Reversible Boolean function (RBF) is a one-to-one function which maps n-bit input to n-bit output. Reversible logic synthesis has been widely studied due to its connection with low-energy computation as well as quantum computation. In this paper, we give a structured decomposition for even RBFs. Specifically, for n≥q 6, any even n-bit RBF can be decomposed to 7 blocks of (n-1)-bit RBF, where 7 is a constant independent of n and the positions of these blocks have a large degree of freedom. Moreover, if the (n-1)-bit RBFs are required to be even as well, we show for n≥q 10, even n-bit RBF can be decomposed to 10 even (n-1)-bit RBFs. In short, our decomposition has block depth 7 and even block depth 10. Our result improves Selinger's work in block depth model, by reducing the constant from 9 to 7 and from 13 to 10, when the blocks are limited to be even. We emphasize that our setting is a bit different from Selinger's work. In Selinger's constructive proof, each block is placed in one of two specific positions and thus the decomposition has an alternating structure. We relax this restriction and allow each block to act on arbitrary (n-1) bits. This relaxation keeps the block structure and provides more candidates when choosing the positions of blocks.

In order to analyze the deformation characteristics and mechanisms caused by high tectonic stress in gentle dip strata, a physical modeling with circular tunnel was designed. The model was constructed by the so-called "Physically Finite Elemental Slab Assemblage (PFESA)" to bring about the structural effect of the deep strata. The gravity was fixed while the lateral pressure increased step by step to mimic high tectonic stress. In order to observe the displacement in different area, the sketches of monitoring points and frame in the model surface were drawn down through video pictures in different periods and to be compared. For the sake of analyzing the deformation and failure mechanism of layers, rock structural mechanics models were set up for the left side and right side in the same stratum, respectively. For verifying the experimental phenomenon and its mechanism, infrared images were utilized based on the temperature variation mechanisms of material. Through systematic study, this paper enriches the research methods of model test and can provide a certain reference for practical engineering of similar conditions.

Rockburst occurred frequently during deep mining in China. The mechanism of rockburst is very complicated and related to many factors. In order to investigate the influence of moisture contents of rockmass on rockburst, we conducted a series of laboratory rockburst experiments of sandstone under three different moisture contents by the Modified True-Triaxial Apparatus (MTTA), in which the acoustic emission (AE) system was employed to monitor the internal damage of rock mass. A high-speed video camera was utilized to record the detail of rockburst. Based on the experimental results, the AE characteristics, such as AE count, AE energy, and AE frequency, were analyzed. The rockburst process, type, and indensity under different moisture contents were discussed. The research results show that with the increase of moisture contents, rock strength was soften, the elastic and the cumulative damage of the rock were reduced, resulting in a gradual decrease in AE cumulative counts and cumulative energy over the course of rockburst. This study provides an experimental basis and reference for better understanding to the rockburst mechanism and control.

Objective

China's family planning program focuses on younger women. Women older than 50 years, especially those in rural areas, are ineligible for free services and often have few other care options. Few studies have examined the sexual and reproductive health demands and unmet needs of these women.

Methods

This cross-sectional, interviewer-administered survey included 1,652 rural women aged 50 to 64 years from seven provinces in China. We examined women's sexual and reproductive health status, knowledge, and service demands, and whether they still had an intrauterine device (IUD).

Results

Educational levels were low, and most were rural farmers or housewives. The mean age at menopause was 48.9 years, and 52.4% reported climacteric symptoms. The mean frequency of sex in the last month was 1.8 times. About 47.4% of women had undergone a gynecological examination during the past 2 years. The first choice for care was family planning clinics (31.2%) followed by township hospitals (28.4%). Identified service needs included women's health check-ups (56.5%), sexual health knowledge (54.4%), women's health knowledge (35.4%), menopause counseling (34.8%), and IUD removal after menopause (17.0%). Among 519 postmenopausal women who used an IUD, 19.1% had not had it removed. On multivariate regression, awareness of correct time for IUD removal, beliefs about sex after menopause, receiving formal health education, and undergoing gynecological examination were significantly associated with having had IUD removal.

Conclusions

A large proportion of middle-aged women in rural China lack sexual and reproductive health services, including IUD removal after menopause. A comprehensive program of sexual and reproductive health services is needed for middle-aged women in rural China.

Background

There is a very large population of internal migrants in China, and the majority of migrant women are of childbearing age. Little is known about their utilization of prenatal care and factors that influence this. We examined this using data from a large national survey of migrants.

Methods

5372 married rural to urban migrant women aged 20-34 who were included in the 2014 National Dynamic Monitoring Survey on Migrants and who delivered a baby within the previous two years were studied. We examined demographic and migration experience predictors of prenatal care in the first trimester and of adequate prenatal visits.

