Em In Diameter Research Articles

Analysis of the 19th Century Historic Archaeological Material Culture Remains from the Browning Site in Smith County, Texas

The Browning site (41SM195A) is located on a 3800 m2 alluvial terrace that overlooks the Auburn Creek floodplain in eastern Smith County, Texas. This setting is near the headwaters of a stream system in the Harris Creek drainage; Harris Creek meets the Sabine River ca. 34 km to the north. In the vicinity of the Browning site, the valley, being narrow with steep valley walls, offers few locations suitable for either prehistoric or historic occupations. Soils here arc Entisols; they vary in depth from 30-70 em across the landform, terminating at a sandstone C-horizon. These arc soils that formed mostly under forest vegetation and are dominantly sandy or loamy. The Browning site falls within the Pineywoods vegetation area and represents the western extent of the pine and deciduous forests of the Southeastern U.S. coastal plain. Archaeological investigations at the Browning site have been carried out intermittingly for several years by the junior author. That work has led to the recognition that it is a stratified site with two very distinct occupations, an early to mid-19th century assemblage of historic artifacts primarily in an upper zone (0-20 em bs) overlying a buried (20-50 em bs) Late Woodland period occupation. The historic occupation is in the center of the terrace, covering approximately 500m2• The historic artifacts arc found primarily in the upper sediments, but due probably to pedoturbations, they have been found as deep as 50 em in the underlying prehistoric archaeological deposits. Excavations at the Browning site have consisted of 41 1 x 1 m units (with a total excavated volume of 20.4 m3) and 22 shovel tests. Surface collections were obtained from the site in 1996 and 2002. The 22 shovel tests excavated at the site were conducted first to better ascertain the limits of the site and identify areas of concentrated cultural activity; ST 4, 8-9, 12, and 19 contained 19th century historic artifacts. Once a buried prehistoric occupation zone was identified, units were placed primarily in cardinal directions to better define the occupation zone's boundaries and levels of occupational intensity, and also sample the overlying 19th century component. The I x 1 m units were excavated in arbitrary l 0 em levels and the soil was dry-screened for artifacts through I /4-inch hardware cloth except for a fine screen sample from Unit I that was water-screened through I /32-inch mesh. A level sheet was completed at the end of each level. Profiles were drawn of one wall of each unit or a common wall when several units were joined. The shovel tests followed the same procedures, except they were excavated in arbitrary 20 em levels. One feature had four refined earthenware sherds (as well as two prehistoric artifacts) and 15 small pieces of animal bone. This was a shallow pit with a very dark grayish-brown sandy loam fill (with charcoal flecks) and a rounded bottom that was 63 em in diameter and extended from 22-29 em bs.

Study on lymph node metastasis in 292 patients with early gastric cancer

To evaluate the status of lymph node metastasis (LNM) and reasonable procedure in early gastric cancer (EGC). Two hundred and ninety-two patients with histologically proven mucosal or submucosal gastric cancer who underwent gastrectomy/lymphadenectomy were included in this study. The numbers of total dissected lymph node were all above 15 in all patients. The clinical characteristics, pathologic features, and LNM were assessed by univariate and multivariate analysis. LNM were observed in 43 of 292 cases (14.7%), and 6.4% in mucosal lesions and 22.4% in submucosal lesions. The LNM was identified in 12.7% at the first level, 7.2% at the second level and 0.34% at the third level. The LNM frequency was found in the 6, 3, 4, 1, 5 lymph node (from high to low) consequently at the first level and the 7, 8a lymph node at the second level. The EGC with nodal involvement and the tumors < 2.0 cm in diameter were all depressed type. The diameter of elevated type with LNM was no less than 3.0 cm in this series. The depth of invasion and lymphatic vessel involvement were independent influencing factors in LNM on multivariate analysis (P<0.05). Less extensive surgery might be considered for the elevated type EGC, and tumors <or= 2.0 cm in diameter and mucosal lesions. Gastrectomy with D1 plus No.7, 8a lymphadenectomy might be carried out in the depressed type/<or= 3.0 cm in diameter, or in the elevated type/> 3.0 cm in diameter. With respect to the depressed type EGC/tumors > 3.0 cm in diameter, gastrectomy with D2 lymphadenectomy is proper.

