alginate as wound dressings

alginate as wound dressings
alginate as wound dressings

Enhanced healing of mitomycin C-treated healing-impaired wounds in rats with hydrosheets composed of chitin/chitosan, fucoidan,and alginate as wound dressings

Kaoru Murakami,DDS1;Masayuki Ishihara,PhD,DEng2;Hiroshi Aoki,PhD3;Shingo Nakamura,PhD4;

Shin-Ichiro Nakamura,MD5;Satoshi Yanagibayashi,MD5;Megumi Takikawa,MD5;Satoko Kishimoto,PhD, DVM2;Hidetaka Yokoe,PhD,DDS1;Tomoharu Kiyosawa,PhD,MD5;Yasunori Sato,PhD,DDS1

1.Department of Oral and Maxillofacial Surgery,

2.Research Institute,National Defense Medical College,Tokorozawa,Saitama,Japan,

3.Research and Development Department,Hokkaido Industrial Technology Center,Hakodate,Hokkaido,Japan,

4.Department of Surgery,and

5.Department of Plastic and Reconstructive Surgery,National Defense Medical College,Tokorozawa,Saitama,Japan

Reprint requests:

Kaoru Murakami,DDS,Department of Oral and Maxillofacial Surgery,National Defense Medical College,3-2Namiki Tokorozawa, Saitama359-8513,Japan.

Tel:181429951211;

Fax:181429911611;

Email:dr22056@ndmc.ac.jp

Manuscript received:October7,2009 Accepted in?nal form:May14,2010 DOI:10.1111/j.1524-475X.2010.00606.x ABSTRACT

To create a moist environment for rapid wound healing,a hydrosheet composed of alginate,chitin/chitosan,and fucoidan(ACF-HS)has been developed as a functional wound dressing.The aim of this study was to evaluate the accelerating effect of ACF-HS on wound healing for rat mitomycin C-treated healing-impaired wounds.Full-thickness skin defects were made on the back of rats and mitomycin C was applied onto the wound for10minutes to prepare a healing-impaired wound.After thoroughly washing out the mitomycin C,ACF-HS was applied to the healing-impaired wounds.The rats were later euthanized and histological sections of the wounds were prepared.The histological examinations showed signi?cantly advanced granulation tissue and capillary formations in the healing-impaired wounds treated with ACF-HS on days7and14,in comparison with that in alginate?ber(Kaltostat s),hydrogel wound dressing(DuoAC-TIVE s),and nontreatment(negative control).Furthermore,in cell culture stud-ies,ACF-HS-absorbed serum and?broblast growth factor-2was found to be proliferative for?broblasts and endothelial cells,respectively,and ACF-HS-absorbed serum was found to be chemoattractive for?broblasts.However,our results may not be strictly comparable with general healing-impaired wound models in humans because of the cell damage by mitomycin C.In addition,more biocompatibility studies of fucoidan are essential due to the possibility of renal toxicity.

Numerous wound dressings have been developed to pro-mote wound healing.1The ideal dressing needs to ensure that the wound remains moist with exudate,but is not macerated,and it should ful?ll the prerequisites concern-ing structure and biocompatibility.2Furthermore,it should be noncytotoxic and nonantigenetic,guarantee a uniform cell distribution,maintain cell viability and phe-notype,and should induce migration and proliferation of epithelial,?broblast,and endothelial cells(EC),etc.,and the synthesis of extracellular matrix components required for wound repair.3Besides those features,an ideal wound dressing should have certain other properties like the ease of application and removal,and proper adherence so that there will not be any area of nonadherence left to create ?uid-?lled pockets for the proliferation of bacteria.4 Various studies indicate that chitin/chitosan5–8or algin-ate3,4,9accelerates wound healing and remedies using chi-tin/chitosan or alginate in wound treatments are already on the market.However,the chitin/chitosan or the algin-ate has been used as?lament,?ber,powder,granule, sponge,or composite with cotton or polyester in most of the studies.1,3,10,11Because generation of a moist healing environment requires a relatively high three-dimensional interaction between the wound and these healing agents, the accelerating effect of the chitin/chitosan or the alginate products on the market could not be exploited enough due to the relatively low(one-or two-dimensional)interaction between the wound and these healing agents.In this study, we prepared composite hydrosheets composed of alginate, chitin/chitosan,and fucoidan(ACF-HS)produced from their blended powders.ACF-HS gradually absorbed the medium,supplemented with and without fetal bovine

ACF-HS Hydrosheet composed of alginate,chtin/chitosan,and fucoidan

DFCs Human dermal?broblast cells

DMEM Dulbecco’s minimal essential medium

DMVECs Human dermal microvacular endothelial cells

FBS Fetal bovine serum

FGF-2Fibroblast growth factor-2

H&E Hematoxylin&eosin

PBS Phosphate-buffered saline

Wound Repair and

Regeneration

serum(FBS),without any maceration and the?uid ab-sorbance reached constant during18hours(data not shown).Therefore,the application of ACF-HS was ex-pected to effectively absorb exudate,suitable for good moist healing.Furthermore,ACF-HS possessed many ad-vantages as an ideal wound dressing for the repair of heal-ing-impaired wounds as described above.

The healing of a wound proceeds in three overlapping phases,namely(i)in?ammation,(ii)proliferation,includ-ing granulation tissue formation,and(iii)matrix forma-tion and remodeling.12This sequential process requires the interaction of cells in the dermis and epidermis,as well as the activity of chemical mediators released from in?am-matory cells,?broblasts,and keratinocytes.13,14The pro-liferation of mesenchymal cells and EC,as well as the in?ux of macrophages,composing granulation tissue, serve to replace the lost dermis and to provide substrates and inducers for reepithelialization.15

Mitomycin C,an antitumor agent inhibits various cell-proliferations including?broblasts,keratinocytes,and EC,probably through the inhibition of DNA,RNA,and protein synthesis,16,17and we applied mitomycin C to full-thickness skin incisions to obtain a healing-impaired wound model in rat.18In the present study,we observed that ACF-HS induced migration and proliferation of ?broblasts and EC in vitro.The objective in this study was to evaluate the effectiveness of the ACF-HS for re-pairing mitomycin C-treated healing-impaired wounds in rats,compared with those of only alginate(Kaltostat s)-treated,hydrogel(DuoACTIVE s)-treated,and nontreat-ed wounds.

MATERIALS AND METHODS

Preparation of hydrosheet composed of alginate,

chitin/chitosan,and fucoidan(ACF-HS)

ACF-HS was prepared as follows.Dry powders of algin-ates(Wako Pure Chemical Industries,Ltd.,Oosaka, Japan),chitin(Chitin Powder from Crab Shells,Acetylat-ion rate approximate100mol/mol%grade,Nacalai Tes-que Inc.,Kyoto,Japan),chitosan(Chitosan5,Wako Pure Chemical Industries Ltd.),and fucoidan extracted and puri?ed from Kjellmaniella crossifolia(Gagome-kombu in Hokkaido Hakodate)by the method of Nishide et al.,19 (60:20:2:4w/w)were?rst blended with a mortar and pes-tle and were then mixed with a high-speed mixer(Janke& Kunkel GmbH&Co.Kg.,Staufen,Germany).The mixed powder(0.77g)was spread on a sterile supporter(No.2 grade round?lter paper[70mm in diameter;Toyo Roshi Kaisha Ltd.,Tokyo,Japan]),and distilled water was sprayed on the spread powder to partially dissolve the powder and to generate pastes on surfaces of the powder. The pastes with the supporters were soaked in50%ethanol for5seconds,and then in distilled water for1minute.The swelled pastes were treated with2M CaCl2for20seconds to make calcium alginate hydrogel on the surface of pastes, and then with5%acetate.The generated hydrosheets were spiked using a needle-pointed?ower holder(8.6needles [0.9mm in diameter]on1cm2:330pin holes/sheet)and then soaked in distilled water for3minutes.The hydro-sheets were again treated with2M CaCl2for20seconds,following soaking in phosphate-buffered saline(PBS)for1 minute,and then were soaked in distilled water for10 minute.

