Localization of Ectopic Hyperparathyroidism: Ultrasound Versus 99mTc-sestamibi, 4-Dimensional Computed Tomography, and 11C-choline Positron Emission Tomography/Computed Tomography.

OBJECTIVE: To investigate the usefulness of ultrasound (US) for the localization of ectopic hyperparathyroidism and compare it with 99mTc-sestamibi (99mTc-MIBI), 4-dimensional computed tomography (4D-CT), and 11C-choline positron emission tomography/ computed tomography (PET/CT). METHODS: Of the 527 patients with surgically confirmed primary hyperparathyroidism, 79 patients with ectopic hyperparathyroidism were enrolled. The diagnostic performance of US, 99mTc-MIBI, US + MIBI, 4D-CT, and 11C-choline PET/CT was calculated, and the factors affecting the sensitivity of US and 99mTc-MIBI were analyzed. RESULTS: Eighty-three ectopic parathyroid lesions were found in 79 patients. The sensitivity was 75.9%, 81.7%, 95.1%, 83.3%, and 100% for US, 99mTc-MIBI, US + MIBI, 4D-CT, and 11C-choline PET/CT, respectively. The difference in sensitivity among these different modalities did not achieve statistical significance (P > .05). The US sensitivity was significantly higher for ectopic lesions in the neck region than for those in the anterior mediastinum/chest wall (85.9% vs. 42.1%, P < .001). The 99mTc-MIBI and 4D-CT sensitivity was not significantly different between these two groups (84.1% vs. 94.6%, P = .193 and 81.3% vs. 85.7%, P = 1). The 11C-choline PET/CT sensitivity was 100% in both groups. CONCLUSIONS: US is a valuable tool for the localization of ectopic hyperparathyroidism, especially for ectopic lesions in the neck region.

Programmable Morphing Hydrogels for Soft Actuators and Robots: From Structure Designs to Active Functions.

Nature provides abundant inspiration and elegant paradigms for the development of smart materials that can actuate, morph, and move on demand. One remarkable capacity of living organisms is to adapt their shapes or positions in response to stimuli. Programmed deformations or movements in plant organs are mainly driven by water absorption/dehydration of cells, while versatile motions of mollusks are based on contraction/extension of muscles. Understanding the general principles of these morphing and motion behaviors can give rise to disruptive technologies for soft robotics, flexible electronics, biomedical devices, etc. As one kind of intelligent material, hydrogels with high similarity to soft biotissues and diverse responses to external stimuli are an ideal candidate to construct soft actuators and robots.The objective of this Account is to give an overview of the fundamental principles for controllable deformations and motions of hydrogels, with a focus on the structure designs and responsive functions of the corresponding soft actuators and robots. This field has been rapidly developed in recent years with a growing understanding of working principles in natural organisms and a substantial revolution of manufacturing technologies to devise bioinspired hydrogel systems with desired structures. Diverse morphing hydrogels and soft actuators/robots have been developed on the basis of several pioneering works, ranging from bending and folding deformations of bilayer hydrogels to self-shaping of non-Euclidean hydrogel surfaces, and from thermoactuated bilayer gel "hands" to electrodriven polyelectrolyte gel "worms". These morphing hydrogels have demonstrated active functions and versatile applications in biomedical and engineering fields.In this Account, we discuss recent progress in morphing hydrogels and highlight the design principles and relevant applications. First, we introduce the fundamentals of basic deformation modes, together with generic structure features, actuation strategies, and morphing mechanisms. The advantages of in-plane gradient structures are highlighted for programmable deformations by harnessing the out-of-plane buckling with bistability nature to obtain sophisticated three-dimensional configurations. Next, we give an overview of soft actuators and robots based on morphing hydrogels and focus on the working principles of the active systems with different structure designs. We discuss the advancements of hydrogel-based soft robots capable of swift locomotion with different gaits and emphasize the significances of structure control and dynamic actuation. Then we summarize versatile applications of hydrogel-based actuators and robots in biomedicines, cargo delivery, soft electronics, information encryption, and so forth. Some hydrogel robots with a built-in feedback loop and self-sensing system exhibit collaborative functions and advanced intelligence that are informative for the design of next-generation hydrogel machines. Finally, concluding remarks are given to discuss future opportunities and remaining challenges in this field. For example, miniature hydrogel-based actuators/robots with therapeutic or diagnostic functions are highly desired for biomedical applications. The morphing mechanisms summarized in this Account should be applicable to other responsive materials. We hope that this Account will inspire more scientists to be involved in this emerging area and make contributions to reveal novel working principles, design multifunctional soft machines, and explore applications in diverse fields.

