Preliminary Results from the CHOMPTT Laser Time-Transfer Mission

CubeSat Handling of Multisystem Precision Time Transfer (CHOMPTT) is a demonstration of precision ground-to-space time-transfer using a laser link to an orbiting CubeSat. The University of Florida-led mission is a collaboration with the NASA Ames Research Center. The 1U optical time-transfer payload was designed and built by the Precision Space Systems Lab at the University of Florida. The payload was integrated with a NASA Ames NOdeS-derived spacecraft bus to form a 3U spacecraft. The CHOMPTT satellite was successfully launched into low Earth orbit on 16 December 2018 on NASA’s ELaNa XIX mission using the Rocket Lab USA Electron vehicle. Here we describe the mission and report on the status of this unique technology demonstration. We use two satellite laser ranging facilities located at the Kennedy Space Center and Mount Stromlo, Australia to transmit nanosecond, 1064 nm laser pulses to the CHOMPTT CubeSat. These pulses are timed with an atomic clock on the ground and are detected by an avalanche photodetector on CHOMPTT. An event timer records the arrival time with respect to one of the two on-board chip-scale atomic clocks with an accuracy of 200 ps (6cm light-travel time). At the same time, a retroreflector returns the transmitted beam back to the ground. By comparing the transmitted and received times on the ground and the arrival time of the pulses at the CubeSat, the time difference between the ground and space clocks can be measured. This compact, power efficient and secure synchronization technology will enable advanced space navigation, communications, networking, and distributed aperture telescopes in the future

Three-dimensional organotypic co-culture model of intestinal epithelial cells and macrophages to study Salmonella enterica colonization patterns

Three-dimensional models of human intestinal epithelium mimic the differentiated form and function of parental tissues often not exhibited by two-dimensional monolayers and respond to Salmonella in key ways that reflect in vivo infections. To further enhance the physiological relevance of three-dimensional models to more closely approximate in vivo intestinal microenvironments encountered by Salmonella, we developed and validated a novel three-dimensional co-culture infection model of colonic epithelial cells and macrophages using the NASA Rotating Wall Vessel bioreactor. First, U937 cells were activated upon collagen-coated scaffolds. HT-29 epithelial cells were then added and the three-dimensional model was cultured in the bioreactor until optimal differentiation was reached, as assessed by immunohistochemical profiling and bead uptake assays. The new co-culture model exhibited in vivo-like structural and phenotypic characteristics, including three-dimensional architecture, apical-basolateral polarity, well-formed tight/adherens junctions, mucin, multiple epithelial cell types, and functional macrophages. Phagocytic activity of macrophages was confirmed by uptake of inert, bacteria-sized beads. Contribution of macrophages to infection was assessed by colonization studies of Salmonella pathovars with different host adaptations and disease phenotypes (Typhimurium ST19 strain SL1344 and ST313 strain D23580; Typhi Ty2). In addition, Salmonella were cultured aerobically or microaerobically, recapitulating environments encountered prior to and during intestinal infection, respectively. All Salmonella strains exhibited decreased colonization in co-culture (HT-29-U937) relative to epithelial (HT-29) models, indicating antimicrobial function of macrophages. Interestingly, D23580 exhibited enhanced replication/survival in both models following invasion. Pathovar-specific differences in colonization and intracellular co-localization patterns were observed. These findings emphasize the power of incorporating a series of related three-dimensional models within a study to identify microenvironmental factors important for regulating infection

CHOMPTT (CubeSat Handling of Multisystem Precision Timing Transfer): From Concept to Launch Pad

Here we present the evolution of a university nanosatellite mission, demonstrating state of the art ground-to-space clock synchronization. The CHOMPTT (CubeSat Handling of Multisystem Precision Time Transfer) mission will be presented from its original concept as a candidate for the University NanoSatellite Program 8 to a spacecraft ready for launch in Fall of 2017 on ELaNa XIX (Educational Launch of Nanosatellites). This technology may be used in the future for precision navigation beyond the GPS sphere, networking of satellite swarms, synchronization of terrestrial time standards over continental distances, and verification of new space atomic clocks. The 3U CubeSat houses a 1 kg, 1U OPTI (Optical Precision Timing Instrument) payload, designed and built at the University of Florida, and a 1.5U EDSN/NODeS-derived bus from NASA Ames Research Center. The OPTI payload comprises 1) a supervisor board that handles payload data, power management, and mode settings, 2) an optics assembly with six 1 cm retroreflectors and four laser diodes used as a beacon for ground-tracking, and 3) two fully redundant timing channels, each consisting of a chip-scale atomic clock (CSAC), a microprocessor with clock counter, a picosecond event timer, and an avalanche photodetector (APD) with band-pass filter. Several iterations of OPTI have been designed, developed, and tested leading to its final configuration – a laboratory breadboard (v1.0), a 1.5U high altitude balloon design (v2.0), an engineering unit (v3.0), and the flight unit (v3.1). In-lab testing of OPTI indicates a short-term precision of 100 ps, equivalent to a range accuracy of 3 cm, which is below the primary mission objective of \u3c 200 ps. The long-term timing accuracy is 20 ns over one orbit (1.5 hours), limited by the frequency stability of the on-board CSACs. After the spacecraft reaches its nominal 500 km, 85 deg inclination orbit, an experimental laser ranging facility at the Kennedy Space Center in Florida will track CHOMPTT and emit 1064 nm nanosecond optical pulses toward it. The laser pulses will then reflect off the retroreflector array mounted on the nadir face of CHOMPTT, returning the pulses to the laser ranging facility, which will record the round-trip time-of-flight. An APD will record the arrival time of the pulses at the nanosatellite. By combining the arrival time of the pulse at the CubeSat and the transmit and receive times of the pulse at the laser ranging facility, the clock discrepancy between the ground and CubeSat atomic clocks can be determined. The design and verification of the flight version of CHOMPTT will be reviewed and an overview of the lifetime development and progression of CHOMPTT from the inception to launch pad will be presented

