1.Characterization of the shared microbial profile between infected extraction socket and maxillary sinus in patients with odontogenic maxillary sinusitis
LU Chang ; QIN Yicheng ; WANG Ye ; XU Min ; LIN Jiang
Journal of Prevention and Treatment for Stomatological Diseases 2025;33(12):1041-1052
Objective:
To explore whether infected granulation tissue in tooth extraction sockets and maxillary sinus pus share a common microbial profile at the subspecies-strain level in patients with odontogenic maxillary sinusitis (OMS), providing evidence for infection origin tracing and precise antimicrobial therapy in OMS.
Methods:
This study was reviewed and approved by the institutional ethics committee. Nine consecutive OMS patients who underwent synchronous endoscopic sinus surgery and tooth extraction from October 2020 to August 2022 were prospectively enrolled. Under general anesthesia, paired specimens were collected from infected extraction-socket granulation tissue and maxillary sinus pus. Bacterial DNA was extracted, and the full-length 16S rRNA gene was sequenced on the Illumina MiSeq platform. Amplicon sequence variants (ASVs) were generated using the DADA2 algorithm and taxonomically annotated to the subspecies level against the Human Oral Microbiome Database. The detection rate of shared ASVs between the two sites and their relative abundance in sinus pus were compared. Functional profiles were predicted using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2 (PICRUSt2).
Results:
Shared ASVs were identified in seven of the nine patients. Fusobacterium, Parvimonas, Porphyromonas, and Prevotella were the most prevalent genera. Porphyromonas gingivalis and Fusobacterium nucleatum were co-detected in multiple patients, with relative abundances exceeding 5% in sinus pus of several cases. Identical ASVs of F. nucleatum or Porphyromonas spp. were detected in six patients; the ASVs corresponding to F. nucleatum subsp. nucleatum and Porphyromonas endodontalis were significantly more abundant in sinus pus than in extraction-socket granulation tissue. PICRUSt2 functional profiling revealed that the proportion of socket-derived microbes in sinus pus was strongly correlated with 10 pathways, including ferroptosis, adipocytokine signaling, and apoptosis, et al. Except for biotin metabolism, the remaining pathways showed weak correlation with the proportion of extraction socket-derived ASVs in the extraction-socket granulation tissue and maxillary sinus pus. Removing F. nucleatum ASVs markedly attenuated these associations
Conclusion
At the subspecies-strain level, this study confirmed the presence of a shared microbial profile between infected extraction-socket granulation tissue and maxillary sinus pus in patients with odontogenic maxillary sinusitis. The co-detected subspecies-strains with high relative abundance in maxillary sinus pus included Fusobacterium nucleatum subsp. nucleatum and Porphyromonas endodontalis, thus providing strain-level microbiological evidence for infection source tracing in OMS.
2.Constructing core outcome set for clinical research on traditional Chinese medicine treatment of post-stroke aphasia.
Ya-Nan MA ; Min-Jie XU ; Yu-Ai YANG ; Jian CHEN ; Qiao-Sheng REN ; Ying LI ; Jing-Ling CHANG
China Journal of Chinese Materia Medica 2025;50(1):238-253
According to the principle and current domestic and international construction processes of core outcome set(COS) and the characteristics of post-stroke aphasia, this study built COS with evidence-based support for traditional Chinese medicine(TCM) treatment of post-stroke aphasia. Firstly, a comprehensive review was conducted on the articles about the TCM treatment of post-stroke aphasia that were published in the four major Chinese databases, three major English databases, and three clinical registration centers over the past five years. The articles were analyzed and summarized, on the basis of which the main part of the COS for clinical research on the TCM treatment of post-stroke aphasia was formed. Secondly, clinical doctors and related nursing personnel were interviewed, and important outcome indicators in the clinical diagnosis and treatment process were supplemented to form a pool of core outcome indicators. Two rounds of Delphi surveys were carried out to score the importance of the core outcome indicators in the pool. Finally, a consensus meeting of experts was held to establish the COS for clinical research on the TCM treatment of post-stroke aphasia. The final COS included a total of 268 studies [236 randomized controlled trials(RCTs), 21 Meta-analysis, and 11 clinical registration protocols] and 20 open questionnaire survey results. After two rounds of Delphi surveys, a total of 14 outcome indicators and their corresponding measurement tools were included in the expert consensus meeting. The final expert consensus meeting determined the COS for post-stroke aphasia, which included 9 indicator domains and 12 outcome indicators.
