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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Effects of electrolytic machining conditions on the geometry and size of tungsten needle

Yeh, Chia-chi 20 August 2007 (has links)
In this study, an electrolytic micro-machining tester is employed to investigate the effects of the supply voltage, the immerse depth of tungsten rod, and the machining time on the current waveform, the material removal rate, and the geometry of the tungsten needle. The tungsten rod to be electrolyzed is dipped in an aqueous electrolyte of 10 wt% sodium hydroxide as the anode, and the stainless steel ring as the cathode. The spindle rotating speed and the stirring rotating speed are set to be 100 rpm and 200rpm, respectively. According to analyze the topography of the tungsten needle, four machined regimes have been identified as:¡]1¡^non-machined regime,¡]2¡^incomplete machined regime,¡]3¡^complete machined regime,¡]4¡^over machined regime. In order to obtain the perfect tungsten needle, the experiments are conducted in the complete machined regime. Results show that the tungsten rod becomes a short cone for the immerse depth of 5 mm, and a long cone for the depth of 10mm. When the immerse depth of 10 mm and the supply voltage of 3V, the surface of tungsten needle becomes rough slightly and the tip radius of tungsten needle is about 2£gm. With increasing the supply voltage to 4.5 V, the surface of tungsten needle is uniform with a downward trend in material removal rate, and the tip radius can achieve a submicron. For the supply voltage of 6V, because the material removal rate varies violently, it becomes very difficult to control the diameter of tungsten needle. During the machining time between 0 to 10 min for the supply voltage of 4.5V, the diameter of tungsten rod is decreased from 1000 to 200£gm, but during the machining time between 10 to 12.5 min, the tungsten rod gradually transforms into the needle due to a downward trend in current, and the tip radius is decreased from 200£gm to submicron. Hence, the machining time must be controlled accurately to manufacture the needle in a submicron radius.
32

Effect of aspiration cytology in the diagnosis of breast cancer

Chen, Pi-Fang 08 July 2008 (has links)
Objective: The incidence rate and mortality of breast cancer are increasing in Taiwan during recent years. The incidence rate of breast cancer is ranked number one among top ten female cancers, and the mortality of breast cancer is ranked fourth among cause of death for female cancer sufferers. The most common age group for breast cancer is between 40 and 50 years old. Breast cancer causes huge disease burdens for individual, family and society. The breast sonography and fine needle aspiration cytology (FNAC) are common screening methods for breast cancer diagnosis. Nevertheless, little study has focused on the benefits of combing these two methods in clinical application. This study aims to fill such research gap. Method: This study conducted medical chart reviews and collected 2,776 observations that were under breast sonography and FNAC examination from a regional hospital locates in southern Taiwan. The diagnosis categories for sonography include: malignant, benign, and probably benign tumor. The diagnosis categories for FNAC include: malignant, benign, and suspicious for malignant. Results: Among 2,776 observations, there were 555 observations (20%) had operation in the studied hospital. The operation results indicated that 205 (36.9%) observations were with malignant status, and 350 (63.1%) observations were with benign status. The diagnosis categories of both sonography and FNAC were significantly associated with the operation results (p<0.001). The FNAC had specificity in 100%, false positive ratio in zero, and positive predictive value in 100%. The Odds ratios for sonography diagnosis categories, age groups, and tumor sizes were OR=4.132 (95%CI: 1.5¡V11.6), OR=31.957 (95% CI: 3.7¡V272.4), OR=0.457 (95% CI: 0.1¡V1.5), respectively. When combining sonography and FNAC in parallel tests, the diagnosis accuracy was 89.2%, sensitivity was 90.2%, specificity was 88.6%, positive predictive value was 82.2%, and negative predictive value was 93.9%. When combining sonography and FNAC in serial testing, the diagnosis accuracy was 88.1%, sensitivity was 67.8%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 84.1%. Conclusion: Combining sonography and FNAC in breast cancer diagnosis can increase the accuracy, decrease false positive ratio and false negative ratio. These two methods can be conducted during outpatient visit and are fast, accurate and cost-effective tools for breast cancer diagnosis. These two methods particularly appropriate for younger female patients for early screening, early intervention, and may increase the survival rates.
33

