63results about How to "Does not cause death" patented technology

The invention discloses an intelligently-adjusting planting device for plants. The intelligently-adjusting planting device comprises a base, a water spraying pipe, a soil humidity detector and a controller, wherein a first water storage tank with a liquid level raising device is arranged in the base; a water inlet communicated with the first water storage tank is formed in the base; the water spraying pipe is used for spraying water to the plants; a water supplying valve is arranged on the water spraying pipe; a water inlet of the water spraying pipe is communicated with a water outlet of the liquid level raising device; the soil humidity detector is used for detecting the humidity of plant soil in real time and transmitting a soil humidity signal; the controller is used for controlling the opening / closing of the water supplying valve according to the received soil humidity signal. According to the intelligently-adjusting planting device for the plants, which is disclosed by the invention, the humidifying and watering operation of vegetation can be automatically realized without manual operation, so that the cultivation quality is improved while labor force is saved.

A tree planting device capable of making a tree conveniently moved comprises an inner cylinder and an outer cylinder. The tree is planted on the inner side of the inner cylinder, the outer side of the inner cylinder is rotationally sleeved with the outer cylinder, a plurality of inner shear holes are formed in the circumferential side face of the inner cylinder, a plurality of outer shear holes are formed in the circumferential side face of the outer cylinder, each outer shear hole right faces one inner shear hole, outer operation parts are arranged in a top opening of the outer cylinder, inner operation parts staggered with the outer operation parts are arranged in a top opening of the inner cylinder, the outer cylinder can rotate the outer operation parts thereon to right face the inner operation parts, and when the outer operation parts are in place, the outer shear holes and the inner shear holes originally right facing the outer shear holes are staggered. The roots of the tree can penetrate out of the shear holes and stretch into soil to absorb nutrients; during transplanting, force is applied to the inner and outer operation parts oppositely so that the inner and outer operation parts can move opposite to each other, the roots stretching into the soil are cut off due to relative movement of the inner shear holes and the outer shear holes, and then a crane and other machines are used for hoisting the whole device for transplanting.

The invention discloses a tetraodotoxin deratizing poison bait which consists of one or more of tetraodotoxin, tetraodotoxin bacterial broth, internal organs of globefish, blood of globefish or ovary of globefish. The bait material consists of one or more of rotten rice, swill-cooked dirty oil and peanut cakes or bean cakes after oil expression. The tetraodotoxin deratizing poison bait is reliable in virulence, definite in toxicity, good in deratizing effect, and easy to degrade, and free from toxic pollution, residuals and secondary poisoning. The components are recycled resources and simple and easy to obtain. In the preparation process of the deratizing poison bait, water liquids are not doped, so that the poison bait is good in dissolubility and palatability.

The invention discloses a method for cultivating parent fishes of Atlantic salmons in complete fresh water, which comprises the steps of: (1) selecting a breeding pond; (2) controlling cultivation conditions, wherein the cultivation water temperature is controlled to be between 4 and 15 DEG C; the cultivation current gradually changes 3 times per hour and the water flow is 0.04 to 0.09 m<3> / s, 0.5 to 0.8 m<3> / s and 1.3 to 2.0 m<3> / s respectively; and the natural lighting is adopted; (3) selecting the parent fishes; (4) selecting feeds, wherein Atlantic salmon breeding feeds of which the publication number of the patent application is CN101156655A is adopted; and (5) cultivating the parent finishes. According to the living characteristics of parent finishes of the Atlantic salmons, the method can stimulate the gonadogenesis of the parent fishes and improve the success rate of the mature parent fishes by adopting unique pond design and particular water flow control.

The invention relates to a method for massively producing photosynthetic bacteria under a natural ecological condition, which comprises the steps of: 1, preparing a photosynthetic bacteria culture medium; 2, culturing a photosynthetic bacteria mother liquor; and 3, massively producing the photosynthetic bacteria. The pH value of the prepared photosynthetic bacteria culture medium is 8.4 and the prepared photosynthetic bacteria culture medium has high-content sodium acetate; in the step of massively producing the sodium acetate, treated water is placed in a water pool of above 10m<3>, the prepared photosynthetic bacteria culture medium is added according to the proportion, after the photosynthetic bacteria culture medium is fully completed and is balanced with an outside temperature, the photosynthetic bacteria mother liquor is added in the water pool and uniformly stirred for placing for 4-5h, packaging in a transparent container, adding a cover for sealing, placing a place irradiated by sunshine, and fermenting for 2-4 days to obtain photosynthetic bacteria liquid. The photosynthetic bacteria are cultured under the natural condition without complex equipment, strict culture conditions and expensive culture media, thus the production cost of the photosynthetic bacteria can be greatly saved, and the popularization and the use of products are favored.