Ten sheets soaked in50%ethanol were cross-linked with22mL of the cross-linking reagent(Ethylene glycol diglycidyl ether;Wako Pure Chemical Industries Ltd.)in 800mL of ethanol(50%)and1M acetate/Na-acetate buffered solution at pH5.8(50%)at501C for5hours. The cross-linked hydrosheets were thoroughly washed with distilled water for removal of the cross-linking reagent and70%ethanol for sterilization.Each product was vacuum-packed and sterilized by soaking it with boiled water for20seconds.The impregnation of original ACF-HS was about1.2–1.4g on a hydrosheet(70mm in diameter),the?nal ACF-HS weight was about3.8–3.9g/ sheet after vacuum packing and it well–adsorbed the exudate but was not macerated(data not shown).

In vitro cytotoxicity testing of ACF-HS

Human dermal?broblast cells(DFCs)and dermal micro-vascular endothelial cells(DMVECs)(Takara Biochemi-cal,Tokyo,Japan)were cultured in Dulbecco’s minimal essential medium(DMEM;Iwaki,Tokyo,Japan)supple-mented with10%heat-inactivated FBS(Iwaki),antibiot-ics(100U/mL penicillin G and100m g/mL streptomycin), and5ng/mL?broblast growth factor(FGF)-2(R&D Sys-tems,Minneapolis,MN)for only DMVECs in an atmo-sphere of5%CO2in air and100%relative humidity.The DFCs and DMVECs used in this work were between the fourth and sixth passages.

For the cell assay,round ACF-HS and?lter paper as a control(12mm in diameter)were plated on the center of each well of a12-well tissue culture plate(well diameter; 22mm,Sumitomo Bakelite,Tokyo,Japan)with a cloning ring(inner10mm and outer12mm;Iwaki Corp.)as a sinker and incubated for18hours in DMEM-supple-mented10%FBS for DFCs and supplemented10%FBS and10ng/mL FGF-2for DMVECs.Subsequently DFCs and DMVECs were plated with an initial density of 20,000cells/well on the outside of the ACF-HS and paper after washing them twice with the fresh medium supple-mented with5%FBS and with the fresh medium supple-mented with5%FBS and5ng/mL FGF-2,respectively, and grown in each medium for3days.After incubation, the used ACF-HS,control paper,and media were removed and500m L of freshly prepared medium including50m L of WST-1reagent(Cell Counting Kit,Dojindo,Kumamoto, Japan)was added to each well.After1hour of incubation at371C,the optical density was read at450nm to evaluate the cell growth,using a UV-VIS spectrophotometer(UV-1200;Shimazu,Tokyo,Japan).The values of the optical density were proportional to the number of viable cells (data not shown).

Migration assay of cultured DFCs

For DFC migration assay,the cloning ring(inner10mm and outer12mm)was plated on the center of each well of a 12-well tissue culture plate.DFCs were plated with an ini-tial density of50,000cells/well on the outside of the ring and grown in DMEM-supplemented5%FBS for3days until the cultures became con?uent.Subsequently,the cells Hydrosheets composed of alginate,chitosan,and fucoidan

Murakami et al.

were incubated for1day in DMEM without FBS.Round ACF-HS,Kaltostat s(Convatec Limited,Tokyo,Japan), and?lter paper as a control(12mm in diameter),which were soaked with DMEM-supplemented10%FBS for18 hours and were rinsed three times with DMEM(without FBS),were plated on the cell-free area with the cloning ring as a sinker.And the lost cell layer(1.4mm width)was made the outside edge of each sheet with a plastic micro-pipette tip(for200m L).Subsequently,DFCs were cultured for3days in DMEM(without FBS).Recovery of the lost cell layer by scratching the cells with the plastic micropi-pette tip was monitored by phase-contrast microscopic photography(Leica,Tokyo,Japan).For statistical analy-sis,the number of cells,which had migrated into the lost cell layer on the culture plates was determined by the microscopic observation.

Creation of mitomycin C-treated skin wounds

Under the general anesthesia,the dorsal area was totally depilated and two full-thickness round wounds(about 10mm in diameter)were created on the upper back of each rat(male Sprague-Dawley rats,weighting200–250g [Nippon SLC Co.,Ltd.,Saitama,Japan])using a pair of sharp scissors and a scalpel.To prepare mitomycin C (Wako Pure Chemical Industries Ltd.)-treated round wounds,mitomycin C solution(1mg/mL in PBS)was ap-plied onto the wound for10minutes.After thoroughly washing out the mitomycin C using distilled water,ACF-HS(about10mm in diameter)was applied to the wound, and Kaltostat s and DuoACTIVE s(Convatec Limited, Tokyo,Japan)(about10mm in diameter)were also applied to the wound by suture as a positive control.Sim-ilar full-thickness round wounds treated with mitomycin C were also prepared as a control.These wounds were wrapped with plastic sheets to protect the wounds.The ACF-HS,Kaltostat s,and DuoACTIVE s were changed on day3because of a large amount of absorbed exudate from the mitomycin C-treated wounds.The ACF-HS, Kaltostat s,and DuoACTIVE s were removed from the wounds on day7and the skin including the wound was then removed from each rat for histological examinations on days7and14.The wound closure rates were evaluated by measuring the open wound area.These animal experi-ments were approved and carried out following the guide-lines for animal experimentation of the National Defense Medical College,Tokorozawa,Saitama,Japan.

Histological examination

The removed skins including wound tissue were?xed in a 10%formaldehyde solution,embedded in paraf?n,and sectioned in4m m increments(Yamato Kohki Inc.,Asaka, Saitama,Japan).The sections were made perpendicular to the anterior–posterior axis and perpendicular to the sur-face of the wound.The sections were positioned on a glass slide,and stained with hematoxylin&eosin reagent.In each section,a randomized area(microscopic?eld,mag-ni?cation?200)showing the granulation and capillary formations was photographed and the thickness of granu-lation formation and the number of capillary lumens per microphotograph were evaluated.Only mature vessels containing erythrocytes were counted.Statistical analysis

Statistical analyses were carried out by the post hoc Tukey’s test for multiple comparisons.Regarding the wound closure rate,statistical analyses were performed by the Student’s t test.p-Values were calculated using the software Stat Mate III for Windows(ATMS Co.,Tokyo,Japan).

RESULTS

In vitro cytotoxicity and migration assay of ACF-HS

In this experiment,the DFCs and DMVECs did not adhere to and grow on the ACF-HS,probably due to their hyperhydrous structure(data not shown).However, DFCs did grow well beside the ACF-HS in DMEM sup-plemented with5%FBS(Figure1A).Similarly,DMVECs also grow well beside the ACF-HS soaked for18hours in DMEM supplemented with5%FBS in the presence of 5ng/mL FGF-2(Figure1A).Because growth rates of the cells in the presence of ACF-HS were identical to those in control,ACF-HS has no cytotoxicity for at least DFCs and DMVECs.

After the ACF-HS was soaked in DMEM supple-mented with10%FBS for DFC culture and supplemented with10%FBS and10ng/mL FGF-2for DMVEC culture, DFCs and DMVECs were cultured with DMEM without FBS and with DMEM supplemented with only5%FBS, respectively(Figure1B).These results clearly showed that ACF-HS could absorb the components of FBS and FGF-2, which could stimulate proliferations of these cells.

Figure2shows the effect of ACF-HS soaked in DMEM-supplemented10%FBS for18hours on the ?broblast migration during the3day incubation.In the presence of ACF-HS,the cells migrated to the lost cell area faster than the control culture(for3day-incubation,ACF-HS,195?38cells;Kaltostat s,106?26cells;Filter paper [control],97?24cells).

