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The activity of Jupiter family comets, 60P/Tsuchinshan 2 and 62P/Tsuchinshan 1, is analysed by creating their Secular light curves (SLCs). We collected 850 observations in apparitions 1995, 2005, 2012, and 2018 for 60P/Tsuchinshan 2 and 471 observations in apparitions 1998, 2004, and 2017 for 62P/Tsuchinshan 1. We obtained the main activity parameters: turn-on distance (RON) and time (TON), turn-off distance (ROFF) and time (TOFF), photometric age (P-AGE), and time age (T-AGE). The results show that both comets could be classified as middle-age comets in early apparitions, due to P-AGE ≳30 comet yr, and their activity lasting for more than 300 d similar to those of comets 32P/Comas-Sola and 67P/Churyumov–Gerasimenko. The orbital changes (decrease of perihelion distance) of comets 60P/Tsuchinshan 2 and 62P/Tsuchinshan 1 in recent apparitions enhanced their activity with different characteristics, which was proved by the increased brightness amplitude or space range of activity and the decreased P-AGE; meanwhile, they are entering the range of young comets, and are classified as Lazarus comets.

Comet 60P/Tsuchinshan is a Jupiter family comet. Since the discovery of 60P/Tsuchinshan, little research for cometary activity has been conducted on this comet, though it has returned to perihelion several times. To study the physical properties and activity characteristic of 60P/Tsuchinshan during its 2018–2019 apparition, we observed 60P/Tsuchinshan with broadband B, V, and R filters from 2018 November to 2019 March by using the 80 cm Yaoan High Precision Telescope at Yaoan Station of Purple Mountain Observatory, Chinese Academy of Sciences. Morphological analysis and photometric studies of 60P/Tsuchinshan were performed. The color indices, Af ρ values, and dust production rates of 60P/Tsuchinshan were obtained. Morphological analysis showed that the comet was active and several images showed a spiral structure in the inner coma; this structure is regardless of the enhancement methods and cannot be explained by the rotation of 60P. The Af ρ curve showed that the peak activity of 60P/Tsuchinshan was at about 10 days after perihelion. Compared to other Jupiter family comets at similar heliocentric distances, we found that 60P/Tsuchinshan was a very active comet. Dynamical analysis showed that 60P/Tsuchinshan’s perihelion distance was reduced from 1.77 to 1.62 au due to the close encounter with Jupiter that occurred on 2008 December 20; this may increase its activity in the next apparition.

As a new class of comet, main belt comets (MBCs) have attracted more and more attention in recent years. To study activity and physical properties of three MBCs 176P/LINEAR, 238P/Read and 288P/(300163) 2006 VW139, we carried out broadband CCD photometry of three MBCs on UT 2016 November 18–19 with the 1-m optical telescope at Lulin Observatory in Taiwan. By comparing cometary surface brightness profiles to stellar surface brightness profiles, and by comparing cometary absolute magnitude to the expected magnitude of inactive nucleus, we found that 176P/LINEAR was inactive, while 238P/Read and 288P/(300163) 2006 VW139 were active. By photometric studies, we obtained the Afρ values and the dust production rates. Finally, the activity of three MBCs were discussed. Our photometric results show that the total dust mass of 238P/Read and 288P/(300163) 2006 VW139 obtained in this work are of the same magnitude as the majority of known MBCs.

As a new class of comet, main belt comets (MBCs) have attracted more and more attention in recent years. To study activity and physical properties of three MBCs 176P/LINEAR, 238P/Read and 288P/(300163) 2006 VW139, we carried out broadband CCD photometry of three MBCs on UT 2016 November 18–19 with the 1-m optical telescope at Lulin Observatory in Taiwan. By comparing cometary surface brightness profiles to stellar surface brightness profiles, and by comparing cometary absolute magnitude to the expected magnitude of inactive nucleus, we found that 176P/LINEAR was inactive, while 238P/Read and 288P/(300163) 2006 VW139 were active. By photometric studies, we obtained the Afρ values and the dust production rates. Finally, the activity of three MBCs were discussed. Our photometric results show that the total dust mass of 238P/Read and 288P/(300163) 2006 VW139 obtained in this work are of the same magnitude as the majority of known MBCs.

