A Nomogram Based on Conventional Ultrasound Radiomics for Differentiating Between Radial Scar and Invasive Ductal Carcinoma of the Breast.

ABSTRACT: We aimed to develop and validate a nomogram based on conventional ultrasound (CUS) radiomics model to differentiate radial scar (RS) from invasive ductal carcinoma (IDC) of the breast. In total, 208 patients with histopathologically diagnosed RS or IDC of the breast were enrolled. They were randomly divided in a 7:3 ratio into a training cohort (n = 145) and a validation cohort (n = 63). Overall, 1316 radiomics features were extracted from CUS images. Then a radiomics score was constructed by filtering unstable features and using the maximum relevance minimum redundancy algorithm and the least absolute shrinkage and selection operator logistic regression algorithm. Two models were developed using data from the training cohort: one using clinical and CUS characteristics (Clin + CUS model) and one using clinical information, CUS characteristics, and the radiomics score (radiomics model). The usefulness of nomogram was assessed based on their differentiating ability and clinical utility. Nine features from CUS images were used to build the radiomics score. The radiomics nomogram showed a favorable predictive value for differentiating RS from IDC, with areas under the curve of 0.953 and 0.922 for the training and validation cohorts, respectively. Decision curve analysis indicated that this model outperformed the Clin + CUS model and the radiomics score in terms of clinical usefulness. The results of this study may provide a novel method for noninvasively distinguish RS from IDC.

High extinction ratio super pixel for long wavelength infrared polarization imaging detection based on plasmonic microcavity quantum well infrared photodetectors.

Polarization imaging detection has its unique advantage in discriminating the man-made objects from natural objects. Grating integrated super pixel for polarization imaging detection can simultaneously obtain the first three elements of the Stokes vector, which is the trend of infrared polarization imaging detection in recent years. Here, we demonstrate the first super pixel for long wavelength infrared polarization imaging detection with the extinction ratio of its four polarization directions more than 100. The measured highest polarization extinction ratio is as high as 136, which is the highest reported value of long wavelength infrared polarization imaging detection super pixel. The mechanism is attributed to the excellent mode selectivity of plasmonic microcavity according to the results of three-dimensional theoretical simulation. The experimental responses of the super pixel with four polarization directions are in good agreement with the Malus' Law. In addition, the super pixel can accurately resolve the Stokes parameters at the same time. It is expected to develop the super pixel into a new generation of practical high-polarization-discriminating long wavelength infrared focal plane array.

Moiré Phonons in Twisted Bilayer MoS2.

The material choice, layer thickness, and twist angle widely enrich the family of van der Waals heterostructures (vdWHs), providing multiple degrees of freedom to engineer their optical and electronic properties. The moiré patterns in vdWHs create a periodic potential for electrons and excitons to yield many interesting phenomena, such as Hofstadter butterfly spectrum and moiré excitons. Here, in the as-grown/transferred twisted bilayer MoS2 (tBLMs), one of the simplest prototypes of vdWHs, we show that the periodic potentials of moiré patterns also modify the properties of phonons of its monolayer MoS2 constituent to generate Raman modes related to moiré phonons. These Raman modes correspond to zone-center phonons in tBLMs, which are folded from the off-center phonons in monolayer MoS2. However, the folded phonons related to crystallographic superlattices are not observed in the Raman spectra. By varying the twist angle, the moiré phonons of tBLM can be exploited to map the phonon dispersions of the monolayer constituent. The lattice dynamics of the moiré phonons are modulated by the patterned interlayer coupling resulting from periodic potential of moiré patterns, as confirmed by density functional theory calculations. The Raman intensity related to moiré phonons in all tBLMs are strongly enhanced when the excitation energy approaches the C exciton energy. This study can be extended to various vdWHs to deeply understand their Raman spectra, moiré phonons, lattice dynamics, excitonic effects, and interlayer coupling.

Pixel-level plasmonic microcavity infrared photodetector.

Recently, plasmonics has been central to the manipulation of photons on the subwavelength scale, and superior infrared imagers have opened novel applications in many fields. Here, we demonstrate the first pixel-level plasmonic microcavity infrared photodetector with a single quantum well integrated between metal patches and a reflection layer. Greater than one order of magnitude enhancement of the peak responsivity has been observed. The significant improvement originates from the highly confined optical mode in the cavity, leading to a strong coupling between photons and the quantum well, resulting in the enhanced photo-electric conversion process. Such strong coupling from the localized surface plasmon mode inside the cavity is independent of incident angles, offering a unique solution to high-performance focal plane array devices. This demonstration paves the way for important infrared optoelectronic devices for sensing and imaging.