In vivo healing-impaired wound model in rat

In our wound healing model,two full-thickness circular skin wounds(10mm in diameter)were made on the back of the rats.The rate of wound closures for mitomycin C-treated and nontreated(control)wounds were evaluated by determination of the unclosed wound area as a function of time(Figure3).Mitomycin C is known to inhibit var-ious cell proliferations in cell cultures including?bro-blasts,keratinocytes,and EC,probably through the inhibition of DNA,RNA,and protein synthesis,16,17and we applied the mitomycin C to full-thickness skin incisions to obtain a healing-impaired wound model in rat.The wound closures in the control wounds occurred faster than the mitomycin C-treated wounds and about50%wound closure was achieved within7days.On the other hand,the mitomycin C-treated wounds took more than18days to reach50%wound closure(Figure3).Furthermore,few granulation tissue and capillary formations were observed in the mitomycin C-treated wounds on day7(Figure3). Thus,healing of the mitomycin C-treated wounds were signi?cantly delayed and in this study we used this treat-ment with mitomycin C as a healing-impaired wound model in rats.

Hydrosheets composed of alginate,chitosan,and fucoidan Murakami et al.

Histological observations on repair of the healing-impaired wounds

We evaluated the effectiveness of ACF-HS for repairing mitomycin C-treated wounds in rats,compared with those of only alginate (Kaltostat s )-treated,DuoACTIVE s -treated,and nontreated wounds.No sign of undesirable in?ammation and infection formation were observed in any mitomycin C-treated wounds.Fast wound closures and progress of wound contraction and reepithelialization were observed in only ACF-HS-applied wounds during 14days (Figure 4A).Furthermore,signi?cant stimulatory

effects were shown on granulation tissue and capillary for-mations on day 7(Figure 5)and on day 14(Figure 6)in

only ACF-HS-applied wounds.

ACF-HS-treated wounds signi?cantly enhanced reepithelialization during the ?rst 7days as well as during 7–14days (after removal of ACF-HS),compared with that of Kaltostat s ,DuoACTIVE s ,and plastic wrap (control)wounds (data not shown).It was speculated that the prog-ress of epithelium formation occurred together with en-hanced granulation tissue and capillary formations after removal of ACF-HS (Figure 7).

On the other hand,in the non-mitomycin C-treated wounds,no statistically signi?cant differences between treat-ments with ACF-HS,Kaltostat s ,and plastic wrap (control)were observed throughout the entire study period regarding the granulation tissue and capillary formations (Figure 4B).Thus,the introduction of ACF-HS had little effect on the normal (non-mitomycin C-treated)wound healing.

DISCUSSION

When ACF-HS were applied to open mitomycin C-treated wounds in rats,a signi?cant effect was shown on reepithelialization,granulation tissue and capillary forma-tions for the entire study period.In fact,ACF-HS

enhanced

Figure 1.Cytotoxity and stimulatory effect of ACF-HS on the growth of DFCs and DMVECs.The ACF-HS was soaked for 18hours using DMEM with 5%FBS,and DFCs (A)were cultured in DMEM with 5%FBS for 3days and DMVECs (B)in DMEM with 5%FBS and 5ng/mL FGF-2.On the other hand,the ACF-HS was soaked for 18hours using DMEM with 10%FBS for DFC cultures (A)and using DMEM with 10%FBS and 10ng/mL FGF-2for DMVEC cultures (B),and DFCs were cultured in DMEM (without FBS)and DMVECs in DMEM with 5%FBS (without FGF-2).n p <0.001.ACF-HS,hydrosheet composed of alginate,chitin/chitosan,and fucoidan;DFCs,human dermal ?broblast cells;DMEM,Dulbecco’s minimal essential medium;DMVECs,human dermal micro-vacular endothelial cells;FBS,fetal bovine serum;FGF-2,?broblast growth

factor-2.

Figure 2.Effect of ACF-HS on migration of ?broblasts.The numbers of migrated ?broblasts in the lost cell areas (1.4mm width)between gray bars and black line in each microphoto-graph were determined by phase-contrast microscopic obser-vation as described in the text.ACF-HS,Kaltostat s ,and control (Filter paper)were placed on the area of gray bars and the black line represented original edges of the lost cell areas.The data represent the mean ?SE of six determinations.n p <0.005vs.control.ACF-HS,hydrosheet composed of alginate,chitin/chitosan,and fucoidan.

Hydrosheets composed of alginate,chitosan,and fucoidan

Murakami et al.

reepithelialization during 3–7days before the removal of ACF-HS from the wound on day 7,that is,the presence of ACF-HS on wound did not inhibit reepithelialization.Thus,the applications of ACF-HS signi?cantly enhanced reepithelialization,granulation tissue,and capillary for-mations in the healing-impaired mitomycin C-treated wounds.

However,mitomycin C-treated wounds in rats may not be strictly relevant to well-known impaired clinical wounds such as pressure or diabetic ulcers in humans.With regard to the advanced granulation tissue and cap-illary formations,the present work in vitro showed that ACF-HS had a chemoattractive effect on ?broblasts and stimulated proliferation of both ?broblasts and EC (Fig-ures 1and 2).It is possible that the ACF-HS absorbs some substances involved in inductions of cell proliferation and migration,such as growth factors and cytokines,from blood plasma or exudate in the wound,and that the absorbed substances stimulate proliferation and migration of the cells.In contrast with ACF-HS,DuoACTIVE s ,which is a commercially available hydrogel wound dressing,

also absorbed the liquids,but much less than ACF-HS (data not shown).

It is interesting to note that application of ACF-HS had only a minor effect on the degree of healing in nontreated wounds with mitomycin C (Figure 4B).Although the mech-anism responsible for the minor effect of ACF-HS in the nontreated wounds is not completely understood,it is likely that the migration of suf?cient in?ammatory cells including neutrophils has a signi?cant effect on the formations of wound granulation tissue and capillaries.Thus,it is possible that the normal wound has a suf?cient amount of growth factors in the wound ?uid to induce migration and prolifer-ation of epithelial cells,?broblasts,and EC achieving a max-imal rate of healing,and thus only a minor increase in wound repair is possible upon application of ACF-HS.

Alginate has been used in a number of biomedical appli-cations such as wound dressings,tissue engineering,

and

Figure 3.Wound closure of mitomycin C-treated ( )and con-trol (non-mitomycin C-treated)( )wounds of rats.The data represent the mean ?SE of six rats.The statistical signi?cance of wound closure was evaluated on postwounding days 2,4,7,9,12,14,and 18in both mitomycin C-treated and control wounds (upper,left panel).n Student’s t test,p <0.001.The right panel represents photographic ?ndings of wound repair of mitomycin C-treated (right in each photograph)and control (left)wounds.The photographs of the wound at days 0,2,4,7,9,12,14,and 18are representative of six rats in each group.Histological photographs (lower,left panel)of wound re-pair of mitomycin C-treated (right photograph)and control (left)wounds on day 7are representative of six wounds stained with hematoxylin &eosin (H&E)in each group.Arrows show mature vessels containing erythrocytes and edges of the granulation of each

wound.

Figure 4.Closure of wounds covered with ACF-HS,Kalto-stat s ,in contrast with ACF-HS,DuoACTIVE s ,and control.Mi-tomycin C-treated wounds (A)and nontreated wounds (B)on the indicated day were representative of eight wounds (four rats)covered with ACF-HS,Kaltostat s ,DuoACTIVE s ,or none (control).The data represent the mean ?SE of eight rats.The statistical signi?cance of wound closure was evaluated on post-wounding days 3,5,7,10,and 14.n Tukey’s test,p <0.01,n 58,vs.control.ACF-HS,hydrosheet composed of alginate,chitin/chitosan,and fucoidan;DFCs,human dermal ?broblast cells.

