Quality of Bulk Cdte Substrates and Its Relation to Intrinsic Defects

Both the cadmium vacancy (Vcd) and the tellurium vacancy (VTe) in CdTe are identified by means of electron paramagnetic resonance (EPR). The VCd is a double acceptor and the EPR spectrum is observed in its single negative charge state. The symmetry is found to be trigonal, which can be explained in a model in which the hole occupies a dangling bond t2 orbital and the orbital degeneracy is removed by a static Jahn-Teller distortion. The hyperfine interaction shows that the hole is localised on one of the four Te neighbours. The EPR spectrum of VTe+ reveals cubic (unperturbed) symmetry and the hyperfine structure shows that the unpaired electron is equally spread over the four Cd neighbours.

Photo-EPR measurements locate the 0/+ state of VTe at Ev + 0.2 eV and the 2−/− acceptor level of VCd to be situated less than 0.47 eV above the valence band.

[Abdominal vacuum therapy for the open abdomen - a retrospective analysis of 82 consecutive patients]

BACKGROUND

The therapy for open abdomen remains challenging. Abdominal vacuum therapy seems to simplify the treatment and to enable a direct fascial closure in a high percentage of the patients.

PATIENTS AND METHODS

A retrospective analysis of 82 consecutive patients who underwent abdominal vacuum therapy between January 2005 and December 2007 was undertaken. Indications, -duration of treatment, complications as well as rate and type of abdominal wall closure were evaluated.

RESULTS

The 82 consecutive patients consisted of 46 % female and 54 % male patients with a median age of 65.5 years. The most frequent diagnoses were colorectal carcinoma (24 %, n = 28, colon n = 18 and rectum n = 10), inflammatory bowel dis-ease (13 %), perforated peptic ulcer (9 %), necrotising pancreatitis (7 %), peritoneal carcinosis (5 %), ileus (5 %) and mesenteric ischaemia (4 %). The predominant indication for vacuum therapy was peritonitis (88 %). Vacuum therapy treatment was applied for a median of 6 days (range: 1-73 days). 18 patients (22 %) received intraabdominal foam dressings without the fenestrated polyurethane layer. In 70 % of all cases the abdominal vacuum therapy was performed without complications. 16 patients (19.5 %) developed intestinal fistulas. However, fistulas were not observed among the patients who were treated with foam dressings without a polyurethane layer. Abdominal bleeding was observed in 8 patients (10 %) and a persistent abdominal compartment syndrome was seen in one patient. Nine patients (11 %) died during hospitalisation. After completion of the intraabdominal vacuum therapy, -direct fascial closure was feasible in 35 patients (43 %). In 47 patients (57 %) an absorbable synthetic mesh was required for fascial closure. Symptomatic incisional hernias -occurred in 22 % of the patients.

CONCLUSION

Abdominal vacuum therapy simplifies the treatment of patients with abdominal catastrophes such as peritonitis or necrotising pancreatitis. The cost-effective intraperitoneal use of a foam dressing without a fenestrated polyurethane layer was possible without an increased rate of fistulas. This retrospective analysis demonstrates that abdominal vacuum therapy can be performed without complications in the majority of patients. Furthermore, direct fascial closure is possible in almost half of the patients.

A reproducible porcine model of acute liver failure induced by intrajejunal acetaminophen administration

BACKGROUND AND AIMS

Severe intoxication following acetaminophen overdose is the most common cause of acute liver failure (ALF) in many Western European and North American countries. A reproducible large animal model of acetaminophen intoxication has not been successfully evaluated previously.

METHODS

Eight male pigs underwent acetaminophen intoxication receiving an initial enteric bolus of 250 mg/kg body weight acetaminophen followed by an acetaminophen plasma level (300-450 mg/l) adapted enteric maintenance dose of 1,000-3,000 mg/h to the onset of ALF (prothrombin time value <30%). Vital and ventilation parameters were continuously recorded until death. Saline, hydroxyethyl starch, fresh frozen plasma and erythrocyte units were used for volume substitution, and norepinephrine to prevent severe hypotension.

RESULTS

All animals developed ALF after 25 ± 3 h, which was confirmed by laboratory values, the clinical course and histological examinations. All animals died due to ALF after a further 21 ± 5 h, precipitated by cerebral edema.

CONCLUSIONS

Using an initial enteric acetaminophen bolus, followed by body weight-adapted acetaminophen plasma level intoxication, it was possible to establish a reproducible, clinically relevant porcine model which may be used for the investigation of novel therapeutic approaches in this life-threatening condition.

