The role of colloidal plasmonic nanostructures in organic solar cells.

Plasmonic particles can contribute via multiple processes to the light absorption process in solar cells. These particles are commonly introduced into organic solar cells via deposition techniques such as spin-coating or dip-coating. However, such techniques are inherently challenging to achieve homogenous surface coatings as they lack control of inter-particle spacing and particle density on larger areas. Here we introduce interface assisted colloidal self-assembly as a concept for the fabrication of well-defined macroscopic 2-dimensional monolayers of hydrogel encapsulated plasmonic gold nanoparticles. The monolayers showed a pronounced extinction in the visible wavelength range due to localized surface plasmon resonance with excellent optical homogeneity. Moreover this strategy allowed for the investigation of the potential of plasmonic monolayers at different interfaces of P3HT:PCBM based inverted organic solar cells. In general, for monolayers located anywhere underneath the active layer, the solar cell performance decreased due to parasitic absorption. However with thick active layers, where low hole mobility limited the charge transport to the top electrode, the plasmonic monolayer near that electrode spatially redistributed the light and charge generation close to the electrode led to an improved performance. This work systematically highlights the trade-offs that need to be critically considered for designing an efficient plasmonically enhanced organic solar cell.

Scaling properties of the shear modulus of polyelectrolyte complex coacervates: a time-pH superposition principle.

We analyze the scaling properties of pH-dependent shear modulus spectra of complex coacervates made of weak polyanions and strong polycations. For the first time, we report on a "time-pH superposition principle". This principle implies that the charge density in complex coacervates made of not fully charged polyions only influences the time scale of the relaxation dynamics, but not the mechanisms of the underlying dynamics.

Supposedly identical microplastic particles substantially differ in their material properties influencing particle-cell interactions and cellular responses.

Microplastics and its putative adverse effects on environmental and human health increasingly gain scientific and public attention. Systematic studies on the effects of microplastics are currently hampered by using rather poorly characterised particles, leading to contradictory results for the same particle type. Here, surface properties and chemical composition of two commercially available nominally identical polystyrene microparticles, frequently used in effect studies, were characterised. We show distinct differences in monomer content, ζ-potentials and surface charge densities. Cells exposed to particles showing a lower ζ-potential and a higher monomer content displayed a higher number of particle-cell-interactions and consequently a decrease in cell metabolism and proliferation, especially at higher particle concentrations. Our study emphasises that no general statements can be made about the effects of microplastics, not even for the same polymer type in the same size class, unless the physicochemical properties are well characterised.

Spectral field mapping in plasmonic nanostructures with nanometer resolution.

Plasmonic nanostructures and -devices are rapidly transforming light manipulation technology by allowing to modify and enhance optical fields on sub-wavelength scales. Advances in this field rely heavily on the development of new characterization methods for the fundamental nanoscale interactions. However, the direct and quantitative mapping of transient electric and magnetic fields characterizing the plasmonic coupling has been proven elusive to date. Here we demonstrate how to directly measure the inelastic momentum transfer of surface plasmon modes via the energy-loss filtered deflection of a focused electron beam in a transmission electron microscope. By scanning the beam over the sample we obtain a spatially and spectrally resolved deflection map and we further show how this deflection is related quantitatively to the spectral component of the induced electric and magnetic fields pertaining to the mode. In some regards this technique is an extension to the established differential phase contrast into the dynamic regime.

Experimental evidence of the electrostatic contribution to the bending rigidity of charged membranes.

We address the issue of the origin of the bending rigidity of a charged membrane formed from amphiphilic molecules. Electrostatic effects are investigated by direct measurement of the force necessary to deform a catanionic membrane as function of the ionic strength of the medium by means of an atomic force microscope (AFM). Using continuum mechanical modeling of membrane deformation, we derive the bending rigidity of the catanionic membranes and monitor for the first time its decrease in response to increasing salt concentration.

Bacterial protein patterning by micro-contact printing of PLL-g-PEG.