Hydrosheets composed of alginate,chitosan,and fucoidan Murakami et al.

drug delivery.There are reports suggesting that a certain alginate dressing (e.g.,Kaltostat s )can enhance wound heal-ing by stimulating monocytes to produce elevated levels of various cytokines such as interleukin-6.9Production of these cytokines at the wound site results in proin?ammatory stim-ulants,which are advantageous to wound healing.

Chitin is a linear homopolymer of 1,4b -linked N -acetyl-D -glucosamine,and chitosan is a partially deacetylated chitin.10Chitin and chitosan have been proposed as bio-materials,having a range of biomedical and industrial applications because of their beneficial biological proper-ties.11These properties include hemostasis,antimicrobial activity,stimulation of wound healing,tissue-engineering scaffolds,and drug delivery.

Fucoidans are vegetal fucose-containing polysaccha-rides extracted from brown algae and have low anticoag-ulant activity.The contents of fucose,uronic acid,and

sulfate in the fucoidan were determined with the extracted

and puri?ed fucoidan.19Fucoidan is known to bind to heparin-binding growth factors such as FGF-1and FGF-2as similar to heparin,and fucoidan and low molecular weight fucoidan enhance FGF-2activity and FGF-2-in-duced tube formation of EC.20Fucoidan also modulates the effect of transforming growth factor-b 1on wound re-pair.21Furthermore,fucoidan–chitosan hydrogel 22and chitosan ?lm containing fucoidan 23were reported as wound healing accelerators.Fucoidan is expected to ab-sorb,stabilize,and activate other heparin-binding cyto-kines in the exudate,which induce angiogenesis and wounds repair.Thus,the hydrosheet composed of these three components (alginate,chitin/chitosan,and fucoidan)may be recognized as a functional wound dressing for healing-impaired wounds.However,Because suf?cient data are not yet available on the complete toxicity

pro?le

Figure 5.Histological examination of wounds covered with ACF-HS,Kaltostat s ,DuoACTIVE s ,and control.Each wound of rat on day 7was representative of eight wounds (four rats)covered with ACF-HS,Kaltostat s ,DuoACTIVE s ,or none (con-trol).In left panel,black arrows show formed granulation tis-sues and the squares show the sites for microphotographs (right panels).In right panels,black arrows show blood vessels containing erythrocytes.ACF-HS,hydrosheet composed of alginate,chitin/chitosan,and fucoidan;DFCs,human dermal ?broblast

cells.

Figure 6.Histological examination of wounds covered with ACF-HS,Kaltostat s ,DuoACTIVE s ,and control.Each wound of rat on day 14was representative of eight wounds (four rats)covered with ACF-HS,Kaltostat s ,DuoACTIVE s ,or none (con-trol).In left panel,black arrows show formed granulation tis-sues and the squares show the sites for microphotographs (right panels).In right panels,black arrows show blood vessels containing erythrocytes.ACF-HS,hydrosheet composed of alginate,chitin/chitosan,and fucoidan;DFCs,human dermal ?broblast cells.

Hydrosheets composed of alginate,chitosan,and fucoidan

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of the hydrosheets in humans,standard toxicologic studies need to be completed before using this hydrogel as a therapy in human subjects.In fact,research has shown that orally ingested fucoidan (75%w/w)decreased lym-phocytes in human subjects,24and that intravenous fucoi-dan failed to protect the kidney from ischemic damage and might have renal toxicity.25

In summary,ACF-HS possesses many advantages as a wound dressing for the repair of healing-impaired wounds.The application of ACF-HS signi?cantly stimulate repair of mitomycin C-treated healing-impaired wounds in rats.Thus,the ACF-HS formulation may be a promising new wound dressing for repair of healing-impaired wounds.

ACKNOWLEDGMENTS

This study was supported by the Research Fund for Defense Medicine from Defense Ministry of Japan.The authors state that they have no con?ict of interest.

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胎膜早破病人的护理

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经纬仪的使用方法

创作编号:BG7531400019813488897SX 创作者:别如克* 经纬仪的使用方法 经纬仪是测量工作中的主要测角仪器。由望远镜、水平度盘、竖直度盘、水准器、基座等组成。测量时,将经纬仪安置在三脚架上,用垂球或光学对准器将仪器中心对准地面测站点上,用水准器将仪器定平,用望远镜瞄准测量目标,用水平度盘和竖直度盘测定水平角和竖直角。按精度分为精密经纬仪和普通经纬仪;按读数设备可分为光学经纬仪和游标经纬仪;按轴系构造分为复测经纬仪和方向经纬仪。此外,有可自动按编码穿孔记录度盘读数的编码度盘经纬仪;可连续自动瞄准空中目标的自动跟踪经纬仪;利用陀螺定向原理迅速独立测定地面点方位的陀螺经纬仪和激光经纬仪;具有经纬仪、子午仪和天顶仪三种作用的供天文观测的全能经纬仪;将摄影机与经纬仪结合一起供地面摄影测量用的摄影经纬仪等。 一、经纬仪的结构

DJ6经纬仪是一种广泛使用在地形测量、工程及矿山测量中的光学经纬仪。主要由水平度盘、照准部和基座三大部分组成。 1、基座部分 用于支撑基照准部,上有三个脚螺旋,其作用是整平仪器 2、照准部 照准部是经纬仪的主要部件,照准部部分的部件有水准管、光学对点器、支架、横轴、竖直度盘、望远镜、度盘读数系统等。 3、度盘部分 DJ6光学经纬仪度盘有水平度盘和垂直度盘,均由光学玻璃制成。水平度盘沿着全圆从0°~360°顺时针刻画,最小格值一般为1°或30′ 二、经纬仪的安置方法 1)三脚架调成等长并适合操作者身高,将仪器固定在三脚架上,使仪器基座面与三脚架上顶面平行。 2)将仪器舞摆放在测站上,目估大致对中后,踩稳一条架脚,调好光学对中器目镜(看清十字丝)与物镜(看清测站点),用双手各提一条架脚前后、左右摆动,眼观对中

妇产科护理论文:胎膜早破的观察及护理体会

妇产科护理论文:胎膜早破的观察及护理体会 我院收治住院孕妇1 537人,胎膜早破76人,现将临床护理注意事项报告如下。 1 临床资料 我院2007年1月至2009年6月,住院孕妇1 537人,发生胎膜早破76人,占总住院人数4.94%,其中妊娠37周以上57人,占胎膜早破总人数的75%;妊娠36周以下19人,占胎膜早破总人数的26%,其中2例孕32~34周胎膜早破者安胎至37周,年龄21~37岁,平均29岁。18例给予保胎、抗炎治疗,12例宫缩抑制无效自然分娩,7例经抗炎、抑制宫缩、促胎肺成熟、绝对卧床休息等保胎治疗措施,在妊娠36周及37周以上结束分娩。 2 胎膜早破的临床诊断及临床表现 孕妇自觉有阴道流液,继而有少量间断性排出,当咳嗽、打喷嚏、负重等负压增加时,羊水即流出。阴道检查后穹隆有羊水池,pH呈碱性。阴道后穹隆液体涂片有羊齿状结晶,或涂片查见羊水成分。 3胎膜早破的原因 ①下生殖道感染。引起胎膜炎,使胎膜局部张力下降导致破裂;②羊膜囊内压力升高,常见于双胎妊娠、羊水过多、巨大儿;③胎先露部高浮、头盆不称、胎位异常,胎膜受压不均匀导致破裂;④营养因素,如缺乏维生素C、锌及铜,可使胎膜张力下降而破裂;⑤宫颈内口松弛,前羊水囊进入,受压不