Ternary SnS(2-x)Se(x) Alloys Nanosheets and Nanosheet Assemblies with Tunable Chemical Compositions and Band Gaps for Photodetector Applications.

Ternary metal dichalcogenides alloys exhibit compositionally tunable optical properties and electronic structure, and therefore, band gap engineering by controllable doping would provide a powerful approach to promote their physical and chemical properties. Herein we obtained ternary SnS(2-x)Se(x) alloys with tunable chemical compositions and optical properties via a simple one-step solvothermal process. Raman scattering and UV-vis-NIR absorption spectra reveal the composition-related optical features, and the band gaps can be discretely modulated from 2.23 to 1.29 eV with the increase of Se content. The variation tendency of band gap was also confirmed by first-principles calculations. The change of composition results in the difference of crystal structure as well as morphology for SnS(2-x)Se(x) solid solution, namely, nanosheets assemblies or nanosheet. The photoelectrochemical measurements indicate that the performance of ternary SnS(2-x)Se(x) alloys depends on their band structures and morphology characteristics. Furthermore, SnS(2-x)Se(x) photodetectors present high photoresponsivity with a maximum of 35 mA W(-1) and good light stability in a wide range of spectral response from ultraviolet to visible light, which renders them promising candidates for a variety of optoelectronic applications.

[Diversity and classification system of weed community in Harbin City, China].

To analyze the causes of weed community diversity and their strategies of adaption to the high heterogeneity of urban habitats, weed communities in the central urban area of Harbin, China were studied, and a classification system was established for the weed communities. There were 175 weed species, belonging to 128 genera and 38 families. The heterogeneous urban habitats and species' temporal niche differentiation resulted in the highly diversified weed communities. The high proportions of mono-species dominance and annual species dominance communities were their response to the unstable urban habitats under human disturbances with high intensities and frequencies. A four-level classification system was established in terms of plant species and habitat conditions. Within this system, the identified 1763 weed communities could be categorized into two types of life form, 5 types of dormancy form, 22 community groups, and 119 dominance communities.

Single InAs nanowire room-temperature near-infrared photodetectors.

Here we report InAs nanowire (NW) near-infrared photodetectors having a detection wavelength up to ∼1.5 µm. The single InAs NW photodetectors displayed minimum hysteresis with a high Ion/Ioff ratio of 10(5). At room temperature, the Schottky-Ohmic contacted photodetectors had an external photoresponsivity of ∼5.3 × 10(3) AW(-1), which is ∼300% larger than that of Ohmic-Ohmic contacted detectors (∼1.9 × 10(3) AW(-1)). A large enhancement in photoresponsivity (∼300%) had also been achieved in metal Au-cluster-decorated InAs NW photodetectors due to the formation of Schottky junctions at the InAs/Au cluster contacts. The photocurrent decreased when the photodetectors were exposed to ambient atmosphere because of the high surface electron concentration and rich surface defect states in InAs NWs. A theoretical model based on charge transfer and energy band change is proposed to explain this observed performance. To suppress the negative effects of surface defect states and atmospheric molecules, new InAs NW photodetectors with a half-wrapped top-gate had been fabricated by using 10 nm HfO2 as the top-gate dielectric.

Revealing the hidden relationship by sparse modules in complex networks with a large-scale analysis.

One of the remarkable features of networks is module that can provide useful insights into not only network organizations but also functional behaviors between their components. Comprehensive efforts have been devoted to investigating cohesive modules in the past decade. However, it is still not clear whether there are important structural characteristics of the nodes that do not belong to any cohesive module. In order to answer this question, we performed a large-scale analysis on 25 complex networks with different types and scales using our recently developed BTS (bintree seeking) algorithm, which is able to detect both cohesive and sparse modules in the network. Our results reveal that the sparse modules composed by the cohesively isolated nodes widely co-exist with the cohesive modules. Detailed analysis shows that both types of modules provide better characterization for the division of a network into functional units than merely cohesive modules, because the sparse modules possibly re-organize the nodes in the so-called cohesive modules, which lack obvious modular significance, into meaningful groups. Compared with cohesive modules, the sizes of sparse ones are generally smaller. Sparse modules are also found to have preferences in social and biological networks than others.