Characteristics of American Marten Den Sites in Wyoming

We examined characteristics of den structures and den sites used by female American marten (Martes americana) for natal and maternal dens in the Sierra Madre Range, Wyoming. During 1988-95, we located 18 natal dens (parturition sites) and 97 maternal dens (sites where kits were present exclusive of parturition) used by 10 female marten. Important den structures included rock crevices (28%), snags (25%), red squirrel (Tamiasciurus hudsonicus) middens (19%), and logs (16%). Resource selection function (RSF) analysis showed that an individual selection model provided a significantly better fit than a null model or pooled selection model, indicating that the sample of marten selected maternal den sites that differed from random sites, and that individual animals did not select maternal den sites in the same manner. Six marten individually exhibited significant selection for maternal den sites within home ranges. Overall selection coefficients for maternal dens indicated the number of squirrel middens was the most important variable, followed by number of snags 20-40 em diameter at breast height (dbh), number of snags 2:41 em dbh, and number of hard logs 2:41 em in diameter. Selection of natal den sites was also significant via comparison between selection and no-selection models, with number of middens, number of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) >20 em dbh, and number of hard logs 2:41 em in diameter the most important variables in descending order of importance. Large logs, large snags, and large, live spruce and fir trees are important characteristics for marten den sites in the central Rocky Mountains. The prominence of middens at den sites suggests red squirrels provide important denning structures as well as prey for marten.

Lipiodol-CT for hepatocellular carcinoma

Lencioni et al. have nicely presented a positive predictive value of Lipiodol CT for intrahepatic metastasis of hepatocellular carcinoma (HCC) based on 32 consecutive patients undergoing hepatectomy [1]. Lipiodol-CT has been generally regarded as a highly sensitive examination to detect intrahepatic metastases because these mostly occur in hypervascular HCC (advanced or classic HCC, histopathologically moderately or poorly differentiated) and have a similarly hypervascular character. However, there has been no direct confirmation of high sensitivity and specificity by this method. Theoretically and clinicopathologically, Lipiodol is distributed in loci according to their vascularity. Long-term deposits are noted in the necrotic area of the tumor and liver parenchyma, especially after embolization [2]. Thus, any hypervascular nodular lesion such as small cavernous hemangioma and focal nodular hyperplasia and nontumorous area such as focal inflammation and arterioportal shunt could be false-positive cases of intrahepatic metastasis, although the durations of deposit are different case by case [2]. Such cases have been sporadically reported [3, 4]. Lencioni et al. have defined a positive finding of intrahepatic metastasis at Lipiodol-CT as a small, rounded, well-delineated retention less than 2 em in diameter but have not described any pathologic definition or finding. In general, intrahepatic metastases are present in cases with HCC associated with portal tumor thrombus, multiple in number, small in size, and located adjacent to the main tumor [5]. However, intrahepatic metastasis is not a self-evident lesion, especially in patients at high risk for HCC who often have multicentricoccurring tumors of different or same subtype. Even when using DNA analysis, pathologists cannot necessarily confirm whether or not a particular lesion is an intrahepatic metastasis [5, 6].

Multiple plantar epidermoid cysts harboring carcinoembryonic antigen and human papillomavirus DNA sequences

mon than large CMN (1%vs. 0.005%).9 Rhodes and associates'? estimated a cumulative melanoma risk of 2.6% to 4.9% for persons with a small CMN (less than 10 em in diameter). Illig et al. l l suggested that the small CMN is a potential precursor of MM and prophylactic excision might be the treatment of choice. However, the malignant potential associated with small eMN is still controversial. 8, '0, 12, 13 A small CMN as a precursor of MM must be documented by parents' statement, photographs, or medical records, and confirmed by showing a remnant of the congenital nevus histologically. Distinguishing a small CMN from an acquired nevus isdifficult, but a CMN is more likely to have nevus cells in the lower two thirds of the reticular dermis and to show involvement of dermal appendages and neurovascular structures. It has been estimated that only one of every 170,000 cutaneous MMs arises in direct contiguity with a small CMN.IO Consensus on preventive excision has not been reached, and the tendency is to postpone excision until the onset of puberty.14, 15

