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Distant blazar discovery supports rapid black hole formation in the early universe

Bioengineers at Caltech have developed a new imaging technology that could offer surgeons a fast and cost-effective way to image tissue samples in the operating room to determine whether the entirety of a tumor has been removed or if additional cuts are needed. The researchers describe the new technique, which they call parallel ultraviolet photoacoustic microscopy (PUV–PAM), in a paper in Science Advances . In the current leading method to quickly sample and image tissue samples obtained during surgery, a biopsy is conducted to obtain a tissue sample that is then frozen, stained to enhance viewability, and sliced into thin sections that are mounted on glass slides. Then, an optical microscope for histology is used for a detailed examination of the tissues. The presence of tumor cells on the surface of a tissue sample indicates that the surgeon has cut through, not around, the tumor—meaning that a portion of the tumor remains inside the patient, who will then need a follow-up surgery to have more tissue removed. Frozen section pathology faces challenges such as tissue artifacts and reduced staining quality, affecting diagnostic accuracy and surgical decision-making. Caltech's new PUV–PAM technique would simplify and speed up that process, removing the need to freeze, section, or stain tissue samples. Even relatively thick samples with irregular surfaces that are typically too thick to image with microscopy can be directly imaged using the new method. That could give oncologists the ability to analyze biopsy samples right in the operating room , providing them with the ability to remove additional tissue as deemed necessary without follow-up surgeries. "We hope this new imaging system can provide more opportunities for intraoperative pathological examination of slide-free specimens in oncology surgeries. We believe it has the potential to revolutionize intraoperative histology," says Rui Cao, lead author of the new paper, who conducted the work in the lab of Lihong Wang, Caltech's Bren Professor of Medical Engineering and Electrical Engineering. Cao is now an assistant professor of biomedical engineering at Case Western Reserve University. The new approach is based on a technique pioneered by Wang's lab called photoacoustic microscopy (PAM). Using PAM, a tissue sample is excited with a low-energy laser, which causes the tissue to vibrate. The system measures the ultrasonic waves emitted by the vibrating tissue. Because the nuclei of cells absorb more light than the surrounding material, PAM reveals the sizes and distribution of those nuclei along with the packing density of cells. Cancerous tissue tends to have larger nuclei and more densely packed cells. Wang's lab has previously developed several PAM systems for imaging bone and breast tissue samples. But to make the systems viable for use within the operating room, they needed to significantly increase the technique's imaging speed, which has been limited by the speed of the ultraviolet lasers used to excite the tissues. To bypass this laser speed problem, the researchers divided a single laser beam into eight smaller laser "spots" all operating in parallel. This makes the imaging much faster because the spots can cover the sample area much faster. Furthermore, PUV-PAM uses a combination of two scanning techniques to achieve fast imaging speed for slide-free tissues. Taken together, these enhancements make the new technique about 40 times faster than state-of-the-art methods previously developed in Wang's laboratory. "With the current system, we can image a 1 cm 2 sample at 1.3 micron resolution within about five minutes," Cao says. "And we demonstrate in the paper that this technique is effective in a variety of tissue types." "We believe that leveraging advanced ultraviolet lasers with higher pulse rates and integrating more parallel channels could significantly enhance the speed of imaging further with this technique," says Wang, who is also the Andrew and Peggy Cherng Medical Engineering Leadership Chair and executive officer for medical engineering at Caltech. More information: Rui Cao et al, Optical-resolution parallel ultraviolet photoacoustic microscopy for slide-free histology, Science Advances (2024). DOI: 10.1126/sciadv.ado0518

(Source: Nasdaq) Wall Street’s main indexes rose on Wednesday, regaining some ground lost in the previous session, as investors anticipated an interest rate cut from the Federal Reserve and awaited clues on what policymakers could do in 2025. The Fed is widely expected to reduce interest rates by 25 basis points at its last meeting of the year. The announcement is expected at 2 p.m. ET on Wednesday. With a rate cut expected by most investors, more focus is on the Fed’s summary of economic projections (SEP), which includes policymakers’ forecasts for the economy and the “dot plot” of their expectations for interest rates over the longer term. Comments from Chair Jerome Powell will also be watched for clues on how the central bank will determine policy next year, as recent economic data has shown both strong growth and persistent inflation that could keep the Fed from cutting rates as much as previously forecast. “The prevailing view is that the Fed will accompany the rate cut with hawkish comments, indicating that it’s time to take a pause in loosening monetary policy,” said David Morrison, senior market analyst at Trade Nation. “This seems wise, given the incoming Trump administration, the recent uptick in inflation, decent U.S. economic growth and the strength of the U.S. stock market.” At 12:00 p.m. ET, the Dow Jones Industrial Average (.DJI), rose 160.68 points, or 0.37%, to 43,610.58, the S&P 500 (.SPX), gained 12.56 points, or 0.21%, to 6,063.10 and the Nasdaq Composite (.IXIC), gained 37.96 points, or 0.19%, to 20,147.02. Higher interest rates are typically negative for the equity market, making less risky investments more attractive and pressuring companies’ stock prices as their growth slows. Tesla (TSLA.O), edged up 1%, reversing early losses, after rising over 14% in the last three sessions, while AI giant Nvidia (NVDA.O), jumped 3.5% after hitting an over two-month low on Tuesday. Birkenstock (BIRK.N), advanced 6.3% after the footwear maker beat market expectations for fourth-quarter results, while General Mills (GIS.N), fell 2.5% as the Cheerios maker slashed its annual profit forecast. The Dow is set to snap a nine-session losing streak, its longest since February 1978, lifted by UnitedHealth Group’s (UNH.N), 3.2% rise. Despite some jitters over future Fed policy, stocks are on track to end the year strong with the S&P 500 up over 27%, the Nasdaq up over 34% and the Dow up nearly 16%. The rally has been fueled by technology companies that capitalized on the euphoria around artificial intelligence, the prospects of a lower rate environment and hope of pro-business policies from the incoming Donald Trump administration. Crypto-focused stocks slipped as bitcoin fell more than 2%. MARA Holdings (MARA.O), and Riot Platforms (RIOT.O), down 1.5% and 2.2%, respectively. Advancing issues outnumbered decliners by a 1.03-to-1 ratio on the NYSE, while declining issues outnumbered advancers by a 1.02-to-1 ratio on the Nasdaq. The S&P 500 posted five new 52-week highs and eight new lows, while the Nasdaq Composite recorded 67 new highs and 106 new lows. Source: Reuters (Reporting by Lisa Mattackal and Purvi Agarwal in Bengaluru; Editing by Maju Samuel)ASP Isotopes Inc. Shareholder Notice: Robbins LLP Reminds Investors of the ASPI Securities ...