Results

12.6% of migrant women reported no examination in the first trimester and 27.6% had less than 5 prenatal visits during their latest pregnancy. Multivariate analysis indicated that demographic predictors of delayed and inadequate care included lower educational level, lower income and not having childbearing insurance. Migrating before pregnancy, longer time since migration, having migrated a greater distance, and not returning to their home town for delivery were correlated with better prenatal care.

Conclusions

Many internal migrant women in China do not receive adequate prenatal care. While internal migration before pregnancy seems to promote adequate prenatal care, it also creates barriers to receiving care. Strategies to improve prenatal care utilization include expanding access to childbearing insurance and timely education for women before and after they migrate.

Background

China has a large migrant population, including many young unmarried women. Little is known about their sexual behavior, contraceptive use, and risk of unintended pregnancy.

Methods

475 unmarried female migrants aged 15-24, working in 1 of 6 factories in 2 districts of Changzhou city, completed an anonymous self-administered questionnaire in May 2012 on demographic characteristics, work and living situation, and health. We examined demographic and migration experience predictors of sexual and contraceptive behavior using bivariate and multivariate regressions.

Results

30.1% of the respondents were sexually experienced, with the average age at first sex of 19 years (standard deviation=3). 37.8% reported using contraception at first sex, 58.0% reported using consistent contraception during the past year, and 28.0% reported having at least 1 unintended pregnancy with all unintended pregnancies resulting in abortion. Those who had had at least 1 abortion reported having on average 1.6 abortions [SD=1] in total. Migrating with a boyfriend and changing jobs fewer times were associated with being sexually experienced. Younger age, less education, and changing jobs more times were associated with inconsistent contraceptive use.

Conclusion

These findings demonstrate there is an unmet need for reproductive health education and services where these women work as well as in their hometown communities. This education must begin early to reach young women before they migrate.

Great attention has been focused on the design of electrocatalysts to enable electrochemical water splitting-a technology that allows energy derived from renewable resources to be stored in readily accessible and non-polluting chemical fuels. Herein we report a bifunctional nanotube-array electrode for water splitting in alkaline electrolyte. The electrode requires the overpotentials of 58 mV and 184 mV for hydrogen and oxygen evolution reactions respectively, meanwhile maintaining remarkable long-term durability. The prominent performance is due to the systematic optimization of chemical composition and geometric structure principally-that is, abundant electrocatalytic active sites, excellent conductivity of metallic 1T' MoS₂, synergistic effects among iron, cobalt, nickel ions, and the superaerophobicity of electrode surface for fast mass transfer. The electrode is also demonstrated to function as anode and cathode, simultaneously, delivering 10 mA cm^-2 at a cell voltage of 1.429 V. Our results demonstrate substantial improvement in the design of high-efficiency electrodes for water electrolysis.

Development of natural protein-based fibrous scaffolds with tunable physical properties and biocompatibility is highly desirable to construct three-dimensional (3D), fully cellularized scaffolds for wound healing. Herein, we demonstrated a simple and effective technique to construct electrospun 3D fibrous scaffolds for accelerated wound healing using a photocrosslinkable hydrogel based on gelatin methacryloyl (GelMA). We found that the physical properties of the photocrosslinkable hydrogel including water retention, stiffness, strength, elasticity and degradation can be tailored by changing the light exposure time. We further observed that the optimized hydrogel fibrous scaffolds which were soft and elastic could support cell adhesion, proliferation and migration into the whole scaffolds, facilitating regeneration and formation of cutaneous tissues within two weeks. Such tunable characteristics of the fibrous GelMA scaffolds distinguished them from other reported substrates developed for reconstruction of wound defects including glutaraldehyde-crosslinked gelatin or poly (lactic-co-glycolic acid) (PLGA), whose physical and chemical properties were difficult to modify to allow cell infiltration into the 3D scaffolds for tissue regeneration. We anticipate that the ability to become fully cellularized will make the engineered GelMA fibrous scaffolds suitable for widespread applications as skin substitutes or wound dressings.

Statement of significance

In present study, we generate three-dimensional photocrosslinkable gelatin (GelMA)-based fibrous scaffolds with tunable physical and biological properties by using a combined photocrosslinking/electrospinning approach. The developed GelMA fibrous scaffolds can not only support cell viability and cell adhesion, but also facilitate cell migration and proliferation, accelerating regeneration and formation of cutaneous tissues. In addition, the physical properties of the engineered fibrous GelMA hydrogel including water retention capability, mechanical properties and biodegradability can be tuned to accommodate different patients' needs, making it a promising candidate for skin tissue engineering.