Cystic Degeneration in Porcine Ovaries ‐ First Communication: Morphology of Cystic Ovaries, Interpretation of the Results

Contents: The morphological appearance of ovarian structures in 79 sows with ovarian cysts was examined. Sixty sows had been culled due to sterility; 19 sows had been repeatedly investigated clinically before slaughter. It was found that cystic ovaries without corpora lutea (CL) had the largest diameter and volume (151.3 cm3), in comparison to both cystic ovaries with CL (85.7 cm3) and normalovaries (16.9 cm3). The number of cysts on ovaries without corpora lutea was approximately twice as high as on the ovaries with CL (23.3 vs 12.1 cystslsow; p &lt; 0.001). A combined form of degeneration consisting of large (&gt; 1.5 cm in diameter) and small (1.5 em in diameter) cysts was found in 63% of the animals, whereas degeneration with only small cysts occured in 8% of the cases. Dark CL, interpreted as being functional, were mainly present in animals with up to 10 cysts per sow (24 out of 27 sows, p &lt; 0.001); pale CL, interpreted as being weakly functional, were mainly found on ovaries with more than 10 cysts (19 out of 23 sows; p &lt; 0.001). Based on macroscopical differentiation cyclic activity was found to be dependent to the number of cysts. Regular or irregular estrous cycles were observed in oligocystic animals (10 cysts/animal) with functional CL (58%). Up to 75% of the animals with pale or absent CL showed no estrous activity.

Bilateral basal cell carcinoma of the breasts

A 71-year-old white woman had scaly plaques on both breasts for 1 year. The plaque on the right breast was 3 em in diameter with a rolled border extending onto the areola. The plaque on the left breast had a similar appearance and was 2 X 3 em in diameter with ulceration in the areola. She had had a basal cell carcinoma and a melanoma excised from her back 8 months previously. After histopathologic confirmation of basal cell carcinoma, wide excisions were performed. At the 6-month postoperative follow-up examination no evidence of recurrence was found. Findings of each biopsy specimen showed an ulcerated, superficial basal cell carcinoma. The stroma between the tumor islands was heavily infiltrated with plasma cells and lymphocytes. The excised specimens had identical histologic features. The lesions were completely excised.

A simple technique for fine-scale, vertical sectioning of fresh sediment cores

Biogeochemical processes occurring at the sediment-water interface and within the very near-surface sediments are known to affect or control what occurs above or below the sediment surface (see reviews ofNowell 1983· Jumars and Nowell 1984; Nowell and Jumars 1984; Grant and Mad~en 1986; Butman 1987; Rumohr et a!. 1987). Studies of these phenomena often require vertical sampling of the variables of interest over very fine (e.g., millimeter) spatial scales. Existing techniques for such fine-scale vertical sectioning of fresh sediment cores were developed primarily for studies of porewater chemistry (Craven et a!. 1986; Jahnke et a!. 1986; Reimers and Smith 1986) and of the distributions of meiofauna or microbes (Boaden and Platt 1971; Joint et a!. 1982; Palmer and Molloy 1986), where only very small samples (cores ::53.0 em in diameter) are required. Furthermore, in most cases, the verticalsectioning technique requires subcoring a much larger sediment sample (e.g., a box core) after it is taken. This potentially introduces error (contamination between layers) when sectioning at millimeter intervals, because near-surface sediments within the sample may mix vertically

