Broadband high-efficiency dielectric metalenses based on quasi-continuous nanostrips

Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical systems.Simultaneous broadband and high-efficiency characteristics are highly attractive for the practical implementation of metasurfaces.However,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits simultaneously.In this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this limitation.Via quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally demonstrated.The quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power efficiency.The average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same thickness.The proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.

Measuring Cognitive and Psychosocial Accessibility to Modern Contraception: A Comprehensive Framework

Nowadays, more than ever, the improvement of access to family planning (FP) has become an international goal. What constitutes access to FP? Current human rights-based contraceptive guidelines indicate that access begins as soon as women or couples express a desire to avoid pregnancy and their risk of unintended pregnancy is established. However, few studies have sought to define and measure cognitive and psychosocial access to contraception. To propose a comprehensive framework for the cognitive and psychosocial accessibility of contraception, we critically analyzed the literature on attitudes toward FP. The main dimensions that emerged were knowledge about FP, fear of side effects, approval of contraception, and contraceptive agency. We then identified and adjusted some questions that can capture these dimensions more comprehensively. As a result, we developed a questionnaire module comprising 15 questions, which was integrated into the 6th round of the PMA2020 survey in Burkina Faso in 2019. This research highlighted that previous studies have collected separate dimensions of contraceptive access, and the psychosocial dimension tended to be neglected. Our results demonstrate that it is possible to collect comprehensive data on cognitive and psychosocial dimensions of access to family planning.

Female Contraception: Comparative Study of Biometrics and Vascularization of the Uterus at Sylvanus Olympio University Hospital (Togo)

Female contraception uses both hormonal and non-hormonal methods. The aim of the study is to determine the impact of female contraception on uterine vascularisation and the endometrium. Method: It was a descriptive comparative study with an analytical aim. It took place at the University Clinic of Obstetrics Gynaecology and the Radiology and Medical imaging Department of Sylvanus Olympio University Hospital in Lomé over a two-month period from May 15, 2023 to July 15, 2023. Group 1 included women using a modern contraceptive method and group 2 women not using a modern contraceptive method. Epidata 3.1 and R 4.0.4 software were used to process the data. Results: Each group included 50 women. There were no significant differences in uterine and endometrial biometrics. All women on contraception had their zone 1 vascularized, without vascularisation of zone 2, without significant difference with women without contraception The pulsatility index was greater than 3 in 51% (n = 51) of women, including 62.7% (n = 32) of women without contraception and 37.3% (n = 19) of women on contraception, with a statistically significant difference (p = 0.009). Conclusion: Contraceptive methods do not influence the biometry of the uterus. However, uterine artery Doppler indices can predict abnormal uterine bleeding.

High-efficiency Carbonation Modification Methods of Recycled Coarse Aggregates

To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.

The Use of Modern Contraception after Childbirth in an Urban Health Center in Bangui, CAR

Introduction: The use of modern postpartum contraception not only reduces unplanned pregnancies but also improves the well-being of mother and child. The present study aims to identify the determinants of postpartum contraceptive use in a first level health facility. Methodology: This was a 6-month cross-sectional study conducted at the Urban Health Center of Castors. Postpartum women who presented within 42 days of delivery and who had a live child were included after informed consent. Results: Of 318 women enrolled during the study period, 106 were currently using a modern contraceptive method, for a prevalence of 33.3%. The mean age of the women was 25.3 years (±3.6), with extremes of 14 and 49 years. The age group [20 to 29] was the most represented with 52.8%. More than half of the women were in couples (54.7%) and had completed secondary education (53.8%). These women were mostly students (42.5%) and primiparous or pauciparous (70.7%). The most used contraceptive method was injectables (depot medroxyprogesterone acetate) (43.4%), followed by male condoms (23.6%) and oral contraceptives (17.9%). The unmet need for contraception was 40.6%. The main reasons for non-use were the desire to have more children (41.5%), fear of side effects (34.9%) and spousal opposition (12.3%). Factors associated with contraceptive non-use were educational level, occupation and parity. Conclusions: The rate of modern contraceptive use in the postpartum period is low in the study population. Interventions to increase the use of effective contraceptive methods are needed, especially among young women.

