Control of Self-Winding Microrobot Using an Electromagnetic Drive System: Integration of Movable Electromagnetic Coil and Permanent Magnet.

Achieving precise control over the motion position and attitude direction of magnetic microrobots remains a challenging task in the realm of microrobotics. To address this challenge, our research team has successfully implemented synchronized control of a microrobot's motion position and attitude direction through the integration of electromagnetic coils and permanent magnets. The whole drive system consists of two components. Firstly, a stepper motor propels the delta structure, altering the position of the end-mounted permanent magnet to induce microrobot movement. Secondly, a programmable DC power supply regulates the current strength in the electromagnetic coil, thereby manipulating the magnetic field direction at the end and influencing the permanent magnet's attitude, guiding the microrobot in attitude adjustments. The microrobot used for performance testing in this study was fabricated by blending E-dent400 photosensitive resin and NdFeB particles, employing a Single-Layer 4D Printing System Using Focused Light. To address the microrobot drive system's capabilities, experiments were conducted in a two-dimensional and three-dimensional track, simulating the morphology of human liver veins. The microrobot exhibited an average speed of 1.3 mm/s (movement error ± 0.5 mm). Experimental results validated the drive system's ability to achieve more precise control over the microrobot's movement position and attitude rotation. The outcomes of this study offer valuable insights for future electromagnetic drive designs and the application of microrobots in the medical field.

Maternal exposure to particulate matter from duck houses restricts fetal growth due to inflammatory damage and oxidative stress.

The composition of particulate matter (PM) in poultry farms differs significantly from that of atmospheric PM as there is a higher concentration of microbes on farms. To assess the health effects of PM from poultry farms on pregnant animals, we collected PM from duck houses using a particulate sampler, processed it via centrifugation and vacuum concentration, and subsequently exposed the mice to airborne PM at 0.48 mg/m3 (i.e., low concentration group) and 1.92 mg/m3 (i.e., high concentration group) on the fifth day of pregnancy. After exposure until the twentieth day of pregnancy or spontaneous delivery, mice were euthanized for sampling. The effects of PM from duck houses on the pregnancy toxicity of mice were analyzed using histopathological analysis, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction (qPCR). The results showed that exposure to PM had adverse effects on pregnant mice that reduced their feed intake in both groups. Microscopic lesions were observed in the lungs and placentas of pregnant mice, and the lesions worsened with increased PM concentrations, as shown by alveolar wall thickening, the infiltration of inflammatory cells in pulmonary interstitium, congestion, edema, and cellular degeneration of placenta. In pregnant mice in the high concentration group, exposure to PM significantly increased the expression of inflammatory cytokines in the lungs and placentas, caused oxidative stress, and decreased estrogen level in the blood. Exposure to PM also resulted in the reduced litter sizes of pregnant mice and shorter body and tail lengths in the fetuses delivered. Beyond that, exposure to PM significantly downregulated the levels of antioxidant factor superoxide dismutase and neurotrophic factor Ngf in the brains of fetuses. Collectively, exposure to a high concentration of PM by inhalation among pregnant mice caused significant pregnancy toxicity that led to abnormal fetal development due to inflammatory damage and oxidative stress. These findings established a foundation for future studies on the underlying mechanisms of pregnancy toxicity induced by exposure to PM.

Studies on the airborne bacterial communities and antimicrobial resistance genes in duck houses based on metagenome and PCR analysis.

The threat of antimicrobial resistance (AMR) is on the rise globally, especially with the development of animal husbandry and the increased demand for antibiotics. Livestock and poultry farms, as key sites for prevalence of antibiotic-resistant bacteria (ARB), can spread antimicrobial resistance genes (ARGs) through microbial aerosols and affect public health. In this study, total suspended particulate matter (TSP) and airborne culturable microorganisms were collected from duck houses in Tai'an, Shandong Province, and the bacterial communities and airborne ARGs were analyzed using metagenomics and PCR methods. The results showed that the bacterial communities in the air of duck houses were mainly Actinobacteria, Firmicutes, Proteobactria, Chlamydia, and Bcateroidetes at the phylum level. At the genus level, the air was dominated by Corynebacterium, Jeotgalicoccus, Staphylococcus, Brevibacterium, and Megacoccus, and contained some pathogenic bacteria such as Staphylococcus aureus, Corynebacterium diphtheriae, Klebsiella oxytoca, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were also potential hosts for ARGs. The airborne ARGs were mainly macrolides (10.97%), penicillins (10.73%), cephalosporins (8.91%), streptozotocin (8.91%), and aminoglycosides (8.02%). PCR detected 27 ARGs in airborne culturable microorganisms, and comparative analysis between PCR and the metagenomic data revealed that a total of 9 ARGs were found to the same, including macrolides ErmA, ErmF, tetracyclines tetG, tetX, methicarbamazepines dfrA12, dfrA15, aminoglycosides APH3-VI, ANT2-Ⅰ, and sulfonamides sul2. Moreover, inhalation exposure modeling showed that the workers in duck houses inhaled higher concentrations of ARB, human pathogenic bacteria (HPB) and human pathogenic antibiotic-resistant bacteria (HPARB) than hospital workers. These results provide new insights into airborne microorganisms and ARGs in animal farms and lay the foundation for further study.