Three Cases of Primary Adenosquamous Carcinoma of Stomach

Adenosquamous carcinoma of stomach is a mixed glandular-epidermoid tumor where both components are neoplastic. Its incidence is extremely rare. The five theories on the origin of squamous components are 1) island of ectopic squamous epithelium in the gastric mucosa, 2) squamous metaplasia of gastric epithelium, 3) squamous differentiation in a preexisting adenocarcinoma, 4) endothelial cell differentiated toward squamous elements, and 5) totipotential undifferentiated cells of the gastric mucosa. We experienced three cases of adenosquamous carcinoma. Case 1 was a 71-year-old female patient. ; an ulcerative lesion was present in the pylorus, measuring 5cm in diameter. Case 2 was a 57-year-old male patient. ; an ulcerative lesion is present in the pylorus, measuring 6 em in diameter. Case 3 was a 58-year-old female patient. ; an ulcerative lesion was present in the body and fundus, measuring 10cm in diameter. Microscopic examination revealed a mixed malignant squamous and adenomatous component.

YAG laser endoscopic treatment of an esophageal and sigmoid stricture after end-to-end anastomosis stapling

Endoscopic laser photocoagulation has many advantages over electrocautery. It avoids direct contact with tissue, controls the thermal reaction, and obviates current flow through the tissue. New applications are being devised in the treatment of gastrointestinal tract disorders.1,2 In addition to laser coagulation for the treatment of bleeding gastrointestinal lesions, we used laser endoscopy for the treatment of gastrointestinal tract strictures caused by the end-toend anastomosis (EEA) auto-suture stapling procedure in two cases. power output of 100 watts and a sigmoidofiberscope (Olympus CF-1TS2) was done. Conditions of the irradiation were power output, 80 watts; irradiational pulses, 1.0 sec; and total energy, 2507 joules. The lesion was vaporized from the inner side with laser applied at locations of 12, 6, 3, and 9 o'clock. Follow-up sigmoidoscopy 1 week later showed a wider orifice (1.5 em in diameter) (Fig. IB). Closure of the T-colostomy was done in January 1983. Barium enema at that time showed a smooth passage (Fig. 2), and bowel movements were normal during 4 months' follow-up.

Curability of gastrointestinal lymphoma with combined surgery and radiation

Of a total of 1394 patients with non-Hodgkin's lymphomas seen at the Princess Margaret Hospital between January 1, 1967 and December 31, 1978, 150 presented with gastrointestinal involvement. One hundred-thirteen of those patients had localized (Stage I & II) disease. Prognostic factors affecting outcome included hulk of residual disease after initial surgery and presence of B-symptoms. Patients with Stage IA and IIA with gross residual lysphoma less than 2 1 2 em in diameter treated with post-operative abdominal irradiation achieved 85% 10 years failure-free rate and 88% 10 year actuarial cause specific survival. The above group is considered curable with surgery and low dose adjuvant radiation.

バレイショでんぷんに関する育種学的研究 ＩＩ でんぷん粒径および無機成分含量の品種間および種間差異

The present tests had studied to find out the variations in diameter of starch granule and inorganic constituents among various potato varieties and breeding lines, and Solanum species, respectively. The each characteristics among potato varieties or breeding lines varied to the extent ranging 13.7-40.9 ?Em in diameter of starch granule, 100-439 mg in ash, 26-128 mg in P, 19-65 mg in K, 2.2-7.5 mg in Mg, and 0.2-2.4 mg/100g in Ca content. Similarly, the each characteristics among Solanum species varied to the extent ranging 13.0-39.1 ?Em in diameter of starch granule, 73-494 mg in ash, 21-101 mg in P, and 6-68 mg/100g in K content. We also recognized several varieties or breeding lines which showed less 200 mg/100g in ash and over 28.0 pm in diameter of starch granule. These results are thought as very useful to select the excellent varieties or breeding lines as cross parents for future breeding work.