The invention relates to an application of antifolic in constructing a mouse model with neural tube defects (NTDs). Specifically, an anti-folic acid metabolism drug is adopted for intervening a pregnant mouse to generate folic acid dysbolism and cause abnormal embryonic development of the mouse, thereby constructing a mouse model with NTDs. The method adopted by the invention has simplicity of operation, good repeatability, high teratogenesis rate and stable effect, and simulates an animal model close to human on the pathogenesis of NTDs by obstructing normal metabolism of folic acid, thereby facilitating further studies on congenital anomalies, especially NTDs.

The invention provides water-soluble nutritional essential oil for livestock, poultry and aquatic product cultivation and a preparation method and application thereof, and belongs to the technical field of feed products. The water-soluble nutritional essential oil is prepared from the following components in parts by weight: 10-500 parts of animal and vegetable oil, 0.1-100 parts of a vitamin, 0.1-150 parts of amino acid, 10-800 parts of ultrapure water, 1-250 parts of a thickening agent, 0.1-100 parts of an additive and 10-500 parts of an emulsifying agent, and is further prepared from the components in parts by weight: 5-250 parts of natural plant essential oil, 50-800 parts of a traditional Chinese medicine extracting solution, 0.1-10 parts of an antioxidant, 10-300 parts of minerals and / or 90-150 parts of an acidifying agent. The water-soluble nutritional essential oil is scientific in proportion and balanced in nutrition, and has growth promoting and health-care effects on cultured objects, a further formula can comprehensively replace antibiotics, and the water-soluble nutritional essential oil has disease-resistant and treatment effects, is completely water-soluble, cannot cause oxygen deficit of aquatic organisms, and can remarkably increase economic benefits of the cultivation industry.

The invention discloses a rodenticide and belongs to the technical field of insect damage removal. The invention provides the rodenticide which is low in cost, high in palatability, easy to store and significant in rat killing effect. The rodenticide comprises 10-80 parts by weight of base material, 0.002-0.5 part by weight rat killing active ingredient and 2-40 parts by weight auxiliary material. The base material is prepared by solid-liquid separation, breaking, sorting, slurrying, dryness and grinding of kitchen waste into powder; a protein content in the base material powder is greater than or equal to 20%; a starch content is greater than or equal to 45%; an oil content is less than 7%; and a water content is less than 10%. The rat killing active ingredient is a safe second generation rat killing active ingredient. The auxiliary material comprises an excipient, an adhesive, a water absorber, a surfactant, a preservative, a colorant, a corrigent and a solvent. The rodenticide is high in palatability, suitable for long-time rat destruction, good in rat killing effect and low in cost; and a novel approach is provided for comprehensive utilization of the kitchen waste.

The invention belongs to the technical field of tree nursery stock cultivation, and particularly relates to a method for increasing the transplanting survival rate of xanthoceras sorbifolia bunge bare-root nursery stocks. The method comprises the steps of 1, farming preparation pretreatment of a planting site; 2, lifting of transplanted seedlings, shaping and clearing of root systems, and planting; 3, field management after xanthoceras sorbifolia bunge bare-root nursery stock transplantation. The first step further comprises the steps of selecting the planting site which contains neutral or alkalescent loam with a pH value ranging between 7 and 8.5, wherein the depth of the soil layer is 60-80 cm; preparing the planting site, wherein farmyard manure is applied 3000 kg / mu before farming preparation; preparing soil and ridging. The second step further comprises the steps of conducting seedling lifting manually, wherein the root systems are cut neatly during seedling lifting; shaping and clearing the root systems; planting the nursery stocks. The third step further comprises the steps of water control of forest land; soil loosening and weeding; final management and maintenance, wherein fertilization and irrigation are conducted three to four times and soil loosening and weeding are conducted twice each year since the second to fifth year. By the adoption of the method, the transplanting survival rate of the xanthoceras sorbifolia bunge bare-root nursery stocks is successfully increased to over 85% from below 20% before measures are taken, and technical assurance is provided for improved variety popularization of xanthoceras sorbifolia bunge.

