Nanoscale chemical characterization of materials and interfaces by tip-enhanced Raman spectroscopy.

Materials and their interfaces are the core for the development of a large variety of fields, including catalysis, energy storage and conversion. In this case, tip-enhanced Raman spectroscopy (TERS), which combines scanning probe microscopy with plasmon-enhanced Raman spectroscopy, is a powerful technique that can simultaneously obtain the morphological information and chemical fingerprint of target samples at nanometer spatial resolution. It is an ideal tool for the nanoscale chemical characterization of materials and interfaces, correlating their structures with chemical performances. In this review, we begin with a brief introduction to the nanoscale characterization of materials and interfaces, followed by a detailed discussion on the recent theoretical understanding and technical improvements of TERS, including the origin of enhancement, TERS instruments, TERS tips and the application of algorithms in TERS. Subsequently, we list the key experimental issues that need to be addressed to conduct successful TERS measurements. Next, we focus on the recent progress of TERS in the study of various materials, especially the novel low-dimensional materials, and the progresses of TERS in studying different interfaces, including both solid-gas and solid-liquid interfaces. Finally, we provide an outlook on the future developments of TERS in the study of materials and interfaces.

Ultralow-Frequency Tip-Enhanced Raman Scattering Discovers Nanoscale Radial Breathing Mode on Strained 2D Semiconductors.

Collective excitations including plasmons, magnons, and layer-breathing vibration modes emerge at an ultralow frequency (<1 THz) and are crucial for understanding van der Waals materials. Strain at the nanoscale can drastically change the property of van der Waals materials and create localized states like quantum emitters. However, it remains unclear how nanoscale strain changes collective excitations. Herein, ultralow-frequency tip-enhanced Raman spectroscopy (TERS) with sub-10 nm resolution under ambient conditions is developed to explore the localized collective excitation on monolayer semiconductors with nanoscale strains. A new vibrational mode is discovered at around 12 cm-1 (0.36 THz) on monolayer MoSe2 nanobubbles and it is identified as the radial breathing mode (RBM) of the curved monolayer. The correlation is determined between the RBM frequency and the strain by simultaneously performing deterministic nanoindentation and TERS measurement on monolayer MoSe2. The generality of the RBM in nanoscale curved monolayer WSe2 and bilayer MoSe2 is demonstrated. Using the RBM frequency, the strain of the monolayer MoSe2 on the nanoscale can be mapped. Such an ultralow-frequency vibration from curved van der Waals materials provides a new approach to study nanoscale strains and points to more localized collective excitations to be discovered at the nanoscale.

Use of Period Analysis to Timely Assess Five-Year Relative Survival for the Patients With Bone Cancer.

Background: While timely assessment of long-term survival for patients with bone cancer is essential for evaluation on early detection and prognosis level of treatment of bone cancer, those data are extremely scarce in China. We aimed to timely and accurately assess long-term survival for patients with bone cancer in Eastern China. Methods: Patients diagnosed with bone cancer during 2004 - 2018 from four cancer registries with high-quality data from Taizhou, Eastern China were included. Five-year relative survival (RS) of bone cancer patients was calculated by period analysis for overall and the stratification. We further predicted 5-year RS during upcoming 2019 - 2023 using a model-based period analysis and survival data during 2004 - 2018. Results: Overall, 5-year RS for patients with bone cancer during 2014 - 2018 reached 46.6%, being 40.8% for male and 51.0% for female. Five-year RS declined along with aging, decreasing from 58.9% for age < 45 years to 41.5% for age > 60 years, while 5-year RS for urban area was higher compared to rural area (59.1% vs. 44.3%). The 5-year RS during upcoming 2019 - 2023 reached 48.3%. We found a clear upward trend in 5-year RS during 2004 - 2023 for overall and the stratification by sex, age at diagnosis, and region. Conclusions: We found that, for first time in China using period analysis, most up-to-date 5-year RS for patients with bone cancer reached 46.6% during 2014 - 2018, and is projected to reach 48.3% for the period 2019 - 2023, which has important implications for timely evaluation on early detection and prognosis level of treatment for patients with bone cancer in Eastern China.