Biomimetic micro-patterned surfaces of three S-layer (fusion) proteins, wild type (SbpA), enhanced green fluorescence protein (SbpA-EGFP) and streptavidin (SbpA-STV), were built by microcontact printing of poly-L-lysine grafted polyethylene glycol (PLL-g-PEG). The functionality of the adsorbed proteins was studied with atomic force microscopy and fluorescence microscopy. Atomic force microscopy (AFM) measurements showed that wild-type SbpA recrystallized on PLL-g-PEG free areas, while fluorescent properties of SbpA-EGFP and the interaction of SbpA-streptavidin heterotetramers with biotin were not affected due to the adsorption on the micro patterned substrates.

Direct method to study membrane rigidity of small vesicles based on atomic force microscope force spectroscopy.

Mechanical properties of lipidic membranes such as their bending rigidity are governing liposome morphology and play an important role in processes like membrane fusion and adhesion. Force versus deformation measurements are the most direct means to determine this, but so far experimental data is scarce and mainly stems from techniques that are limited to giant vesicles. We present atomic force microscope force spectroscopy as a method allowing force-deformation measurements of submicron vesicles. Bending rigidities of small unilamellar dipalmitoylphosphatidylcholine (DPPC) liposomes (R<200 nm) can be derived from the force-deformation data using analytical models based on shell theory and are in good agreement with independent measurements.

Expression of DNA excision-repair-cross-complementing proteins p80 and p89 in brain of patients with Down Syndrome and Alzheimer's disease.

Although deficient DNA repair was proposed for neurodegenerative disorders including Down syndrome (DS), repair proteins for nucleotide excision repair have not been studied in brain yet. As one of the hypotheses for the pathogenesis of brain damage in DS and Alzheimer's disease (AD), is oxidative stress, and cells of patients with DS were shown to be more susceptible to ionizing irradiation. We decided to study expression of excision repair-cross-complementing (ERCC) gene products, proteins 80 and 89, representatives of repair genes known to be involved in the repair of different types of DNA damage. ERCC2-protein 80 kDa and ERCC3-protein p89 were determined in five individual brain regions of controls, aged DS and AD patients. Although different in the individual regions, DNA repair proteins were consistently higher in temporal and frontal lobes of patients with DS and higher in all brain regions of patients with AD. Our results are the first to describe DNA repair gene protein patterns in human brain regions providing the basis for further studies in this area. We showed that DNA repair genes ERCC2 and ERCC3 (excision-repair-cross-complementing) for nucleotide excision repair were increased at the protein level with the possible biological meaning that this increase may be compatible with and indicate ongoing (oxidative?) DNA damage.

Cortical circulation of long bones.

Intravascular injections of India ink in the femora of adult dogs revealed the existence of two distinct vascular systems in the cortex. One courses through the entire thickness of the cortex and is a regular, longitudinal network of uniform capillaries which is in continuity with the periosteal and endosteal networks. Once the haversian systems form a second network appears, radiating from the bone marrow. That system, primarily transverse, anastomoses in the haversian canals with the capillaries of the first system. Therefore, the merging of the two networks occurs primarily in the middle layer of the cortex. The direction of the arterial blood flow in the mature animal is predominantly centrifugal, while the venous drainage is centripetal. In the immature animal, the contribution of the periosteal network is much greater. Because the two cortical systems are profusely anastomosed with each other and with the periosteal and endosteal circulatory networks, the blood can flow in either direction, depending on physiological conditions.

Recurrent posterior instability of the shoulder.

Seven cases of recurrent posterior instability of the shoulder were reviewed, three with recurrent subluxation and four with recurrent posterior dislocations. All were treated surgically, one by inverted Putti-Platt, one by glenoplasty and five by posterior bone block procedures. The follow-up goes from three to 17.5 years (mean 8.5 years). Clinical history and physical examination were the most accurate diagnostic methods. There were three excellent, one fair, and one poor results with two failures. The poor result and failure cases are due to technical errors, particularly because of wrong positioning of the graft in posterior bone block procedures. We suggest a bone graft with a projection of at least 15 mm beyond the glenoid rim to obtain a good result with this technique. Osteoarthritis does not seem to develop at long-term in our patients even with a poor result except for those with iatrogenic origin. The functional results are stable over time except for patients with osteoarthritis.

