Magnetic field-induced ring currents in aromatic and antiaromatic molecules cause characteristic shielding and deshielding effects in the molecules' NMR spectra. However, it is difficult to analyze (anti)aromaticity directly from experimental NMR data if a molecule has multiple ring current pathways. Here we present a method for using the Biot-Savart law to deconvolute the contributions of different ring currents to the experimental NMR spectra of polycyclic compounds. This method accurately quantifies local and global ring current susceptibilities in porphyrin nanorings, as well as in a bicyclic dithienothiophene-bridged [34]octaphyrin. There is excellent agreement between ring current susceptibilities derived from both experimental and computationally-predicted chemical shifts, and with ring currents calculated by the GIMIC method. Our method can be applied to any polycyclic system, with any number of ring currents, provided that appropriate NMR data are available.
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http://dx.doi.org/10.1039/d2sc05923a | DOI Listing |
Sensors (Basel)
December 2024
State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China.
To avoid wear and tear of the slip ring due to electrical corrosion, the slip ring needs to undergo the running-in process under atmospheric conditions without current after assembly. To address the urgent demand for long-service capability space conductive slip rings in the aerospace field, the running-in behavior and failure mechanism between the AgCuNi alloy and Au-electroplated layer are investigated using a ball-on-disc tribometer in this paper. The results show that the transfer film composed of Au plays an important role in modifying the friction during the sliding process.
View Article and Find Full Text PDFJ Orthop Surg Res
January 2025
Center for Rehabilitation Research, School of Allied Health Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
Background: The sacroiliac joints (SIJ) are specialized articulations in the pelvis that allow load transfer between the upper and lower body. Traumatic pelvic disruption often requires surgical fixation of at least one of these joints. Subsequent SIJ pain is associated with asymmetries in joint laxity or stiffness.
View Article and Find Full Text PDFInt J Surg Case Rep
December 2024
Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India. Electronic address:
Introduction And Importance: Adenosquamous carcinoma (ASC) of the colon is a rare malignancy, representing approximately 0.06 % of colorectal cancers (CRC). It is characterized by the coexistence of adenocarcinoma and squamous cell carcinoma components.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS), Shanghai 201800, China.
The integration of a photodetector that converts optical signals into electrical signals is essential for scalable integrated lithium niobate photonics. Two-dimensional materials provide a potential high-efficiency on-chip detection capability. Here, we demonstrate an efficient on-chip photodetector based on a few layers of MoTe on a thin film lithium niobate waveguide and integrate it with a microresonator operating in an optical telecommunication band.
View Article and Find Full Text PDFCurr Top Med Chem
January 2025
Department of Pharmacy, Harlal Institute of Management and Technology (HIMT), Plot no-8, knowledge park-1,Greater Noida, Uttar Pradesh -201310, India.
Background: A heterocyclic molecule containing five rings, three carbon atoms, two nitrogen atoms, and a single endocyclic bond is called pyrazoline. Because of its intriguing electrical characteristics and potential for dynamic applications, pyrazoline is one type of electron-rich nitrogen carrier that is becoming more and more popular. This study synthesizes pyrazoline derivatives using a variety of techniques to demonstrate a highly biological function.
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