Salmonella infection is an important foodborne consumer health concern that can be mitigated during food processing. Bacteriophage therapy imparts many advantages over conventional chemical preservatives including pathogen specificity, natural derivation, potency, and providing a high degree of safety. The objective of this study aimed to isolate and characterize a phage that effectively control Salmonella food contamination. Out of 35 isolated phages, LPSE1 demonstrated a broad Salmonella host range, robust lytic ability, extensive pH tolerance, and prolonged thermal stability. The capacity for phage LPSE1 to control Salmonella Enteritidis-ATCC13076 in milk, sausage, and lettuce was established. Incubation of LPSE1 at 28°C in milk reduced recoverable Salmonella by approximately 1.44 log10 CFU/mL and 2.37 log10 CFU/mL at MOI of 1 and 100, respectively, as relative to the phage-excluded control. Upon administration of LPSE1 at an MOI of 1 in sausage, Salmonella count decreased 0.52 log10 at 28°C. At MOI of 100, the count decreased 0.49 log10 at 4°C. Incubation of LPSE1 on lettuce reduced recoverable Salmonella by 2.02 log10, 1.71 log10, and 1.45 log10 CFU/mL at an MOI of 1, 10, and 100, respectively, as relative to the negative control. Taken together, these findings establish LPSE1 as an effective weapon against human pathogenic Salmonella in various ready to eat foods.

Application of bacteriophages to eliminate foodborne pathogens in food matrices is an emerging research field. In this study, a promising phage candidate specific for Salmonella strains was screened and its ability to decrease Salmonella counts in some food, such as milk, sausage, and lettuce, was investigated. A total of 58 Salmonella phages were isolated from a wastewater treatment plant, sewage near a river, farm ditch near a lake, and poultry house. Among them, phages LPST10, LPST18, and LPST23 were highly efficient in infecting Salmonella Typhimurium ATCC 14028. In particular, phage LPST10 could infect all the tested Salmonella Typhimurium and Salmonella Enteritidis strains with high efficiency. Bacterial challenge tests revealed that phage LPST10 and its combination with phages LPST18 and LPST23 could consistently inhibit the growth of multiple strains. Phage LPST10 presented a lysis time of about 50 min with a burst size of 101 PFU/CFU, exhibited two distinct phases in the one-step growth curve, and was stable at a pH range of 3–13 that corresponds to the pH of most of the foods (pH 3.5–7.5) and at temperatures between 30 °C and 60 °C. Transmission electron microscopy demonstrated that phage LPST10 belongs to the Siphoviridae family, with an icosahedral head with a diameter of 83.26 nm and tail length and width of approximately 144.89 nm and 10.9 nm, respectively. A significant decrease in the bacterial counts (0.92–5.12 log10 CFU/sample) and an increase in phage titers (0–2.96 log10 PFU/sample) were observed in different food matrices tested. These results demonstrated that phage LPST10 is a promising candidate for controlling Salmonella contamination in foods owing to its safety and effectiveness.

Over the next decade the gravitational physics community will benefit from dramatic improvements in many technologies critical to the tests of gravity and gravitational-wave detection. The highly accurate deep space navigation, interplanetary laser ranging and communication, interferometry and metrology, high precision frequency standards, precise pointing and attitude control, together with the drag-free technologies will revolutionize the field of the experimental gravitational physics. Deep-space laser ranging will be ideal for gravitational-wave detection, and testing relativity and measuring solar-system parameter to an unprecedented accuracy. ASTROD I is such a mission with single spacecraft; it is the first step of ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) with 3 spacecraft. In this paper, we will present the progress of ASTROD and ASTROD I with emphases on the acceleration noises, mission requirement, charging simulation, drag-free control and low-frequency gravitational-wave sensitivity.