Toughening Hydrogels by Forming Robust Hydrazide-Transition Metal Coordination Complexes.

Energy dissipation based on dynamic fracture of metal ligands is an effective way to toughen hydrogels for specific applications in biomedical and engineering fields. Exploration of new kinds of metal-ligand coordinates with robust bonding strength is crucial for the facile synthesis of tough gels. Here a hydrogel toughening strategy based on the formation of robust coordination complexes between the hydrazide ligands and zinc ions is reported. The resultant hydrogels exhibit high strength and toughness at room temperature. Their mechanical properties show temperature dependence due to the dynamic nature of coordination bonds. In addition, the amine group of hydrazides in the gel matrix provides a reactive site for Schiff's base reaction, enabling surface modification without influence on overall mechanical performances of the gel. The hydrazide ligands are easy to synthesize and can coordinate very well with several transition metals. Such a metal-ligand coordination should be suitable to develop tough soft materials with versatile applications.

High-frequency ultrasound features in vulvar lichen sclerosus and correlation with histopathology.

BACKGROUND: Vulvar lichen sclerosus (VLS) is a chronic inflammatory disease initially involving anogenital areas. Noninvasive assessment is essential for precise management in VLS. We aim to analyze high-frequency ultrasound (HFUS) features and correlate HFUS with histopathological changes. MATERIALS AND METHODS: Forty patients with histopathologically confirmed VLS lesions were retrospectively identified from August 2020 to September 2021. The clinical manifestations, dermoscopic images as well as both 20 and 50 MHz HFUS images were assessed. HFUS assessment included epidermal morphology, hypoechoic dermal band thickness, and hypoechoic dermal band internal echo. We compared HFUS images with histopathology, and Pearson's correlation coefficient was used to assess the relationship between hypoechoic dermal band thickness and histopathological depth. RESULTS: Hypoechoic dermal band was present in 100% (40/40) VLS lesions. There was a significant linear positive correlation between the histopathological depth and corresponding hypoechoic dermal band thickness, with a Pearson correlation coefficient of 0.685 (p < 0.001). Besides, 95% (38/40) lesions revealed smooth epidermis, and the internal echo of hypoechoic dermal band was assessed as homogeneous in 60% (24/40) and inhomogeneous in 40% (16/40) lesions. CONCLUSION: HFUS characteristics, as well as measurable hypoechoic dermal band thickness, may provide valuable information in the precise diagnosis and the treatment monitoring of VLS.

A comparative study of melanocytic nevi classification with dermoscopy and high-frequency ultrasound.

BACKGROUND: Melanocytic nevi (MN) can be classified into three subtypes according to the depth of the nests of nevus cells which is important for management. High-frequency ultrasound (HF-US) can clearly reveal the lesion size, contour, depth, and internal structures. However, the HF-US studies of MN according to subtypes are limited. We aimed to describe the HF-US features of MN and explore its value in accurate classification. MATERIALS AND METHODS: This retrospective study was conducted from January 2018 to November 2019. Eighty-five patients with MN were included and examined by 50 and 20 MHz HF-US. The HF-US features were recorded including morphological flatness, depth, shape, boundary, internal echogenicity, hyperechoic spots, lateral acoustic shadow, posterior echoic patterns, mushroom signs, and straw-hat signs. Each image was evaluated by two physicians independently, and the consistency was tested. RESULTS: Eleven lesions could not be detected by HF-US. The rest 74 lesions underwent ultrasonic analysis. MN appeared as strip-shaped or oval, hypoechoic areas localized in the epidermis and dermis under ultrasonography. A strong consistency between HF-US and dermoscopy of determining the lesion depth was achieved (κ = 0.935, p < 0.001). The hyperechoic spots were found in 57.6% intradermal nevi. The mushroom signs were seen in 34.8% intradermal nevi, and the straw-hat signs were seen in all the compound nevi. CONCLUSION: MN can be correctly classified using HF-US, and it had a strong correlation with dermoscopic and clinical classification. HF-US could further reveal the internal morphological features of MN, which may support more precise classification and management.