CHOMPTT (CubeSat Handling of Multisystem Precision Timing Transfer): From Concept to Launch Pad

Here we present the evolution of a student satellite mission: CHOMPTT (CubeSat Handling of Multisystem Precision Time Transfer), from its original concept as a candidate for the University NanoSatellite Program 8 (UNP8), to a spacecraft ready for launch in Fall of 2017 on ELaNa XIX (Educational Launch of Nanosatellites). The 3U CubeSat houses a 1 kg, 1U OPTI (Optical Precision Timing Instrument) payload, designed and built at the University of Florida, and a 1.5U EDSNNODeS-derived bus from NASA Ames Research Center. The OPTI payload comprises of: 1) a supervisor board that handles payload data, power regulation, and mode settings, 2) an optics assembly of six 1 cm retroreflectors and four laser beacon diodes for ground-tracking; and 3) two fully redundant timing channels, each consisting of: a chip-scale atomic clock, a microprocessor with clock counter, a picosecond event timer, and an avalanche photodetector (APD) with band-pass filter. Several iterations of OPTI have been developed, tested, and designed to achieve its current functionality and design a laboratory breadboard design, a 1.5U high altitude balloon design, engineering unit design, and its current flight unit design. In-lab testing of the current OPTI design indicates a short-term precision of 100 ps, equivalent to a range accuracy of 3 cm necessary to achieve our primary objective of 200 ps time transfer error, and a long-term timing accuracy of 20 ns over one orbit (1.5 hours). After the spacecraft reaches its nominal 500 km orbit at a 85 degree inclination, an experimental laser ranging facility at Kennedy Space Center in Florida, will track and emit 1064 nm nanosecond optical pulses at the CHOMPTT spacecraft. The laser pulses will then reflect off the retroreflector array mounted on the nadir face of CHOMPTT, and return the pulse to the laser ranging facility where the laser ranging facility will record the round-trip duration of the laser pulses. At the same time the pulse arrives at the spacecraft and is reflected by the array, an APD will record the arrival time of the pulses at the nanosatellite. By comparing the arrival of the pulse at the CubeSat and the duration of the round-trip of the laser pulse, the clock discrepancy between the ground and CubeSat atomic clocks can be determined, in addition to the CubeSats range from the facility. The design and verification of the flight version of CHOMPTT will be reviewed and an overview of the lifetime development and progression of CHOMPTT from the inception to launch pad will be presented

CubeSat Handling of Multisystem Precision Time Transfer

No abstract availabl

Sertoli cell tumor in a Mallard duck

Sertoli cell tumors are primary testicular neoplasms that can present with a variety of clinical signs that may include certain paraneoplastic syndromes. To date, orchiectomy has been the only treatment option mentioned in the literature for avian species. Due to the difficult anatomic location of the testes in birds and the potential for metastasis, this is not always a viable option. This report describes a Mallard with a Seroli cell tumor that was not amenable to surgical removal and was treated with carboplatin chemotherapy. This and other forms of chemotherapy may prove to be useful in the treatment of these tumors in birds, and should be explored further

