Sequential processing: control of nanomorphology in bulk heterojunction solar cells

Bulk heterojunction organic photovoltaic devices based on poly[N-9'-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole) (PCDTBT)/[6,6]-phenyl C(70) butyric acid methyl ester (PC(70)BM) can be successfully fabricated by a sequential solution deposition process. When the top layer is deposited from an appropriate cosolvent, the PC(70)BM penetrates a predeposited bottom layer of PCDTBT during the spin-casting process, resulting in an interdiffused structure with a layer-evolved bulk heterojunction (LE-BHJ) nanomorphology. The PCDTBT:PC(70)BM LE-BHJ solar cells prepared with an optimized cosolvent ratio have comparable power conversion efficiency to the conventional BHJ solar cells. The nanomorphology of the optimized PCDTBT:PC(70)BM LE-BHJ mixture was found to have better vertical connectivity than the conventional BHJ material.     

Color-tunable electrophosphorescent device fabricated by a photo-bleaching method

We demonstrated an efficient color-tunable electrophosphorescent device fabricated by a photo-bleaching method. Electroluminescence studies indicate that excellent device performance can be achieved through efficient Förster energy transfer from the conjugated polymer to the iridium complexes by improving their miscibility. The use of a very low concentration of red phosphorescent dye and the easy degradation characteristics of conjugated structure of the red dopant enable color-tuning from red to green emission by a simple UV-irradiation process without a sacrifice of luminescent properties.tp     

Decolorization and COD reduction of UASB pretreated poultry manure wastewater by electrocoagulation process: a post-treatment study

The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material, time of electrolysis, current density, initial pH, and electrolyte concentration were further studied to optimize conditions for the post-treatment of UASB pretreated poultry manure wastewater. Preliminary tests conducted with two types of sacrificial electrodes (Al and Fe) resulted that Al electrodes were found to be more effective for both COD and color removals than Fe electrodes. The subsequent EC tests performed with Al electrodes showed that optimal operating conditions were determined to be an initial pH of 5.0, a current density of 15mA/cm(2), and an electrolysis time of 20min. The results indicated that under the optimal conditions, about 90% of COD and 92% of residual color could be effectively removed from the UASB effluent with the further contribution of the EC technology used as a post-treatment unit. In this study, the possible acute toxicity of the EC effluent was also evaluated by a static bioassay test procedure using guppy fish (Lebistes reticulatus). Findings of this study clearly indicated that incorporation of a toxicological test into conventional physicochemical analyses provided a better evaluation of final discharge characteristics.     

Excess epicardial fat mass misrepresented as cardiomegaly in dry-weight assessment of a dialysis patient

Obesity is a major health problem that has entered the nephrology community and is challenging our conventional management strategies. In this case report, we present a morbidly obese dialysis patient whom dry-weight assessment was disturbed by excess epicardial fat mass due to obesity. This case suggests that problems related to obesity seem not to be limited to dealing with obesity-associated kidney injury, chronic kidney disease and mortality, but also other concepts in nephrology such that, as described, excess epicardial fat mass related to morbid obesity in this patient erroneously suggested a high cardiothoracic index, and misled patient management. Interpretation of chest X-ray in dry-weight assessment should take into account the patient's body weight especially in obese cases and alternative diagnostic methods for correct determination of fluid status are highly needed.     

Electrical Graphene Aptasensor for Ultra‐Sensitive Detection of Anthrax Toxin with Amplified Signal Transduction

Detection of the anthrax toxin, the protective antigen (PA), at the attomolar (aM) level is demonstrated by an electrical aptamer sensor based on a chemically derived graphene field‐effect transistor (FET) platform. Higher affinity of the aptamer probes to PA in the aptamer‐immobilized FET enables significant improvements in the limit of detection (LOD), dynamic range, and sensitivity compared to the antibody‐immobilized FET. Transduction signal enhancement in the aptamer FET due to an increase in captured PA molecules results in a larger 30 mV/decade shift in the charge neutrality point (V_g,min) as a sensitivity parameter, with the dynamic range of the PA concentration between 12 aM (LOD) and 120 fM. An additional signal enhancement is obtained by the secondary aptamer‐conjugated gold nanoparticles (AuNPs‐aptamer), which have a sandwich structure of aptamer/PA/aptamer‐AuNPs, induce an increase in charge‐doping in the graphene channel, resulting in a reduction of the LOD to 1.2 aM with a three‐fold increase in the V_g,min shift.     

Oriented immobilization of antibodies with GST-fused multiple Fc-specific B-domains on a gold surface

We have constructed a novel platform for the oriented buildup of immunoglobulins on a gold surface for a surface plasmon resonance imaging microarray. To this end, genetically engineered glutathione S-transferase proteins bearing one, two, and three Fc-specific B-domains in protein G from Streptococci (GST-GB1, -GB2, and -GB3, respectively) were produced. In order to tether these GST-GBx proteins specifically, a novel glutathione-derivatized ligand (LA-GSH) was also synthesized from a biaminated tri(ethylene glycol) backbone. Each end of the backbone was further functionalized with a maleimide group for a glutathione modification and a lipoic acid for surface immobilization. The glutathione ligand demonstrated a negligible nonspecific protein adsorption toward other spectator proteins while showing a strong specific association toward GST-GBx proteins. This Fc-specific surface exhibited at least a 2-fold enhancement in the immunoglobulin density (from human and mouse) with its antigen capture capability totally conserved compared to a covalently tethered GBx proteins. A single antibody tethered on the GST-GB3 is estimated to capture two antigens (enhanced green fluorescent protein), and this antigen capture ratio seems to be the most efficient value ever observed.     

