A 76-84 GHz SiGe power amplifier array employing low-loss four-way differential combining transformer

This paper presents holistic design of a novel four-way differential power-combining transformer for use in millimeter-wave power-amplifier (PA). The combiner with an inner radius of 25 µm exhibits a record low insertion loss of 1.25 dB at 83.5 GHz. It is designed to simultaneously act as a balanced-to-unbalanced converter, removing the need for additional BALUNs typically required in differential circuits. A complete circuit comprised of a power splitter, two-stage differential cascode PA array, a power combiner as well as input and output matching elements was designed and realized in SiGe technology with f/f 170/250 GHz. Measured small-signal gain of at least 16.8 dB was obtained from 76.4 to 85.3 GHz with a peak 19.5 dB at 83 GHz. The prototype delivered 12.5 dBm output referred 1 dB compression point and 14 dBm saturated output power when operated from a 3.2 V dc supply voltage at 78 GHz.

Ultrafast low-loss 42-70 GHz differential SPDT switch in 0.35 μm SiGe technology

This paper presents an ultrafast wideband low-loss single-pole double-throw (SPDT) differential switch in 0.35 µ m SiGe bipolar technology. The proposed topology adopting current-steering technique results in a total measured switching time of 75 ps , which suggests a maximum switching rate of 13 Gb/s, the fastest ever reported at V-band. In addition, the switch exhibits an insertion loss lower than 1.25 dB and an isolation higher than 18 dB from 42 GHz to 70 GHz. © 2006 IEEE.

Parsing parallel evolution:Ecological divergence and differential gene expression in the adaptive radiations of thick-lipped Midas cichlid fishes from Nicaragua

The study of parallel evolution facilitates the discovery of common rules of diversification. Here, we examine the repeated evolution of thick lips in Midas cichlid fishes (the Amphilophus citrinellus species complex) - from two Great Lakes and two crater lakes in Nicaragua - to assess whether similar changes in ecology, phenotypic trophic traits and gene expression accompany parallel trait evolution. Using next-generation sequencing technology, we characterize transcriptome-wide differential gene expression in the lips of wild-caught sympatric thick- and thin-lipped cichlids from all four instances of repeated thick-lip evolution. Six genes (apolipoprotein D, myelin-associated glycoprotein precursor, four-and-a-half LIM domain protein 2, calpain-9, GTPase IMAP family member 8-like and one hypothetical protein) are significantly underexpressed in the thick-lipped morph across all four lakes. However, other aspects of lips' gene expression in sympatric morphs differ in a lake-specific pattern, including the magnitude of differentially expressed genes (97-510). Generally, fewer genes are differentially expressed among morphs in the younger crater lakes than in those from the older Great Lakes. Body shape, lower pharyngeal jaw size and shape, and stable isotopes (dC and dN) differ between all sympatric morphs, with the greatest differentiation in the Great Lake Nicaragua. Some ecological traits evolve in parallel (those related to foraging ecology; e.g. lip size, body and head shape) but others, somewhat surprisingly, do not (those related to diet and food processing; e.g. jaw size and shape, stable isotopes). Taken together, this case of parallelism among thick- and thin-lipped cichlids shows a mosaic pattern of parallel and nonparallel evolution. © 2012 Blackwell Publishing Ltd.

40-70 GHz 13 Gbps 1-dB loss SPST and SPDT differential switches in 0.35 μm SiGe technology

This paper presents the design and characterization of ultrafast wideband low-loss single-pole single-throw (SPST) and single-pole double-throw (SPDT) differential switches. The SPDT switch exhibits insertion loss of lower than 1.25 dB from 42 to 70 GHz and isolation of better than 20 dB from 40 to 65 GHz. Similar low-loss and broadband characteristics are also observed from the measured SPST switch. The proposed switch topologies adopting current-steering technique and implemented in 0.35 µm SiGe bipolar technology result in a switching time of only 75 ps. This suggests a maximum switching speed of 13 Gbps, the fastest ever reported at V-band.

Arsenate causes differential acute toxicity to two P-deprived genotypes of rice seedlings (Oryza sativa L.)

Significant genotypic difference in response to arsenate toxicity in rice (Oryza sativa) was investigated in root elongation, arsenate uptake kinetics, physiological and biochemical response and arsenic (As) speciation. Uptake kinetics data showed that P-deprived genotype 94D-54 had a little higher As uptake than P-deprived 94D-64, but the difference was not large enough to cause acute toxicity in P-deprived 94D-54. There was no difference in tissue P concentrations between the two genotypes under P deficient conditions. In addition, arsenic speciation in plant tissues (using high performance liquid chromatography-inductively coupled plasma mass spectrometry) was not different between P pretreatments and between genotypes. P-deprived genotype 94D-54 suffered much higher stress induced by arsenate toxicity than P-deprived genotype 94D-64, in terms of lipid peroxidation, tissue H2O2 concentrations and exosmosis of K, P and As. However, P-deprived 94D-54 also had higher overproduction of enzymatic antioxidants (with higher GPX, SOD, CAT) and NPT (non-protein thiols) than P-deprived 94D-64. It appeared that, the higher sensitivity of P-deprived 94D-54 to arsenate toxicity might cause the overproduction of NPT, thus leading to the depletion of GSH and to the accumulation of H2O2. The differential sensitivity of the two genotypes has major implications for breeding rice for As affected paddy soil.