Humans
;
Aphasia/therapy*
;
Stroke/complications*
;
Medicine, Chinese Traditional
;
Drugs, Chinese Herbal/therapeutic use*
;
Treatment Outcome
3.Studies on common irritant components in three different base sources of Polygonati Rhizoma.
Yu-Xin GU ; Hong-Li YU ; Min SHEN ; Xin-Zhi WANG ; Kui-Long WANG ; Jie CAO ; Qian-Lin CHEN ; Yan-Qing XU ; Chang-Li SHEN ; Hao WU
China Journal of Chinese Materia Medica 2025;50(12):3223-3231
To explore the common irritant components in different base sources of Polygonati Rhizoma(PR). A rabbit eye irritation experiment was conducted to compare the irritant effects of raw products of Polygonatum kingianum, P. officinale, and P. multiflorum. The irritant effects of different solvent extraction parts and needle crystals of PR were compared, and the irritant components were screened. The morphology and structure of the purified needle crystal of PR were observed by microscope and scanning electron microscope and characterized by X-ray diffraction. Rabbit eye irritation and mouse abdominal inflammation model were used to evaluate rabbit eye irritation scores, inflammatory mediators, inflammatory factors levels in the peritoneal exudate of mice, with the peritoneal pathological section used as indicators. The inflammatory effect of needle crystals of PR was studied, and the content of calcium oxalate in three kinds of PR was determined by HPLC. The common protein in three kinds of PR was screened and compared by double enzymatic hydrolysis in solution combined with mass spectrometry. The results showed that three kinds of PR raw products had certain irritant effects on rabbit eyes, among which P. kingianum had the strongest irritant effect. There were no obvious irritant effects in the different solvent extraction parts of P. kingianum. Compared with the blank group, the needle crystal of PR had a significant irritant effect on rabbit eyes, and the inflammatory mediators and inflammatory factors in the peritoneal exudate were significantly increased(P<0.05) in a dose-dependent manner. Meanwhile, the peritoneal tissue of mice was damaged with significant inflammatory cell infiltration after intraperitoneal injection of needle crystal, indicating that needle crystal had an inflammatory effect. Microscope and scanning electron microscope observations showed that the needle crystals of PR were slender, with a length of about 100-200 μm and sharp ends. X-ray diffraction analysis showed that the needle crystals of PR were calcium oxalate monohydrate crystals. The results of HPLC showed that the content of calcium oxalate in P. kingianum was the highest among the three kinds of PR. It was speculated that the content of needle crystal in P. kingianum was higher than that in P. officinale and P. multiflorum, which was consistent with the results of the rabbit eye irritation experiment. The results of mass spectrometry showed that ribosome inactivating protein and mannose/sialic acid binding lectin were related to inflammation and cell metabolism in all three kinds of PR. There was no obvious irritant effect in different solvent extracts of PR. The calcium oxalate needle crystal contained was the main irritant component of PR, and three kinds of PR contained common ribosome inactivating protein and mannose/sialic acid binding lectin, which may be related to the inflammatory irritant effect of PR.
Animals
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Rabbits
;
Mice
;
Polygonatum/chemistry*
;
Drugs, Chinese Herbal/toxicity*
;
Rhizome/chemistry*
;
Male
;
Eye/drug effects*
;
Female
;
Humans
4.Mechanism of Euphorbiae Ebracteolatae Radix processed by milk in reducing intestinal toxicity.
