On the Role of Contact Resistance and Electrode Modification in Organic Electrochemical Transistors

Contact resistance is renowned for its unfavorable impact on transistor performance. Despite its notoriety, the nature of contact resistance in organic electrochemical transistors (OECTs) remains unclear. Here, by investigating the role of contact resistance in n‐type OECTs, the first demonstration of source/drain‐electrode surface modification for achieving state‐of‐the‐art n‐type OECTs is reported. Specifically, thiol‐based self‐assembled monolayers (SAMs), 4‐methylbenzenethiol (MBT) and pentafluorobenzenethiol (PFBT), are used to investigate contact resistance in n‐type accumulation‐mode OECTs made from the hydrophilic copolymer P‐90, where the deliberate functionalization of the gold source/drain electrodes decreases and increases the energetic mismatch at the electrode/semiconductor interface, respectively. Although MBT treatment is found to increase the transconductance three‐fold, contact resistance is not found to be the dominant factor governing OECT performance. Additional morphology and surface energy investigations show that increased performance comes from SAM‐enhanced source/drain electrode surface energy, which improves wetting, semiconductor/metal interface quality, and semiconductor morphology at the electrode and channel. Overall, contact resistance in n‐type OECTs is investigated, whilst identifying source/drain electrode treatment as a useful device engineering strategy for achieving state of the art n‐type OECTs.     

Penicillamine-induced myasthenia in chronic rheumatoid arthritis (author's transl)]

A myasthenic reaction developed after an average latency of seven to eight months in 12 female patients (average age 51 years) treated with penicillamine for chronic rheumatoid arthritis. In most of them only the purely ocular form was noted, but generalisation of various degrees also occurred. When penicillamine had been discontinued the myasthenic signs were almost always fully reversible, recurring once again when treatment with penicillamine was started. In some instances a transitory symptomatic treatment with cholinesterase inhibitors was necessary. The occurrence of the myasthenic signs in these circumstances is probably similar to the anti-basal membrane nephropathy induced by penicillamine.     

A new method of treatment for mallet finger. A preliminary report

An infant with a typical Edwards syndrome and a modal chromosome number of 46 is reported. In all cells analyzed one chromosome G was missing and an additional chromosome similar to a pair No. 16 was present. The phenotype of the child indicates that the extra element is a translocation between G and 18 chromosomes as in one case described previously.     

Penetration and flow of acrylic bone cement

Fixation of prosthetic joint components into bone is influenced by the degree of mechanical interdigitation of the acrylic into cancellous interstices. The rheology of polymerizing polymethylmethacrylate was studied by pressurizing acrylic bone cement with a piston apparatus to produce flow into cylindrical cavities one to 3 mm in diameter. The acrylic penetration per unit of applied pressure increased with increasing cavity diameter. This suggests that greater penetration should occur in cancellous bone containing larger interstitial cavities. More than one-half (64 %) of the filling observed in our experiments took place within the first second of pressure application. Short duration, high level pressure pulses are the most effective means to achieve maximum penetration. Clinically, this is accomplished by vigorous finger packing. The cement should be pressurized as early as possible within the rasped cavity (immediately after dough stage if possible). The depth of penetration for 4-minute pressurization averaged three times that for 6 1/2-minute pressurization for the range of hole sizes and pressure levels tested.     

In Trinidad: angular stomatitis and pregnancy

Riboflavin deficiency is endemic in Trinidad. A syndrome is observed peculiar to pregnancy. It occurs in the second trimester in women with low blood riboflavin levels. Treatment with riboflavin gives clinical improvement in mothers and raises fetal blood levels. Early biochemical diagnosis and treatment of subclinical deficiency is of value to the Trinidadian mother but protection to the fetus is doubtful. This is because of the effect of multiple limiting factors in which the mother is deficient.     

The effect of various treatments in vitro and in vivo on the binding of 125I-labeled anti-rat serum albumin Fab'' to rat tissue polyribosomes

With 125I-labeled Fab' specific for rat liver serine dehydratase it has been possible to localize polyribosomes synthesizing the enzyme under several different environmental conditions. Evidence is presented to show that, following the administration of amino acids in vivo, the relative synthetic capabilities of free and membrane-bound polyribosomes synthesizing serine dehydratase vary with time. Early during the period of induction of the enzyme by administration of amino acids or by feeding a high protein diet the majority of the newly synthesized enzyme is derived from membrane-bound polyribosomes. Later in the induction process an increasing proportion of the enzyme is synthesized by the free polyribosomes. Subcellular localization studies clearly show that serine dehydratase is synthesized by both subclasses of hepatic membrane-bound polyribosomes, the loose and tight membrane-bound polyribosomes, as well as by the free polyribosomes. It was found that the membrane-bound polyribosomes are the preferential sites of synthesis of the majority of serine dehydratase molecules in the Morris hepatomas 5123C and 7800. It is concluded that the synthesis of the enzyme, serine dehydratase, in rat liver is not discretely compartmentalized in either class of free or membrane-bound polyribosomes. Rather, the relative proportions of the serine dehydratase synthesizing polyribosomes within these two classes of polyribosomes can vary depending on the metabolic and physiologic state of the liver cell.     

Identification of cholesterol as a possible interference in the analysis of fish tissue for industrial chemical residues

The presence of cholesterol in cleaned up fish tissue extracts has been established by gas-liquid chromatography and confirmed by mass spectrometry. It was found both in extracts cleaned up by gel permeation chromatography and in those extracts prepared by the AOAC method for nonfatty foods. It is not normally observed in routine residue analyses because selective gas chromatographic detectors such as electron capture are commonly used.     

Diphosphonate treatment of Paget's disease

Ethane-1-hydroxy-1, 1-diphosphonate (EHDP) was administered in a dose of 20 mg/kg/d to 21 patients with symptomatic Paget's disease. All patients were treated for 6 months and then followed for an additional 6 months. There was a striking decline in serum alkaline phosphatase and urinary hydroxy-proline excretion observed after 3 months of therapy which was not significantly improved in the succeeding 3 months. Concomitantly there was marked improvement in clinical symptoms and bone scans. Following cessation of therapy, continued biochemical and clinical evidence of remission persisted. Several patients on repeat treatment with EHDP appeared to respond promptly. Side effects were minimal except for a possibly related osteomalacia and increased incidence of pathologic fractures.     

Release of proteins from the inner surface of squid axon membrane labeled with tritiated N-ethylmaleimide

Proteins in the inner surface of the squid axon membrane were labeled by intracellular perfusion of [3H]N-ethylmaleimide (NEM), which forms covalent bonds with free sulfhydryl groups. The excitability of the axon was unaffected by the [3H]NEM perfusion. After washout of the unbound label, the perfusate was monitored for the release of labeled proteins. Labeled proteins were released from the inner membrane surface by potassium depolarization of the axon only in the presence of external calcium ions. Replacement of the fluoride ion in the perfusion medium by various anions also caused labeled protein release. The order of effectiveness was SCN- greater than Br- greater than Cl- greater than F-. The extent of labeled protein release by the various anions was correlated with their effects on axonal excitability. The significance of these results is discussed.