[Rupture of the extensor apparatus of the knee]. / Des ruptures de l'appareil extenseur du genou : A propos de 45 cas.

The authors describe 45 cases of rupture of the extensor apparatus of the knee (excluding fracture of the patella).Some new ideas are put forward concerning the frequent cause by road accidents and the contribution of certain predisposing features which cause degenerative changes of the tendon.Operation was performed in all cases. The extensor apparatus was reconstructed by suture, cerclage or reinsertion, together with the use of procedures described by Mac Laughlin and Scuderi.The results are presented in detail. 90% are very good or good but complications during operation or in the post operative phase were frequent and occurred in 27% of the cases.

[Shoulder radiographic evaluation. Radiographic examination of shoulder and scapular girdle trauma (author's transl)]. / Le complet radiologique de l'épaule. Approche radiologique des traumatismes de l'épaule et de la ceinture scapulaire.

The Shoulder Radiographic Evaluation ("Complet Radiologique de l'Epaule") is completed by four positions: Standard A-P, Axillary axial view, Profil of the scapula, A-P in arm abduction. This paper focuses on the radiographic examination of the components of scapular girdle and shoulder articular complex. Several positions are described as routine positions in trauma. This radiographic procedure is of helpful interest for clinical, therapeutic and forensic applications.

[Tuberculous trochanteritis: value of ultrasonic diagnosis and x-ray computed tomography. Apropos of 3 cases]. / La trochantérite tuberculeuse: intérêt de l'échographie et de la scanographie. A propos de trois observations.

Trochanteritis is a rare osteoarticular site of tuberculosis which initiates within the serous bursa of the gluteus maximus and extends only secondarily to the greater trochanter. Its course is a slow one. Diagnosis is usually delayed but should be made earlier by the use of ultrasound and the CT scan. These provide details of the bone remodelling detected on standard radiography, and show the presence of a variable fluid collection of a topography that attaches it to the serous bursa of gluteus maximus, and provides a guide to diagnostic needle puncture for biopsy. Overall data allow improved adaptation of medico-surgical treatment.

[X-ray computed tomography in the study of anterior instability of the shoulder. Study of a series of 23 cases]. / Apport de la scanographie dans l'étude de l'instabilité antérieure de l'épaule. Etude d'une série de 23 cas.

The place of standard CT scan imaging more particularly when combined with double contrast arthrography, is defined in the preoperative screening of patients with anterior instability of the shoulder. The joint scan provides complete data on the anatomic elements of the shoulder lesion, particularly with reference to the glenoidal labrum and the anterior capsular structure. It is also of major diagnostic value in painful subluxations.

[Os acromiale: significance--diagnosis--pathology. Apropos of 28 cases including 2 with fracture separation]. / L'os acromial: signification--diagnostic--pathologie. A propos de 28 observations dont 2 décollements-fractures.

In relation to two rare cases of fracture-separation of the os acromiale, 26 other cases of defective epiphysial fusion were studied. A review of the literature confirmed the rarity of this anomaly of the scapula which predisposes to subacromial impingement and rotator cuff rupture. The diagnosis is radiological. It requires both an antero-posterior and an axillary view which, together with a CT scan, precisely shows the os acromiale. It should be distinguished from a fracture of the acromion to avoid unnecessary immobilisation and post-traumatic effects. Degenerative changes provoke an impingement syndrome, the surgical treatment of which must include arthrodesis of this ossicle.

[Paralysis of the serratus anterior muscle. Results of treatment of 12 cases including 9 surgically treated and a general review of the literature]. / La paralysie du grand dentelé. Résultat du traitement de 12 cas dont 9 opérés et revue générale de la littérature.