[Imaging in the Diagnosis of Breast Cancer in Elderly Women].

The breast cancer diagnosed in the women at or above age 70 is defined as breast cancer in the elderly.As the population keeps aging,breast cancer in the elderly presents increasing incidence and high mortality.Early detection,early diagnosis,and early treatment might improve the prognosis of these patients. Comprehensively evaluating the functional age of elderly patients is essential for the individualized treatment. Medical imaging plays a key role in the screening,early diagnosis,therapy selection,evaluation of neoadjuvant therapy efficacy,and postoperative follow-up.We reviewed the current literature and focused on the role of medical imaging in the diagnosis and treatment recommendations for breast cancer in the elderly.

Magneto-Orientation of Magnetic Double Stacks for Patterned Anisotropic Hydrogels with Multiple Responses and Modulable Motions.

Reported here is a multi-response anisotropic poly(N-isopropylacrylamide) hydrogel developed by using a rotating magnetic field to align magnetic double stacks (MDSs) that are fixed by polymerization. The magneto-orientation of MDSs originates from the unique structure with γ-Fe2 O3 nanoparticles sandwiched by two silicate nanosheets. The resultant gels not only exhibit anisotropic optical and mechanical properties but also show anisotropic responses to temperature and light. Gels with complex ordered structures of MDSs are further devised by multi-step magnetic orientation and photolithographic polymerization. These gels show varied birefringence patterns with potentials as information materials, and can deform into specific configurations upon stimulations. Multi-gait motions are further realized in the patterned gel through dynamic deformation under spatiotemporal light and friction regulation by imposed magnetic force. The magneto-orientation assisted fabrication of hydrogels with anisotropic structures and additional functions should bring opportunities for gel materials in biomedical devices, soft actuators/robots, etc.

The value of contrast-enhanced ultrasound for sentinel lymph node identification and characterisation in pre-operative breast cancer patients: A prospective study.

OBJECTIVE: To explore the feasibility of sentinel lymph node (SLN) identification by contrast-enhanced ultrasound (CEUS) in pre-operative breast cancer patients and the value of enhancement patterns for diagnosing lymph node metastases and characterising axillary nodal burden. METHODS: 110 consecutive breast cancer patients were enrolled. Before the surgery, microbubbles were injected intradermally. The lymphatic drainage pathway was detected to identify the SLNs. Blue dye and indocyanine green (ICG) fluorescence were used to trace SLNs during the operation. The enhancement patterns of SLNs were recorded and compared with the final pathological diagnosis. RESULTS: SLN detection rate was 96.4 % of 110 patients, 134 SLNs were detected in total. The sensitivity, specificity, positive-predictive value, negative-predictive value and accuracy of predicting SLNs metastases by CEUS enhancement patterns were 100 %, 52.0 %, 43.4 %, 100 % and 64.9 %, respectively. No metastatic SLNs were presented as homogeneous enhancement. Low nodal burden with 0-2 SLN metastases in 92.5 % nodes presented as heterogeneous enhancement. No enhancement pattern was proved to be SLN metastases in 100 % patients. CONCLUSIONS: CEUS is a feasible approach for SLN identification. CEUS enhancement patterns can be helpful in recognising metastatic SLNs and nodal burden. KEY POINTS: • CEUS is a feasible approach for SLN identification and characterisation. • The enhancement patterns on CEUS can be helpful in recognising metastasised SLNs. • Homogeneous enhancement pattern has the highest negative-predictive value.

Clinical Values of Combined Diffused Optical Tomography and PET-CT in the Diagnosis of Breast Cancer.

Objective To investigate the clinical values of combined diffused optical tomography (DOT) combined positron emission tomography-computed tomography (PET-CT) in the diagnosis of breast cancer. Methods We performed DOT and PET-CT examinations in 38 patients with 40 lesions and compared these images with the pathological results to analyze the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value of these two techniques and their combination.Results The sensitivity,specificity,accuracy,positive predictive value,and negative predictive value in diagnosing breast cancer were 78.26%,76.47%,77.50%,72.22%,and 81.81% for DOT,86.96%,82.35%,85.00%,86.96%,and 82.35% for PET-CT,and 86.96%,94.12%,90.00%,95.23%,and 84.21% for the combination of PET-CT and DOT.Conclusions DOT and PET-CT are both effective diagnostic methods for breast cancer.Combined DOT and PET-CT can improve the diagnostic efficacy in terms of specificity,positive predictive value,and accuracy.