均匀及胎膜发育不良,导致胎膜早破;⑥妊娠晚期性生活。 4 护理 4.1 产妇护理 4.1.1 心理护理:由于胎膜早破的患者常以急诊方式入院。入院时,孕妇常有焦虑、紧张心理。此时护理人员要热情接待产妇,同情、体贴、关心她们,多与其接触交谈,运用心理学知识了解患者心理活动,了解她们的心理状态和要求,不厌其烦地为其解释,使她们产生信任和安全感。护士必须心怀一颗真挚慈爱之心,身临其境地为患者服务。评估产妇的生理心理状况,对分娩的相关知识进行有的放矢地教育与指导,并在整个产程中给产妇持续的生理、心理、情感支持,最大限度地调动产妇的主观能动性,和医务人员密切配合,顺利度过人生最难忘时刻。 4.1.2 体位:胎膜早破的孕妇,采取绝对卧床休息,床尾抬高30°,讲述卧床的重要性,介绍医院环境,主管医生和护士,胎位不正、胎先露部未衔接者,协助孕妇绝对卧床休息,床上大小便,取左侧卧位,抬高臀部,防止脐带脱垂,取臀高卧位,以降低宫腔内压力,减少羊水流出。也可间断取左侧卧位,减轻右旋的子宫对腹主动脉、下腔静脉的压迫,增加静脉的回流,促进子宫胎盘血液循环。避免不必要的肛诊与阴道检查。 4.1.3 饮食方面的护理:指导胎膜早破的孕妇进食高蛋白、高热量、清淡、易消化食物,以增加机体抵抗力。由于孕妇绝对卧床,活动减少,肠蠕动减慢,容易引起便秘。所以应多进食纤维较多的蔬菜及水果,如韭菜、青菜、香蕉等。使孕妇保持大便通畅,便秘者给予口服缓泻剂或肛用开塞露。羊水过少应指导

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4、脚螺旋:调节脚螺旋,将仪器精确整平。 5、水平制动螺旋:旋紧水平制动螺旋,照准部被固定。望远镜无法在水平方向转动。 6、水平微动螺旋:水平制动螺旋旋紧后,旋转水平微动螺旋,照准部在水平方向微微转动。 7、竖直制动螺旋:旋紧竖直制动螺旋,望远镜被固定在支架上无法转动。

8、目镜调焦螺旋:转动目镜调焦螺旋,使十字丝清晰。 9、水平度盘反光镜:调整水平度盘反光镜,读书窗数字明亮。 10、竖直度盘反光镜:调整竖直度盘反光镜,使读数窗读数明亮。 11、读数显微镜:调节读数显微镜,使读书清晰。

12、配盘手轮:调整配盘手轮, 改变水平度盘读数。 水准仪操作步骤方法详解图解 发布: 2009-10-06 09:32 | 作者: admin | 查看: 4次水准仪操作步骤方法详解图解 步骤图解 1、安放三角架:调节三脚架腿至适当 高度,尽量保持三脚架顶面水平。如 果地面松软,应将架腿踩入土中。 2、连接螺旋:旋紧连接螺旋, 将水准仪和三脚架连接在一 起。

3、脚螺旋:调节脚螺旋,使圆水准气泡居中。 4、制动螺旋:旋紧制动螺旋,望远镜被固定。 5、水平微动螺旋:在制动螺旋旋紧后,调节水平微动螺旋,望远镜在水平方向微小转动。 6、目镜调焦螺旋:调节目镜调焦螺旋,使十字丝清晰成像。

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例胎膜早破患者护理方案 三年制大专助产3班 赵芬 前言 胎膜在临产前破裂,称胎膜早破(prematureruptureofmembrane,PRom),俗称破水。妊娠满37周后胎膜早破率10%;妊娠不满37周的胎膜早破率2.0%~3.5%,发生率约占分娩总数的6~12%。其发生率占分娩总数的2.7%~17%。可发生于妊娠期及分娩期。早产胎膜早破患者再次妊娠时,胎膜早破的发生率可达16~32%。胎膜早破常致早产、围产儿死亡、宫内及产后感染率升高,因此要重视孕期卫生指导及产前检查,早发现、早治疗。 病例资料 .1 一般情况 邬某某,女,28岁,已婚,家庭主妇,湖南益阳南县人。 .2 健康史 患者因停经7+月,阴道流液伴腹胀痛8+小时入院。患者末次月经XX年05月03日,推算预产期XX年2月10日。早孕反应不明显,早孕期间无感冒,毒物药物,放射线接触史,孕两个月有腹痛,无阴道流血史,在家口服中药保胎一

个月,停经4+月感胎动正常至今。定期不定期做检查四次,查血压,胎位,胎心正常,孕期查:血尿常规正常,自诉肝肾功能,空腹血糖,甲功,乙肝三对,TP+HIV均正常(未见报告单)血型“o”型RH阳性;丈夫血型不详;糖筛查第一第二阶段均低风险;外院系统彩超:胎儿偏小,球拍状胎盘,余未见异常。孕期未行oGTT.于今晨3+时突然出现阴道大量流液,之后伴阵发性腹痛,5~6分钟腹胀1次,11小时腹胀痛进行加剧,遂在当地医院就诊,考虑胎膜早破,孕周小,建议转上级医院。门诊以“1胎膜早破;2宫内孕32周单活胎先兆早产”收住院。 .3 身体状况 入院体格检查:T:36.5℃,P:99次/分,R:20次/分,BP:137/83mmHg发育正常,营养中等,自动体位,神清合作,皮肤巩膜无黄染,全身浅表淋巴结不肿大,头颅五官大小形态正常,唇红,咽无充血,扁桃体不肿大,甲状腺不肿大,胸廓形态正常,双侧语颤正常,叩诊清音,双肺呼吸音清晰,无啰音,心尖搏动位于左第五肋间锁骨中线内侧,心界不大,心率99次/分,律齐,无杂音。腹部膨隆,肝脾扪诊欠满意,双肾区无叩痛,移动性浊音阴性,肠鸣音4次/分,肛门及外生殖器无异常,四肢脊柱无畸形,腹壁反射存在,双膝正常,布克氏征阴性,双侧巴彬斯基征阴性。

精密光学经纬仪的构造及使用方法

§3.2 精密光学经纬仪的构造及使用方法 控制测量中,需用经纬仪进行大量的水平角和垂直角观测。使用经纬仪进行角度观测,最重要的环节是:仪器整平、照准和读数。我们围绕这三个环节,对光学经纬仪的构造和使用方法作如下介绍。 3.2.1 水准器 由前节可知,测角时必须使经纬仪的垂 直轴与测站铅垂线一致。这样,在仪器结 构正确的条件下,才能正确测定所需的角 度。要满足这一要求,必须借助于安装在 仪器照准部上的水准器,即照准部水准器。 照准部水准器一般采用管状水准器。管水 准器是用质量较好的玻璃管制成,将玻璃 管的内壁打磨成光滑的曲面,管内注入冰 点低,流动性强,附着力较小的液体,并 留有空隙形成气泡,将管两端封闭,就成 为带有气泡的水准器,如图3-3所示。 1. 水准轴与水准器轴 为了便于观察水准器的倾斜量,在水准管的外壁上刻有若干个分划,分划间隔一般为2mm ,其中间点称为零点。 水准器安置在一个金属框架内,并安装在经纬仪照准部支架上,所以把这种管状水准器称为照准部水准器。照准部水准器框架的一端有水准器校正螺旋,通过校正螺旋,使照准部水准器的水准器轴与仪器垂直轴正交。 所谓水准器轴,就是过水准器零点O ,水准管内壁圆弧的切线,如图3-3所示。另外,由于水准管内的液体比空气重,当液体静止时,管内气泡永远居于管内最高位置,如图3-3中的'O 位置。显然,过'O 作圆弧的切线,此切线总是水平的,我们称此切线为水准轴由此可知,使其水准轴与水准器轴相重合,即气泡最高点'O 与水准器分划中心O 重合,这时经纬仪的垂直轴与测站铅垂线重合,这个过程称为整置仪器水平。 2. 水准器格值 我们知道,当水准器倾斜时,水准 管内的气泡便会随之移动。不同的水准 器,虽然倾斜的角度完全相同,各自的 气泡移动量不会完全相同。这是因为不 同的水准器,它们的灵敏度不同。灵敏 度以水准器格值表示。所谓水准器格值, 就是当水准气泡移动一格时,水准器轴 所变动的角度,也就是水准管上的一格 所对应的圆心角。 如前所述,水准管的内壁是一圆弧,圆弧的曲率半径愈大,水准管上一格所对应的圆图3-3 水准轴与水准器轴