[Pain therapy in addicted patients]

Each individual is entitled to an adequate and sufficient pain therapy. However, only a few studies have examined the peculiarities of pain management in drug-dependent or formerly addicted patients. Any addiction is disadvantageous for a successful pain therapy, since some of the prescribed drugs may themselves cause addiction. Drug-dependent patients are often tolerant to opioids. Additionally, there is a risk of iatrogenic pain becoming chronic due to disregard for already known risk factors and comorbidities. However, a history of addiction should not prevent sufficient pain therapy, especially since there is no risk of addiction when the pain therapy employed is adequate for the pathophysiology involved. There are adequate pain therapies for addicted patients. The best results are achieved by taking into account the physiological and psychological peculiarities of drug-dependent patients. Importantly, this should be combined with a variety of different, optimized, multimodal therapeutic regimes, as well as with an interdisciplinary approach.

Comparison of standard endoscopic submucosal dissection (ESD) versus an optimized ESD technique for the colon: an animal study

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) is a promising therapeutic technique for en bloc resection of large gastrointestinal tumors. However, this technique has disadvantages such as a long intervention time, complexity of the procedure, and a higher rate of complications. The primary aims of the study were to show the feasibility of ESD in the pig colon and to evaluate a new ESD technique comprising the use of a newly developed hybrid knife for colon procedures combining RF (radiofrequency) application and a distance-dependent water-jet application.

MATERIALS AND METHODS

ESD was conducted at three different locations in the colon according to the computer-generated randomization list, using either the standard technique (injection needle, flex knife, and hook knife as therapeutic instruments and DRY CUT and SWIFT COAG as RF currents), or the new ESD technique (hybrid knife as the therapeutic instrument combined with the new cutting mode ENDO CUT D) in 12 healthy pigs. The perforation and bleeding rates were documented and statistically analyzed. Intervention time, resected specimen size, thermal and mechanical damage of the resection bed, and number of instrument changes required were also recorded.

RESULTS

A total of 16 and 18 ESD procedures were performed by the standard and new techniques, respectively. Complete en bloc resection was achieved in all cases. The standard ESD technique showed a perforation rate of 25 % (4/16) whereas the new ESD technique resulted in a 5.5 % perforation rate (1/18) ( P = 0.035); bleeding rates were similar. The new ESD technique was significantly safer compared with the standard ESD technique.

CONCLUSIONS

A new ESD technique for the successful en bloc resection in thin-walled regions such as pig colon has been described. This procedure is as effective as the standard procedure but is easier to handle and significantly safer.

Electrostatic extraction of cold molecules from a cryogenic reservoir

We present a method which delivers a continuous, high-density beam of slow and internally cold polar molecules. In our source, warm molecules are first cooled by collisions with a cryogenic helium buffer gas. Cold molecules are then extracted by means of an electrostatic quadrupole guide. For ND3 the source produces fluxes up to (7+/- 4(7)) x 10(10) molecules/s with peak densities up to (1.0+/- 0.6(1.0)) x 10(9) molecules/cm3. For H2CO the population of rovibrational states is monitored by depletion spectroscopy, resulting in single-state populations up to (82+/-10)%.

Degreasing and risk of non-Hodgkin lymphoma

OBJECTIVE

To investigate the relationship between selected solvent-related workplace tasks (degreasing, painting, gluing, stripping paint, staining) and risk of non-Hodgkin lymphoma (NHL).

METHODS

We analysed occupational data from a large population-based case-control study of NHL conducted in the USA. For participants reporting occupations with possible exposure to organic solvents, job-specific interview modules were administered to elicit in-depth information on solvent-related workplace tasks and other exposure-related factors (225 cases, 189 controls). Unconditional logistic regression models were fit to calculate odds ratios (ORs) and 95% CI for average frequency, maximal frequency and cumulative number of hours having performed each task. Individuals with jobs rated as unexposed to organic solvents in the workplace (180 cases, 213 controls) were used as a reference group.

RESULTS

We observed an increased risk of NHL among subjects in the highest category of maximal degreasing frequency (>520 h/year: OR 2.1, 95% CI 0.9 to 4.9, trend test p = 0.02). We found similar associations for the highest levels of average frequency and, among men, cumulative number of hours. Other solvent-related tasks were not associated with NHL.

CONCLUSION

Findings from this case-control analysis of solvent-related tasks suggest that frequent degreasing work may be associated with an elevated risk of NHL.