Value of Acoustic Radiation Force Impulse Imaging in the Diagnosis of Early Non-alcoholic Steatohepatitis.

Objective To evaluate the value of acoustic radiation force impulse(ARFI)imaging in the diagnosis of early non-alcoholic steatohepatitis(NASH).Methods Totally 32 SD rats were randomly divided into high-fat diet group(n=24)and normal-diet group(n=8)by using the random number table. At the end of the 4th,8th,12th,and 16th week,six rats from the high-diet group and two rats from the normal-diet group were selected blindly for weighting,blood biochemical test,conventional ultrasound,and ARFI imaing. HE staining was used for pathological observation. Results None of the 32 rats developed liver fibrosis. Based on the pathological results,these rats were divided into M1 [mild-to-moderate simple fatty liver(SS)],M2(severe SS),M3(severe SS with early NASH),and C groups(normal control). Early NASH was seen only in the severe hepatic steatosis groups,and its distribution had a significant difference(P=0.006). The diagnostic accuracy of conventional ultrasound based on histological results was 34.4%(11/32). The ARFI value of M3 group was significantly lower than that of M2 group [(1.16±0.04)m/s vs.(1.22±0.05)m/s;t=2.301,P=0.04),and the low-density lipoprotein of M3 group was significantly higher than M2 group [(1.53±0.07)mmol/L vs.(1.21±0.22)mmol/L;t=3.075,P=0.01),while other clinical indicators had no statistical difference between these two groups. Conclusions The development of early NASH is associated with the severity of hepatic steatosis. ARFI value can provide important information to identify early NASH in patients with severe hepatic steatosis.

Role of Thyroid Ultrasound in the Diagnosis of Thyroid Nodules with Atypia of Undetermined Significance.

Objective To evaluate the role of ultrasound for thyroid nodules with atypia of undetermined significance(AUS).Methods From January 2014 to December 2015,83 thyroid nodules with AUS diagnosed by ultrasound-guided fine-needle aspiration biopsy were collected from 1984 subjects. On the basis of ultrasonic features,each thyroid nodule was prospectively classified into one of three categories: low suspicion for malignancy,intermediate suspicion for malignancy,and high suspicion for malignancy. Results Among 83 lesions,19 lesions(22.9%) were confirmed malignant,8 lesions (9.6%)were benign,56 lesions (67.5%)had no abnormal changes during clinical follow-up. The nodules were solitary in 36 cases (43.4%)and multiple in 47 cases(56.6%).The maximum diameter was (1.2±0.7)cm. Based on the ultrasonic feature of 19 malignant cases,16 cases (84.2%) were classified as high suspicion for malignancy,2 cases(10.5%) as intermediate suspicion for malignancy,and 1 case(5.3%) for low suspicion for malignancy. Univariate and multivariate analyses revealed that the degree of malignancy of thyroid nodules was significantly associated with ultrasound image classification[OR=9.23(2.96-28.79),P=0.00],but not with age,gender,nodule number,and nodule size (all P>0.05).Conclusion Ultrasound diagnosis by using the present thyroid ultrasound classification system can be helpful for distinguishing malignant and benign AUS thyroid nodules.

Correlation between Ultrasound-guided Diffuse Optical Tomography and Hypoxia-inducible Factor-1Α of Breast Cancer.

Objective To investigate the correlation between ultrasound-guided diffuse optical tomography (US-DOT) and hypoxia-inducible factor-1Α (HIF-1Α) of breast cancer. Methods Totally 69 patients with pathologically confirmed breast cancer underwent preoperative conventional breast ultrasonography examinations and US-DOT at Peking Union Medical College Hospital From October 2007 to February 2010 were enrolled in this study.After surgery,immunohistochemical staining of HIF-1Α and CD34 were performed,and the differences of total hemoglobin concentration (THC) and microvessel density (MVD) between HIF-1Α positive and negative groups were analyzed. Results HIF-1Α was positive in 12 cases (17.4%) and negative in 57 cases (82.6%). The average THC and MVD of HIF-1Α-positive cases were (274.763±77.661) Μmol/L and (33.8±10.8)/0.2 mm(2) respectively. The average THC and MVD of HIF-1Α-negative cases were (228.059±65.760)Μmol/L and (28.4±7.4)/0.2 mm(2). MVD(t=2.049,P=0.04) and THC(t=2.167,P=0.034) of HIF-1Α-positive group were significantly higher than those of HIF-1Α-negative group. Conclusions HIF-1Α can promote tumor angiogenesis and thus increase the blood supply and THC. As an indicator of tumor blood supply,THC can indirectly reflect the angiogenic activity of breast cancer.