(word完整版)It+willbe+时间段+before等表示“在……之后……才”的句型总结,推荐文档

It + will be + 时间段 + before等表示“在……之后……才”的句型总结 一、用于句型“It + will be + 时间段 + before...”句型中,表示“要过多久才…”,也可用于“It + may be + 时间段 + before...”,表示“也许要过多久才……”。Before 后的句子中用一般现在时态。 其否定形式“It will/would not be +时间段+ before…”表示“不久就……,过不了多久就……”。 【典型考例】 (1)The field research will take Joan and Paul about five months; it will be a long time _____ we meet them again.(2007安徽卷) A. after B. before C. since D. when (2)—How long do you think it will be ______China sends a manned spaceship to the moon? (2006福建卷) —Perhaps two or three years. A. when B. until C. that D. before (3)It ________ long before we _______ the result of the experiment.( 上海春招2002) A. will not be...will know B. is...will know C. will not be...know D. is...know (4) Scientists say it may be five or six years_________ it is possible to test this medicine on human patients. (2004福建) A. since B. after C. before D. when 解析:答案为BDCC。考题 (1)(2)before 用于肯定的“It + will be + 时间段 + before...”句型中,表示“要过多久…才…”。 (3)before在本题中用于否定句,意为“过不了多久就会……”, 状语从句要用一般现在时代替一般将来时,可知C项为正确答案,句意是:要不了多久我们就会知道试验的结果了。 (4)宾语从句中含有句型“It + may be + 时间段 + before...”,表示“也许要过多久才……”,故选择答案C。 二、用于句型“it was +时间段+ before …”表示“过了(多长时间)才……”。其否定形式“ it was not +时间段+ before …”意为“不久就……”, “没过(多长时间)就……”。 【典型考例】 It was some time ___________we realized the truth. (2005山东) A. when B. until C. since D. before 解析:答案为D。before用于句型“it was +时间段+ before …”表示“过了(多长时间)才……”。该题题意是“过了一段时间我们才意识到事情的真相”。故正确答案为C项。

胎膜早破护理常规

胎膜早破护理常规 【护理评估】 一、一般情况 1、评估患者的生命体征、意识、皮肤情况。 2、询问患者受伤史、既往史、手术史、饮食、睡眠、过敏史、用药情况。 3、了解患者对疾病的认识及心理活动。 二、专科评估 1、详细询问病史,了解诱发胎膜早破的原因,确定胎膜破裂的时间、妊娠周数,是否有宫缩及感染的征象发生。 2、观察孕妇阴道液体流出的情况,是否有增加腹压动作时流出液体。由于孕妇突发阴道流液,可能紧张不安,担心影响胎儿及自身健康,有些孕妇可能想象到胎膜早破的发生以及带来的种种不良结局,甚至产生恐惧心理。 【护理要点】 1、破膜后立即听胎心音,观察羊水量、性状、破膜时间 并记录。 2、嘱病人绝对卧床休息,若胎先露尚未衔接则应抬高臀部, 以防脐带脱垂。 3、嘱病人用消毒会阴垫,并协助孕妇及时更换。给予1: 2000新洁尔灭液会阴冲洗,每天2次,以保持外阴清洁,预

防宫内感染。 4 、严密观察胎心音变化,听胎心音每半小时或1小时1 次。必要时给予胎儿监护。 5 、严密观察羊水的量、性状、颜色及有无异味,如羊水有 污染,则应尽快结束分娩。 6 、破膜时间超过12小时,遵医嘱给予抗生素预防感染。 7 、加强巡视,及时发现产妇生活需要并给予协助。 8、尽量减少肛查次数,如需做阴道检查,应严格无菌操作。 9 、测体温、脉搏、呼吸每日4次。 10 、如孕周小于37周,有产兆而无感染征象者,遵医嘱给 予保胎治疗,以预防早产。 11、如孕周大于37周,观察12~18小时无宫缩,可遵医嘱 静滴催产素引产,或根据情况做好剖宫产的术前准备。 【健康教育】 1 、向孕妇详细讲解胎膜早破的原因、临床表现及有可能出 现的危险如早产、脐带脱垂、感染等,让其有思想准备,并能积极配合医疗护理工作。 2 、嘱孕妇计数胎动,教会其计数胎动的方法及正常范围,如有异常及时通知医护人员。 3、嘱孕妇绝对卧床,以免大量羊水流出造成脐带脱垂。

电子经纬仪使用方法_以及如何放线

中文名称:电子经纬仪使用方法,以及如何放线经纬仪英文名称:theodolite;transit 定义1:测量水平和竖直角度的测绘仪器。应用学科:测绘学(一级学科);测绘仪器(二级学科)定义2:测量水平和垂直角度和方位的仪器。应用学科:机械工程(一级学科);光学仪器(二级学科);大地测量仪器-经纬仪(三级学科)定义3:测量水平角、垂直角以及为视距尺配合测量距离的仪器。应用学科:水利科技(一级学科);水利勘测、工程地质(二级学科);水利工程测量(三级学科)以上内容由全国科学技术名词审定委员会审定公布 求助编辑百科名片 经纬仪,测量水平角和竖直角的仪器。是根据测角原理设计的。目前最常用的是光学经纬仪。 目录 构造 分类 用途和工作原理 自制方法 编辑本段构造 经纬仪结构机器部件一、经纬仪的结构(主要常用部件):经纬仪 1望远镜制动螺旋2 望远镜3 望远镜微动螺旋4 水平制动5 水平微动螺旋6 脚螺旋9 光学瞄准器10物镜调焦11目镜调焦12 度盘读数显微镜调焦

13 竖盘指标管水准器微动螺旋14 光学对中器15 基座圆水准器16 仪器基 座17 竖直度盘18 垂直度盘照明镜19 照准部管水准器20水平度盘位置变换手轮望远镜与竖盘固连,安装在仪器的支架上,这一部分称为仪器的照准部,属于仪器的上部。望远镜连同竖盘可绕横轴在垂直面内转动,望远镜的视准轴应与横轴正交,横轴应通过水盘的刻画中心。照准部的数轴(照准部旋转轴)插入仪器基座的轴套内,照准部可以作水平转动。 编辑本段分类 经纬仪根据度盘刻度和读数方式的不同,分为游标经纬仪,光学经纬仪和电子经纬仪。目前我国主要使用光学经纬仪和电子经纬仪,游标经纬仪早已淘汰。电子经纬仪光学经纬仪光学经纬仪电子经纬仪光学经纬的水 平度盘和竖直度盘用玻璃制成,在度盘平面的周诶边缘刻有等间隔的分经纬仪划线,两相邻分划线间距所对的圆心角称为度盘的格值,又称度盘的最小分格值。一般以格值的大小确定精度,分为:DJ6 度盘格值为1° DJ2 度盘格值为20′ DJ1 (T3)度盘格值为4′ 按精度从高精度到低精度分: DJ07,DJ1,DJ2,DJ6,DJ30等(D,J分别为大地和经纬仪的首字母)经纬仪是测量任务中用于测量角度的精密测量仪器,可以用于测量角度、工程放样以及粗略的距离测取。整套仪器由仪器、脚架部两部分组成。应用举列(已知A、B两点的坐标,求取C点坐标):是在已知坐标的A、B两点中一点架设仪器(以仪器架设在A点为列),完成安置对中的基础操作以后对准另一个已知点(B点),然后根据自己的需要配置一个读数1并记录,然后照准C点(未知点)再次读取读数2。读数2与读书1的差值既为角BAC的角度值,再精确量取AC、BC的距离,就可以用数学方法计算出C点的精确坐标。一些建设项目的

