The Effect of Withdrawal Rate on Crystal Structure Perfection, Microstructure and Creep Resistance of Single Crystal Castings Made of CMSX-4 Nickel-Based Superalloy.

This study focuses on the evaluation of the crystal structure perfection in the single crystal made of CMSX-4 nickel superalloy and its effect on creep resistance. Single crystal castings were manufactured by directional solidification process at the withdrawal rate of 1, 3, 5 and 7 mm/min. Light (LM) and electron (SEM, TEM) microscopy, X-ray diffraction and Mossbauer spectroscopy were used for evaluation of the microstructure and crystal structure perfection. Castings were also subjected to creep tests. The best creep resistance was obtained for the casting manufactured at the withdrawal rate of 3 mm/min, characterized by the highest crystal structure perfection compared to the other castings examined.

Initiating palliative care in the emergency department.

BACKGROUND: In 2006, nearly a quarter of a million patients either arrived dead or died in the Emergency Department (ED). The role of palliative care (PC) in the ED is not well defined, and education of medical students and residents in the area is sparse. OBJECTIVES: We use an illustrative case to discuss important concepts in PC for the emergency physician (EP). The reader should be able to define hospice and PC, recognize its importance in the practice of Emergency Medicine, and understand the benefits PC has for the patient, the patient's family and caregivers, and the health care system as a whole. DISCUSSION: PC excels at treating pain and addressing end-of-life issues. Families and caregivers of patients benefit from PC in terms of improved personal quality of life after the patient's death. PC is more cost-effective than traditional medical care. CONCLUSION: Research on PC in the ED is sparse but it is a growing need, and the EP will need to become proficient in the delivery of PC in the ED.

Do emergency physicians admit more or fewer patients on busy days?

BACKGROUND: Although the issues concerning the impact of emergency department (ED) overcrowding have been the subject of much recent concern, there are few data regarding the effect of ED census on emergency physician behavior with respect to the decision to admit patients. Admission rates might either increase or decrease on busy days, when the system and the physician are under stress. STUDY OBJECTIVE: The purpose of this study was to determine if ED physicians change their admitting behavior depending on ED census. METHODS: This was a retrospective review of 3 months' data (92 consecutive days, July 9-October 9, 2006) in a community ED with an annual census of approximately 70,000 patients and an emergency medicine residency program. We defined each of the 92 days to be either "busy" (> 180 patients seen), "slow" (< 147 patients seen) or "medium" (147-180 patients seen). We then compared the rates of admission to the hospital on the "busy," "medium," and "slow" days. We also compared each attending physician's personal rates of admission on slow days to his or her rate of admission on medium or busy days. ED staffing was constant throughout the study period. All comparisons were with chi-squared. RESULTS: There were 14,969 patients seen in the ED during the 92 study days. On "busy" days, 20.1% of the 3400 patients were admitted to the hospital; on "medium" days, 20.6% of the 9057 patients were admitted; on "slow" days, 19.7% of the 2512 patients were admitted. There was no significant association between the level of patient volume in the ED and rate of admission (p = 0.55). When comparing each of 14 attending physicians to him- or herself, there was no significant association found between rate of admission and ED census (all p values > 0.3). All three categories of days, "busy," "medium," and "slow" did not differ in terms of acuity as judged by triage level distribution. CONCLUSION: The likelihood of a patient's admission vs. discharge is not affected by ED patient volume. Furthermore, we found no evidence that an individual physician's admitting behavior was associated with ED patient volume.

Multiplexed NMR: an automated CapNMR dual-sample probe.

A new generation of microscale, nuclear magnetic resonance (CapNMR) probe technology employs two independent detection elements to accommodate two samples simultaneously. Each detection element in the dual-sample CapNMR probe (DSP) delivers the same spectral resolution and S/N as in a CapNMR probe configured to accommodate one sample at a time. A high degree of electrical isolation allows the DSP to be used in a variety of data acquisition modes. Both samples are shimmed simultaneously to achieve high spectral resolution for simultaneous data acquisition, or alternatively, a flowcell-specific shim set is readily called via spectrometer subroutines to enable acquisition from one sample while the other is being loaded. An automation system accommodates loading of two samples via dual injection ports on an autosampler and two completely independent flowpaths leading to dedicated flowcells in the DSP probe.