Relationship Between Sonographic Characteristics and Afirma Gene Expression Classifier Results in Thyroid Nodules With Indeterminate Fine-Needle Aspiration Cytopathology.

OBJECTIVE: The purpose of this article is to investigate whether specific clinical and sonographic characteristics are predictive of a benign Afirma test result. MATERIALS AND METHODS: We conducted a retrospective study of Afirma gene expression classifier analysis performed in 44 patients with 45 indeterminate thyroid fine-needle aspiration (FNA) cytologic results between March 2013 and April 2014. Of these, 33 of 45 nodules (73.3%) were repeat atypia of undetermined significance (AUS) and follicular lesions of undetermined significance (FLUS), or follicular neoplasm (FN) and suspicious for a follicular neoplasm (SFN) before Afirma testing. RESULTS: Of the 45 nodules, 21 (46.7%) were cytologically diagnosed as FLUS, 16 (35.6%) were diagnosed as AUS, and eight (17.8%) were diagnosed as FN or SFN. By Afirma testing, 23 of the 45 nodules (51.1%) were benign, 21 (46.7%) were suspicious, and one (2.2%) had nondiagnostic results. The mean (± SD) nodule size was smaller in the Afirma-benign group than in the Afirma-suspicious group (1.8 ± 0.8 cm [95% CI, 1.4-2.1] vs 2.2 ± 0.8 cm [95% CI, 1.8-2.6]; p < 0.035). No sonographic feature was statistically significantly different between the Afirma-benign and -suspicious groups, including nodule solidity (p = 0.225), echogenicity (p = 0.543), calcification (p = 0.542), and hypervascularity (p = 0.976). All nodules were ovoid shaped and had circumscribed margins in both Afirma groups. CONCLUSION: Smaller nodule size was the only characteristic associated with a benign diagnosis on Afirma testing. Sonographic characteristics are not helpful in cases that had a repeat indeterminate FNA finding before Afirma testing.

Value of Quantitative Three-dimensional Doppler Ultrasound in the Differentiation of Benign and Malignant Thyroid Nodules.

OBJECTIVE: To investigate the role of quantitative three-dimensional (3D) power Doppler ultrasound in differentiating malignant and benign thyroid nodule. METHODS: A total of 92 lesions in 86 patients were preoperatively examined using 3D power Doppler ultrasound. The Virtual Organ Computer-aided Analysis(VOCAL)-imaging program was used to analyze the stored volume ultrasound. The differences in the mean gray value (MG), vascularization index (VI), flow index(FI), and vascularization flow index (VFI) were compared between benign and malignant lesions. RESULTS: The MG of the malignant thyroid nodules was significantly lower than that of the benign ones (28.27±7.21 vs. 32.89±8.73,P=0.007). The benign nodules had significantly higher VI,FI,and VFI than the malignant nodules [VI:(40.43±26.55)% vs. (26.87±23.06)%,P=0.011;FI:41.03±7.19 vs. 37.51±7.17,P=0.022;VFI:18.23±14.60 vs. 11.47±12.47, P=0.009]. Also,76.5% (39/51) of the malignant nodules and 92.7% (38/41) of the benign nodules had higher VIs in the shell of the lesion than that of the whole lesion,and 80.4%(41/51) of the malignant nodules and 95.1% (39/41) of the benign nodules had higher FIs in the shell of the lesion than that of the whole lesion. CONCLUSIONS: Quantitative 3D power Doppler ultrasound provides a useful tool in distinguishing benign and malignant thyroid nodules. The malignant thyroid nodules have lower echoes than the benign nodules, wherese the benign nodules have larger blood flow than the malignant nodules.