TRANSCRIPTOME ANALYSIS OF VIBRIO PARAHAEMOLYTICUS IN TYPE III SECRETION SYSTEM 1 INDUCING CONDITIONS

Vibrio parahaemolyticus is a bacterial pathogen capable of causing gastroenteritis, wound infections and septicemia. Its virulence factors include two type III secretion systems (T3SS1 and T3SS2) that cause host-cell cytotoxicity and enterotoxicity, respectively. This dissertation presents analysis of the genome of V. parahaemolyticus to identify T3SS associated genes, construction of comparative transcriptomic profiles of T3SS1 activity, and targeted analysis of T3SS1 regulatory gene exsE.To identify secreted proteins, chimeric fusions were constructed between putative effector protein leader sequences and a leaderless phospholipase, yplA. These constructs were subsequently expressed using the heterologous host Yersinia enterocolitica. Screens included genes from T3SS1 and T3SS2 associated regions and the entire V. parahaemolyticus genome; several T3SS1 and T3SS2 secreted proteins were identified, as well as seven additional genes located elsewhere in the genome.To identify genes involved in cytotoxicity, a mini-Tn5 transposon insertional knockout library was generated and screened for loss of T3SS1-dependent cytotoxicity towards HeLa cells. Thirty-six insertional mutants were identified; 17 were associated with T3SS1 and 17 unique genes were identified that may contribute to T3SS1-dependent cytotoxicity.ExsE is an important regulatory protein for T3SS1; deletion of exsE did not affect T3SS1 transcription or synthesis, but it did result in attenuated cytotoxicity towards HeLa cells characterized by reduced autophagy and decreased adherence to host cells. However, exsE deletion had no detectable effect on T3SS1-dependent mortality using an intrapulmonary infection of mice, suggesting other regulatory pathways may be involved during in vivo infection.Comparative transcriptional profiles of V. parahaemolyticus were assembled from T3SS1 inducing (DMEM induction, exsA overexpression, HeLa cell infection) and non-inducing (LB-S, exsD overexpression) conditions, which revealed differences in transcription of iron acquisition genes between DMEM and exsA induction. These types of genes also predominate early during HeLa infection but are overshadowed by nitrate and inorganic transport genes by mid- to late-infection. Expression patterns of T3SS1 associated genes were also analyzed over the course of HeLa cell infection. Thirteen unique upregulated genes were identified in common between DMEM and exsA induction, and 33 unique genes were identified that showed upregulation over the course of HeLa infection

Transcriptome analysis of Vibrio parahaemolyticus in type III secretion system 1 inducing conditions

Vibrio parahaemolyticus is an emerging bacterial pathogen capable of causing inflammatory gastroenteritis, wound infections and septicemia. As a food-borne illness, infection is most frequently associated with the consumption of raw or undercooked seafood, particularly shellfish. It is the primary cause of Vibrio-associated food-borne illness in the United States and the leading cause of food-borne illness in Japan. The larger of its two chromosomes harbors a set of genes encoding type III section system 1 (T3SS1), a virulence factor present in all V. parahaemolyticus strains that is similar to the Yersinia ysc T3SS. T3SS1 translocates effector proteins into eukaryotic cells where they induce changes to cellular physiology and modulate host-pathogen interactions. T3SS1 is also responsible for cytotoxicity towards several different cultured cell lines as well as mortality in a mouse model. Herein we used RNA-seq to obtain global transcriptome patterns of V. parahaemolyticus under conditions that either induce (growth in DMEM media, in trans expression of transcriptional regulator exsA) or repress T3SS1 expression (growth in LB-S media, in trans exsD expression) and during infection of HeLa cells over time. Comparative transcriptomic analysis demonstrated notable differences in the expression patterns under inducing conditions and was also used to generate an expression profile of V. parahaemolyticus during infection of HeLa cells. In addition, we identified several new genes that are associated with T3SS1 expression and may warrant further study

Transcriptome analysis of Vibrio parahaemolyticus in type III secretion system 1 inducing conditions

Vibrio parahaemolyticus is an emerging bacterial pathogen capable of causing inflammatory gastroenteritis, wound infections, and septicemia. As a food-borne illness, infection is most frequently associated with the consumption of raw or undercooked seafood, particularly shellfish. It is the primary cause of Vibrio-associated food-borne illness in the United States and the leading cause of food-borne illness in Japan. The larger of its two chromosomes harbors a set of genes encoding type III section system 1 (T3SS1), a virulence factor present in all V. parahaemolyticus strains that is similar to the Yersinia ysc T3SS. T3SS1 translocates effector proteins into eukaryotic cells where they induce changes to cellular physiology and modulate host-pathogen interactions. T3SS1 is also responsible for cytotoxicity toward several different cultured cell lines as well as mortality in a mouse model. Herein we used RNA-seq to obtain global transcriptome patterns of V. parahaemolyticus under conditions that either induce [growth in Dulbecco's Modified Eagle Medium (DMEM) media, in trans expression of transcriptional regulator exsA] or repress T3SS1 expression (growth in LB-S media, in trans exsD expression) and during infection of HeLa cells over time. Comparative transcriptomic analysis demonstrated notable differences in the expression patterns under inducing conditions and was also used to generate an expression profile of V. parahaemolyticus during infection of HeLa cells. In addition, we identified several new genes that are associated with T3SS1 expression and may warrant further study