The invention relates to a method for cleaning crocodile hatching eggs and belongs to the field of hatching of hatching eggs. The method includes the specific steps that the hatching eggs are cleaned through warm potassium permanganate water at the temperature of 26-40DEG C, the hatching eggs are quickly and gently placed into another clean incubator after being cleaned, and the shell of one of each nest of eggs is marked by a pencil after the eggs are cleaned so that the hatching eggs can be conveniently placed on a hatching frame and managed during a hatching period in the subsequent process; the cleaned hatching eggs are placed into a potassium permanganate disinfection solution which has the concentration ranging from 0.1% to 0.9% and is prepared by warm water for 40-80 seconds, then, the water is drained off, the hatching eggs are gently placed on the hatching frame in a hatching room in sequence with the marking directions kept upward and unchanged, and the hatching frame is marked for preservation management. According to the method, active ingredients of the hatching eggs can be kept to the maximum, the shells of the hatching eggs can be cleaned and microorganisms and stains of the shells can be removed under the condition that the shells of the hatching eggs are not broken, normal hatching of embryos in the shells is not affected, the malformation of young crocodiles and even death of the embryos can be avoided better, and the method for cleaning the crocodile hatching eggs is good in effect.

An aeroponic cultivation device for Dendrobium officinale is characterized in that: a vertical hollow column (1) is used as a cultivation base; atomization nozzles (2) are arranged in the hollow column from up to down; the atomization nozzles are connected to a liquid supplying pool (4) by a pipeline (3); the pipeline (3) is provided with a water pump (5). According to the invention, the atomizing time can be regulated based on the temperature and the humidity, and requirements of plants for water and fertilizer can be satisfied; the cultivation method has the beneficial effects that: a three-dimensional planting technology is adopted, compared with the conventional cultivation method, a lot of land can be saved, and the land utilization rate is improved by greater than 5 times; the planting matrix is not needed, and the investment cost is saved; interplanting can be performed, through adoption of the aeroponic cultivation technology, interplanting can be performed in the forest or the sanmu medical materials, and the economic benefits can be significantly improved by adoption of the sanmu medical materials or other economic forest formed by trees with high economic values such as cinnamomum camphora and osmanthus fragrans; the cultivation method is suitable for the growth of the Dendrobium officinale.

The invention discloses a tree grafting method for a scion without an interface. For conventional scion in-vitro grafting, both a scion and a rootstock need interfaces, so that the grafting range and the grafting effect are limited. The method of the invention comprises the following steps of: cutting a rectangular groove which is1.0-1.8 cm in depth and 0.8-1.2 cm in width on the stem or the branch of a large rootstock, and embedding a scion plant or a scion branch in the rectangular groove of the rootstock in an integral mode. When the method is used for grafting, the rootstock is provided with an interface, and the scion is not provided with an interface; as the scion plant grows thicker and the callus of the groove of the rootstock expands continuously, the scion and the rootstock gradually heal into an integral. The grafting method has high survival rate and obvious economic benefit and ecological scenic benefic.

The invention discloses a breeding method for improving the mutation frequency of silkworms. The breeding method includes the following steps that first, silkworm larvae at all developmental stages from four-instar third-day larvae to matured silkworms are taken as silkworm larvae to be handled; second, irradiation holes matched with conceptacle portions of the silkworm larvae to be handled in shape and size are manufactured in a baffle plate of the thickness of 1.5-2.5mm, and then the irradiation holes are aligned with the conceptacle portions of the silkworm larvae to be handled; the conceptacle portions of the silkworm larvae to be handled are irradiated by rays for irradiation through the irradiation holes; third, the irradiated larvae and the control larvae which are not irradiated are bred with the same method, and the matured silkworms are made to spin, spin cocoons and undergo eclosion; fourth, the irradiated eclosion larvae are made to mate with eclosion matured silkworms which are not irradiated, and eggs are laid; mutations of the next generation of bred irradiated silkworms are selected.