Chang-Li SHEN ; Hao WU ; Hong-Li YU ; Hong-Mei WEN ; Xiao-Bing CUI ; Hui-Min BIAN ; Tong-la-Ga LI ; Min ZENG ; Yan-Qing XU ; Yu-Xin GU
China Journal of Chinese Materia Medica 2025;50(12):3204-3213
This study aimed to investigate the correlation between changes in intestinal toxicity and compositional alterations of Euphorbiae Ebracteolatae Radix(commonly known as Langdu) before and after milk processing, and to explore the detoxification mechanism of milk processing. Mice were intragastrically administered the 95% ethanol extract of raw Euphorbiae Ebracteolatae Radix, milk-decocted(milk-processed), and water-decocted(water-processed) Euphorbiae Ebracteolatae Radix. Fecal morphology, fecal water content, and the release levels of inflammatory cytokines tumor necrosis factor-α(TNF-α) and interleukin-1β(IL-1β) in different intestinal segments were used as indicators to evaluate the effects of different processing methods on the cathartic effect and intestinal inflammatory toxicity of Euphorbiae Ebracteolatae Radix. LC-MS/MS was employed to analyze the small-molecule components in the raw product, the 95% ethanol extract of the milk-processed product, and the milky waste(precipitate) formed during milk processing, to assess the impact of milk processing on the chemical composition of Euphorbiae Ebracteolatae Radix. The results showed that compared with the blank group, both the raw and water-processed Euphorbiae Ebracteolatae Radix significantly increased the fecal morphology score, fecal water content, and the release levels of TNF-α and IL-1β in various intestinal segments(P<0.05). Compared with the raw group, all indicators in the milk-processed group significantly decreased(P<0.05), while no significant differences were observed in the water-processed group, indicating that milk, as an adjuvant in processing, plays a key role in reducing the intestinal toxicity of Euphorbiae Ebracteolatae Radix. Mass spectrometry results revealed that 29 components were identified in the raw product, including 28 terpenoids and 1 acetophenone. The content of these components decreased to varying extents after milk processing. A total of 28 components derived from Euphorbiae Ebracteolatae Radix were identified in the milky precipitate, of which 27 were terpenoids, suggesting that milk processing promotes the transfer of toxic components from Euphorbiae Ebracteolatae Radix into milk. To further investigate the effect of milk adjuvant processing on the toxic terpenoid components of Euphorbiae Ebracteolatae Radix, transmission electron microscopy(TEM) was used to observe the morphology of self-assembled casein micelles(the main protein in milk) in the milky precipitate. The micelles formed in casein-terpenoid solutions were characterized using particle size analysis, fluorescence spectroscopy, ultraviolet spectroscopy, and Fourier-transform infrared(FTIR) spectroscopy. TEM observations confirmed the presence of casein micelles in the milky precipitate. Characterization results showed that with increasing concentrations of toxic terpenoids, the average particle size of casein micelles increased, fluorescence intensity of the solution decreased, the maximum absorption wavelength in the UV spectrum shifted, and significant changes occurred in the infrared spectrum, indicating that interactions occurred between casein micelles and toxic terpenoid components. These findings indicate that the cathartic effect of Euphorbiae Ebracteolatae Radix becomes milder and its intestinal inflammatory toxicity is reduced after milk processing. The detoxification mechanism is that terpenoid components in Euphorbiae Ebracteolatae Radix reassemble with casein in milk to form micelles, promoting the transfer of some terpenoids into the milky precipitate.
Animals
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Mice
;
Milk/chemistry*
;
Drugs, Chinese Herbal/chemistry*
;
Male
;
Tumor Necrosis Factor-alpha/immunology*
;
Intestines/drug effects*
;
Interleukin-1beta/immunology*
;
Tandem Mass Spectrometry
;
Female
5.Comparison of short-term clinical efficacy between CO external fixation and internal fixation with steel plate in the treatment of unstable distal radius fractures.
Min-Rui FU ; Chang-Long SHI ; Yong-Zhong CHENG ; Ming-Ming MA ; Zheng-Lin NIU ; Hai-Xiang SUN ; Jing-Hua GAO ; Zhong-Kai WU ; Yi-Ming XU
China Journal of Orthopaedics and Traumatology 2025;38(1):10-17
OBJECTIVE:
To evaluate the short-term clinical efficacy of external fixation and internal fixation with steel plate in the treatment of unstable distal radius fractures (AO-23C type), based on the principles of Chinese osteosynthesis (CO).
METHODS:
Forty-eight patients with unstable distal radius fractures between January 2022 and February 2023 were retrospectively analyzed and divided into the CO external fixation group and internal fixation group. CO external fixation group consisted of 25 patients, including 7 males and 18 females, aged from 37 to 56 years old with an average of ( 52.6±11.3) years old. Among them, there were 7 patients of traffic accidents and 18 patients of falls, resulting in a total of 25 patients of closed fractures and no open fractures, the treatment was conducted using closed reduction and CO external fixation. The internal fixation group consisted of 23 patients, comprising 8 males and 15 females, age ranged from 41 to 59 years old, with an average age of(53.3±13.7) years old. Among them, 8 patients resulted from car accidents while the remaining 15 patients were caused by falls. All 23 patients were closed fractures without any open fractures observed. The technique of open reduction and internal fixation with steel plate was employed. The perioperative data, including injury-operation time, operation duration, blood loss, and length of hospital stay, were assessed in both groups. Additionally, the QuickDASH score and visual analogue scale (VAS) were evaluated. Range of motion and grip strength assessment, imaging findings such as palmar inclination angle, ulnar declination angle, radius length, articular surface step, intra-articular space measurements were also examined along with any complications.