[Correlation of Contrast-enhanced Ultrasound with Expression of Hypoxia Inducible Factor-1α in Transplanted Mice Mammary Cancer].

OBJECTIVE: To investigate the correlation of contrast-enhanced pattern with expression of hypoxia inducible factor-1α (HIF-1α) and microvessel density (MVD) in mice breast cancer. METHODS: A total of 22 mice were implanted with breast cancer cells (Ca761) subcutanously in the thigh. The tumors were examined with conventional ultrasound and contrast-enhanced ultrasound (CEUS) on days 4,6,7,8,9,10,and 11 after implantation and then sacrificed. Three or four mice were included each time. Expressions of HIF-1α and MVD in cancer tissues were detected immunohistochemically. Correlation of contrast-enhanced patterns with expression of HIF-1α and MVD in breast cancer was analyzed. RESULTS: Mice were divided into 3 groups according to the tumor volume:group 1 (volume<0.05 cm(3),n=5),group 2 (volume 0.05-0.75 cm(3),n=9),and group 3 (volume>0.75 cm(3),n=8). The CEUS pattern was different in different groups:four mice in group 1 presented as type 1 (peripheral ring enhancement with no enhancement within the tumor) and 1 case presented as type 2 (peripheral ring enhancement with deep penetration). Most mice in group 2 presented as type 3 (homogeneous or heterogeneous enhancement in the whole tumor,n=5). In group 3,most mice presented as type 4 (peripheral ring enhancement with focal nodular enhancement within the tumor,n=7). Contrast-enhanced pattern was significantly different in different volume groups (P<0.01). Enhanced pattern (type 1-4) was closely correlated with tumor volume (r=0.841,P<0.05). The expression of HIF-1α was negatively correlated with enhanced patterns (type 1-4) (r=-0.596,P＝0.003),but not with tumor volume (P>0.05). There was no significant difference in MVD values between different enhanced patterns (type 1-4),and there was no correlation between the MVD and tumor volumes (P>0.05). CONCLUSION: CEUS can be used as a noninvasive tool to monitor tumor angiogenesis in tumor and the enhanced patterns may reflect the expression of HIF-1α inside the tumor.

[Automated breast volume scanning in the diagnosis of breast intraductal papilloma].

OBJECTIVE: To investigate the value of automated breast volume scanning (ABVS) in the diagnosis of breast intraductal papilloma (IDP). METHODS: Totally 239 lesions in 213 women who were scheduled for open biopsy were investigated in this study. The patients underwent both ABVS and conventional ultrasound (US). According to the imaging diagnostic standards of IDP, the diagnostic accuracy for ABVS was calculated, and then compared with US, using histopathological examination as the gold standard. RESULTS: Among the 239 breast lesions studied, 85 were pathologically proved to be malignancies and 154 benign lesions, among which there were 26 cases of IDP. ABVS found 41 cases of IDP (17.2%), with the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy being 88.5%, 91.5%, 56.1%, 98.5%, and 91.2%, respectively. In contrast, US found 32 cases of IDP (13.4%), with the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy being 73.1%, 93.9%, 59.4%, 96.6%, and 91.6%, respectively. CONCLUSION: ABVS coronal images can better display the structures of dilated lactiferous ducts and the intraluminal echoes, increase the diagnostic accuracy of IDP, and thus provide more information for the diagnosis and differential diagnosis of IDP.

[Clinical and ultrasonic features of breast cancer in women older than 80 years].

OBJECTIVE: To summarize the clinical and ultrasonic features of breast cancer in women aged 80 and older. METHODS: A total of 60 patients (62 lesions) aged 80 and older with pathologically confirmed breast cancer from September 1993 to October 2012 were enrolled in this study and their clinical manifestations, ultrasonic features, therapeutic methods, and prognoses were analyzed. RESULTS: Most patients (83.3%) went to see a doctor because of nodules touched by themselves. The average diameter of the carcinoma was (2.4±1.1)cm. Most tumors (75.8%) were invasive ductal carcinomas, followed by the mucinous carcinoma (11.3%). Among the 45 lesions with ultrasound records, 40 (88.9%) were irregular in morphology; the aspect ratio of 35 lesions (77.8%) was less than 1;24 lesions (53.3%) had indistinct boundary;calcification existed in 21 lesions (46.7%); and 16 lesions (35.6%) had rear echo attenuation. The preoperative diagnostic accuracy of ultrasonography was 93.5%. In addition, 45 patients (75.0%) underwent breast tumor extended resection, 13 (21.7%) received modified radical mastectomy, 2 patients (3.3%) underwent simple breast resection. No death was noted during the operation and there was no major peri-operative complications. Of 31 patients with complete follow-up records, 7 had recurrence or metastasis and 1 died of heart disease. CONCLUSIONS: Most breast cancers in women older than 80 years are relatively large, with typical ultrasonic features. The preoperative diagnosis is often accurate. Few lymphatic metastases exist, and the prognosis is good. Conservative surgeries are preferred for these elderly patients.