Clinical efficacy and biomarker analysis of neoadjuvant camrelizumab plus chemotherapy for early-stage triple-negative breast cancer: a experimental single-arm phase II clinical trial pilot study.

BACKGROUND: Triple-negative breast cancer (TNBC) is associated with a dismal prognosis. Immune checkpoint inhibitors have shown promising antitumor activity in neoadjuvant settings. This single-arm, phase II trial aimed to evaluate the efficacy and safety of camrelizumab plus chemotherapy as the neoadjuvant therapy (NAT) in early TNBC. METHODS: Patients received eight cycles of camrelizumab plus nonplatinum-based chemotherapy. The primary endpoint was total pathological complete response (pCR). Secondary endpoints included the breast pathological complete response (bpCR), adverse events (AEs). Multiomics biomarkers were assessed as exploratory objective. RESULTS: Twenty of 23 TNBC patients receiving NAT underwent surgery, with the total pCR rate of 65% (13/20) and bpCR rate of 70% (14/20). Grade ≥3 treatment-related AEs were observed in 14 (60.9%) patients, with the most common AE being neutropenia (65.2%). Tumor immune microenvironment was analyzed between pCR and non-pCR samples before and after the NAT. Gene expression profiling showed a higher immune infiltration in pCR patients than non-pCR patients in pre-NAT samples. Through establishment of a predictive model for the NAT efficacy, TAP1 and IRF4 were identified as the potential predictive biomarkers for response to the NAT. Gene set enrichment analysis revealed the glycolysis and hypoxia pathways were significantly activated in non-pCR patients before the NAT, and this hypoxia was aggravated after the NAT. CONCLUSION: Camrelizumab plus nonplatinum-based chemotherapy shows a promising pCR rate in early-stage TNBC, with an acceptable safety profile. TAP1 and IRF4 may serve as potential predictive biomarkers for response to the NAT. Aggravated hypoxia and activated glycolysis after the NAT may be associated with the treatment resistance.

Optical frequency domain reflectometry with broadened frequency sweep range assisted by a dual electro-optic frequency comb.

We propose an optical frequency domain reflectometry (OFDR) with the assistance of a dual electro-optic frequency comb (EOFC), which is intended to improve the system spatial resolution. As the spatial resolution of an OFDR system is inversely proportional to the frequency sweep range, the EOFC acts as a multi-frequency light source for collecting Rayleigh backscattering signals, which are combined to extend the effective frequency sweep range. By utilizing this technique, we have successfully expanded the experimental frequency sweep range to hundreds of gigahertz, achieving a sub-millimeter spatial resolution.

Exploitation pattern assessment of the Japanese mantis shrimp (Oratosquilla oratoria) resource in the coastal waters of the Shandong Peninsula.

The exploitation pattern of the invertebrate resource (Oratosquilla oratoria) was investigated in the coastal waters of the Shandong Peninsula, along with the seasonal variation in body length structure, spatial distribution in abundance, and interannual stock status. Results showed that the model with only catch data suggested both stocks in the north and south were suffering from extreme fishing pressure without explicit recovery (North: B2019/BMSY = 0.468 and F2019/FMSY = 1.88 in CMSY. South: B2019/BMSY = 0.349 and F2019/FMSY = 2.59 in CMSY). However, the other two assessment models indicated that the northern stock began to gradually recover as the fishing pressure dropped to an appropriate level after the original overfished status (North: B2019/BMSY = 0.738 and F2019/FMSY = 0.882 in AMSY, B2019/BMSY = 0.831 and F2019/FMSY = 0.774 in BSM. South: B2019/BMSY = 0.164 and F2019/FMSY = 1.44 in AMSY, B2019/BMSY = 0.384 and F2019/FMSY = 1.76 in BSM). Overall, the stock status in the north was better than that in the south. This study suggested that spatial exploitation pattern and quarterly differences should be considered in fishery management process.

