After the reform and the opening, the economy of our country has developed rapidly, and the living conditions of the people have become better and better. As a result, they have a lot of time to pay ...attention to their health, which has promoted the rapid development of the sports and fitness industry in my country. In response to the increasing development of the sports and fitness sector of my country, the current state of the administration of members of the sports fitness industry does not keep pace with the development of the sports and fitness industry of my country. Based on this, this article uses a fuzzy decision tree algorithm to establish a decision tree based on the characteristics of customer data and loses existing customers. Analyzing the situation is of strategic significance for improving the competitiveness of the club. This article selects the 7 most commonly used data sets from the UCI data set as the initial experimental data for model training in three different formats and then uses the data of a specific club member to conduct experiments, using these data files as training samples to construct a vague analysis of the decision tree to overturn the customer to analyze the main factors of customer change. Experiments show that the fuzzy decision tree ID3 algorithm based on mobile computing has the highest accuracy in the Iris data set, reaching 97.8%, and the accuracy rate in the Wine data set is the smallest, only 65.2%. The mobile computing-based fuzzy decision tree ID3 algorithm proposed in this paper obtained the highest correct rate (86.32%). This shows that, compared to traditional analysis methods, the blurred decision tree obtained for churn client analysis has the advantages of high classification accuracy and is understandable so that ideal classification accuracy can be achieved when the tree is small.
Cyanido‐bridged dimetallic complexes are attracting attention due to their varied structures and properties. However, homochiral cyanido‐bridged dimetallic complexes are rare, and making them ...ferroelectric is a great challenge. Introducing C−F⋅⋅⋅K interactions between the guest chiral cations and the host KFe(CN)62− framework, gives three‐dimensional cyanido‐bridged dimetallic multiferroics, R‐ and S‐3‐fluoropyrrolidinium2KFe(CN)6 (R‐ and S‐3‐FPC). The mirror‐symmetric vibrational circular dichroism (VCD) signal shows their enantiomeric nature. R‐ and S‐3‐FPC crystallize in the same chiral‐polar space group P21 at 298 K. Piezoresponse force microscopy (PFM), polarizing optical microscopy, and temperature‐dependent second‐harmonic generation (SHG) measurements show their multiferroic properties (the coexistence of ferroelectricity and ferroelasticity), in line with the Aizu notation of 222F2. R‐3‐FPC shows excellent ferroelectricity with saturated polarization up to 9.4 μC cm−2.
The first homochiral multiferroic dimetallic cyanides were constructed by the introduction of rarely seen C−F⋅⋅⋅K interactions, which show a saturated polarization of 9.4 μC cm−2, larger than those of other ferroelectric dimetallic cyanides.
Achieving a periodic domain structure in ferroelectric materials to tailor the macroscopic properties or realize new functions has always been a hot topic. However, methods to construct periodic ...domain structures, such as epitaxial growth, direct writing by scanning tips, and the patterned electrode method, are difficult or inefficient to implement in emerging molecular ferroelectrics, which have the advantages of lightweight, flexibility, biocompatibility, etc. An efficient method for constructing and controlling periodic domain structures is urgently needed to facilitate the development of molecular ferroelectrics in nanoelectronic devices. In this work, it is demonstrated that large‐area, periodic and controllable needle‐like domain structures can be achieved in thin films of the molecular ferroelectric trimethylchloromethyl ammonium trichlorocadmium (TMCM‐CdCl3) upon the application of tensile strain. The domain evolution under various tensile strains can be clearly observed, and such processes are accordingly identified. Furthermore, the domain wall exhibits a superior piezoelectric response, with up to fivefold enhancement compared to that of the pristine samples. Such large‐area tunable periodic domain structure and abnormally strong piezoresponse are not only of great interests in fundamental studies, but also highly important in the future applications in functional molecular materials.
By applying tensile strain to the thin film of molecular ferroelectric trimethylchloromethyl ammonium trichlorocadmium (TMCM‐CdCl3), a large area of highly ordered periodic domain structures can be obtained. The density and width of these periodic domains can be adjusted by the magnitude of strain and the thickness of the film, respectively, and the piezoelectric response at the domain wall is enhanced.
Vitamin D deficiency is a candidate risk factor for a range of adverse health outcomes. In a genome-wide association study of 25 hydroxyvitamin D (25OHD) concentration in 417,580 Europeans we ...identify 143 independent loci in 112 1-Mb regions, providing insights into the physiology of vitamin D and implicating genes involved in lipid and lipoprotein metabolism, dermal tissue properties, and the sulphonation and glucuronidation of 25OHD. Mendelian randomization models find no robust evidence that 25OHD concentration has causal effects on candidate phenotypes (e.g. BMI, psychiatric disorders), but many phenotypes have (direct or indirect) causal effects on 25OHD concentration, clarifying the epidemiological relationship between 25OHD status and the health outcomes examined in this study.
Transient implantable piezoelectric materials are desirable for biosensing, drug delivery, tissue regeneration, and antimicrobial and tumor therapy. For use in the human body, they must show ...flexibility, biocompatibility, and biodegradability. These requirements are challenging for conventional inorganic piezoelectric oxides and piezoelectric polymers. We discovered high piezoelectricity in a molecular crystal HOCH
(CF
)
CH
OH 2,2,3,3,4,4-hexafluoropentane-1,5-diol (HFPD) with a large piezoelectric coefficient
of ~138 picocoulombs per newton and piezoelectric voltage constant
of ~2450 × 10
volt-meters per newton under no poling conditions, which also exhibits good biocompatibility toward biological cells and desirable biodegradation and biosafety in physiological environments. HFPD can be composite with polyvinyl alcohol to form flexible piezoelectric films with a
of 34.3 picocoulombs per newton. Our material demonstrates the ability for molecular crystals to have attractive piezoelectric properties and should be of interest for applications in transient implantable electromechanical devices.