Enhanced plasmonic resonant excitation in a grating gated field-effect transistor with supplemental gates.

An alternative-grating gated AlGaN/GaN field-effect transistor (FET) is proposed by considering the slit regions to be covered by a highly doped semiconductor acting as supplemental gates. The plasmonic resonant absorption spectra are studied at THz frequencies using the FDTD method. The 2DEGs, under supplemental gates, modulated by a positive voltage, can make the excitation of the higher order plasmon modes under metallic fingers more efficient in comparison to ungated regions in common slit-grating gate transistors. Moreover, the supplemental gates can confine the electric field of dipole oscillation between metallic gate fingers under THz radiation. The competition of the near-field enhancement and screening effect of the supplemental gate fingers results in the intensity of the higher order plasmon resonances being maximized at increased doping concentration. Our results demonstrate the possibility of significant improvement in the excitation of plasmon resonances in FETs for THz detection.

Phase separation induced by Au catalysts in ternary InGaAs nanowires.

We report a novel phase separation phenomenon observed in the growth of ternary In(x)Ga(1-x)As nanowires by metalorganic chemical vapor deposition. A spontaneous formation of core-shell nanowires is investigated by cross-sectional transmission electron microscopy, revealing the compositional complexity within the ternary nanowires. It has been found that for In(x)Ga(1-x)As nanowires high precursor flow rates generate ternary In(x)Ga(1-x)As cores with In-rich shells, while low precursor flow rates produce binary GaAs cores with ternary In(x)Ga(1-x)As shells. First-principle calculations combined with thermodynamic considerations suggest that this phenomenon is due to competitive alloying of different group-III elements with Au catalysts, and variations in elemental concentrations of group-III materials in the catalyst under different precursor flow rates. This study shows that precursor flow rates are critical factors for manipulating Au catalysts to produce nanowires of desired composition.

The dependence of structural stability and tunable gap on the Si components of ZnSe/Si bi-coaxial nanowire heterostructures.

The bare and hydrogen-passivated ZnSe/Si bi-coaxial nanowire heterostructures along [110] direction have been investigated by using the first-principle calculations within density functional theory. The structural stability and electronic property of ZnSe/Si bi-coaxial nanowire heterostructures have been shown by changing the Si components. It is found that the ZnSe/Si nanowires have zero gaps at lower Si components, and then they have the increasing gap at higher Si components. It is seen clearly that there is the transition of band gap form zero to nonzero. With increasing Si components, the ZnSe/Si nanowires can be also achieved as n-type or p-type, in agreement qualitatively with the experimental observations. In addition, the structural stabilities and the cohesive energies of ZnSe/Si bi-coaxial nanowires are changed obviously with the different Si components.

Effect of electrodes on geometric and transport properties of the graphene-based nanomolecular devices.

Graphene-based nanomolecular devices are formed by connecting one of the prototype molecular materials of graphene nanoribbons to two Au electrodes. The geometric structure and electronic properties are calculated by using density functional theory. Basing on the optimized structure and the electronic distributions, we obtain the transport properties of the devices by using the Green's functional method. It is found that that the geometry structures of the molecule and the transport properties are sensitive to the distance between source and drain electrodes. With increasing the distances, the curvature radius of the atomic plane is increased, and the deformation energy is decreased. The current versus voltage curves have almost same threshold voltage with different distances between the electrodes. The transmission probability, the density of states and the external bias voltage play important role in determining the transport properties of the molecular devices.

Geometry and stability of Cu(n)N (n=1-6) and Cu(3n)N(n) (n=1-5) clusters.

The gradient-corrected density functional calculation is applied to search the lowest-energy configurations of Cu(n)N (n=1-6) clusters and the calculation indicated that Cu(3)N cluster is the most stable one. Based on the result, we further investigate the equilibrium geometries and stabilities of the Cu(3n)N(n) (n=2-5) clusters. We found that in Cu(6)N(2) cluster, N atoms formed a separate N(2) molecule away from the other part of the cluster. Furthermore, it was shown that the lowest-energy configurations of Cu(3n)N(n) (n=3-5) are stable with the nitrogen atoms well separated by the copper atoms. Therefore, it can be concluded that the Cu(3)N cluster can be used as a building block for the construction of the cluster-assembled compounds.

[Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission among close contacts].

UNLABELLED: Study on human case of avian influenza in Guangzhou 2006 without causing human-to-human transmission OBJECTIVE: To explore the possibility of transmission from a human case of avian influenza to his close contacts. METHODS: Close contacts of the human case of avian influenza in Guangzhou 2006 were found out according to the definition and methods publicized by the Ministry of Health, People's Republic of China. Epidemiological investigation and medical observation were carried out. Serum antibodies were tested in some of the close contacts. RESULTS: The avian influenza patient had never left Guangzhou in the month prior to disease onset. No contact history with dead or diseased poultry was found. A total of 56 close contacts, including his girl friend, relatives, friends and medical staff who had taken care of him, were brought under medical observation for 7 days but none of them showed signs of infection. CONCLUSION: Unlike SARS, direct contact with patient contracted with avian influenza at the end of incubation period and in the stage of illness through flying droplets, saliva, mucous membrane and skin injuries will not lead to human-to-human transmission, indicating the virus' ability to pass from human to human is limited.

[The effects of 4 laboratory test kits in early detecting of severe acute respiratory syndrome coronavirus].

OBJECTIVE: To compare the 4 test kits on severe acute respiratory syndrome coronavirus (SARS-CoV) gene, antigen and antibody for early diagnose of SARS patients. METHODS: Three enzyme linked immunosorbent assay (ELISA) kits were used to detect SARS-CoV IgG, IgM and N protein and fluorescent polymerase chain reaction (F-PCR) kit was used to detect SARS-CoV RNA. RESULTS: In 162 serum samples, 90.2% (55/61) became N protein positive in 1 - 5 days and 92.8% (13/14) became positive IgM and IgG in 15 - 18 days after the onset of disease, respectively. On 82 gorgling samples, the positive rates of F-PCR were 56.3% (14/24) in 1 - 5 days and 71.4% (10/14) in 6 - 9 days after the onset. CONCLUSION: Other than F-PCR, N protein had good effect in the early detection on dubious patients which could lead to effective prevention and control of the epidemic.

[Study on the epidemiology and measures for control on severe acute respiratory syndrome in Guangzhou city].

OBJECTIVE: To analyze the epidemiological characteristics, related risk factors, measures for its control of severe acute respiratory syndrome (SARS). METHODS: Data on epidemiological features, pathogens and measures for control were collected and analyzed. RESULTS: Since Jan 2003, infectious atypical pneumonia (AP) has become epidemic in Guangzhou city. The first autochthonous case was identified on Jan 2nd. Number of cases started to increase since February and reached peak in the early 10 days of February. Hereafter the epidemic tended to decline in March and since early April, the average number of new cases began to decrease, less than 10 per day. Epidemiological studies revealed that the number of cases aged between 20 and 50 was higher than that below the age of 20. Of the total 966 cases, 429 were males versus 537 females. Geographically, the epidemics covered all 13 districts of Guangzhou, but 95% of the cases concentrated in 7 urban districts. As for professional distribution, health care workers accounted for 28.67% of the total cases. There were 36 deaths, aged from 5 to 89, with half of them older than 60. Out of the victims, 38.9% of them had complications as hypertension, diabetes, heart diseases and COPD etc. Data regarding the clustering features of cases showed that there were 42 families having 2 or more cases in one family, while 277 health workers suffered from SARS were concentrated in 28 hospitals. Only one outbreak took place in a public setting but no outbreak was reported in schools. Relevant research also indicated that SARS could be classified as an air-borne infectious disease, transmitted through aerosol and droplets, but close contact also played an important role in the mode of transmission. The disease was highly infectious, suggesting that people who had close contact with patients in the place with poor ventilation was in greater risk of getting infection. The incubation period ranged from 1 to 11 days (mainly from 3 to 8 days), with an average of 5 days. According to our observation, the following measures might be effective such as: early diagnosis, isolation and treatment provided to the patients, and suspected cases under medical observation should also be put in separate places. Improving ventilation and regular disinfection over air and stuff in hospital wards were also recommended. In order to prevent iatrogenic infection, sense on self-protection among health care workers must be strengthened. Patients were not allowed to be visited by any one other than hospital staff. CONCLUSION: SARS is a preventable disease and can be under control. It is of great importance to prevent clustered SARS cases and the prevention of iatrogenic infection is essential.