The differential diagnosis of lichenoid keratosis and seborrheic keratosis with reflectance confocal microscopy: a preliminary study.

BACKGROUNDS AND OBJECTIVES: Lichenoid keratosis (LK, or lichen planus-like keratosis, LPLK) and seborrheic keratosis (SK) present as similar benign keratotic lesions on cosmetically sensitive area, but require different therapies. Both lesions can be easily differentiated based on histological evaluation of biopsy materials. However, the biopsies may cause scarring and result in hyper-pigmentation, which reduces the compliance of the patients to be treated. In this study, we investigated the role of reflectance confocal microscopy (RCM) in the non-invasive differential diagnosis of LK and SK. PATIENTS AND METHODS: Cases with facial brown patches or plaques suspicious of SK were enrolled in the study. After written informed consent was obtained, the lesions were photographed, imaged by RCM, and then biopsied. The RCM findings were analyzed and correlated with histology results. Evaluation of the RCM pictures and confirmation with histological results were conducted by two independent dermatologists. RESULTS: In total, 10 cases were enrolled in the study. The main characteristics of LK lesions observed by RCM were the disarray of the dermal-epidermal junction (DEJ), and marked inflammatory infiltrates in the superficial dermis; while prominent cerebriform pattern, or elongated cords with bulbous projections without significant inflammation reaction, were the features of SK. Among the 10 cases, clinically suspicious of facial SK, 4 were determined as LK, 6 as SK by RCM imaging, and all the RCM findings were confirmed by histological results. CONCLUSIONS: The RCM features of LK and SK have significant difference, highlighting the important role of RCM in the differential diagnosis of LK and SK, avoiding biopsies and allowing safe treatments.

The modified shrinkage classification modes could help to guide breast conserving surgery after neoadjuvant therapy in breast cancer.

Purpose: The traditional shrinkage classification modes might not suitable for guiding breast conserving surgery (BCS) after neoadjuvant therapy (NAT). Aim was to explore the modified shrinkage classification modes to guide BCS after NAT. Methods: From April 2010 to 2018, 104 patients were included. All patients underwent MRI examinations before and after NAT. Residual tumors were removed and divided into more than 30 tissue blocks at 5-mm intervals. After performing routine procedures for paraffin-embedded histology, we made semiserial sections (6-µm thick). The MRI and pathology 3D models were reconstructed with 3D-DOCTOR software. Combined with traditional shrinkage modes and efficacy of NAT, we derived modified shrinkage classification modes which oriented by BCS purpose: modified concentric shrinkage modes (MCSM) and modified non concentric shrinkage modes (MNCSM). The MCSM means the longest diameter of residual tumor was less than 50% and ≤2cm in comparison with the primary tumor before NAT. Other shrinkage modes were classified as MNCSM. Results: According to traditional shrinkage modes, 50 (48.1%) cases were suitable for BCS;while 70 (67.3%) cases were suitable for BCS according to the modified shrinkage modes (p=0.007). The consistency of MRI 3D reconstruction in assessing modified shrinkage classification modes was 93.2%, while it was 61.5% when assessing traditional shrinkage modes. Multivariate analysis showed that primary tumor stage, mammographic malignant calcification, molecular subtypes and nodal down-staging after NAT were independent predictors of modified shrinkage modes (all p<0.05). A nomogram was created based on these four predictors. With a median follow-up time of 77 months, the recurrence/metastasis rate in the MCSM and MNCSM group was 7.1% and 29.4%, respectively. Conclusion: Modified shrinkage classification modes could help to guide the individualized selection of BCS candidates and scope of resection after NAT. MRI 3D reconstruction after NAT could accurately predict modified shrinkage modes and extent of residual tumor.

Mutant Allele Frequency-Based Intra-Tumoral Genetic Heterogeneity Related to the Tumor Shrinkage Mode After Neoadjuvant Chemotherapy in Breast Cancer Patients.