Multiple Autotransplantation of Rat Mammary Tumors Induced by 7,12-Dimethylbenz[ a ]anthracene: Brief Communication 2

Mammary tumors induced in outbred Sprague-Dawley rats by 7,12-dimethylbenz]a]anthracene were excised, cut into 1- to 2-mm3 pieces, and then autotransplanted sc along the mammary line at six sites. Following an average period of 20--30 days, these autografts grew to approximately 2 cm in diameter in 32 of 48 rats (67%). Autografts in the other 33% of the rats remained dormant. Mammary tumors transplanted into allogeneic hosts failed to grow. Tumors derived from autotransplantation were indistinguishable from their primary tumors with respect to their histologic features, the nature of hormone dependency, the content of estrogen receptors, and their ability to incorporate [3H]leucine. Furthermore, autotransplanted tumors derived from a single primary tumor varied little with regard to the preceding parameters; thus they provided an opportunity for serial sampling of individual tumors for repeated morphologic and biochemical evaluations.

PROBABILITY OF PROMPT NEUTRON EMISSION FROM SPONTANEOUS FISSION OF Pu&lt;sup&gt;240&lt;/sup&gt;

The probability distribution of prompt neutron number from the spontaneous fission of Pu240 has been measured by use of a spherical liquid scintillation detector 60 em in diameter. The experimental distribution can be well represented by a Gaussian distribution with σ=1.08. This result was compared with the experimental results of B. C. Diven, A. Hicks and J. W. Boldeman, and is in agreement with the semi-emperical theoretical distribution given by J. Terrel. The absolute efficiency of the detector for the fission neutron of Pu240 has been found to be 0.759 ± 0.011, based on the average number of prompt neutrons per fission for spontaneous fission of Pu240 v=2.154±0.028[5].

An operative staging system and a megavoltage radiotherapeutic technic for cerebellar medulloblastomas.

CEREBELLAR MEDULLOBLASTOMA is one of the most common types of primary intracranial tumors in children. The treatment of this tumor, unfortunately, is considered as “one of the darkest chapters in pediatric neurosurgery” (1). Cushing (2) reported an average survival of five and six-tenths months in 14 patients with medulloblastoma who received no postoperative radiotherapy. Ingraham and Matson (3) stated that “to our knowledge, no patient with cerebellar medulloblastoma has ever been cured.” Although medulloblastoma has long been known as the most sensitive primary brain tumor to ionizing radiation, the radiotherapy results for this tumor with respect to long-term survival is still very disappointing. In order to better evaluate the response of medulloblastoma to irradiation and to improve the survival rate, the operative records of 100 consecutive cases of tissue-proved medulloblastoma at the Neurological Institute, Columbia-Presbyterian Medical Center were arbitrarily taken in a period from 1940 to 1967 and were reviewed as to their primary location, extent of invasion, and gross subarachnoid seeding in correlation with radiation dose, technic, and survival results when possible. The age and sex distribution in this series is shown in TABLE I. Since clinical staging is inaccurate and sometimes misleading in many inaccessible human cancers, we have sought to develop an operative staging system for medulloblastomas with the International TNM-staging designation. The letter T stands for the primary tumor, subdivided to T1, T2, T3, T4, according to its size and the extent of involvement. Since there are no lymphatic channels in the brain, the letter N is omitted in our staging. The letter M stands for metastasis. In the cases of medulloblastoma, the cerebrospinal fluid pathway is the most important route of metastasis. The extent of metastasis is subdivided to Mo, Ml, M2, M3. Our proposed operative staging system for cerebellar medulloblastoma is as follows (Fig. 1): T1—Tumor less than 3 em in diameter and limited to the classic midline position in the vermis, the roof of the fourth ventricle, and less frequently to the cerebellar hemispheres. T2—Tumor more than 3 em in diameter, further invading one adjacent structure or partially filling the fourth ventricle. T3—It may be subdivided into T3a and T3b. T3a: Tumor further invading two adjacent structures or completely filling the fourth ventricle with extension into the aqueduct of Sylvius, foramen of Magendie, or foramen of Luschka, thus producing marked internal hydrocephalus. T3b: Tumor arising from the floor of the fourth ventricle or brain stem and filling the fourth ventricle.

Addition of polymer to radiopaque contrast material to decrease catheter flow resistance.