RESULTS:
The follow-up duration ranged from 0 to 24 months, with an average duration of (16.0±3.8) months. The CO external fixation exhibited significantly shorter time from injury to operation (2.4±3.3) d vs (7.4±3.7) d, shorter operation duration (56.27±15.23) min vs (74.10±5.26) min, lower blood loss (14.52±6.54) ml vs (32.32±10.03) ml, and reduced hospitalization days (14.04±3.24 )d vs (16.45±3.05) d compared to the internal fixation group (P<0.05). The QuickDASH score at 12 months post-operation was (8.21±1.64) in the CO external fixation group, while no significant difference was observed in the internal fixation group (7.04±3.64), P>0.05. There were no statistically significant differences in VAS between two groups at 6 weeks, as well as 1 and 3 months post-surgery (P>0.05). Additionally, there were no significant disparities observed in terms of range of motion and grip strength between two groups at the 2-year follow-up after the operation (P>0.05). After 12 months of surgery, the CO external fixation group exhibited a significantly smaller palmar inclination angle (17.90±2.18) ° vs (19.87±3.21) °, reduced articular surface step (0.11±0.03) mm vs (0.17±0.02) mm, and shorter radius length (8.16±1.11) mm compared to the internal fixation group (9.59±1.02) mm, P<0.05. The ulnar deviation angle and intra-articular space did not show any significant difference between two groups (P>0.05). The reduced fell within the allowable range between the CO external fixation group (23 out of 25 cases) and the internal fixation group (21 out of 23 cases) was not statistically significant (P=0.29). There was no significant difference in complications between the two groups(P>0.05).
CONCLUSION
Both the CO external fixation and open reduction with plate internal fixation demonstrate clinical efficacy in managing unstable distal radius fractures. The CO external fixation offers advantages in shorter injury-to-operation times, reduced intraoperative blood loss, and decreased surgical durations, while radial shortening is more effectively controlled by internal fixation.
Humans
;
Male
;
Female
;
Middle Aged
;
Radius Fractures/physiopathology*
;
Adult
;
Bone Plates
;
Fracture Fixation, Internal/methods*
;
External Fixators
;
Retrospective Studies
;
Fracture Fixation/methods*
;
Wrist Fractures
6.Comprehensive Analysis of Oncogenic, Prognostic, and Immunological Roles of FANCD2 in Hepatocellular Carcinoma: A Potential Predictor for Survival and Immunotherapy.
Meng Jiao XU ; Wen DENG ; Ting Ting JIANG ; Shi Yu WANG ; Ru Yu LIU ; Min CHANG ; Shu Ling WU ; Ge SHEN ; Xiao Xue CHEN ; Yuan Jiao GAO ; Hongxiao HAO ; Lei Ping HU ; Lu ZHANG ; Yao LU ; Wei YI ; Yao XIE ; Ming Hui LI
Biomedical and Environmental Sciences 2025;38(3):313-327
OBJECTIVE:
Hepatocellular carcinoma (HCC) is sensitive to ferroptosis, a new form of programmed cell death that occurs in most tumor types. However, the mechanism through which ferroptosis modulates HCC remains unclear. This study aimed to investigate the oncogenic role and prognostic value of FANCD2 and provide novel insights into the prognostic assessment and prediction of immunotherapy.
METHODS:
Using clinicopathological parameters and bioinformatic techniques, we comprehensively examined the expression of FANCD2 macroscopically and microcosmically. We conducted univariate and multivariate Cox regression analyses to identify the prognostic value of FANCD2 in HCC and elucidated the detailed molecular mechanisms underlying the involvement of FANCD2 in oncogenesis by promoting iron-related death.
RESULTS:
FANCD2 was significantly upregulated in digestive system cancers with abundant immune infiltration. As an independent risk factor for HCC, a high FANCD2 expression level was associated with poor clinical outcomes and response to immune checkpoint blockade. Gene set enrichment analysis revealed that FANCD2 was mainly involved in the cell cycle and CYP450 metabolism.