Signal2signal: Pushing the Spatiotemporal Resolution to the Limit by Single Chemical Hyperspectral Imaging.

There is growing interest in developing a high-performance self-supervised denoising algorithm for real-time chemical hyperspectral imaging. With a good understanding of the working function of the zero-shot Noise2Noise-based denoising algorithm, we developed a self-supervised Signal2Signal (S2S) algorithm for real-time denoising with a single chemical hyperspectral image. Owing to the accurate distinction and capture of the weak signal from the random fluctuating noise, S2S displays excellent denoising performance, even for the hyperspectral image with a spectral signal-to-noise ratio (SNR) as low as 1.12. Under this condition, both the image clarity and the spatial resolution could be significantly improved and present an almost identical pattern with a spectral SNR of 7.87. The feasibility of real-time denoising during imaging was well demonstrated, and S2S was applied to monitor the photoinduced exfoliation of transition metal dichalcogenide, which is hard to accomplish by confocal Raman spectroscopy. In general, the real-time denoising capability of S2S offers an easy way toward in situ/in vivo/operando research with much improved spatial and temporal resolution. S2S is open-source at https://github.com/3331822w/Signal2signal and will be accessible online at https://ramancloud.xmu.edu.cn/tutorial.

Maxillary pain is the first indication of the presence of multiple myeloma: A case report.

Multiple myeloma is a primary malignancy of bone marrow characterized by the clonal proliferation of plasma cells and production of monoclonal immunoglobulin. The disease occurs more frequently in males, with the average age at diagnosis being ∼60 years. The first manifestation of multiple myeloma is varied and depends on the sites and extent of involvement. The predominant clinical symptoms of multiple myeloma are associated with bone pain and renal dysfunction. Neoplastic cells usually produce large amounts of monoclonal immunoglobulin light or heavy chains that can be detected in serum or urine, while plasmacytoma may be identified on marrow biopsy. The present study reported on the case of a 69-year-old male patient presenting with a complaint of a painful lesion in the left maxilla. Physical examination, imaging, laboratory investigations and biopsy were conducted, confirming the diagnosis of multiple myeloma. The results obtained suggest that the dentist should address oral manifestations as first indications of multiple myeloma.

Serum DJ-1 as a diagnostic marker and prognostic factor for pancreatic cancer.

OBJECTIVE: DJ-1 is an oncoprotein secreted by cancer cells. Therefore, it might be a diagnostic or prognostic biomarker for pancreatic cancer (PC). METHODS: The study involved 47 patients with PC, 43 with chronic pancreatitis, and 40 healthy subjects. We assayed the serum level of DJ-1 and the conventional tumor marker carbohydrate antigen 19-9 (CA 19-9) to define the diagnostic and prognostic value of DJ-1 for PC. RESULTS: Serum DJ-1 level was elevated in patients with PC compared with those with chronic pancreatitis and healthy individuals. The area under the curve (AUC) of serum DJ-1 was higher than CA 19-9 (DJ-1 vs. CA19-9, 0.8735 ± 0.0356 vs. 0.6647 ± 0.0572 ng/mL), and an 87.5% sensitivity was reached with a combination of serum DJ-1 and CA19-9. No association of serum DJ-1 level with tumor node metastasis (TNM) classification or tumor resectability was found. However, after resection, the median serum DJ-1 level was decreased from 2.00 to 0.78 ng/mL. In addition, higher serum DJ-1 was correlated with shorter overall survival as analyzed by both Kaplan-Meier test (P = 0.018) and COX regression analysis (P = 0.013). The median overall survival time of PC patients with serum DJ-1 level greater than or equal to 2.06 ng/mL was 7.00 ± 1.11 months, whereas that of patients with lower DJ-1 levels was 13.0 ± 2.5 months. CONCLUSIONS: These findings indicate the potential clinical significance for serum DJ-1 level to be used for the diagnosis and prognosis prediction of patients with PC.