The shrinkage mode of tumor extent after neoadjuvant chemotherapy (NAC) is an important index to evaluate the odds of breast-conserving surgery. However, there is no sufficient measurement to predict the shrinkage mode after NAC. In this study, we analyzed 24 patients' formalin-fixed, paraffin-embedded samples before and after treatment and analyzed 456 cancer-related genes panel by using target next-generation sequencing. Meanwhile, the pathological shrinkage mode was reconstructed in three dimensions after surgery, and the genetic heterogeneity level was estimated by mutant-allele tumor heterogeneity (MATH). We measured the genetic intra-tumor heterogeneity and explored its correlation with the shrinkage mode after NAC. A total of 17 matched pair samples of primary tumor tissue and residual tumor tissue were successfully accessed. It was found that the most common mutated genes were TP53 and PIK3CA in both samples before and after NAC, and no recurrent mutations were significantly associated with the shrinkage mode. Besides, the MATH value of formalin-fixed, paraffin-embedded samples before and after NAC was analyzed by the area under the curve of the receiver operating characteristic, and it is feasible to classify patients into concentric shrinkage mode and non-concentric shrinkage mode in NAC based on the MATH threshold of 58. Our findings indicate that the MATH value was associated with the shrinkage mode of breast cancer in a non-linear model. Patients with the MATH value below the threshold of 58 before and after NAC displayed a concentric shrinkage mode. The area under the curve was 0.89, with a sensitivity of 0.69 and specificity of 1. Our study might provide a promising application of intra-tumor heterogeneity that is measured by MATH to make a choice of surgery.

Laboratory indicators predict axillary nodal pathologic complete response after neoadjuvant therapy in breast cancer.

The purpose was to integrate clinicopathological and laboratory indicators to predict axillary nodal pathologic complete response (apCR) after neoadjuvant therapy (NAT). The pretreatment clinicopathological and laboratory indicators of 416 clinical nodal-positive breast cancer patients who underwent surgery after NAT were analyzed from April 2015 to 2020. Predictive factors of apCR were examined by logistic analysis. A nomogram was built according to logistic analysis. Among the 416 patients, 37.3% achieved apCR. Multivariate analysis showed that age, pathological grading, molecular subtype and neutrophil-to-lymphocyte ratio were independent predictors of apCR. A nomogram was established based on these four factors. The area under the curve (AUC) was 0.758 in the training set. The validation set showed good discrimination, with AUC of 0.732. In subtype analysis, apCR was 23.8, 47.1 and 50.8% in hormone receptor-positive/HER2-, HER2+ and triple-negative subgroups, respectively. According to the results of the multivariate analysis, pathological grade and fibrinogen level were independent predictors of apCR after NAT in HER2+ patients. Except for traditional clinicopathological factors, laboratory indicators could also be identified as predictive factors of apCR after NAT. The nomogram integrating pretreatment indicators demonstrated its distinguishing capability, with a high AUC, and could help to guide individualized treatment options.

Lay abstract The purpose of this study was to integrate more pretreatment indicators, including clinicopathological factors and simple laboratory indicators, to predict axillary nodal pathologic complete response (apCR) after neoadjuvant therapy for breast cancer. The authors collected the pretreatment clinicopathological factors and laboratory indexes of 416 nodal-positive patients with breast cancer. The authors then built a nomogram to predict the therapeutic effect in axillary lymph nodes. Among 416 patients, 37.3% (155 of 416) achieved apCR. The results showed that age, pathological grading, molecular subtype and neutrophil-to-lymphocyte ratio were independent predictors of apCR. Based on these four factors, a nomogram was then built. This nomogram helped to predict apCR. In addition to traditional clinicopathological factors, laboratory indicators were also identified as predictive factors of apCR after neoadjuvant therapy. Integrating pretreatment indicators might help to predict apCR and guide individualized treatment options.

Rayleigh speckle-based wavemeter with high dynamic range and fast reference speckle establishment process assisted by optical frequency combs.

Compact speckle-based spectrometers that acquire lightwave wavelength from the speckle generated by turbid media are promising for high-resolution spectral analysis. For these devices, the reference establishment process is time consuming, and it is very difficult to obtain reference speckles covering a wide bandwidth with high resolution, which restricts the dynamic range in frequency (the ratio of bandwidth to resolution). In this Letter, we introduce optical frequency combs (OFCs) to the system to overcome these problems, which exist in the wavemeter based on Rayleigh speckle obtained from a single-mode fiber. In the experiment, the proposed wavemeter has a 1.5 nm bandwidth with 60 am resolution, covering a dynamic range in the frequency of 2×107, and a fast reference speckle establishment process that takes only 0.9 ms. The proposed method assisted by OFCs is a good prospect for a more practical speckle-based wavemeter with higher dynamic ranges.

