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Refereed/Peer-reviewed Background: Upper arm lymphedema is a common complication one year after breast cancer surgery, which profoundly impacts patients' quality of life. Case summary: We reported a case of lymphedema induced by prolonged sun exposure 11 years after breast cancer surgery. Conclusion: Breast screening, patient education and follow-up after hospital discharge could help to prevent upper-arm lymphedema.

BACKGROUND Lymphomas are the second most common malignancy of the head and neck. In this region, the vast majority of extranodal lymphomas are located in the palatine tonsil, accounting for about 51%. Tonsillar lymphomas are aggressive tumors with intermediate- or high-grade histology. We here report a case of primary non-Hodgkin’s lymphoma of the palatine tonsil and analyze its ultrasound features. CASE SUMMARY A 40-year-old man presented with right palatine tonsil swelling for 2 mo after a cold, accompanied by dysphagia, snoring, and suffocation. He had no sore throat, fever, or history of upper respiratory tract infection or tuberculosis. The patient was generally in good health and denied other diseases. He was diagnosed with acute tonsillitis initially and treated with antibiotics for 7 d. However, there was no improvement with the treatment. Tonsil biopsy and ultrasound-guided biopsy of the biggest lymph node of the right neck showed the typical pathology of non-Hodgkin lymphoma. CONCLUSION Primary lymphoma of the tonsils is rare, and its diagnosis is challenging. Ultrasound is a useful modality in diagnosing oropharyngeal diseases, and can clearly show the features of this tumor, but the final diagnosis should be established by histology.

The groundwater level has been continuously decreasing due to climate change and long-time overexploitation in the Xiong’an New Area, North China, which caused the enhanced mixing of groundwater in different aquifers and significant changes in regional groundwater chemistry characteristics. In this study, groundwater and sediment pore-water in drilling cores obtained from a 600 m borehole were investigated to evaluate hydrogeochemical processes in shallow and deep aquifers and paleo-environmental evolution in the past ca. 3.10 Ma. Results showed that there was no obvious change overall in chemical composition along the direction of groundwater runoff, but different hydrochemical processes occurred in shallow and deep groundwater in the vertical direction. Shallow groundwater ( 1000 mg/L) and high concentrations of Mn and Fe, while deep groundwater had better water quality with lower salinity. The high TDS values mostly occurred in aquifers with depth 500 m below land surface. Water isotopes showed that aquifer pore-water mostly originated from meteoric water under the influence of evaporation, and aquitard pore-water belonged to Paleo meteoric water. In addition, the evolution of the paleoclimate since 3.10 Ma BP was reconstructed, and four climate periods were determined by the δ18O profiles of pore-water and sporopollen records from sediments at different depths. It can be inferred that the Quaternary Pleistocene (0.78–2.58 Ma BP) was dominated by the cold and dry climate of the glacial period, with three interglacial intervals of warm and humid climate. What’s more, this study demonstrates the possibilities of the applications of pore-water on the hydrogeochemical study and further supports the finding that pore-water could retain the feature of paleo-sedimentary water. © 2021 China Geology Editorial Office.

On July 4, 2006, an earthquake of MS5.1 took place in Wen’an, Hebei Province, just at the south center of China’s Capital Circle area digital seismograph network. It is the strongest event recorded ever since the network went into operation in 2002. We processed the vast amounts of phase data yielded by the 107 digital seismic stations between 2002∼2007 using Wadati method. In order to improve the precision and stability of shear and compressional wave velocities (vP/vS) calculation, we impose a number of restrictions on the computation environment and condition, e.g., the earthquakes are densely concentrated, selected stations are limited in range, the number of stations involved in the computation is larger than 5 and linear fitting features high precision and small error. Under these restrictions, the study shows that vP/vS in and around Wen’an and Tangshan underwent a normal-low-normal process one year before Wen’an earthquake, vP/vS became obviously low and the low ratio lasted for about one year, meanwhile, little variation of vP/vS was seen in Xingtai, northwest of Beijing, southwest of Beijing, Beijing-Tianjin and Beijing; after the quake, the vP/vS returned normal in Wen’an and Tangshan. Error and stability analysis of the calculated result for vP/vS shows it is convincible that anomaly appeared in and around Wen’an and Tangshan before Wen’an earthquake.