before用法归纳

before用法知多少? 在高考中,状语从句是每年高考单项填空部分必考的题目之一,考查的重点是考生容易混淆并且近似的连词在逻辑行文和语篇结构中的使用。before作连词的用法一直是高考的重点,也是学生感觉掌握起来比较头疼的地方。下面选取近几年各省市的高考试题进行归纳分析,使考生通过典型实例,把握高考对before所引导的句型的命题规律,帮助同学们更好地解答此类题目。 1. before作为连词时的基本意义是“在……之前”,用于表示时间或顺序。 You can’t borrow books from the school library ______ you get your student card. (2009上海,32) A. before B. if C. while D. as 【解析】选A。考查连词,该句的意思是:在你得到你的学生卡之前你不能从学校图书馆借书。before表示先后顺序。 2. 表示“过了多久才……”,说明主句的持续时间比较长而从句的动作缓缓来迟。 (1) The American Civil War lasted four years _______ the North won in the end. (2005广东,30) A. after B. before C. when D. then 【解析】选B。本题考查连词before表示“在多久之后才……”的用法,根据本句含义“美国南北战争持续了四年,北方才最终取得胜利”,可知本题应选B。 (2) Several weeks had gone by I realized the painting was missing. (2004宁夏,39) A. as B. before C. since D. when 【解析】选B。before表示“过多久才……”。句意:几个星期已经过去了,我才意识到油画丢了。内含的意思是油画丢了好几个星期了,我才意识到。 3. 表示从句动作还没来得及发生或完成,主句动作就已经发生或完成了,意为“尚未……就”,“没来得及……就”,常用于before sb. can/ could…。 —Why didn’t you tell him about the meeting? ( 2006四川,35) — He rushed out of the room _________ I could say a word. A. before B. until C. when D. after 【解析】选A。本题考查连词before表示“还没来得及……就……”的用法。句意为:我还没来得及说一句话,他就冲出了房间。 4. 表示“以免,以防,趁……还没有……”,强调动作的必要性,以避免或防止从句动作的发生。 He made a mistake, but then he corrected the situation _____ it got worse.(2003北京) A. until B. when C. before D. as 【解析】选C。由made a mistake和转折词but可知本题句意是“他犯了一个错误,但在事情进一步恶化之前他改变了形势。”故答案正确答案为C项。

have got的详细用法回顾.doc

Module 4 &5需要掌握的重点语法和词组: 复习:have的用法及否定句、一般疑问句的变法。 ①have的意思是:________,它的单数形式是:_______。have是_______词。 例如:我有许多好朋友。_____ _____ many good friends.他有许多好朋友。_____ _____ many good friends. ②把下列两道题改为否定句: 1、I have many good friends:_____________________________ 总结:have 的句子改为否定句要_______________________________________________________________ 2、He has a dog:_________________________ 总结:has的句子改为否定句要_____________________________________ 同样的道理:请将下列两道题改为一般疑问句: I have many good friends:_____________________________ 总结:______________________________________ He has a dog:_________________________ 总结:________________________________________________________ 练习: 一、用have的正确形式填空: 1、He_____two brothers. 2、I_____a beautiful picture. 3、Betty_____ a lovely dog. 4、They_____some friends here. 二、请将下列的句子改为否定句和一般疑问句。 1-3题改为否定句:1、He has two brothers. ___________________________________________________ 2、I have a beautiful picture. ___________________________________________________ 3、Betty has some friends here. ___________________________________________________ 4-6题改为一般疑问句: 4、They have a good teacher. _________________________________肯定回答:_________________ 5、I have some cards. __________________________________________否定回答:____________________ 6、Tony has a sister. __________________________________________否定回答:____________________ 三、请用所给词的适当形式填空。 1、I _________ (have)a brother,but I_________ (not have)a sister. 2、He _________ (have)a beautiful pen. _________ you_________(have)a pen? 3、Lingling _________ (have)an English dictionary. 4、_________ Tony_________(have)a car? have got 的用法及否定句、一般疑问句的变法。 ①have got 表示_________________________________ 例:我有一只猫。I have got a cat. have got 的第三人称单数形式是:____________________________ ②have got可以缩写为:_______________ 例如:I have got a cat = ________________________ has got 可以缩写为:_______________ 例如:He has got a cat = ________________________ 练习:请用has got或have got填空。 1、I a bike. 2、He a bike. 3、You a bike.

J2光学经纬仪实验操作方法

J2-2光学经纬仪实验操作方法 目录 ○1仪器用途 ○2仪器主要技术参数 ○3仪器结构 ○4仪器使用方法 ○5仪器的调整 ○6仪器的维护 ○7可供附件 仪器用途 J2-2经纬仪是一种精密光学测角仪器,此种仪器在国防建设、大地测量中占很重要的地位。可以广泛应用于国家和城市的三、四等三角测量。同时亦可用于铁路、公路、桥梁、水利、矿山以及大型企业的建筑,大型机器的安装和计量等工作。 仪器主要技术参数 一测回水平方向标准偏差±2″ 一测回垂直角测量标准偏差±6″ 望远镜正象 物镜通光口径φ40mm 放大倍率30 视场(1000m处)24m 最短视距离2m 乘常数100 加常数不清0 度盘和测微器具 水平度盘直径90mm 垂直度盘直径70mm 全园刻度值勤360 度盘最小格值勤20′ 测微器最小格值勤1′ 自动归零补偿器 补偿精度过±0.3″ 补偿范围±3′ 读数显微镜 水平系统放大率48 x 垂直系统放大率62 x 水准器 长水准器20″/2mm 圆水准器具8′/2mm 光学对点器

视场角7°30′ 调焦范围0.3~6m 仪器重量 净重6kg 毛重9kg 一、望远镜 望远镜成正像、采用了双胶合一分离的物镜和对称式目镜。此种结构的望远镜,其成象质量以及在亮度和清晰方面均较好。 望远镜镜筒的上、下二面均装光学粗瞄准器,以便于在正倒镜观测时均可用其进行粗瞄。筒内装有反光板,以便于夜间观测时用其照明分划板。 望远镜分划板上附有保护玻璃片,以便于当分划板有污点时,可以清除,而不致于有十字丝脱色和其他损伤现象。 逆时针方向转动卡环(7),可根据用户所需,置换不同倍率的目镜。 二、竖轴系 本仪器采用的是半运动轴系。此种轴系的幌动角比标准园式园柱小(在同样参数条件下),轴系中的钢珠和轴套锥面具有自动归心作用,所以间隙的大小对轴的幌动影响不大。 半运动式轴系的优点的摩擦力矩小,耐磨性好,当轴套锥面磨损后,在更换直径不同的钢珠后仍可继续使用。同时温度对其影响也较小。 三、读数系统 本仪器采用了对径符合数字读数方式。因此,我们选用了透射工式度盘和1:1透镜式转象系统。并用移动光楔测微器作为测微系统。 移动光楔测微器的原理是光线通过光楔时,光线会发生转角不变。因此通过光楔移动后,由于光线的偏转点改变了而偏转角不变。因此,通过光楔的光线就产生了平行位移地动以这实现其测微的目的。 四、竖盘指标自动归零补偿器 本仪器采用了悬摆补偿器,它能消除仪器整平后的乘余误差给竖盘读数带来的影响,其原理是当仪器竖轴有一小倾角时,悬挂平板相应地的反向摆转一角度,使得通过平板的光线产生偏移,以此来消除竖轴倾斜时对竖盘读数的影响。支架上的按钮(图2),是用来检查补偿器是否正常工作的,整平仪器后,揿一下按钮,竖盘刻线(读数窗中)互相摆开,然后缓慢回复到初始位置,则补助偿工作正常。否则应排除故障。 仪器使用方法 本仪器配用三爪式基座。 一、置中 1、垂球对中 将三脚架架于测站点之上,悬挂垂球于三脚架三角基座下面的中心固定螺旋的弦线上,并使之对准站点中心,压脚架之脚尖入土中,使三脚架稳固。 仪器从箱中取出,一手握扶照准部,一手握住三角基座,小心地放于三角架头上,转动中心固定螺旋,将仪器轻轻地固定于脚架上,再转动脚螺旋(16),使园水泡(20)居中,将仪器在三角架上精细地移动,使垂球尖端正确对测站点,然后拧紧中心固定螺旋。 若对仪器上面的高点定中心,可自该点挂一垂球,当仪器整平和望远镜视准轴在水平位置时,使粗瞄准器上的红点对准垂球尖端。 2、光学对点器对中 精确的对则使用光学对点器,操作如下:先旋转对点器(18)目镜,使分划板清晰,再拉伸对点器镜管,使对中标志清晰。 滑动仪器,使测站点居于分划板的小圆圈中央。 将仪器照准部转动180°后检查仪器对中情况,然后拧紧中心固定螺旋。 仪器整平后再精细对中一次。