RECENT SHIP-MODEL studies have shown that long-chain, high-molecular-weight polymers reduce fluid-friction drag on ship hulls (2). A similar effect was demonstrated in pipeline flows and was quickly adapted by various industries interested in reducing the cost of pumping fluids through pipelines. Recent experiments have explored the biological applicability of this phenomenon (3, 5). This report describes the use of long-chain, high-molecular-weight polymers to reduce frictional drag in high-speed injection catheters. Previous work in this laboratory (1) has shown that catheters used clinically in high-speed injections generally operate in a turbulent flow condition. Reynolds numbers in the range of 6,000–15,000 are found in catheters under these conditions. The application of classical engineering hydrodynamics is useful in the description of pressure-flow characteristics of injection catheters (1). The addition of high-molecular-weight polymers reduces frictional drag only in turbulent flow conditions. However, White and Hoyt (5) have found that fluids to which polymers have been added maintain a laminar flow even though the calculated Reynolds number is 4,000–5,000. Methods In order to measure drag reduction, a system was devised which enabled us to measure flows and pressures accurately during injection through a steel catheter of fixed length and diameter. Using this type of catheter eliminates not only the problems of expansion in polyethylene catheters but also the flow variation due to whipping or motion of the catheter during the injection. In these experiments, an injector driven by gas at a constant pressure was used. This injector produces a square pulse of pressure and flow with no over-shoot or undershoot. Pressure was measured at the injection nozzle with a Statham Model PG769 high-pressure transducer with ranges of 0–1,000 psi. This transducer was mounted in a specially built chamber which could be connected to the output nozzle of any injector system and provided a precise measurement of pressure at the proximal end of the catheter. Flow was calculated by measuring the volume injected over a fixed period of time. The injector was electronically controlled and injection time was set at 1.0 ± 0.01 second. The catheter used in this study was constructed from stainless-steel hypodermic tubing 50 em long and 0.16 em in diameter. Injections were made at room temperature with water and a number of contrast materials. After the normal pressure-flow relationship was established for each contrast medium through the catheter and injection system, poly-ethylene oxide (Polyox) 3 in quantities of 30 parts per million (ppm) was added to the solutions of the various contrast materials and the water.

Peroral irradiation of carcinoma of the oral tongue.

THE TREATMENT of squamous–cell carcinoma of the oral part of the tongue has developed in the hands of many workers along surgical lines; others emphasizing radiation therapy have evolved a variety of technics. At the University of Michigan orthovoltage radiation (200–220 kV) was the only agent available for ex–ternal irradiation until 1955. Since it was not possible to deliver a high dose to a tumor of the tongue using opposing or multiple fields without producing undesirable radiation damage of the jaw, a peroral technic with malleable thin–walled lead cones was developed for the treatment of certain lingual lesions and frequently was used as the sole method of radiotherapy. It avoided radiation exposure of the mandible, the soft tissues of the face, and the major salivary glands. This method produced encouraging results which persuaded us to favor it over radium needle implants as the preferred mode of treatment in selected carcinomas of the tongue. This technic is certainly not original with us, having been first attempted by Brickner (5) in 1903 and used rather extensively by Martin (13). Ebenius (9), Baclesse et al. (4), and Ennuyer and Bataini (10) also described such technics; Castigliano and Sklaroff (7) conceived and used cones individually fashioned for each lesion. Among others, Sharp et al. (19), Ash and Millar (3), and Frazell and Lucas (12) employed this technic in conjunction with interstitial and external irradiation. More recently Phillips (17) reported on use of the method for various oral carcinomas. This report reviews our experience with peroral radiotherapy of squamous-cell carcinoma of the oral part of the tongue from 1940 through 1960. We have classified the extent of the neoplasm according to the following TNM classification adhering to the principle of using the category of lesser extent in doubtful situations: T1—tumor less than 3 em in diameter. T2—tumor 3 to 5 ern in diameter with a possible minimal extension to the floor of the mouth or deep muscle infiltration. T3—tumor more than 5 em which may extend to include half of the tongue, with possible limited extension to the floor of the mouth. T4—tumor involving more than half of the tongue or massive extension to the floor of the mouth with involvement of the mandible, extension into the base of the tongue, or marked extension into the tonsillar structures. The cervical node involvement was classified in the following way: N0—no palpable adenopathy. N1—homolateral adenopathy, mobile. N2—bilateral or contralateral adenopathy, mobile. N3—fixed adenopathy, homolateral or bilateral.

