Effect of Double-Ovsynch and Presynch-Ovsynch on postpartum ovarian cysts and inactive ovary in high-yielding dairy cows.

Introduction: Optimizing the management of dairy cattle reproduction can reduce postpartum ovarian disease in high-yielding dairy cows and thus enhance ranch economic benefit. The hypothesis of this study was that the Double-Ovsynch (DO) protocol in high-producing dairy cows would result in a lower incidence of follicular cysts but a higher incidence of luteal cysts compared to those undergoing the Presynch-Ovsynch (PS) protocol. Methods: In this experiment, 384 cows (204 primiparous and 180 multiparous) were allocated to the DO group, which followed the protocol: GnRH-7d-PGF2α-3d-GnRH-7d-Ovsynch-56 h (GnRH-7d-PGF2α-56 h-GnRH-16hTAI), starting on 39 ± 3 days in milk (DIM). Additionally, 359 cows (176 primiparous and 183 multiparous) were assigned to the PS group, which followed the protocol: PGF2α-14d-PGF2α-12d-Ovsynch-56 h, starting on 31 ± 3 DIM. In DO, B-mode ultrasound examinations were conducted 1 day after the GnRH-7d-PGF2α-3d-GnRH protocol to diagnose the presence of ovarian diseases followed by reexamination after 7 days of suspected cases. In PS, B-mode ultrasound examinations were conducted 1 day after the PGF2α-14d-PGF2α protocol to diagnose the presence of ovarian diseases followed by reexamination after 7 days. For all cows confirmed to having ovarian diseases, a second B-mode ultrasound examination was conducted at the time of the second GnRH and timed artificial insemination (TAI). If the ovary showed a normal developing follicle in combination with normal ovulation, the ovarian disease was considered to be cured. Results: The current study revealed no significant difference in the overall incidence and cure rate of postpartum ovarian diseases between DO and PS (incidence rate: 3.9% vs. 6.7%, cure rate: 50% vs. 41.7%, DO vs. PS). Also, there was no significant difference in the incidence and cure rate of luteal cysts between DO and PS (incidence rate: 2.9% vs. 2.2%, cure rate: 50.0% vs. 50.0%). The incidence of follicular cysts was significantly lower in the DO group than in the PS group (0.8% vs. 2.8%, DO vs. PS, p = 0.037), but there was no significant difference in the cure rates (66.7% vs. 50%). The occurrence of inactive ovary was lower in DO compared to PS (0.2% vs. 1.7%, p = 0.047). There was no significant difference in the pregnancy rate between the DO and PS groups (48.2% vs. 41.8%), although the DO group had a higher rate. What is different from our assumption is that PS did not effectively reduce the incidence of postpartum luteal cysts.

High-energy high-dose microfocus X-ray computed tomography driven by high-average-current photo-injector.

High-energy, high-dose, microfocus X-ray computed tomography (HHM CT) is one of the most effective methods for high-resolution X-ray radiography inspection of high-density samples with fine structures. Minimizing the effective focal spot size of the X-ray source can significantly improve the spatial resolution and the quality of the sample images, which is critical and important for the performance of HHM CT. The objective of this study is to present a 9 MeV HHM CT prototype based on a high-average-current photo-injector in which X-rays with about 70µm focal spot size are produced via using tightly focused electron beams with 65/66µm beam size to hit an optimized tungsten target. In digital radiography (DR) experiment using this HHM CT, clear imaging of a standard 0.1 mm lead DR resolution phantom reveals a resolution of 6 lp/mm (line pairs per mm), while a 5 lp/mm resolution is obtained in CT mode using another resolution phantom made of 10 mm ferrum. Moreover, comparing with the common CT systems, a better turbine blade prototype image was obtained with this HHM CT system, which also indicates the promising application potentials of HHM CT in non-destructive inspection or testing for high-density fine-structure samples.

First demonstration of the FLASH effect with ultrahigh dose rate high-energy X-rays.

PURPOSE: This study aimed to evaluate whether high-energy X-rays (HEXs) of the PARTER (platform for advanced radiotherapy research) platform built on CTFEL (Chengdu THz Free Electron Laser facility) can produce ultrahigh dose rate (FLASH) X-rays and trigger the FLASH effect. MATERIALS AND METHODS: EBT3 radiochromic film and fast current transformer (FCT) devices were used to measure absolute dose and pulsed beam current of HEXs. Subcutaneous tumor-bearing mice and healthy mice were treated with sham, FLASH, and conventional dose rate radiotherapy (CONV), respectively to observe the tumor control efficiency and normal tissue damage. RESULTS: The maximum dose rate of HEXs of PARTER was up to over 1000 Gy/s. Tumor-bearing mice experiment showed a good result on tumor control (p < 0.0001) and significant difference in survival curves (p < 0.005) among the three groups. In the thorax-irradiated healthy mice experiment, there was a significant difference (p = 0.038) in survival among the three groups, with the risk of death decreased by 81% in the FLASH group compared to that in the CONV group. The survival time of healthy mice irradiated in the abdomen in the FLASH group was undoubtedly higher (62.5% of mice were still alive when we stopped observation) than that in the CONV group (7 days). CONCLUSION: This study confirmed that HEXs of the PARTER system can produce ultrahigh dose rate X-rays and trigger a FLASH effect, which provides a basis for future scientific research and clinical application of HEX in FLASH radiotherapy.

Enhanced microwave absorption of Fe nanoflakes after coating with SiO2 nanoshell.

Fe nanoflakes were prepared by the ball-milling technique, and then were coated with 20 nm-thick SiO(2) to prepare Fe/SiO(2) core-shell nanoflakes. Compared with the uncoated Fe nanoflakes, the permittivity of Fe/SiO(2) nanoflakes decreases dramatically, while the permeability decreases slightly. Consequently, reflection losses exceeding - 20 dB of Fe/SiO(2) nanoflakes are obtained in the frequency range of 3.8-7.3 GHz for absorber thicknesses of 2.2-3.6 mm, while the reflection loss of uncoated Fe nanoflakes almost cannot reach - 10 dB in the same thickness range. The enhanced microwave absorption of Fe/SiO(2) nanoflakes can be attributed to the combination of the proper electromagnetic impedance match due to the decrease of permittivity and large magnetic loss due to strong and broadband natural resonance. The key to the combination is the coexistence of the nanoshell microstructure and the nanoflake morphology.