Wave techniques for noise modeling and measurement

The noise wave approach is applied to analysis, modeling, and measurement applications. Methods are presented for the calculation of component and network noise wave correlation matrices. Embedding calculations, relations to two-port figures-of-merit, and transformations to traditional representations are discussed. Simple expressions are derived for MESFET and HEMT noise wave parameters based on a linear equivalent circuit. A noise wave measurement technique is presented and experimentally compared with the conventional method

Re-evaluating experimental validation in the Big Data Era : a conceptual argument

Non peer reviewe

A 10-Watt X-Band Grid Oscillator

A 100-transistor MESFET grid oscillator has been fabricated that generates an effective radiated power of 660 W at 9.8 GHz and has a directivity of 18.0 dB. This corresponds to a total radiated power of 10.3 W, or 103 mW per device. This is the largest recorded output power for a grid oscillator. The grid drain-source bias voltage is 7.4 V and the total drain current for the grid is 6.0 A, resulting in an overall dc-to-rf efficiency of 23%. The pattern of the SSB noise-to-carrier ratio was measured and found to be essentially independent of the radiation angle. The average SSB noise level was -87 dBc/Hz at an offset of 150 kHz from the carrier. An average improvement in the SSB noise-to-carrier ratio of 5 dB was measured for a 100-transistor grid compared to a 16-transistor gri

Wave computations for microwave education

The analysis of even simple microwave circuits can involve complicated calculations. It is argued that students repeatedly forced through this exercise are left exhausted and never develop understanding and insight into the principles of high-frequency circuit design. The use of computer-aided design software eliminates the network analysis burden, but it is a precarious solution: students easily become dependent on software and never develop analytical skills. A simple wave computational approach to microwave network analysis is discussed. The method is derived from Mason's theory of signal flow graphs and is based on wave variables and scattering parameters. The approach is easily understood and applied as either an analytical tool, or within a microwave CAD analysis engine. PC software using this computational technique is described and its educational applications are discussed

Noise waves and passive linear multiports

Noise waves are a powerful means for characterizing noise in microwave circuits. A simple derivation is given for the relation between a passive circuit's noise-wave correlation matrix and its scattering matrix. It is shown that this relation, referred to as Bosma's theorem, can be readily derived from the fundamental principle that a passive multiport in thermodynamic equilibrium with reflectionless terminations produces uncorrelated output waves

Deciphering signatures of mutational processes operative in human cancer.

The genome of a cancer cell carries somatic mutations that are the cumulative consequences of the DNA damage and repair processes operative during the cellular lineage between the fertilized egg and the cancer cell. Remarkably, these mutational processes are poorly characterized. Global sequencing initiatives are yielding catalogs of somatic mutations from thousands of cancers, thus providing the unique opportunity to decipher the signatures of mutational processes operative in human cancer. However, until now there have been no theoretical models describing the signatures of mutational processes operative in cancer genomes and no systematic computational approaches are available to decipher these mutational signatures. Here, by modeling mutational processes as a blind source separation problem, we introduce a computational framework that effectively addresses these questions. Our approach provides a basis for characterizing mutational signatures from cancer-derived somatic mutational catalogs, paving the way to insights into the pathogenetic mechanism underlying all cancers

Diagnostic value of H3F3A mutations in giant cell tumour of bone compared to osteoclast-rich mimics

Driver mutations in the two histone 3.3 (H3.3) genes, H3F3A and H3F3B, were recently identified by whole genome sequencing in 95% of chondroblastoma (CB) and by targeted gene sequencing in 92% of giant cell tumour of bone (GCT). Given the high prevalence of these driver mutations, it may be possible to utilise these alterations as diagnostic adjuncts in clinical practice. Here, we explored the spectrum of H3.3 mutations in a wide range and large number of bone tumours (n 5 412) to determine if these alterations could be used to distinguish GCT from other osteoclast-rich tumours such as aneurysmal bone cyst, nonossifying fibroma, giant cell granuloma, and osteoclast-rich malignant bone tumours and others. In addition, we explored the driver landscape of GCT through whole genome, exome and targeted sequencing (14 gene panel). We found that H3.3 mutations, namely mutations of glycine 34 in H3F3A, occur in 96% of GCT. We did not find additional driver mutations in GCT, including mutations in IDH1, IDH2, USP6, TP53. The genomes of GCT exhibited few somatic mutations, akin to the picture seen in CB. Overall our observations suggest that the presence of H3F3A p.Gly34 mutations does not entirely exclude malignancy in osteoclast-rich tumours. However, H3F3A p.Gly34 mutations appear to be an almost essential feature of GCT that will aid pathological evaluation of bone tumours, especially when confronted with small needle core biopsies. In the absence of H3F3A p.Gly34 mutations, a diagnosis of GCT should be made with caution

Evaluation of CAY-1, an Experimental, Natural Fungicide, For Control of Strawberry Pathogens

CAY-1 is an experimental, natural product being tested as a potential fungicide. This saponin isolated from Capsicum frutescens interacts with membrane sterols causing leakage of cell components and ultimately cell death in a variety of fungi. CAY-1 and the commercial fungicide captan were tested in an in vitro doseresponse dilution-broth assay. They caused at least 85% growth inhibition of the fungal pathogens Colletotrichum acutatum, C fragariae and C. gloeosporioides when tested at 3.0 μM. Even though CAY-1 strongly reduced the growth of these fungal pathogens in laboratory assays and prevented anthracnose development in detached leaf assays, it did not control foliar or fruit rot diseases of strawberry in field trials

Natural Toxins for Use in Pest Management

Natural toxins are a source of new chemical classes of pesticides, as well as environmentally and toxicologically safer molecules than many of the currently used pesticides. Furthermore, they often have molecular target sites that are not exploited by currently marketed pesticides. There are highly successful products based on natural compounds in the major pesticide classes. These include the herbicide glufosinate (synthetic phosphinothricin), the spinosad insecticides, and the strobilurin fungicides. These and other examples of currently marketed natural product-based pesticides, as well as natural toxins that show promise as pesticides from our own research are discussed

Identification and characterization of an irreversible inhibitor of CDK2

Irreversible inhibitors that modify cysteine or lysine residues within a protein kinase ATP binding site offer, through their distinctive mode of action, an alternative to ATP-competitive agents. 4-((6-(Cyclohexylmethoxy)- 9H-purin-2-yl)amino)benzenesulfonamide (NU6102) is a potent and selective ATP-competitive inhibitor of CDK2 in which the sulfonamide moiety is positioned close to a pair of lysine residues. Guided by the CDK2/NU6102 structure, we designed 6-(cyclohexylmethoxy)-N-(4-(vinylsulfonyl)phenyl)-9H-purin-2-amine (NU6300), which binds covalently to CDK2 as shown by a co-complex crystal structure. Acute incubation with NU6300 produced a durable inhibition of Rb phosphorylation in SKUT-1B cells, consistent with it acting as an irreversible CDK2 inhibitor. NU6300 is the first covalent CDK2 inhibitor to be described, and illustrates the potential of vinyl sulfones for the design of more potent and selective compounds