High-efficiency Planting Techniques of Five Crops a Year for Fresh Edible "Faba Bean/Spring Mazie+Soybean-Autumn Maize/Autumn Soybean"

The high-efficiency planting mode for five crops a year of fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ was introduced, and its yield and economic benefits were compared with the planting mode of three crops a year of ＂faba bean-spring maize/red bean＂. The results showed that the planting method for fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ was much easier to operate with the input-output ratio of about185.6%, and its yield and economic benefits were 2.09 and 1.83 times of that of the planting mode for three crops a year, significantly improving the agricultural yield and income of farmers. In addition, the cropping index of the planting mode for fresh edible fresh edible ＂faba bean/spring maize ＋soybean-autumn maize/autumn soybean＂ reached up to 350%, and planting faba bean once a year and soybean twice a year could make the biological fixation amount of nitrogen increase 350-450kg/m^2, which equaled to up to 700 kg/m^2 of urea, showing significant ecological and social benefits. Based on the comparison results, the high-yield culture techniques of the planting mode of fresh edible ＂faba bean/spring maize＋soybean-autumn maize/autumn soybean＂ were summarized.

Low dose gossypol for male contraception

Aim: To ascertain whether the side effects of gossypol, hypokalemia and irreversibility, could be avoided on dose re-duction. Methods: Seventy-seven male volunteers were divided into 3 groups: control (22 cases), 10 mg gossypol(29 cases) and 12.5 mg (26 cases). Serum levels of testosterone, FSH and LH were measured by RIA and potassiumby flame photometry. Spema counts and motility were examined before and regularly after treatment for the evaluationof contraceptive efficacy. Results: The average sperm density and motility started to decrease significantly by theend of month 2 of medication and gradually reached the infertility levels ( < 4 million /mL) in both treated groups. Af-ter that the 10 mg group was asked to take the same dose every other day for up to a total observation period of 16-18months for the maintenance of infertility. Subjects in the 12.5 mg group did not take gossypol any more so as to ob-serve the length of the loading dose required, but in a few, a maintenance dose of 12.5 mg every other day was insti-tuted for a few more months. In both treated groups, none of the spouses was pregnant during the maintenance dose pe-riod. Serum levels of potassium, FSH, LH and testosterone were not significantly changed and not a single volunteercomplained of myoasthenia. After cessation of drug administratioin, the semen data returned to pretreatment levels.Conclusion: A regimen with 10 or 12.5 mg of gossypol as the daily loading dose and 35 or 43.75 mg as the week-ly maintenance dose could induce infertility in male volunteers without developing hypokalemia or irreversibility.(Asian J Androl 2000 Dec; 2: 283-287)

Vas deferens, a site of male contraception: an overview

The vas deferens is a site which can be exploited for male contraception without undue side effects. The only ef-fective technique available for male contraception is vasectomy, being practiced world wide, despite that it is a perma-nent surgical procedure and its successful reversal is not assured. Although no-scalpel vasectomy minimizes surgicalprocedures, the fate of its reversal is akin to that of vasectomy. Several occlusive and non-occlusive vasal procedureswhich claim to be reversible without surgical intervention, possess more disadvantages than advantages. Vas occlusionwith plug, ' Shug' or medical grade silicone rubber, although claimed to produce reversible azoospermia without affect-ing spermatogenesis, requires skilled microsurgery for their implantation and later removal. RISUG^R, a non-scleroticpolymer styrene maleic anhydride (SMA), could be more advantageous than vasectomy and other vas occlusive proce-dures in that it could be a totally non-invasive procedure by 'no-scalpel injection' and 'non-invasive reversal'. It isclaimed to offer long-term contraception without adverse side effects and also to be possible as a male spacing methodby repeated vas occlusion and non-invasive reversal. The drug is currently under multicentre Phase Ⅲ clinical trial.

