiences. To identify predictors (demographic, psychological) of parents' communication preferences. DESIGN, SETTING, PARTICIPANTS Unblinded, randomized controlled crossover trial (RCT) at the Division of Neonatology of the University Medical Center Mainz, Germany, including German-speaking parents or guardians of infants born preterm between 2010 and 2019 with a birth weight < 1500 g. Inclusion of up to 204 families is planned, with possible revision according to a blinded sample size reassessment. INTERVENTION Embedded in an online survey and in pre-specified order, participants will watch two video vignettes depicting a more optimistic vs. a more pessimistic framing in prognostic disclosure to parents of a preterm infant. Apart from prognostic framing, all other aspects of physician-parent communication are standardized in both videos. MAIN OUTCOMES AND MEASURES At baseline and after each video, participants complete a two-part online questionnaire (baseline and post-intervention). Primary outcome is the preference for either a more optimistic or a more pessimistic prognostic framing. Secondary outcomes include changes in state-anxiety (STAI-SKD), satisfaction with prognostic framing, evaluation of prognosis, future optimism and hope, preparedness for shared decision-making (each assessed using customized questions), and general impression (customized question), professionalism (adapted from GMC Patient Questionnaire) and compassion (Physician Compassion Questionnaire) of the consulting physician. DISCUSSION This RCT will explore parents' preferences concerning prognostic framing and its effects on physician-parent communication. Results may contribute to a better understanding of parental needs in prognostic disclosure and will be instrumental for a broad audience of clinicians, scientists, and ethicists. TRIAL REGISTRATION German Clinical Trials Register DRKS00024466 . Registered on April 16, 2021

Young age at school entry and attention-deficit hyperactivity disorder-related symptoms during primary school : results of a prospective cohort study conducted at German Rudolf Steiner schools

Objectives Young age at school entry (ASE) for students has been related to their impaired mental health in higher grades. To avoid the negative health consequences of young ASE, preschool examinations and individual school entry deferral for young children are routinely performed by some school authorities. We aimed to investigate whether ASE was associated with attention-deficit hyperactivity disorder (ADHD)-related symptoms in pupils attending schools using a selective school enrolment procedure. Design Prospective open cohort study with baseline assessments at school entry and two follow-ups in the second and fourth grades. Setting Up to 128 Rudolf Steiner Schools (Waldorf Schools) located within Germany. Participants Of the 3079 children from whom data were gathered in the second or fourth grade, 2671 children born between 1 July 2001 and 31 October 2002 (age at baseline: mean 6.7, min 5.91, max 7.24 years, 50% girls) were selected for analysis to avoid bias introduced by individuals at the edges of the ASE distribution. Main outcome measures ADHD-related symptoms were assessed at school entry and second and fourth grades by parent-reported and teacher reported versions of the Strengths and Difficulties Questionnaire (Hyperactivity-Inattention Subscale). Results The agreement between parent-reported and teacher-reported symptoms was poor (intra-class correlation: 0.41 and 0.44 in second and fourth grade assessments, respectively). Regarding teacher reports, ASE was negatively associated with ADHD-related symptoms in the second grade (regression coefficient β=−0.66 per year, P=0.0006) and fourth grade (β=−0.56, P=0.0014). Associations remained after adjusting for potential confounders and pre-existing symptoms at baseline. Regarding parent reports, associations were markedly weaker in both grades (second grade: β=−0.22, P=0.12; fourth grade: β=−0.09, P=0.48).Conclusions Using a prospective study design and comprehensive adjustment for confounding and baseline symptoms, we confirmed prior evidence of the association between young ASE and teacher-reported ADHD symptoms in primary school