CONCLUSION
To the best of our knowledge, this is the first study to comprehensively elucidate the oncogenic role of FANCD2. FANCD2 has a tumor-promoting aspect in the digestive system and acts as an independent risk factor in HCC; hence, it has recognized value for predicting tumor aggressiveness and prognosis and may be a potential biomarker for poor responsiveness to immunotherapy.
Humans
;
Carcinoma, Hepatocellular/diagnosis*
;
Liver Neoplasms/diagnosis*
;
Immunotherapy
;
Fanconi Anemia Complementation Group D2 Protein/metabolism*
;
Prognosis
;
Male
;
Female
;
Middle Aged
;
Biomarkers, Tumor/metabolism*
7.Proteomic analysis and validation of DNA repair regulation in the process of hepatocellular carcinoma recurrence
Kai CHANG ; Yanyan WANG ; Zhongyong JIANG ; Wei SUN ; Chenxia LIU ; Wanlin NA ; Hongxuan XU ; Jing XIE ; Yuan LIU ; Min CHEN
Journal of Clinical Hepatology 2024;40(2):319-326
ObjectiveTo investigate the role and mechanism of DNA repair regulation in the process of hepatocellular carcinoma (HCC) recurrence. MethodsHCC tissue samples were collected from the patients with recurrence within two years or the patients with a good prognosis after 5 years, and the Tandem Mass Tag-labeled quantification proteomic study was used to analyze the differentially expressed proteins enriched in the four pathways of DNA replication, mismatch repair, base excision repair, and nucleotide excision repair, and the regulatory pathways and targets that play a key role in the process of HCC recurrence were analyzed to predict the possible regulatory mechanisms. The independent samples t-test was used for comparison of continuous data between two groups; a one-way analysis of variance was used for comparison between multiple groups, and the least significant difference t-test was used for further comparison between two groups. ResultsFor the eukaryotic replication complex pathway, there were significant reductions in the protein expression levels of MCM2 (P=0.018), MCM3 (P=0.047), MCM4 (P=0.014), MCM5 (P=0.008), MCM6 (P=0.006), MCM7 (P=0.007), PCNA (P=0.019), RFC4 (P=0.002), RFC5 (P<0.001), and LIG1 (P=0.042); for the nucleotide excision repair pathway, there were significant reductions in the protein expression levels of PCNA (P=0.019), RFC4 (P=0.002), RFC5 (P<0.001), and LIG1 (P=0.042); for the base excision repair pathway, there were significant reductions in the protein expression levels of PCNA (P=0.019) and LIG1 (P=0.042) in the HCC recurrence group; for the mismatch repair pathway, there were significant reductions in the protein expression levels of MSH2 (P=0.026), MSH6 (P=0.006), RFC4 (P=0.002), RFC5 (P<0.001), PCNA (P=0.019), and LIG1 (P=0.042) in recurrent HCC tissue. The differentially expressed proteins were involved in the important components of MCM complex, DNA polymerase complex, ligase LIG1, long patch base shear repair complex (long patch BER), and DNA mismatch repair protein complex. The clinical sample validation analysis of important differentially expressed proteins regulated by DNA repair showed that except for MCM6 with a trend of reduction, the recurrence group also had significant reductions in the relative protein expression levels of MCM5 (P=0.008), MCM7 (P=0.007), RCF4 (P=0.002), RCF5 (P<0.001), and MSH6 (P=0.006). ConclusionThere are significant reductions or deletions of multiple complex protein components in the process of DNA repair during HCC recurrence.