Approaches to post-testicular contraception

The induction of infertility in males of several species through epididymal interference is more difficult to achieveby reduction of the mounts of epididymal secretions (eg α-glucosidase, L-carnitine) or immunological interferencewith secreted proteins ( eg D/E, P34H, P26h) than by direct actions of drugs on sperm function (eg inhibition ofglyceraldehyde 3-phosphate dehydrogenase by chloro-compounds). The latter approach holds promise for mankind ashuman sperm are susceptible to glycolytic inhibition. Future contraceptive developments may arise from production oftargeted inhibitors, research on the displacement of sperm proteins in the epididymis and interference with sperm plasmamembrane ion channels.

Development of methods of male contraception: impact of the World Health Organization Task Force

Objective: To give an historical record of the research of the World Health Organization (WHO) Task Force to develop methods of male contraception; to examine the social, political, medical, pharmaceutical, funding, and other factors that influenced progress; and to suggest reasons why such methods are only now becoming available. Design: Review of basic and clinical research over 30 years. Setting: Task force of a multinational agency and collaborating agencies. Conclusion(s): Through the involvement of many international scientists, the WHO Task Force has uniquely contributed to the exploratory phases of the research in male contraception and by its multicenter contraceptive efficacy studies has accelerated progress towards the ideal hormonal method. Despite an adverse climate involving social and political attitudes, funding constraints, and pharmaceutical industry hesitations, WHO formed coalitions with governments and international agencies to sustain research with results that apply to men in culturally diverse populations and thereby to influence activities across the whole range of global reproductive health and family planning.

Hormonal contraception in Chinese men: variations insuppression of spermatogenesis with injectable testosteroneundecanoate and levonorgestrel implants

Aim: To explore the causes of the difference in spermatogenic suppression between responders and non-responders in Chinese men treated with levonorgestrel (LNG) implants plus testosterone undecanoate (TU) injectable. Methods: The 16 Chinese volunteers treated were divided into two groups in regard to the sperm count during the treatment period, 7 men in the responder group (Group R), including 6 azoospermia and one severe oligozoospermia, and the remaining 9 in the non-responder group (Group N), including 4 oligozoospermia and 5 with sperm counts greater than 20×106/mL. The differences in serum profiles of FSH, LH, T, LNG and T/LH ratio were compared between the two groups and the correlation between the seminal fluid parameters and serum reproductive hormones was analyzed. Results: The serum FSH level was lower in Group R than that in Group N (P<0.05), while the serum LH and LNG levels were higher in Group R than those in Group N (P<0.05). The sperm density (P<0.01, r=0.235), motility (P<0.01, r=0.326) and vitality (P<0.01, r=0.219) showed significantly positive correlation with the serum FSH level. Conclusion: The blood LNG and T levels, the degree of FSH inhibition and/or the sensitivity of the pituitary-testis axis to exogenous steroids, as well as the individual spermatogenetic potential and the functional status of the Leydig cells may be factors bringing about individual differences in spermatogenic suppression in Chinese men treated with LNG and TU.

Three new methods for male contraception

The methods devised for male contraception are meagre. In the crrrent communication, we review 3 recently de-veloped methods applied for male contraception: testicular suspension, polyester-induced azoospermia and prolactin in-jection. The testicle was suspended in the superficial inguinal pouch close to the scrotal neck using 2 methods: stitchand ball. The azoospermic effect of the polyester sling seems to be due to 1) creation of electrostatic field across theintrascrotal structures, and 2) disordered thermoregulation. Prolactin administration, as a contraceptive method is effi-cient and safe and has the potential to be developed as a male contraceptive. The effect of the above mentioned 3methods is reversible. These methods, especially testicular suspension and polyester suspensors, are simple and easilyapplicable and were well acceptable by the subjects. (Asian J Androl 1999 Dec; 1: 161 - 167)