Predictive factors of pathologically node-negative disease for HER2 positive and triple-negative breast cancer after neoadjuvant therapy.

BACKGROUND: With the improvement of the efficacy of neoadjuvant therapy (NAT) that is guided by molecular subtypes, the rate of pathologically node-negative disease after NAT (ypN0) is increasing for HER2 positive (HER2+) and triple-negative (TN) breast cancer patients. The necessity of axillary surgery for patients with high ypN0 has been questioned. This study aimed to identify patients among HER2+ and TN breast cancer with low risk for axillary metastases after NAT, and, perhaps, they are suitable for selective elimination of axillary surgery staging. METHODS: From January 2010 to August 2018, 865 breast cancer patients who underwent NAT were included in this retrospective clinical study, and 184 patients (21.3%,184/865) suffered from TN and HER2+ breast cancer and received full-course NAT. The correlation among clinicopathological characteristics of HER2+ and TN breast cancer and ypN0 were analyzed. RESULTS: Among the 184 HER2+ and TN breast cancer patients, tumor staging, lymph node staging and Ki-67 before NAT, clinically node-negative disease after NAT (ycN0), and breast radiologic and pathologic complete response (bpCR) were correlated with ypN0 (P<0.05). Lymph node staging before NAT (OR =0.363, P<0.001), ycN0 (OR =4.995, P<0.001) and bpCR (OR =11.285, P<0.001) were the independent effects of ypN0. The ypN0 rate after NAT in cN0/1 patients with bpCR and ycN0 (97.6%, 40/41) was significantly higher than that in cN2/3 patients (62.5%, 10/16) (P<0.001). Among the 37 patients with initial nodal ultrasonography showing cN0 disease, 17 of 17 (100.0%) with and 18 of 20 (90.0%) without bpCR had no evidence of residual nodal disease (P=0.178). Among the 42 patients with cN1 to ycN0, 23 of 24 (95.8%) with and 10 of 18 (55.6%) without bpCR had no evidence of residual nodal disease (P<0.001). Patients without bpCR had a relative risk for nodal residual metastases of 10.560 (95% CI: 2.720-41.003; P<0.001) compared with those with bpCR in cN1 group. CONCLUSIONS: In terms of HER2+ and TN breast cancer patients, clinical lymph node staging before NAT, ycN0 and bpCR were the independent predictors of ypN0. bpCR was highly correlated with nodal status after NAT. The risk of axillary lymph nodes residual metastases after NAT in the patients of bpCR with cN0 and cN1 to ycN0 was less than 5%, thus making it possible to selectively avoid axillary surgery.

Performance of Heat-Insulating Materials Doped with Basalt Fibres for Use in Mines.

To solve high-temperature-induced hazards in mines, heat-insulating materials were prepared by utilising basalt fibres and high-strength ceramsite combined with cementing materials. Through orthogonal tests and data analyses, the optimal combination of the heat-insulating materials doped with basalt fibres was determined as A1B1C1, that is, doping with 45% basalt fibres, a length of the basalt fibres of 6 mm, and doping with 20% ceramsite. The performance indices corresponding to the optimal comprehensive combination of the heat-insulating materials doped with basalt fibres included a density of 1200 kg/m3, thermal conductivity of 0.151 W/(mK), compressive strength of 9.7 MPa, flexural strength of 3.6 MPa, and a water-seepage depth of 25.4 mm. Numerical simulations verified that the materials presented favourable thermal insulation performance.

Long-range and wide-band vibration sensing by using phase-sensitive OFDR to interrogate a weak reflector array.

In this paper, we propose and experimentally demonstrate a novel quasi-distributed fiber-optic vibration sensing system, which can achieve vibration measurement with a wide frequency response over a long distance. The system is based on phase-sensitive optical frequency domain reflectometry (ϕ-OFDR). The sensing part is a single-mode fiber (SMF) with auxiliary weak reflection points along it. By detecting the auxiliary weak reflection points, we can obtain the waveform of the vibration signal. In the experiments, single-point and multi-point vibrations with a wide-frequency response at 100 km are successfully measured, which validated the proposed system. To the best of our knowledge, this is the first time to realize a wide-band vibration waveform measurement over such a long range by using reflectometry-based sensing system.