Automated microflow NMR: routine analysis of five-microliter samples.

A microflow CapNMR probe double-tuned for 1H and 13C was installed on a 400-MHz NMR spectrometer and interfaced to an automated liquid handler. Individual samples dissolved in DMSO-d6 are submitted for NMR analysis in vials containing as little as 10 microL of sample. Sets of samples are submitted in a low-volume 384-well plate. Of the 10 microL of sample per well, as with vials, 5 microL is injected into the microflow NMR probe for analysis. For quality control of chemical libraries, 1D NMR spectra are acquired under full automation from 384-well plates on as many as 130 compounds within 24 h using 128 scans per spectrum and a sample-to-sample cycle time of approximately 11 min. Because of the low volume requirements and high mass sensitivity of the microflow NMR system, 30 nmol of a typical small molecule is sufficient to obtain high-quality, well-resolved, 1D proton or 2D COSY NMR spectra in approximately 6 or 20 min of data acquisition time per experiment, respectively. Implementation of pulse programs with automated solvent peak identification and suppression allow for reliable data collection, even for samples submitted in fully protonated DMSO. The automated microflow NMR system is controlled and monitored using web-based software.

Popliteal artery trauma in a rural level I trauma center.

Popliteal vascular trauma has historically been an urban phenomenon. We hypothesized that rural popliteal artery injury would result more often from blunt mechanisms of injury (MOI), have a longer time to operation, and result in a higher amputation rate. We retrospectively reviewed all cases of popliteal artery injury from December 1994 to May 2001 at our rural trauma center. Age, gender, Injury Severity Score (ISS), MOI, scene transport versus transfer from a referring hospital, time to operation, and operative times were studied. Significance was determined by Student's t test with a P value < or = 0.05. Thirty-two popliteal artery injuries were found. Blunt trauma accounted for 50 per cent of the injuries. Eighty-eight per cent of the patients were transferred from a referring hospital. Patients transported directly from the scene had a higher ISS. Longer operative times translated into an increased need for fasciotomy. The amputation rate was 19 per cent. This is the first attempt to delineate the specific nature of rural popliteal artery trauma. The amputation rate was not different between the two different MOI and was independent of the time to operation. Of those patients receiving an amputation 83 per cent were transferred from another hospital and despite a statistically lower ISS still required an amputation.

Homocysteine prevents total parenteral nutrition (TPN)-induced cholestasis without changes in hepatic oxidative stress in the rat.

BACKGROUND: The role of oxidative stress in total parenteral nutrition (TPN)-associated cholestasis with liver glutathione depletion was recently shown. The aims of this study were to test the appearance of cholestasis and oxidative stress during TPN, and the hypothesis that reducing oxidative stress with a precursor of glutathione (GSH), homocysteine, would restore bile flow. METHODS: Three groups of rats (weight, 179-278 g) were studied: 1) D/aa group received dextrose and amino acids (3.4 g/d); 2) D/aa/L group received the same amount of amino acids, and lipids were added on an equicaloric basis (50 kcal/d) with a lowered amount of dextrose; and 3) a control group, which received dextrose perfusion and had free access to chow. A subgroup of D/aa/L rats (n = 6) received a TPN solution containing homocysteine. After 5 days of TPN, bile was collected during 2 hours. In liver homogenates, GSH, thiobarbituric acid reactive substances (TBARS), and carbonyl content of proteins (Prot-CO) were measured to test the level of oxidative stress and hepatic lipid and protein oxidation. RESULTS: After TPN, bile flow was significantly lower in the D/aa group than in the control group. Addition of lipids further decreased bile flow. Addition of homocysteine to TPN with lipids significantly increased bile flow. Aspartate aminotransferase increased significantly in both TPN groups compared with the control group. gamma-Glutamyl transpeptidase was not different among TPN groups. An increased hepatic lipid oxidation was demonstrated by TBARS level in both TPN groups when compared with the control group. However, the liver GSH contents were not different. Protein oxidation was also significantly increased by TPN. The addition of homocysteine to TPN solution increased bile flow without liver injury or changes of lipid and protein oxidation. DISCUSSION: This study shows that TPN administered to rats induces a decrease of bile flow and an oxidative stress but that the two changes are not directly correlated. Addition of lipids further impairs bile flow but does not increase the occurrence of liver injury. Consequently, it seems more likely that TPN primarily induces a cholestatic effect that in turn induces an oxidative stress rather than inducing an oxidative stress that leads to cholestasis. However, an association of both mechanisms is not totally excluded.