This paper presents an overview of mining seismicity, gas outburst and their origin. The internal relation of mining seismicity and gas outburst in the dynamic process is studied on the basis of the fact that these disasters sometimes occur simultaneously. The examples show a close relationship between mining seismicity and gas outburst in high gassy coal mines. It is proposed that strong mine shocks plus the response of low value and delay time are early warning signals. The mechanism of the relationship between mining seismicity and gas outburst is analyzed by using the location of mining shocks, focus mechanism, cause of mining shocks and conditions of gas outburst. The trigger action of gas fluid on mining shocks, especially the effect of the anomalous property of supercritical fluid on the preparation and occurrence of mining shocks is discussed. According to the similarity between mining-induced earthquakes and tectonic earthquakes in terms of mechanism, the significance of the above results in the study of physics of earthquake source is also discussed.

In the paper, we analyze 117 moderate-strong earthquakes occurred in Chinese mainland (MS≥5.5 in the east and MS≥6.0 in the west) since 1970, among them, 11 earthquakes (about 9%) have direct foreshocks and 63 earthquakes (about 51%) have generalized foreshocks. The predominant time interval between foreshock and main earthquake is no more than 30 days with a spatial distance less than 50 km and a magnitude difference over 1. From the digital seismic data in liaoning Province, we know that direct foreshock had an obvious shear-stress background before the MS=5.6 and MS=5.1 Xiuyan earthquakes occurred on Nov. 29, 1999 and Jan.15, 2000.

Statistical properties of reported earthquake precursors show apparent focal mechanism dependence. Intensity of anomaly is described by the ‘anomaly ratio’ as defined by the number of stations/items reporting anomalies before the target earthquake over the number of stations/items in operation around the target earthquake. Variation of the ‘anomaly ratio’ with the magnitude of the target earthquake was studied for dip-slip earthquakes all over China, strike-slip earthquakes in eastern China, and strike-slip earthquakes in western China, respectively. It is observed that for strike-slip earthquakes, the ‘anomaly ratio’ increases linearly with the magnitude of the target earthquake, while earthquakes in eastern China and western China have different slopes. For dip-slip earthquakes, however, the ‘anomaly ratio’ has no statistically significant change with the magnitude of the target earthquake. Limited data imply that the ‘anomaly ratio’ seems proportional to the apparent stress of the target earthquake. The result might be heuristic for the analysis of candidate earthquake precursors.

In order to explore the predictability of earthquakes, the distribution characteristics of seismic activity in time and space for Huabei and Tangshan area are studied by multifractal theory and box-counting method. The generalized dimensions d(q) of seismic activity energy are estimated, and the geometry structure of multifractal spectrum of them is also analyzed. The results showed that the values of the generalized dimensions are obviously low, and there is a low value process before the large earthquake occurrence and the f(α) spectrum is partial to right. A similar characteristic is found in Tangshan area. The anomalous phenomena revealed the physics essence and some instability before interior crisis of seismogenic system.

Power spectral characteristics of the seismic activities before and after the seven large earthquake — Haicheng, Tangshan, Lancang, Longling, Mabian, Puer and Songpan are studied by spectrum analysis method. The results show that they all have continuous power spectrum and aperiodic behaviour. When the time away from the large earthquake occurrence, the characteristics of the seismic activities are obviously accompanied by stochastic components. About one year before main shock, the moving orbits constructed by spectrum amplitudes showed the contracting tendency. And the properties during that time may display as flicker noise. One’s another time almost mixed whole phase space. But the essence of seismic activities after main shocks is a chaotic state accompanied with much noises.