Insect pheromones are crucial for survival and reproduction because they influence insect behavior, communication, and interactions within and outside the colony. Honey bees (Apis mellifera) have one of the most complex pheromonal communication systems. One pheromone, known as Queen Mandibular Pheromone (QMP), is released by the queen bee to regulate physiology, behavior, and gene expression in the female worker caste. The pheromone acts as a signal of queen presence that suppresses worker reproduction. In the absence of reproduction, young workers focus on taking care of the queen and larvae, known as nurse tasks, while older workers forage. In nurse bees, QMP has fundamental physiological impacts, including increasing abdominal lipid stores and increasing the protein content of hypopharyngeal glands (HPG). The HPG are worker-specific glands that can synthesize royal jelly used in colony nourishment. In workers, larger HPG signifies the ability to secrete royal jelly, while shrunken glands are characteristic of foragers that do not make jelly. While it is known that QMP increases abdominal lipid stores, the underlying mechanism is unclear: Does the pheromone simply make workers consume more pollen which provides lipids and protein, or does QMP also increase lipogenesis? In this study, I measured abdominal lipogenesis as fatty acid synthase (FAS) activity and monitored abdominal protein content and HPG size in caged, nurse-aged worker bees. In cages, workers were exposed to QMP or not, and they were provided with a lipid less diet in a full factorial design experiment. I found that QMP did not influence abdominal FAS activity or protein, but significantly increased HPG size. The data also revealed a significant positive correlation between abdominal protein and HPG size. My results do not support the idea that QMP modulates lipogenesis in worker bees, but my data can be interpreted to reflect that QMP mobilizes abdominal protein for the production of jelly in the HPG. This finding is in line with a previous study revealing a role of honey bee Brood Pheromone in mobilization of a major protein used in jelly production. Overall, my results support a fundamental role of QMP in worker metabolic processes associated with colony nourishment.
Studying the so-called ”hidden” phases of quantum materials—phases that do not exist under equilibrium conditions, but can be accessed with light—reveals new insights into the broader field of structural phase transitions. Using terahertz irradiation as well as hard x-ray probes made available by x-ray free electron lasers (XFELs) provides unique capabilities to study phonon dispersion in these materials. Here, we study the cubic peak of the quantum paraelectric strontium titanate (SrTiO3, STO) below the 110 K cubic-to-tetragonal tran- sition. Our results reveal a temperature and field strength dependence of the transverse acoustic mode in agreement with previous work on the avoided crossing occurring at finite wavevector, as well as evidence of anharmonic coupling between transverse optical phonons and a fully symmetric A1g phonon. These results elucidate previous optical studies on STO and hold promise for future studies on the hidden metastable phases of quantum materials.
Maternal morbidity and mortality rates in the United States continues to rise, with a wide range of contributing factors such as mental illness, cardiovascular disease and systemic inequality. This metastudy provides a holistic view of the research that has been published on the issue of U.S. maternal healthcare from 2000-2022. The patterns of publications on specific topics over time can tell us what is perceived as a current major cause by physicians, public leaders, researchers, and the public. A deeper dive into systemic inequality as a cause of maternal morbidity and mortality highlights it as a major contributor to these high rates, but that progress is slowly being made through the implementation of detection and prevention tactics, as well as accessible prenatal programs and care.
Ultrasonic transducer stacks (modules), which had failed or passed during pulse-echo sensitivity testing, were received from Consortium X. With limited background information on these stacks, the central theme was to determine the origin(s) of failure via the use of thermal and physicochemical characterization techniques.
The optical and scanning electron microscopy revealed that contact electrode layers are discontinuous in all samples, while delaminations between electrodes and pad layer were observed in failed samples. The X-ray diffraction data on the pad PZT revealed an overall c/a ratio of 1.022 ratio and morphotropic boundary composition, with significant variations of the Zr to Ti ratio within a sample and between samples. Electron probe microanalysis confirmed that the overall Zr to Ti ratio of the pad PZT was 52/48, and higher amounts of excess PbO in failed samples, whereas, inductively coupled plasma mass spectrometry revealed the presence of Mn, Al, and Sb (dopants) and presence of Cu (sintering aid) in in this hard (pad) PZT. Additionally, three exothermic peaks during thermal analysis was indicative of incomplete calcination of pad PZT. Moreover, transmission electron microscopy and scanning transmission electron microscopy revealed the presence of parylene at the Ag-pad PZT interface and within the pores of pad PZT (in failed samples subjected to electric fields). This further dilutes the electrical, mechanical, and electromechanical properties of the pad PZT, which in turn detrimentally influences the pulse echo sensitivity.
The use of ethanol as carbon source with or without water steam provides uniform carbonaceous deposition on ZnO nanowire templates. The amount of as-deposited carbonaceous material can be controlled by reaction temperature and reaction time. Due to the catalytic property of ZnO surface, the thicknesses of carbonaceous layers are typically in nanometers. Different methods to remove the ZnO templates are explored, of which hydrogen reduction at temperatures higher than 700 °C is most efficient. The ZnO templates can also be removed under ethanol environment, but the temperatures need to be higher than 850 °C for practical use.
Characterizations of hollow carbon nanofibers show that the hollow carbon nanostructures have a high specific surface area (>1100 m2/g) with the presence of mesopores (~3.5 nm). The initial data on energy storage as electrodes of electrochemical double layer capacitors show that high specific capacitance (> 220 F/g) can be obtained, which is related to the high surface area and unique porous hollow structure with a thin wall.