The invention discloses a porcine actinobacillus pleuropneumoniae attenuated strain and a porcine pleuropneumonia-preventing product prepared from the same, and relates to the fields of microorganisms and immunology. According to the porcine actinobacillus pleuropneumoniae attenuated strain and the porcine pleuropneumonia-preventing product prepared from the same disclosed by the invention, on the basis of a single mutant strain GS7C, a ureC gene segment in a genome is further deleted, and an apxIII-N gene segment with immunogenicity is inserted, and then the double mutant strains (GS7CA) of apxIIC- / apxIA+ and ureC- / apxIII+ which successfully express ApxIII-N proteins are screened by virtue of a sacB negative gene screening system, and the collection number is CGMCC NO. 10016. Experimental data indicates that, the hemolytic activity and urease activity of the double mutant strains are completely lost, the toxicity is greatly reduced, and stable inheritance can be realized; the attenuated live vaccine prepared by the porcine actinobacillus pleuropneumoniae attenuated strain disclosed by the invention has low toxicity, cross protection activity, high bio-safety and stable quality.

The invention relates to a determination method, in particular to a semiquantitative determination method of concentration of ammonium nitrogen in agricultural biogas fluid; the invention aims to provide the semiquantitative determination method of the concentration of the ammonium nitrogen (namely NH4<+>-N) in the agricultural biogas fluid. The determination method comprises the steps: step 1, selection of raw materials: a cylindrical transparent glass tube containing 20ml of deionized water, a dark plastic pipe containing 2.5ml of alkaline sodium hypochlorite solution, a dark plastic pipe containing 2.5ml of phenol solution, a plastic dropper of which the dripping amount is 0.01ml and a colorimetric card; step 2, determination method: sucking up a biogas fluid sample by using the 0.01ml of plastic dropper, dripping one drop of the biogas fluid to the cylindrical transparent glass tube containing 20ml of deionized water, and ensuring that the one drop of the biogas fluid is free of bubbles; then, adding the 2.5ml of alkaline sodium hypochlorite solution and the 2.5ml of phenol solution in the plastic pipes into the cylindrical transparent glass tube, slightly shaking to uniformly mix the added solution and the primary 20ml of deionized water, then standing the mixture for 1 hour, so the color development is completed.

The invention discloses a dry land soil animal numeral field and a construction method thereof. The dry land soil animal numeral field comprises at least one dry land capable of being used for a long time, an automatic monitoring device and an electric power supply device, and the distance between every two dry lands is more than 200 m; a square sample plot is arranged in the center of each dry field, and a certain distance is reserved between the sample plot and the edge of the dry field so as to avoid the edge effect; permanent landmarks are respectively arranged at four corners of the sample plot according to the geographic position, or fences are arranged at the boundary of the dry farmland where the sample plot is located; the interior of each sample plot is divided into a plurality of square grids by basic units, and the automatic monitoring equipment and the power supply equipment are arranged around the sample plot, underground, earth surface or overhead. According to the invention, the field dry land soil animal numeral sample plot is digitalized; namely, the digitalized, automatic and intelligent sample plot with full space coverage, all-weather time and three-dimensional samples is realized in three dimensions of space, time and soil animal diversity.

The invention discloses a method for constructing an in-situ primary lung cancer animal model, and belongs to the field of tumor animal models. Mouse lung cells are cultured into organoids with a specific culture medium, and then the organoids are subjected to gene editing and injected back to the mouse lungs, so that the organoids are developed into tumors. Compared with a genetic engineering tumor animal model, the method disclosed by the invention is short in time consumption and high in tumor formation rate; and compared with a transplanted tumor animal model, the model has an in-vivo micro-environment for tumor generation and development, and is closer to the most real state of lung cancer.

The invention provides an insulin immunogen, a preparation method thereof, an insulin antibody, and a kit. The insulin immunogen is an insulin crosslinked body, is formed through intramolecular crosslinking and / or intermolecular crosslinking of a plurality of insulin monomers, and contains one or a plurality of crosslinked monomers disclosed in the invention, wherein 1, and 2 are independently selected from A chain or B chain, R1 is used for representing a group disclosed in the invention, and R2 and R3 are blank, or R1 and R3 are independently selected from a group disclosed in the inventionor -S-, R2 is selected from C2-C74 straight chain or branched chain alkylene, C2-C74 straight chain or branched chain alkylene with a part of -CH2- randomly substituted by -0-, -S-, -NH, -COO-, -CO-,arylidene, heteto arylidene, cycloalkylene, or groups disclosed in the invention, or R1 and R3 are independently selected from a group disclosed in the invention or -S-, and R2 is selected from arylidene or substituted arylidene, wherein in the substituted arylidene, the -H on the substituted arylidene is substituted by -OH, halogen elements, or alkane. The insulin immunogen can be used for obtaining high potency insulin antibody.