Solid-state molecular rotor-type materials such as host–guest inclusion compounds are very desirable for the construction of molecular ferroelectrics. However, they usually have a low Curie ...temperature (T c) and uniaxial nature, severely hindering their practical applications. Herein, by regulating the anion to control “momentum matching” in the crystal structure, we successfully designed a high-temperature multiaxial host–guest inclusion ferroelectric (MeO–C6H4–NH3)(18-crown-6)TFSA (MeO–C6H4–NH3 = 4-methoxyanilinium, TFSA = bis(trifluoromethanesulfonyl)ammonium) with the Aizu notation of mmmFm. Compared to the parent uniaxial ferroelectric (MeO–C6H4–NH3)(18-crown-6)BF4 with a T c of 127 K, the introduction of larger TFSA anions brings a lower crystal symmetry at room temperature and a higher energy barrier of molecular motions in phase transition, giving (MeO–C6H4–NH3)(18-crown-6)TFSA multiaxial ferroelectricity and a high T c up to 415 K (above that of BaTiO3). To our knowledge, such a record temperature enhancement of 288 K makes its T c the highest among the reported crown-ether-based ferroelectrics, giving a wide working temperature range for applications in data storage, temperature sensing, actuation, and so on. This work will provide guidance and inspiration for designing high-T c host–guest inclusion ferroelectrics.
The prognostic value of Ki-67 expression in colorectal cancer patients was controversial. Therefore, this meta analysis was conducted to ascertain the prognostic value of Ki-67 expression in ...colorectal cancer patients.
The electronic databases, including EMBASE, PubMed, Cochrane Library and Web of Knowledge database, were searched from January 1970 to July 2017. The pooled hazard ratios and 95% confidence intervals were calculated to evaluate the prognostic value of Ki-67 expression for colorectal cancer patients.
Totally 34 eligible studies and 6180 colorectal cancer patients were included in the present meta analysis. The pooled hazard ratios were 1.54(95% CI 1.17-2.02, P = 0.005) for overall survival and 1.43(1.12-1.83, P = 0.008) for disease free survival in univariate analysis. After adjustment of other prognostic factors, the pooled HR was 1.50(95% CI 1.02-2.22, P = 0.03) for overall survival in multivariate analysis.
The present meta analysis demonstrated that high Ki-67 expression is significantly correlated with poor overall survival and disease free survival, indicating that high Ki-67 expression may serve as a valuable predictive method for poor prognosis of colorectal cancer patients.
Ferroelectric materials, whose electrical polarization can be switched under external stimuli, have been widely used in sensors, data storage, and energy conversion. Molecular orbital breaking can ...result in switchable structural and physical bistability in ferroelectric materials as traditional spatial symmetry breaking does. Differently, molecular orbital breaking interprets the phase transition mechanism from the perspective of electronics and sheds new light on manipulating the physical properties of ferroelectrics. Here, we synthesize a pair of organosilicon Schiff base ferroelectric crystals, (R)- and (S)-N-(3,5-di-tert-butylbenzylidene)-1-((triphenylsilyl)oxy)ethanamine, which show optically controlled phase transition accompanying the molecular orbital breaking. The molecular orbital breaking is manifested as the breaking and reformation of covalent bonds during the phase transition process, that is, the conversion between C = N and C-O in the enol form and C-N and C = O in the keto form. This process brings about photo-mediated bistability with multiple physical channels such as dielectric, second-harmonic generation, and ferroelectric polarization. This work further explores this newly developed mechanism of ferroelectric phase transition and highlights the significance of photo-mediated ferroelectric materials for photo-controlled smart devices and bio-sensors.
Ferroelectrics are attractive due to their great application potential in information storage, optoelectronics, spintronics and sensing. As an important characteristic affecting semiconducting ...applications, the energy band structure is important for the development of light-emitting devices. Although it is a tremendous challenge to tune the bandgap in inorganic ferroelectric materials due to the strict requirement of structural symmetry for the fragile ferroelectricity, hybrid organic–inorganic perovskite (HOIP) ferroelectrics, which have a flexible structure, provide a new method to optimize the ferroelectric performance and bandgap. Based on the overview of methods for designing ferroelectrics, this Perspective systematically provides in-depth insight into the relationships between the structure–property and bandgap of HOIP ferroelectrics. In addition, we discussed the challenges and directions of HOIP ferroelectrics in semiconducting applications for the future.
Multifarious molecular ferroelectrics with multipolar axial characteristics have emerged in recent years, enriching the scenarios for energy harvesting, sensing, and information processing. The ...increased polar axes have enhanced the urgency of distinguishing different polarization states in material design, mechanism exploration, etc. However, conventional methods hardly meet the requirements of in situ, fast, microscale, contactless, and nondestructive features due to their inherent limitations. Herein, SHG polarimetry is introduced to probe the multioriented polarizations on a nanosized multiaxial molecular ferroelectric, i.e., TMCM-CdCl3 nanoplates, as an example. Combined with the analysis of the second-order susceptibility tensor, SHG polarimetry could serve as an effective method to detect the polarization orders and domain distributions of molecular ferroelectrics. Profiting from the full-optical feature, SHG polarimetry can even be performed on samples covered by transparent mediums, 2D materials, or thin metal electrodes. Our research might spark further fundamental studies and expand the application boundaries of next-generation ferroelectric materials.
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