8. Curcumin plays an anti-osteoporosis role by inhibiting NF-κB signaling pathway to reduce oxidative stress damage to osteogenesis
Tian-Tian XU ; Hao-Ehun TIAN ; Xin-Min YANG ; Qi-Hua QI ; Dong-Hua LUO ; Chang-Gen WANG
Chinese Pharmacological Bulletin 2024;40(1):46-54
Aim To investigate the mechanism of curcumin inhibition of oxidative stress on osteogenic differentiation and its dose-dependent anti-osteoporosis effect. Methods Cellular oxidative stress models were used, different concentrations of curcumin were added to determinethebone formation markers, and the potential signaling pathways involvedwere detected. Meanwhile, the mouse model of osteoporosis ( ovariecto- mized, 0VX) was used to confirm its effect against osteoporosis. Results In vitro experiments found that low concentrations of curcumin (1-10 μmol · L
9.Study on the Substance Benchmark Characteristic Chromatogram and Multi-Component Content Determination of Classical Formula Fuzi Decoction
Zhen-Zhen PAN ; Yu-Jie XU ; Jia-Hui LIU ; Hui-Min YE ; Zhen-Hua WANG ; Chang-Qing LI
Journal of Guangzhou University of Traditional Chinese Medicine 2024;41(9):2442-2451
Objective To establish a high performance liquid chromatography(HPLC)characteristic chromatogram and multi-component content determination method for the substance benchmark of Fuzi Decoction.Methods The characteristic chromatogram method of Fuzi Decoction substance benchmark was established,and the Similarity Evaluation System of Chromatographic Fingerprint of Traditional Chinese Medicine(2012 Edition)was used to analyze the characteristic chromatograms of 15 batches of Fuzi Decoction substance benchmark samples.The HPLC content determination methods of 1 1 components in the Fuzi Decoction substance benchmark samples were established respectively,and the dry extract rate of 15 batches of Fuzi Decoction substance benchmark samples was determined.Results The similarity of characteristic chromatograms of 15 batches of Fuzi Decoction substance benchmark samples was greater than 0.9,and 12 common peaks were selected and eight of them were identified.The results showed that the contents of benzoylmesaconine,benzoylhypaconine,atractylenolide Ⅲ,ginsenoside Rg1,ginsenoside Re,ginsenoside Rb1,gallic acid,albiflorin,paeoniflorin,1,2,3,4,6-penta-galloyl glucose and benzoyl paeoniflorin were 0.050 3-0.191 1,0.026 7-0.047 0,0.043 0-0.127 6,0.554 6-1.006 8,0.568 7-0.979 5,0.929 9-1.726 1,1.058 9-2.118 4,1.430 3-4.965 5,6.882 9-9.511 1,0.056 1-0.262 5,0.160 6-0.369 0 mg/g,respectively.The average dry extract rate of the 15 batches of Fuzi Decoction substance benchmark samples was 29.54%.Conclusion The established characteristic chromatogram and multi-index content determination method are accurate and stable,which provides a basis for the quality control of the substance benchmark and related preparations of Fuzi Decoction.
10.Preliminary testing and analysis of crosstalk in gross α and gross β measurement using an MPC 9604 low background α/β counter
Jiaang XU ; Gang SONG ; Hailiang LI ; Fangfang WU ; Chang JIN ; Nan MIN ; Xiaoshan WANG
Chinese Journal of Radiological Medicine and Protection 2024;44(11):965-970
Objective:To explore the causes of the crosstalk in the gross α and gross β measurement using an MPC 9604 low background α/β counter.Methods:With the A4 copy paper (70 g/m 2), polyethylene (PE) films (8.7 g/m 2), and 304 stainless steel seperately as shielding materials, the gross α and gross β experiments, gamma spectrometry experiments and solid state nuclear track detection (SSNTD) experiments were conducted by using 241Am and 40K standard materials. A comprehensive analysis encompassing statistical analysis and nuclear physics analysis was performed to reveal the impact of contributing factors on the crosstalk in the gross α and gross β measurement with an MPC 9604 low background α/β counter. Results:241Am powder source experimental result: when two sheets of copy paper were used in the experiment, α-rays did not generate one count in the β channel of the low background α/β counter. The same test with the shielding material of two layers of PE films showed that the α count rate further decreased by about 36.5%, while the β count rate hardly changed. The gross α and gross β experiments and γ spectrometry with the shielding material of stainless steel demonstrated that the characteristic γ ray peaking at 59.5 keV of the 241Am powder source did not generate one count in the β channel. 40K powder source experimental result: when the source was covered with steel of total thickness of 0.965 mm in the gross α and gross β experiments, the γ rays of 40K did not generate one count in the β channel. Compared with naked 40K powder source, when source was covered with one and two sheets of copy paper, the gross α count rate decreased approximately from 3.30 × 10 -3 to 1.50 × 10 -3 and 1.75 × 10 -3, respectively. The SSNTD indicated the presence of other α nuclides in 40K powder source. Conclusions:The β counting in the β channel with the 241Am powder source using MPC 9604 low background α/β counter was, instead of α-rays, caused by the internal conversion electrons and the characteristic X rays of 11.870-22.402 keV emitted from the 241Am powder source, thus this is not a true α/β crosstalk. The α counting in α channel with the 40K powder source, except the contribution of impurity α nuclides, was mainly attributed to the α signals arising from β particles when the amplitude of the piled-up β pules exceeded the discrimination threshold of the detector, therefore it is a true crosstalk.


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