The invention provides an automatic flower and plant watering device and belongs to the technical field of automation equipment used in a garden. The automatic flower and plant watering device comprises a pot body, a control detection device, a soil turning device, a first water tank, a second water tank, a booster pump, a water inlet pipe, a water outlet pipe, a water outlet valve, a distributing pipe and a spray head. The automatic flower and plant watering device achieves automatic flower and plant watering through the control detection device and completes potted soil turning and loosening through the soil turning device, a temperature sensor and a humidity sensor are respectively used for detecting temperature and humidity values of the environment or soil and transferring data to a controller, the controller drives the water outlet valve to work, accordingly flower and plant humidification and watering operation is achieved without manual operation, the cultivation quality is improved while labor is saved, and survival and growth of flowers and plants are promoted.

The invention discloses an internet-based intelligent earthworm breeding system. The system comprises a Bluetooth module, and the Bluetooth module is used for mutually transmitting data between a breeding box terminal and an operation room terminal and issuing an instruction. According to the system, by utilizing the principle that earthworms escape when the survival ambient temperature is lower than 7 DEG C, the earthworms are captured quickly and conveniently without causing the death of the earthworms, the situation that the earthworms do not feed due to strong light by utilizing breeding in a breeding box, a humidity control unit can provide suitable humidity for the growth of the earthworms in hot summer and rainy seasons is avoided, and the situation that the earthworms do not feed or die and are infected by germs since breeding soil is too dry or too wet is avoided; with the assistance of an infrared sensor and a video monitor, whether or not animals such as mice exist in the breeding box can be found, the animals can be timely captured and expelled, and the situation that a large quantity of earthworms are eaten, and the economic loss is caused is avoided.

The invention discloses an alpine-semiarid-area alfalfa seeding method. The method includes steps: variety selection, fine soil preparation, formula fertilization and mulching precise hole sowing, wherein the step of formula fertilization specifically includes: analyzing and testing soil nutrient of a planting land plot, preparing organic compound fertilizer according to nutritional needs of alfalfa and condition of soil nutrient, and applying the prepared compound fertilizer onto the planting land plot; the step of mulching precise hole sowing includes full mulch covering, earthing and compacting and holing and hole sowing, full mulch covering refers to fully covering the planting land plot after going through the step of formula fertilization with mulch, earthing and compacting refers to covering the mulch with a layer of soil, and holing and hole sowing refers to holing the mulch after going through earthing and compacting and sowing alfalfa seeds in holes and then earthing. By the method, wintering rate of alfalfa can be ensured effectively, seedling emergence rate of alfalfa can be increased, unit area yield of alfalfa can be increased, mechanical action is facilitated, and convenience is brought to harvesting.

The invention discloses a preparation method of an in-situ primary gastric cancer tumor model, and belongs to the field of tumor animal models. The method comprises the following steps: culturing mouse gastric epithelial cells into organoids by using a specific culture medium, carrying out genetic modification on the organoids, and injecting the modified organoids back to the mouse stomach so as to develop the organoids into tumors. Compared with a transplanted tumor animal model, the method provided by the invention has a clear gene mutation background, and can effectively simulate the real process of occurrence and development of human gastric cancer. Compared with a genetic engineering tumor animal model, the gastric cancer mouse model with different gene mutation backgrounds can be efficiently constructed, the consumed time is short, the cost is low, and the tumor formation rate is high.

The invention discloses a graphene cladded copper-base biological material as well as a preparation method and an application thereof. The graphene-packaged composite material contains copper and graphene, wherein the surface of copper is totally packaged with graphene. The material has a good cladding effect, the toxin introduced by copper can be eliminated, and the death of cells and the necrosis and edema of tissues are avoided. The material can be taken as an electrode, particularly a neural electrode and can be applied to an in vivo or in vitro signal recording such as the signal recording of neuronal discharging and / or local field potential change. The material and a commercial platinum-iridium alloy electrode do not generate an artifact in a nuclear magnetic resonance imaging technique, and the observation of the quality and an implementation position of a nuclear magnetic resonance is greatly assisted.