A High Aspect Ratio Serpentine Structure for Use As a Strain‐Insensitive,Stretchable Transparent Conductor

The development of strain‐insensitive stretchable transparent conductors (TCs) is essential for manufacturing stretchable electronics. Despite recent progress, achieving a high optoelectronic performance under applied strain of 50% continues to present a significant challenge in this research field. Herein, an ultratall and ultrathin high aspect ratio serpentine metal structure is described that exhibits a remarkable stretching ability (the resistance remains constant under applied strain of 100%) and simultaneously provides an excellent transparent conducting performance (with a sheet resistance of 7.6 Ω ^?1 and a transmittance of 90.5%). It is demonstrated that the highly stretchable transparent conducting properties can be attributed to the high aspect ratio feature. A high aspect ratio (aspect ratio of 17–367) structure permits facile deformation of the serpentine structure with in‐plane motion, leading to a high stretching ability. In addition, this structural feature avoids the classic tradeoff between optical transmittance and electrical conductance, providing a high electrical conductance without decreasing the optical transmittance. The practical utility of these devices is tested by using these TCs as stretchable interconnectors among LEDs or in wearable VOC gas sensors.     

Neither oxidized nor anti-oxidized low-density lipoprotein level is associated with atherosclerosis or mortality in hemodialysis patients

It is anticipated that oxidized low‐density lipoprotein (oxLDL) and anti‐oxLDL are associated with atherosclerosis and mortality. However, data on this issue are controversial and limited. We aimed to investigate the effect of these two markers on the extent and progression of atherosclerosis and mortality in a group of hemodialysis patients. In this prospective observational study with a follow‐up of 36 months, 124 hemodialysis patients were studied. Ninety‐five patients underwent carotid intima media thickness (CA‐IMT) measurement by B‐Mode ultrasonography both at baseline and at the end of the study. oxLDL and anti‐oxLDL were measured by enzyme‐linked immunosorbent assay. The extent and progression of CA‐IMT, along with overall and cardiovascular mortality, were assessed. The mean age at baseline was 54.0 ± 14.8 years, 57.3% male and 20% diabetic. The mean oxLDL and anti‐oxLDL levels were 8.11 ± 3.16 mU/L and 1.30 ± 0.31, respectively. Baseline mean CA‐IMT was 0.82 ± 0.20 mm. Fifteen patients died during a follow‐up period of 28.5 ± 6.6 months, 11 from cardiovascular causes. Only oxLDL, not anti‐oxLDL, was correlated with the extent of atherosclerosis at baseline. However, both had no role in the progression of atherosclerosis. Also, in unadjusted and adjusted models, both parameters were not associated with overall or cardiovascular mortality. Neither oxLDL nor anti‐oxLDL level is associated with the progression of atherosclerosis or mortality in hemodialysis patients.     

Continuous phase-shift lithography with a roll-type mask and application to transparent conductor fabrication

We report the development of a near-field optical nanolithography method using a roll-type phase-shift mask. Sub-wavelength resolution is achieved using near-field exposure of photoresist through a cylindrical phase mask, allowing dynamic and high throughput continuous patterning. As an application, we present the fabrication of a transparent electrode in the form of a metallic wire grid by using the roller-based optical lithography method. To fabricate a mesh-type metal pattern, a specific phase-shift mask was designed and critical experimental parameters were also studied. As a result, a transparent conductor with suitable properties was achieved with a recently built cylindrical phase-shift lithography prototype designed to pattern on 100?mm(2) of substrate area.     

Influence of grain boundaries and voids on the saturated magnetization in Fe/sub 3/O/sub 4/ films at a low magnetic field

We report the magnetic behaviors of Fe/sub 3/O/sub 4/ thin films grown by zero field growth (ZFG) and field growth (FG) techniques during the sputtering process. In FG conditions, an in situ 300 Oe field during growth is applied to a substrate, inducing an easy axis of magnetization. Structural observations obtained by high-resolution transmission electron microscopy measurements clearly depicted a significant reduction of the grain boundaries and voids in the Fe/sub 3/O/sub 4/ films grown under FG conditions, thus explaining the saturated magnetization of the Fe/sub 3/O/sub 4/ films at about 0.01 T. This behavior was expected due to a remarkable reduction of the antiferromagnetic exchange couplings between grains for FG conditions. In addition, the zero-field-cooled magnetization of the ZFG samples showed an abrupt change at about 285 K, confirming the existence of defects or other phases in the ZFG films.