Animating hydrogel knotbots with topology-invoked self-regulation.

Steering soft robots in a self-regulated manner remains a grand challenge, which often requires continuous symmetry breaking and recovery steps for persistent motion. Although structural morphology is found significant for robotic functions, geometric topology has rarely been considered and appreciated. Here we demonstrate a series of knotbots, namely hydrogel-based robots with knotted structures, capable of autonomous rolling and spinning/rotating motions. With symmetry broken by external stimuli and restored by self-regulation, the coupling between self-constraint-induced prestress and photothermal strain animates the knotbots continuously. Experiments and simulations reveal that nonequilibrium processes are regulated dynamically and cooperatively by self-constraints, active deformations, and self-shadowing effect of the photo-responsive gel. The active motions enable the knotbots to execute tasks including gear rotation and rod climbing. This work paves the way to devise advanced soft robots with self-regulated sustainable motions by harnessing the topology.

Reversible Snapping of Constrained Anisotropic Hydrogels Upon Light Stimulations.

Creatures, such as Venus flytrap and hummingbirds, capable of rapid predation through snap-through transition, provide paradigms for the design of soft actuators and robots with fast actions. However, these artificial "snappers" usually need contact stimulations to trigger the flipping. Reported here is a constrained anisotropic poly(N-isopropylacrylamide) hydrogel showing fast snapping upon light stimulation. This hydrogel is prepared by flow-induced orientation of nanosheets (NSs) within a rectangular tube. The precursor containing gold nanoparticles is immediately exposed to UV light for photopolymerization to fix the ordered structure of NSs. Two ends of the slender gel are clamped to form a buckle with bistability nature, which snaps to the other side upon laser irradiation. Systematic experiments are conducted to investigate the influences of power intensity and irradiation angle of the laser, as well as thickness and buckle height of the gel, on the snapping behaviors. The fast snapping is further used to kick a plastic bead and control the switch state. Furthermore, synergetic or oscillated snapping of the gel with two buckles of opposite directions is realized by inclined irradiation of a laser or horizontal irradiation with two lasers, respectively. Such light-steered snapping of hydrogels should merit designing soft robots, energy harvests, etc.

Photo-steered rapid and multimodal locomotion of 3D-printed tough hydrogel robots.

Hydrogels are an ideal material to develop soft robots. However, it remains a grand challenge to develop miniaturized hydrogel robots with mechanical robustness, rapid actuation, and multi-gait motions. Reported here is a facile strategy to fabricate hydrogel-based soft robots by three-dimensional (3D) printing of responsive and nonresponsive tough gels for programmed morphing and locomotion upon stimulations. Highly viscoelastic poly(acrylic acid-co-acrylamide) and poly(acrylic acid-co-N-isopropyl acrylamide) aqueous solutions, as well as their mixtures, are printed with multiple nozzles into 3D constructs followed by incubation in a solution of zirconium ions to form robust carboxyl-Zr4+ coordination complexes, to produce tough metallo-supramolecular hydrogel fibers. Gold nanorods are incorporated into ink to afford printed gels with response to light. Owing to the mechanical excellence and small diameter of gel fibers, the printed hydrogel robots exhibit high robustness, fast response, and agile motions when remotely steered by dynamic light. The design of printed constructs and steering with spatiotemporal light allow for multimodal motions with programmable trajectories of the gel robots. The hydrogel robots can walk, turn, flip, and transport cargos upon light stimulations. Such printed hydrogels with good mechanical performances, fast response, and agile locomotion may open opportunities for soft robots in biomedical and engineering fields.