Study on the Interference Law of Staged Fracturing Crack Propagation in Horizontal Wells of Tight Reservoirs.

Horizontal well multistage fracturing technology is a high-efficiency method for tight oil and gas production, which increases the contact area between the wellbore and stratum by forming multiple transverse hydraulic fractures (HFs). The stress interference caused by the created HFs will affect the propagation geometries of the subsequent HFs, and then affect the overall fracturing treatment performance. In order to study the distribution of HFs and law of interference among multiple fractures during horizontal well multistage fracturing in tight reservoirs, in this paper, the effects of horizontal stress difference, perforation spacing, and net pressure in the created fracture on the initiation and propagation of multiple cracks were specially studied through large-scale hydraulic fracturing experiments and numerical simulation. The results showed that under high horizontal stress difference, multiple HFs with small spacing tended to coalesce at a place where the length has extended to a certain level. It was also found that the initiation pressures of HFs within subsequent stages increase with the rise of net pressure in created HFs, which causes the subsequent fractures to deviate from the direction perpendicular to the horizontal wellbore and then to gradually deflect toward it. Moreover, the ratio of fracture spacing to fracture height, and the net pressure are the key parameters to determine the deflection degree of HFs for multistage fracturing. In addition, the deflection degree of subsequent HFs was expected to enhance with the decreasing ratio of fracture spacing to fracture height and increasing net pressure in created HFs. It was useful for mitigating stress interference to lengthen the stage spacing, control the fracture height, and reduce the net pressure. The research results have a reference value for the optimal design of the fracture spacing for multistage fracturing.

High-resolution wavemeter using Rayleigh speckle obtained by optical time domain reflectometry.

The characteristics of Rayleigh speckle generated from a single-mode fiber are related to the wavelength of the incident lightwave, which makes it possible to use Rayleigh speckle for spectrum measurement. Based on this feature, we propose, to the best of our knowledge, a novel wavemeter with high resolution realized using optical time domain reflectometry to obtain Rayleigh speckle. We show that the spectral resolution is inverse to the probe pulse width, with a spectral resolution of 6 fm corresponding to a 2 µs probe pulse. A correlation coefficient method is introduced to further increase the spectral resolution from 6 to 0.4 fm. Moreover, it is experimentally demonstrated that the system has the capability to resolve dynamic multi-wavelength signals with 25 µs time resolution. The proposed high-resolution wavemeter is a good prospect for cost effectiveness, compactness, and excellent performance of spectral resolution.

Neoadjuvant therapy and sentinel lymph node biopsy in HER2-positive breast cancer patients: results from the PEONY trial.

OBJECTIVE: The aim of the study is to evaluate the optimal timing of sentinel lymph node biopsy (SLNB) in patients with clinical negative axillary lymph nodes (ALNs) before neoadjuvant therapy (NAT) and the feasibility of SLNB substituting for ALN dissection in patients with positive ALNs who convert to node negative, for HER2-positive disease. METHODS: Patients receiving SLNB with dual tracer mapping in the PEONY trial were analyzed. RESULTS: For 80 patients with clinical negative ALNs, the node negative rate by pathology after NAT was 83.8%. SLNB was performed after NAT in 71 patients. The identification rate of sentinel lymph nodes (SLNs) was 100%. For patients with positive ALNs before NAT, the axillary pathologic complete response rate in the dual HER2 blockade arm was significantly higher than that in the single blockade arm (p = 0.002). SLNB was performed in 71 patients. The identification rate was 100% and the false-negative rate was 17.2%. The false-negative rates were 33.3%, 14.3%, and 0 when 1, 2, and more than 2 SLNs were detected. There was no false-negative case when more than 1 SLN and the clipped nodes were removed simultaneously. CONCLUSIONS: For clinical ALN negative patients, HER2-positive subtype is found to have high node negative rate by pathology and it is recommended to undergo SLNB after NAT. For patients with positive ALNs who convert to negative, the false-negative rate is high. Dual tracer mapping, more than 2 SLNs detected, more than 1 SLN identified plus the clips placed are the guarantees for lower false-negative rate.