The invention provides a method for producing melittin, and in particular relates to a method for producing melittin protein by using an agrobacterium rhizogenes K599-mediated soybean transgenic technology; the method can effectively express the melittin protein. Furthermore, a protease cleavage site is used in the middle of the target protein, so that the melittin is enabled not to kill plant cells; after enterokinase is added into the purified melittin, the melittin can be cleaved. The method enables the melittin protein to be successfully expressed in soybean hairy roots for the first time;compared with the melittin previously expressed in prokaryotes, the melittin produced by the method is higher in activity and solubility; furthermore, the melittin protein expressed in plants can beused for preparing medicines after being subjected to crude extraction since no substance, harmful to a human body, exists in the plants.

The invention belongs to the technical field of tree nursery stock cultivation, and particularly relates to a method for increasing the transplanting survival rate of xanthoceras sorbifolia bunge bare-root nursery stocks. The method comprises the steps of 1, farming preparation pretreatment of a planting site; 2, lifting of transplanted seedlings, shaping and clearing of root systems, and planting; 3, field management after xanthoceras sorbifolia bunge bare-root nursery stock transplantation. The first step further comprises the steps of selecting the planting site which contains neutral or alkalescent loam with a pH value ranging between 7 and 8.5, wherein the depth of the soil layer is 60-80 cm; preparing the planting site, wherein farmyard manure is applied 3000 kg / mu before farming preparation; preparing soil and ridging. The second step further comprises the steps of conducting seedling lifting manually, wherein the root systems are cut neatly during seedling lifting; shaping and clearing the root systems; planting the nursery stocks. The third step further comprises the steps of water control of forest land; soil loosening and weeding; final management and maintenance, wherein fertilization and irrigation are conducted three to four times and soil loosening and weeding are conducted twice each year since the second to fifth year. By the adoption of the method, the transplanting survival rate of the xanthoceras sorbifolia bunge bare-root nursery stocks is successfully increased to over 85% from below 20% before measures are taken, and technical assurance is provided for improved variety popularization of xanthoceras sorbifolia bunge.

The invention discloses a unisex four-season health-preserving beverage and a preparation method thereof. The health-preserving beverage is prepared from the following raw materials in parts by weight: 1-10 parts of one or more of peanut leaves, lotus seeds, longan aril, gastrodia elata, vine of multiflower knotweed, lucid ganoderma and spina date seeds; 1-10 parts of one or more of cistanche, codonopsis pilosula, American ginseng, radix pseudostellariae, ginseng or extracts thereof; 1-10 parts of one or more of dendrobium officinale, dogwood, herba epimedii, Chinese chive seeds and schisandra chinensis or extracts thereof; 1 part of folium cortex eucommiae; 1 part of radix astragali; 1 part of rose; 1 part of one or more of Chinese angelica and motherwort; and 1 part of one or more of Chinese yam and hawthorn. The selected traditional Chinese medicines are medicinal and edible foods or new foods similar to the medicinal and edible foods through scientific verification, are rigorous in compatibility, safe and effective, have obvious health-care effects of health care, body building and the like, and can be drunk by men and women.

The invention provides a chemical-free fish farming method and live fish in commercial packaging. The method includes the steps that water containers are arranged, a small amount of live fish is farmed in each water container, one water container is isolated from other water containers, and water is not communicated or leaked between the water containers. Bacterial viruses cannot invade other water containers from one water container with water as a carrier; water fed into the water containers are filtered, purified and disinfected to remove viruses in advance. The live fish is farmed in narrow space and cannot swing all around, the activity is reduced, the breath frequency is reduced, metabolism is slow, and energy consumption is reduced greatly, which is beneficial for conversion and accumulation of nutrient substances. It is avoided that chemical residue of fish exceeds standard, and fish-farming benefits are increased. The live fish in commercial packaging is packaged in the whole water containers, and substituting counterfeiting can be prevented.

This invention relates to a sort of design project of squirt gun which can emit electricity and prevent rebellion, it consists of the compression cylinder, the water jar, the water spout of the water jar, the electron set. This invention resolves the technological problem of the set in the background technique that it can not use at common occasion and it work easily the injury to the innocent person when used, in the moment of the use people can not se the run of the trajectory, and when people contact the other in the close quarter it work easily the injury of themselves.