Hormonal contraception for human males:prospects

Development of an ideal hormonal contraceptive for man has been the goal of several research workers during thepast few decades. Suppression of pituitary gonadotropic hormones, which in turn would inhibit spermatogenesis whilemaintaining normal libido and potentia has been the approach for a contraceptive agent. Intramuscularly administeredand orally active testosterone or testosterone in combination with progesterone have been shown to cause inhibition ofspermatogenesis resulting in azoospermia in normal men. Similarly testosterone has been used in combination with go-nadotropin releasing hormone antagonists and agonists to inhibit pituitary gonadotropic hormone release. Immunologicalapproach to neutralize the circulating levels of follicle stimulating hormone has also been shown to cause inhibition ofspermatogenesis. The available literature shows that testosterone causes reversible azoospermia without any significantside effects in Asian population effectively and appears to be a promising chemical for control of fertility in man.

Adiabatic cooling for cold polar molecules on a chip using a controllable high-efficiency electrostatic surface trap

We propose a controllable high-efficiency electrostatic surface trap for cold polar molecules on a chip by using two insulator-embedded charged rings and a grounded conductor plate. We calculate Stark energy structure pattern of ND3 molecules in an external electric field using the method of matrix diagonalization. We analyze how the voltages that are applied to the ring electrodes affect the depth of the efficient well and the controllability of the distance between the trap center and the surface of the chip. To obtain a better understanding, we simulate the dynamical loading and trapping processes of ND3 molecules in a ｜J, KM = ｜1,-1 state by using classical Monte–Carlo method. Our study shows that the loading efficiency of our trap can reach ～ 88%. Finally, we study the adiabatic cooling of cold molecules in our surface trap by linearly lowering the potential-well depth（i.e., lowering the trapping voltage）, and find that the temperature of the trapped ND3 molecules can be adiabatically cooled from 34.5 m K to ～ 5.8 m K when the trapping voltage is reduced from-35 k V to-3 k V.

Interference with the formation of the epididymal microenvironment——a new strategy for male contraception?

The cystic fibrosis transmembrane conductance regulator (CFIR) or the small conductance cAMP-activated chlo-ride channel encoded by the CFTR gene has been shown to play an important role in the formation of the epididymalfluid microenvironment. Recent work in our laboratory has shown that this protein is also expressed by developing germcells indicating a role of this protein in spermatogenesis. In view of the fact that the CFTR gene has a far reaching andwidespread effect on human reproduction, understanding the role of CFTR in the male reproductive tissues and its inter-vention by pharmacological agents can open a new avenue of research into the development of novel male contracep-tives. (Asian J Androl 2000; 2: 39 - 45 )

Predictors for partial suppression of spermatogenesis of hormonal male contraception

Aim： To analyze factors influencing the efficacy of hormonal suppression of spermatogenesis for male contraception. Methods： A nested case-control study was conducted, involving 43 subjects, who did not achieve azoospermia or severe oligozoospermia when given monthly injections of 500 mg testosterone undecanoate （TU）, defined as partial suppressors compared with 855 subjects who had suppressed spermatogenesis （complete suppressors）. Sperm density, serum testosterone, luteinizing hormone （LH） and follicle stimulating hormone （FSH） concentrations at the baseline and the suppression phase were compared between partial and complete suppressors. Polymorphisms of androgen receptor （AR） and three single nucleotide variants and their haplotypes of FSH receptor （FSHR） genes determined by polymerase chain reaction （PCR） and DNA sequencing technique were compared between 29 partial and 34 complete suppressors. Results： Baseline serum LH level was higher and serum LH as well as FSH level during the suppression phase was less suppressed in partial suppressors. Additionally, in a logistic regression analysis larger testis volume, higher serum FSH concentrations alone, or interaction of serum LH, FSH, testosterone and sperm concentrations were associated with degree of suppression. The distribution of polymorphisms of AR or FSH receptor genes did not differ between partial and complete suppressors. In cases with incomplete FSH suppression （FSH 〉 0.2 IU/L）, the chances of reaching azoospermia were 1.5 times higher in the subjects with more than 22 CAG triplet repeats. Conclusion： Partial suppression of spermatogenesis induced by 500 mg TU monthly injections is weakly influenced by hormonal and clinical features but not polymorphism in AR and FSHR genes.