Early testing of Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) for Swiss needle cast tolerance /

Temel, Fatih. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.
34

Cytological features in equivocal diagnoses (C3/4) of breast fine needle aspiration cytology

Leung, Nga-shan, Phyllis., 梁雅珊. January 2006 (has links)
published_or_final_version / Medical Sciences / Master / Master of Medical Sciences
35

Determining the Relationship Between Needle Nutrition and Post-harvest Needle Retention in Balsam Fir (Abies balsamea (L.) Mill.)

Georgeson, Melissa 21 March 2013 (has links)
The Christmas tree and greenery trade is a multi-million dollar industry in Atlantic Canada. Christmas trees grown in Nova Scotia are shipped internationally especially, to the United States. This thesis was set out to answer the over-arching hypothesis: pre- and post- harvest needle nutrient content influences post-harvest needle retention. Through a series of experiments it was shown that the pre-harvest needle P, Ca, Mg, Mn, Zn and B contents do not appear to be directly linked to post-harvest needle retention. Alternatively, the pre-harvest needle N, K, Cu and Fe contents significantly, but negatively influenced post-harvest needle retention. By maintaining needle N, K, Cu and Fe concentrations below 1.5 %, 0.55 %, 3.7 ppm and 35 ppm, respectively may extend needle retention in balsam fir. Xylem-fed nutrients negatively influenced needle retention. As well, foliar applications of calcium and zinc citrate did not promote needle retention at the concentrations used.
36

Modeling and Control of A Flexible Needle in Soft Tissue

Boroomand, Arefeh Unknown Date
No description available.
37

Effects of ultraviolet-B radiation (UV-B) on needle anatomy and glutathione status of field-grown pines

Laakso, K. (Kirsi) 15 December 1999 (has links)
Abstract It has been suggested that pine needles protect themselves against UV-B radiation via anatomical and chemical changes in the epidermal layer. This could lead to growth reductions if more assimilates are allocated to the protection mechanisms in the epidermis at the expense of the photosynthetic area. If the protection is insufficient, the UV-B radiation could cause oxidative stress. Moreover, the UV-B-induced stress could increase year by year and the responses could become cumulative. Therefore, two different UV-B field experiments were conducted at two sites. The first was a long-term experiment on mature, naturally growing Scots pines (Pinus sylvestris L.) in Oulu (65°N), Finland, during the growing seasons 1996–1998 (25% ozone depletion) and the second one was a one-growing-season experiment on Scots pine and loblolly pine (Pinus taeda L.) seedlings in Maryland (39°N), USA, in 1997 (16% and 25% ozone depletion scenarios). In Scots pine seedlings, UV-B treatments decreased the primary needle length at the early stages, but no significant differences were seen in fully-grown needles. In mature Scots pines, the response was opposite and UV-B accelerated needle growth in young needles. This suggests that at the early stage of development, the primary needles of seedlings are more sensitive than the fascicle needles of adult pines. Thus, the developmental stage of the studied organisms must be taken into account. Scots pine seedlings protected themselves against UV-B by increasing the thickness of the cutin layer and the epidermal wall (outer and periclinal walls and anticlinal wall), which features have been connected to xeromorphic structure, and by reducing significantly the cross-sectional, mesophyll and epidermal areas. In mature Scots pines, similar trends towards smaller cross-sectional and mesophyll areas and significantly reduced epidermal + hypodermal area were seen in fully-grown UV-B-treated needles. Loblolly pine responded to supplemental UV-B by producing more phenolic compounds into epidermal cell walls and epidermal lumen, which could have resulted in thicker outer epidermal walls. In both of the studied species, these protection mechanisms were sufficient to prevent growth reductions in fully-grown current-year needles. This demonstrates the difference between the studied species and shows that no general interpretations can be made on the effects of UV-B radiation on conifers. The cumulative effects of UV-B radiation were studied from current-year and current+2-year old needles of mature Scots pines during the third UV-B exposure season. The UV-B stress was observed in the current+2-year old needles of mature Scots pines as a degradation of total glutathione, GSHtot, and a bigger proportion of oxidized glutathione, GSSG%, in July during the third UV-B exposure season. In current-year needles, no increase in GSSG% was seen in either the first or the third season. After the third experimental season in September, the GSHtot levels decreased in UV-B-treated current-year needles. These results suggest that the effect of UV-B is duration-dependent and cumulative. The longevity of mature Scots pine needles at the study site is four to five years, and the effects of UV-B should thus be studied over the whole life span of a needle.
38