Familial hypocalciuric hypercalcaemia as a differential diagnosis of hyperparathyroidism:studies in a large kindred and a review of surgical experience in the condition

We have studied 46 members of a large kindred with familial hypocalciuric hypercalcaemia (FHH) after a neck exploration failed to cure hypercalcaemia in an asymptomatic patient. Serum calcium, serum phosphate, plasma parathormone and vitamin D metabolites do not distinguish affected members from patients with hyperparathyroidism. Because of the continuing debate as to whether or not FHH is a variant of, or distinct from, hyperparathyroidism, we have carried out a review of surgical experience with subtotal parathyroidectomy in hyperparathyroidism secondary to parathyroid hyperplasia and in FHH. Whereas the procedure is successful in 90 per cent of the former cases only one case of FHH has been cured by it. This provides evidence for the two conditions being aetiologically distinct. Before patients with asymptomatic hypercalcaemia are referred for parathyroid surgery the calcium:creatinine clearance ratio should be measured using a 2 h urine sample collected after an overnight fast and a fasting blood sample. If this ratio is less than 0.01 then screening of first degree relations should be undertaken before any parathyroid surgery is performed. Unnecessary surgery can therefore be avoided.

TGFβ and CCN2/CTGF mediate actin related gene expression by differential E2F1/CREB activation

CCN2/CTGF is an established effector of TGFß driven responses in diabetic nephropathy. We have identified an interaction between CCN2 and TGFß leading to altered phenotypic differentiation and inhibited cellular migration. Here we determine the gene expression profile associated with this phenotype and define a transcriptional basis for differential actin related gene expression and cytoskeletal function.

Acquired differential regulation of caspase-8 in cisplatin-resistant non-small-cell lung cancer

Failure to efficiently induce apoptosis contributes to cisplatin resistance in non-small-cell lung cancer (NSCLC). Although BCL-2-associated X protein (BAX) and BCL-2 antagonist killer (BAK) are critical regulators of the mitochondrial apoptosis pathway, their requirement has not been robustly established in relation to cisplatin. Here, we show that cisplatin can efficiently bypass mitochondrial apoptosis block caused by loss of BAX and BAK, via activation of the extrinsic death receptor pathway in some model cell lines. Apoptosis resistance following cisplatin can only be observed when both extrinsic and intrinsic pathways are blocked, consistent with redundancy between mitochondrial and death receptor pathways in cisplatin-induced apoptosis. In H460 NSCLC cells, caspase-8 cleavage was shown to be induced by cisplatin and is dependent on death receptor 4, death receptor 5, Fas-associated protein with death domain, acid sphingomyelinase and ceramide synthesis. In contrast, cisplatin-resistant cells fail to activate caspase-8 via this pathway despite conserving sensitivity to death ligand-driven activation. Accordingly, caspase-8 activation block acquired during cisplatin resistance, can be bypassed by death receptor agonism. © 2012 Macmillan Publishers Limited

Differential expression of liver fluke β-tubulin isotypes at selected life cycle stages

We have shown that Fasciola hepatica expresses at least six ß-tubulins in the adult stage of its life cycle, designated F.hep-ß-tub1-6 (Ryan et al., 2008). Here we show that different complements of tubulin isotypes are expressed in different tissues and at different life cycle stages; this information may inform the search for novel anthelmintics. The predominant (as judged by quantitative PCR) isotype transcribed at the adult stage was F.hep-ß-tub1 and immunolocalisation studies revealed that this isotype occurred mainly in mature spermatozoa and vitelline follicles. Quantitative PCR indicated that changes occurred in the transcription levels of ß-tubulin isotypes at certain life cycle stages and may be of importance in the efficacy of benzimidazole-based anthelmintic drugs, but there were no significant differences between the triclabendazole (TCBZ)-susceptible Leon isolate and the TCBZ-resistant Oberon isolate in the transcription levels of each of the isotypes. When three well-characterised isolates with differing susceptibilities to TCBZ were compared, only one amino acid change resulting from a homozygous coding sequence difference (Gly269Ser) in isotype 4 was observed. However, this change was not predicted to alter the overall structure of the protein. In conclusion, these findings indicate that there is tissue-specific expression of tubulin isotypes in the liver fluke but the development of resistance to TCBZ is not associated with changes in its presumed target molecule.