INVESTIGATION OF SURFACE TEMPERATURE IN HIGH-EFFICIENCY DEEP GRINDING

A new thermal model with triangular heat flux distribution is given in high-efficiency deep grinding. The mathematical expressions are driven to calculate the surface temperature. The transient behavior of the maximum temperature on contact area is investigated in different grinding conditions with a J-type thermocouple. The maximum contact temperatures measured in different conditions are found to be between 1 000 ℃ and 1 500 ℃ in burn-out conditions. The experiment results show good agreement with the new thermal model.

High-Efficiency Mid-Infrared Picosecond MgO:PPLN Single Resonant Optical Parametric Oscillator

We demonstrate a high-emciency mid-infrared picosecond optical parametric oscillator （OPO） based on MgO doped periodically poled lithium niobate （MgO：PPLN） with a laser diode array （LDA） pumped Innoslab amplifier as the pumping source. Under a 16 W synchronously pumping power, 4.5 W of idler light at 2896nm is obtained. A tuning range of idler light from 2688nm to 3016nm is achieved, within which the highest optical-optical conversion ettlciency from pump power to OPO output is 35.1%. Moreover, a signal light of -500mW from 1644 to 1700nm with a repetition rate of 233.8 MHz is generated.

Assessment of level of knowledge and utilization of emergency contraception among female students of Hawassa University, south Ethiopia

Introduction: Emergency contraception is used as an emergency procedure to prevent unintended pregnancy secondary to an unprotected se xual intercourse and method failure. Hence, this study assessed the level of knowledge and utilization of emergency contraception among undergraduate regular female students of Hawassa University, south Ethiopia. Methods: An institution-based cross-sectional survey was conducted among female students of Hawassa University in December 2012. Seven hundred seventy six of the students were sampled by using multistage sampling technique. Pretested structured questionnaire was used to collect the data. Results: The majority 719 (92.7%) of female university students ever had sexual intercourse and 17 (2.2%) experienced forced sex. Eight (47%) of these 17 students experienced unintended pregnancy all of which resulted in an induced abortion. Three hundred seventy nine (72.2%) of the respondents had knowledge about emergency contraceptives and only 41 (10.8%) of them had ever used emergency contraceptives;oral contraceptive pills were the most widely used form of all emergency contraceptives 41 (10.8%). Age, marital status and age at menarche were associated with knowledge of emergency contraception;moreover, residence, year of study and experience of forced sex were found to be predictors of emergency contraception utilization. Conclusion: Female university students had been experiencing high rate of unintended sexual practice and pregnancy, low knowledge level and utilization of emergency contraceptives;moreover, they had no youth-friendly access to the services. Therefore, there is a need for collaborated effort to improve service access and scale up their utilization level to prevent unwanted pregnancy.

Effect of Structural Parameters on the Performance of NS High-efficiency Composite TraysⅠ.The Effect of Aperture and Opening Ratio on NS High-efficiency Composite Trays

In this paper,the structure and characteristics of the NS high-efficiency composite trays based on the doublelayer aperture jet sieve plate and compositely structured packing were investigated.The effect of aperture and opening ratio of plate on the fluid dynamics of the NS high-efficiency composite trays,such as the dry tray pressure drop,the wet tray pressure drop,the entrainment,the froth height,the leakage and mass transfer characteristics,were investigated.As a result, the low pressure drop,the high efficiency and the high capacity are the main advantages of the NS high-efficiency composite trays compared to other types of trays.According to this study,small aperture is useful for reducing the pressure drop and entrainment with a high mass transfer efficiency;while large aperture can achieve high capacity and efficiency in a broader operating range at the same pressure drop and entrainment.