New taxa of Neosartorya and Aspergillus in Aspergillus section Fumigati

Three new species of Neosartorya and one new Aspergillus of section Fumigati are proposed using a polyphasic approach based on morphology, extrolite production and partial β-tubulin, calmodulin, and actin gene sequences. The phylogenetic analyses using the three genes clearly show that the taxa grouped separately from the known species and confirmed the phenotypic differences. Neosartorya denticulata is characterized by its unique denticulate ascospores with a prominent equatorial furrow; N. assulata by well developed flaps on the convex surface of the ascospores which in addition have two distinct equatorial crests and N. galapagensis by a funiculose colony morphology, short and narrow conidiophores and ascospores with two wide equatorial crests with a microtuberculate convex surface. Aspergillus turcosus can be distinguished by velvety, gray turquoise colonies and short, loosely columnar conidial heads. The four new taxa also have unique extrolite profiles, which contain the mycotoxins gliotoxin and viriditoxin in N. denticulate; apolar compounds provisionally named NEPS in N. assulata and gregatins in N. galapagensis. A. turcosus produced kotanins. N.denticulata sp. nov., N. assulata sp. nov., N. galapagensis sp. nov., and A. turcosus sp. nov. are described and illustrated

Essays On Labor Markets With Search And Information Frictions

This dissertation attempts to analyze the wage determination and matching probability in labor markets with search and information frictions. In the first chapter, I provide a theoretical framework to analyze the role of job-to-job transition in a worker\u27s lifetime wage growth. I use the first-price auction models to analyze the wage determination and job-to-job transition process, and formulate the inference problem about a worker\u27s quality revealed through the worker\u27s past job history. By doing so, I characterize the mechanism through which frequent job transitions convey a negative signal about the worker\u27s quality. The second chapter, joint work with Hanna Wang, focuses on the market for entry-level jobs where job seekers send out costly applications in order to match with a potential employer. With the presence of coordination friction, we characterize the matching probability in a market with heterogeneous workers and show how restricting the search effort can improve social welfare. The third chapter reviews the literature on search and information frictions and identifies the contribution of the two earlier papers

A reset-free anti-harmonic delay-locked loop using a cycle period detector

This paper describes a new delay-locked loop (DLL) circuit that uses a replica delay line and a cycle period detector to solve the false lock problem in the conventional DLLs. The auxiliary loop in the proposed DLL monitors the lock state of the main loop by estimating the cycle period of the input clock and decides whether the main loop is in the coarse lock state or not. The auxiliary loop does not require an external reset or a start-up signal for the coarse lock operation, which is performed in the background without affecting the fine lock operation of the main loop. The proposed DLL is useful in the applications such as wide range DLLs and multiphase clock generators. The proposed DLL was implemented in 0.25- m mixed-mode CMOS technology and its operating frequency ranges from 30 to 200 MHz. Its cycle-to-cycle rms jitter is 12.8 ps at 133 MHz, and it dissipates 30 mW at 2.5 V

A novel human-specific splice isoform alters the critical C-terminus of Survival Motor Neuron protein

Spinal muscular atrophy (SMA), a leading genetic disease of children and infants, is caused by mutations or deletions of Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, fails to compensate for the loss of SMN1 due to skipping of exon 7. SMN2predominantly produces SMNΔ7, an unstable protein. Here we report exon 6B, a novel exon, generated by exonization of an intronic Alu-like sequence of SMN. We validate the expression of exon 6B-containing transcripts SMN6B and SMN6BΔ7 in human tissues and cell lines. We confirm generation of SMN6B transcripts from both SMN1 and SMN2. We detect expression of SMN6B protein using antibodies raised against a unique polypeptide encoded by exon 6B. We analyze RNA-Seq data to show that hnRNP C is a potential regulator of SMN6B expression and demonstrate that SMN6B is a substrate of nonsense-mediated decay. We show interaction of SMN6B with Gemin2, a critical SMN-interacting protein. We demonstrate that SMN6B is more stable than SMNΔ7 and localizes to both the nucleus and the cytoplasm. Our finding expands the diversity of transcripts generated from human SMN genes and reveals a novel protein isoform predicted to be stably expressed during conditions of stress.This article is published as Seo, Joonbae, Natalia N. Singh, Eric W. Ottesen, Brian M. Lee, and Ravindra N. Singh. "A novel human-specific splice isoform alters the critical C-terminus of Survival Motor Neuron protein." Scientific reports 6 (2016), doi: 10.1038/srep30778. Posted with permission.</p

A 2.4GHz 0.25um CMOS Dual-Mode Direct-Conversion Transceiver for Bluetooth and 802.11b

A dual-mode transceiver integrates the transmitter of 0-dBm output power and the receiver for both Bluetooth with 87 dBm sensitivity and 802.11b with 86 dBm sensitivity in a single chip. A direct-conversion architecture enables the maximum reuse and the optimal current consumption of the various building blocks in each mode for a low-cost and low-power solution. A single-ended power-amplifer (PA) driver transmits the nominal output power of 0 dBm with 18-dB gain control in 3-dB steps. Only little area overhead is required in the baseband active filter and programmable gain amplifier (PGA) to provide the dual-mode capability with optimized current consumption. The dc-offset cancellation scheme coupled with PGAs implements the very low high-pass cutoff frequency with a smaller area than required by a simple coupling capacitor. Fabricated in 0.25- m CMOS process, the die area is 8.4 mm2 including pads, and current consumption in RX is 50 mA for Bluetooth and 65 mA for 802.11b from a 2.7-V supply