An analysis of the results of treatment in twelve cases of serratus anterior paralysis, nine of which were treated operatively, and a review of the literature has shown that, in lesions that fail with conservative treatment by physiotherapy, surgical treatment rapidly restores normal strength and function. Long follow-up, between 3 and 23 years, confirms the effectiveness and reliability of muscle transfers, particularly of pectoralis major.

[Fracture of the coracoid process (author's transl)]. / Fractures de l'apophyse coracoïde. A propos de 10 observations.

The authors have treated 10 cases of fracture of the coracoid process of the scapula. The case histories have been reviewed. The mechanism was an indirect one in most cases. Associated lesions such as fractures of the clavicle were frequent. The diagnosis may be difficult and special X-ray techniques were needed. In most of the cases, conservative treatment was indicated. Only one case associated with an acromio-clavicular dislocation was treated operatively.

[Microsurgical transplantation of bone tumors of uncertain prognosis in athymic nude mice]. / Transplantation microchirurgicale chez la souris nude athymique des tumeurs osseuses de pronostic incertain.

Eight cases of human bone or soft tissue tumours were transplanted to nude mice. After such transplants to nude mice which are immunologically deficient, the malignant tumors developed like benign tumours, but maintaining malignant cytological characteristics. The transplants of normal human tissues or of benign tumours decreased in size or remained stable. The technique allowed a change of an original diagnosis of osteosarcoma to a final diagnosis of chondrosarcoma. It made it possible to diagnose a benign osteoblastoma, the diagnosis of which was doubtful before the transplant between osteosarcoma and chondroblastoma. It was possible to diagnose the malignancy of a haemangiopericytoma of muscle. Two aggressive tumours--a non-ossifying fibroma and a giant-cell tumour--were rated as benign after transplantation. This technique also allowed a more precise diagnosis of the grade of one chondrosarcoma and one osteosarcoma. Finally, transplantation also made it possible to test the efficacy of chemotherapy. In a patient so treated, the extreme cell proliferation after transplantation to the nude mouse led to a change in the drugs administered.

[Simultaneous bilateral avulsion of the quadriceps and Achilles tendons in 1 limb and of the patellar tendon in the other in a hyperparathyroid patient on chronic hemodialysis]. / Avulsion bilatérale simultanée des tendons quadricipital et rotulien et rupture du tendon tricipital chez un hémodialysé hyperparathyroïdien.

A case of simultaneous rupture of three tendons is reported in a patient who had suffered a bilateral nephrectomy six years earlier and was on chronic haemodialysis. The quadriceps tendon and the patellar tendon were repaired surgically. The rupture of the tendo Achillis was left untreated. Six days later a parathyroidectomy was performed; nine months later recovery was excellent. A review of the literature has been made. The role of hyperparathyroidism in the strength of the bone-tendon junction is discussed.

[Technical development and radiological surveillance of the Schmitt minimadreporic uncemented total hip prosthesis. Evaluation of 275 arthroplasties with a follow-up of more than 6 years for the oldest cases]. / Conception technique et surveillance radiologique de la prothése totale de hanche non cimentée minimadréporique de D. Schmitt. Bilan de 275 arthroplasties avec un recul supérieur à 6 ans pour les cas les plus anciens.

The authors describe a porous-coated uncemented total hip prosthesis which has been used for more than six years: the Schmitt minimadreporic prosthesis. A homogenous series of 275 arthroplasties has been reviewed with a mean follow-up of three years and five months. The method of radiological assessment of the position of the femoral and acetabular components and their possible loosening is described in detail. Infection (0.72%) and aseptic loosening (1.8%) specific to this type of prosthesis was rare. For the series as a whole there were 92% of good, very good and excellent results and for 81 arthroplasties with a follow-up greater than four years the figure was 90%. The frequency of secondary displacement of the femoral component is emphasised, with 15 prostheses sinking downwards and 96 displacing into varus. Statistical analysis has shown the principal factors affecting the clinical result and has demonstrated the effect of resorption of the calcar in causing downward displacement of the femoral stem and insufficient filling of the medullary cavity on the development of varus angulation of the prosthesis.