Closed bone biopsy by a radiologist.

Percutaneous bone biopsy can be performed either by needle aspiration (1, 2) or by obtaining a core of tissue using a Craig needle (3, 4). The latter is a cutting instrument that obtains a core of bone measuring approximately 0.3 em in diameter. By slight modification of the Craig needle, specimens may now be obtained with relative safety under local anesthesia and occasionally on an outpatient basis. The modified Craig needle is used with either biplane image-intensification fluoroscopy or some type of C-arm that allows needle positioning in two planes. These modifications consist of fashioning each step of the procedure so that a needle can be inserted for local anesthesia as well as for anchoring the instrument (Fig. 1). Technic The patient is positioned on the x-ray table so that the bone to be biopsied can be visualized in two pro jections under image-intensification control. After careful sterile preparation of the skin, a stab wound of approximately 8 mm in length is made under local anesthesia. Local anesthesia is then infiltrated along the projected track of the needle down to the area of the bone. The blunt cannula is inserted down to the bone, and if the patient experiences any pain during this passage the obturator is removed. The central needle is inserted into the cannula, and local anesthesia is injected. After the blunt cannula is directed to the desired site of biopsy, the anchoring needle is inserted into the lumen of the cannula and is passed into the periosteum and cortex of the bone to firmly anchor the blunt cannula. Its position is verified by biplane fluoroscopy. Over the top of the blunt cannula the sleeve is inserted down to the level of the bone. A tube in the sleeve allows an additional needle to be placed in the wall of the sleeve for any needed local anesthesia and later, after the sleeve has been placed down to the bone to be biopsied, this same anesthesia needle will serve as an anchoring needle. Once the sleeve is in position the blunt cannula is removed, and the cutting instrument is inserted through the sleeve. If there is any tendency for the cutting instrument to wander, an anchoring needle can be placed through its lumen to prevent slippage of the biopsy instrument. The cutting instrument is inserted into the bone with a twisting action until the desired depth of specimen has been obtained. This is usually 10–15 mm in length. A clasping worm instrument is inserted through the cutting instrument to insure that the specimen is not lost in the sleeve and biopsy hole. After the specimen is removed, together with the cutting instrument, a tamponading instrument is inserted into the bony defect to control bleeding. After seven to ten minutes the tamponading instrument is removed from the sleeve and the lumen of the sleeve observed to insure that bleeding has, in fact, been controlled. Once satisfied, the radiologist removes the sleeve and compresses the puncture site for four to five minutes. No sutures are required, nor is drainage necessary.

Soil physical conditions of winter and the growth of ryegrass plants: I. effects of compaction and puddling

Abstract Six pot trials with seedling plants of perennial ryegrass (Latium perenne L.) have been carried out to investigate the effects, on growth, of compaction and saturation of the topsoil. In each trial identical soil was packed, in 1 em layers, into a number of 17 em-diameter pots, treatments comprising different degrees of compaction or puddling in the surface 5 em of the soil. Seedling plants at the two-leaf stage were planted in holes 1 em in diameter and 1.2 em deep, their root systems being previously cut down to one root 1.2 em long. The pot soils were kept at high and constant moisture contents by sub-irrigation from shallow water tables, rain being excluded, and the trials were run at winter temperatures. Growth was related to measurements of physical properties of the surface 5 em of the soil. These comprised dry density, moisture content, volume of air pores, the diffusivity of oxygen gas through an extracted core of soil, and the current flowing to a platinum micro-electrode at a depth of ...