Colorado microdissection needle versus cold steel scalpel for incisions in third molar surgery

Mohamed, Allie January 2014 (has links)
Magister Chirurgiae Dentium - MChD / This study compares the CMN to the steel scalpel by assessing incision time, incisional blood loss, postoperative pain, wound healing, and the incidence of lingual and long buccal nerve injury. Twenty standardised cases were included in an analytical prospective case series. Each case had one side cut with CMN and the other side with steel scalpel. Third molar surgery is the most commonly performed procedure by maxillo-facial and oral surgeons, and is associated with expected but transient sequelae such as pain, swelling and trismus. Modalities to reduce the severity of these sequelae are desirable. Several studies report that the use of conventional electrosurgical instruments and the Colorado Microdissection Needle (CMN) resulted in significant reductions in cutting time, incisional blood loss, postoperative pain, with no evidence of increased incidence of wound complications such as dehiscence and infection.
39

Horner Syndrome After Lymph Node Fine Needle Aspiration: Which Is the Culprit?

Al-Abbadi, Mousa A., Youngberg, George, Al-Lozi, Muhammed 01 January 2010 (has links)
No description available.
40

Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle and needle-free injection methods

Gerlach, Bryce Mark January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / Terry A. Houser / Nursery age pigs (n=198) were used to evaluate the difference in the occurrence of injection site abscesses between needle-free jet injection and conventional needle-and-syringe injection systems. Pigs were fed for 21 d prior to treatment administration to acclimate the pigs to the environment of the Kansas State University Segregated Early Weaning (SEW) unit. On d 21 each pig was injected with aluminum hydroxide adjuvant in the neck and ham with needle-free jet injection (Pulse Needle-Free Systems, Lenexa, KS) and conventional needle-and-syringe injection. Needle-free and conventional needle-and-syringe injections were randomly assigned to pig side yielding a total of 396 injections per treatment with a total of 792 injections sites. Immediately prior to injection, the external surface of the injection sites were contaminated with an inoculum of Arcanobacterium pyogenes, a bacterium commonly associated with livestock abscesses. The pigs were then fed for a period of 27 or 28 d. On d 27 or d 28 the pigs were humanely euthanized and sent to the Kansas State Veterinary Diagnostics Laboratory where necropsies were performed and the injection sites harvested for histopathological evaluation. The needle-free jet injection system was associated with more injection site abscesses than the conventional needle-and-syringe injection method for both neck (P=0.0625) and ham (P=0.0313) injection sites. Twelve abscesses were found at injection sites administered via needle-free jet injection method while only 1 abscess was found with the conventional needle-and-syringe injection method. 5 abscesses were found at the neck injection sites and 8 abscesses were found at ham injection sites. There were no significant differences seen in tissue granulation resulting from reaction to the adjuvant. In summary, the implementation of needle-free jet injection systems in market hog production will be beneficial to eliminate needles and needle fragments in meat products but, when in the presence of Arcanobacterium pyogenes, it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants. Although more abscesses were associated with needle-free jet injection, their occurrence was observed at a very low rate given that all injection sites were intentionally contaminated prior to injection.

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