Computer-assisted laparoscopic splenectomy with the da Vinci surgical robot.

Laparoscopic splenectomy has become the standard of care for the surgical treatment of idiopathic thrombocytopenic purpura (ITP). The minimally invasive approach to splenic disorders such as ITP clearly results in the same benefits to the patients as have been demonstrated with the laparoscopic cholecystectomy techniques. New technologies in minimally invasive surgery have resulted in the development of robotic devises that assist the surgeon during the procedures. Robotic surgery is in its infancy at this point in time. Herein, we report a splenectomy performed with the assistance of the da Vinci surgical robot. With advancement of technology, robotic systems will play an integral role in future minimally invasive surgery.

Palm versus soybean oil on intestinal recovery from malnutrition in Guinea pigs.

Recent recommendations on feeding malnourished children do not provide indication on the nature of dietary lipids. Our aim was to compare the effect of palm oil (mainly saturated and monounsaturated fatty acids) and soybean oil (mainly polyunsaturated fatty acids) on the recovery from malnutrition in guinea pigs. In a first experiment, guinea pigs received a balanced (control group) or a maize (malnourished group) diet for 7, 12, and 21 d. In a second experiment, after 12 d of malnutrition, guinea pigs received a rehabilitation diet containing palm or soybean oil. Both rehabilitation diets allowed a partial recovery from the severe weight loss induced by malnutrition. Thiobarbituric acid reactive substances content, measured in intestinal homogenates, increased in malnourished guinea pigs compared with control animals (40%, p < 0.05) and returned to near control values after rehabilitation with palm (10%) but not soybean (43%) oil diet. Intestinal short-circuit current, assessed in jejunal segments mounted in Ussing chambers, increased progressively during malnutrition (p < 0.001) and returned to near control values with both rehabilitation diets. Compared with control animals, the cell turnover (Ki-67 index assessed by immunohistochemistry detection of the Ki-67 antigen) decreased after soybean (-60%, p < 0.01) but not after palm oil. These results confirm that experimental polydeficient malnutrition induces oxidative stress and dysfunction in the intestine. They show a differential effect of palm and soybean oil on these intestinal measurements, suggesting that the composition of dietary lipids may be important in the treatment of malnutrition.

Early experience with telemanipulative robot-assisted laparoscopic cholecystectomy using da Vinci.

In the past decade, robot-assisted surgery has become increasingly used to assist in minimally invasive surgical procedures. In this article we review the evolution of robotic devices, from the first use of an industrial robot for stereotactic biopsies to pioneering work with robots used for hip and prostate surgery, to the development of robotic guidance systems that enabled solo endoscopic surgery, to telemanipulative surgery with master-servant computer-enhanced robotic devices. In addition, we review our early experience with da Vinci Robotic Surgical Systems (Intuitive Surgical, Inc., Mountain View, CA, U.S.A.), which we used to perform robot-assisted laparoscopic cholecystectomies.

Robotic-assisted adrenalectomy for adrenal incidentaloma: case and review of the technique.

An incidental left adrenal mass was found in a patient during an evaluation for mediastinal widening. The patient had no symptoms attributable to adrenal excess. Preoperative biochemical screening was negative for a functioning medullary or cortical adrenal tumor. Surgical resection was successfully completed with the assistance of the da Vinci robotic system. Pathology demonstrated a rare adrenal oncocytoma.