but,than引导定语从句和before,until用法辨析

but和than引导定语从句的用法 一、but可被看作关系代词,引导定语从句,在句中作主语,在意义上相当于 who not或that not,即用在否定词或具有否定意义的词后,构成双重否定。 如:①There is no mother but loves her children.没有不爱自己孩子的母亲。 ②There was no one present but knew the story already.在场的人都知道这个故事。 二、than作关系代词时,一般用在形式为比较级的复合句中,其结构为形容词比较级(more)...than+从句,than在从句中作主语,相当于that,代表它前面的先行词。(这时,它兼有连词和代词的性质,也有学者认为这种用法的than是连词,后面省略了主语what。) 如:①The indoor swimming pool seems to be a great deal more luxious than is necessary.室内游泳池过于豪华。 ②He got more money than was wanted.他得到了更多的钱。运用上述知识翻译下列句子: 1.任何人都喜欢被赞扬。(but) 2.我们大家都想去桂林。(but) 3.没有人不同情那些嗷嗷待哺的孩子。(but) 4.我们班上没有一个人不想帮你。(but) 5.无论多么荒凉,多么难以行走的地方,人们也能把它变成战畅(but)6.这件事情比想象的要复杂。(than) 7.这个广告的效果比预想的要好。(than) 8.这个问题看起来容易,实际上很难。(than) 9.他爸妈给他的零用钱总是超过他的需要。(than) 10.因为这项工程非常困难,所以需要投入更多的劳动力。(than) 答案: 1.There is no one but likes to be praised. 2.There is no one of us but wishes to visit Guilin. 3.There is no man but feels pity for those starving children.4.There is no one in our class but wants to help you. 5.There is no country so wild and difficult but will be made a theatre of war. 6.This matter is more complex than is imagined. 7.This advertisement is more affective than is expected. 8.The problem may be more difficult in nature than would appear.9.He got more pocket money from his parents than was demanded.

水准仪经纬仪使用方法详细图解

水 准 测 量 基本知识 1.水准测量原理 工程上常用的高程测量方法有几何水准测量、三角高程测量、GPS 测高及在特定对象和条件下采用的物理高程测量,其中几何水准测量是目前高程测量中精度最高、应用最普遍的测量方法。 如图2-1所示,设在地面A 、B 两点上竖立标尺(水准尺),在A 、B 两点之间安置水准仪,利用水准仪提供一条水平视线,分别截取A 、B 两点标尺上读数a 、b ,显然 A B H a H b +=+ A 、 B 两点的高差h AB 可写为 AB h a b =- A 点高程H A 已知, 求出 B 点高程 B A AB H H h =+ 我们规定A 点水准尺读数a 为后视读数,B 点水准尺读数b 为前视读数。 图 2-1 如果A 、B 两地距离较远时,可以用连续水准测量的方法。中间可设置转点TP (临时高程传递点,须放置尺垫),如图2-2所示 11h a =, 333h a b =-,……, n n n h a b =-。 123......AB n i h h h h h h =+++=∑

于是,可以求得A 、B 之间的高程差 AB i i h a b =-∑∑ B 点高程 B A AB H H h =+. 图 2-2 2.水准仪介绍: 水准仪是提供水平视线的仪器,按精度分,水准仪通常有DS 05、DS 1、DS 3等几种。其中“D ”和“S ”分别为“”和“水准仪”首字汉语拼音的首字母,而下标是仪器的精度指标,即每千米测量中的偶然误差(以mm 为单位)。目前常用的水准仪从构造上可分为两大类:利用水准管来获得水平视线的“微倾式水准仪”和利用补偿器来获得水平视线的“自动安平水准仪”。此外,还有一种新型的水准仪——“电子水准仪”,它配合条形码标尺,利用数字化图像处理的方法,可自动显示高程和距离,使水准测量实现了自动化。 水准仪主要由望远镜、水准器、基座三部分组成。 (1) DS 3微倾式水准仪 1.仪器介绍

before句型辨析与解析

before句型辨析与解析 It + will be + 时间段+ before等表示“在……之后……才”的句型总结 一、用于句型“It + will be + 时间段+ before...”句型中,表示“要过多久才…”,也可用于“It + may be + 时间段+ before...”,表示“也许要过多久才……”。Before 后的句子中用一般现在时态。 其否定形式“It will/would not be +时间段+ before…”表示“不久就……,过不了多久就……”。 (1)The field research will take Joan and Paul about five months; it will be a long time _____ we meet them again. A. after B. before C. since D. when (2)—How long do you think it will be ______China sends a manned spaceship to the moon? —Perhaps two or three years. A. when B. until C. that D. before (3)It ________ long before we _______ the result of the experiment. A. will not be...will know B. is...will know C. will not be...know D. is...know (4) Scientists say it may be five or six years_________ it is possible to test this medicine on human patients. A. since B. after C. before D. when 解析:答案为BDCC。考题 (1)(2)before 用于肯定的“It + will be + 时间段+ before...”句型中,表示“要过多久…才…”。 (3)before在本题中用于否定句,意为“过不了多久就会……”, 状语从句要用一般现在时代替一般将来时,可知C项为正确答案,句意是:要不了多久我们就会知道试验的结果了。 (4)宾语从句中含有句型“It + may be + 时间段+ before...”,表示“也许要过多久才……”,故选择答案C。 二、用于句型“it was +时间段+ before …” 表示“过了(多长时间)才……”。其否定形式“ it was not +时间段+ before …” 意为“不久就……”, “没过(多长时间)就……”。 It was some time ___________we realized the truth. A. when B. until C. since D. before 解析:答案为D。before用于句型“it was +时间段+ before …” 表示“过了(多长时间)才……”。该题题意是“过了一段时间我们才意识到事情的真相”。故正确答案为C项。 表示“在……之后……才”。副词“才”在汉语中强调某事发生得晚或慢。如果在含有before从句的复合句中,强调从句动作发生得晚或慢时,就可以应用这种译法。 The American Civil War lasted four years _______ the North won in the end. A. after B. before C. when D. then 解析:答案为B。本题考查连词before表示“在……之后才……”之的用法,根据本句含义“美国南北战争持续了四年,北方才最终取得胜利”,可知本题应选B。 三、表示“……还没来得及……就……”。目的在于强调从句动作发生之前,主句动作已发生。 —Why didn't you tell him about the meeting? — He rushed out of the room _________ I could say a word. A. before B. until C. when D. after 解析:答案为A。本题考查连词before表示“……还没来得及……就……”的用法。句意是“我还没来得及说一句话,他就冲出了房间”。 四、表示“在……之前就……”。这时主句与before从句中的两个动作按时间先后依次发生。 It was evening______ we reached the little town of Winchester. A. that B. until C. since D. before 解析:答案为D。本题考查连词before表示“在……之前就……”的用法。句意是“我们到达小镇Winchester 之前就已经是傍晚时分了”。 五、表示“趁……”,“等到……”,或“没等……就…… ”等。

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