Occupation/industry and risk of non-Hodgkin's lymphoma in the United States

AIMS

To identify occupations and industries associated with non-Hodgkin's lymphoma (NHL) in a large population-based, case-control study in the USA.

METHODS

Cases (n = 1189) of histologically confirmed malignant NHL ages 20-74 were prospectively identified in four geographic areas covered by the National Cancer Institute SEER Program. Controls (n = 982) were selected from the general population by random digit dialling (<65 years of age) and from residents listed in Medicare files (65-74 years of age). Odds ratios and 95% confidence intervals for occupations and industries were calculated by unconditional logistic regression analyses, adjusting for age, gender, ethnicity and study centre. Further analyses stratified for gender and histological subtype were also performed.

RESULTS

Risk of NHL was increased for a few occupations and industries. Several white collar occupations, with no obvious hazardous exposures, had elevated risks, including purchasing agents and buyers, religious workers, physical therapists and information clerks. Occupations with excesses that may have exposures of interest include launderers and ironers, service occupations, food/beverage preparation supervisors, hand packers and packagers, roofing and siding, leather and leather products, transportation by air, nursing and personal care facilities, and specialty outpatient clinics. Significantly decreased risks of NHL were found for a number of occupations and industries including post-secondary teachers and chemical and allied products.

CONCLUSIONS

The results of this study suggest that several occupations and industries may alter the risk of NHL. Our results support previously reported increased risks among farmers, printers, medical professionals, electronic workers and leather workers. These findings should be evaluated further in larger studies that have the power to focus on specific exposures and histological subtypes of NHL.

A new surgical model for hepatectomy in pigs

BACKGROUND

Anhepatic animal models are suitable for simulating acute liver failure. Hepatectomy in pigs includes en bloc resection of the vena cava, and therefore, a temporary extracorporeal bypass and total clamping of the inferior vena cava are needed. These steps cause severe depression of circulation with impaired survival.

METHODS

Previous to en bloc hepatectomy including retrohepatic vena cava in 20 female pigs, a Y-shaped bypass was implanted starting with end-to-side anastomosis between the vena cava and the portal vein, followed by anastomosis to the intrathoracic vena cava.

RESULTS

Blood flow was constant during and after hepatectomy because vessels were only partially clamped. No venous stasis of intestinal organs was observed. Hemodynamic parameters like heart rate, mean arterial pressure, central venous pressure, pulse oximetry and intracranial pressure remained extremely stabile during and after hepatectomy. Postoperative survival time was 100% after 12 h. Maximum survival time was 84.9 h and mean survival time 51.2 +/- 18.7 h. All animals died from multiple organ failure. Intracranial pressure remained stable during the surgical procedure and rose continuously until death. The autopsy showed massive brain edema.

CONCLUSIONS

This new surgical technique is safe and easy to perform and permits total hepatectomy with minimal blood loss under stable circulation without requiring an extracorporeal bypass.

Preferences for shared decision making in chronic pain patients compared with patients during a premedication visit

BACKGROUND

There is some evidence that patients' outcomes improve if they are involved in shared decision making (SDM). A chronic pain clinic or premedication visit could be adequate settings for the implementation of SDM. So far, the patients' preference for involvement in decision making and their desire for information have not been tested in anesthesiological settings.

METHODS

A group of chronic pain patients was compared with a group of patients in the premedication visit with respect to SDM, the desire for information and perceived involvement in care. The autonomy preference index (API, measuring preference for involvement and desire for information) and the perceived involvement in care scale (PICS, measuring patients' perception of easier involvement by doctors and information exchange) were administered.

RESULTS

In total, 190 chronic pain patients and 151 patients of premedication were included in this study. Patient of the premedication visit had significantly higher SDM scores. Desire for information was high, but there were no differences between groups. Younger patients [B (estimate) =- 0.3; 95% CI (-0.4) - (-0.1)], women (B = 10.9; 95% CI 6.3-15.4) and patients with higher educational level (B = 10.1; 95% CI 5.6-14.6) had more desire for SDM. PICS scores were basically influenced by groups: chronic pain patients felt more facilitated by doctors [B =- 0.185; 95% CI (-0.4) - (-0.1)] and had more information exchange [B =- 19.5; 95% CI (-15.8) - (-2.4)] than patients in the premedication visit.

CONCLUSION

In both anesthesiological settings, the desire for information was high, but patients in the premedication visit had higher SDM scores, especially young female patients with higher educational level. Real patient-physician interaction showed that premedication patients felt less involved by doctors and had less information exchange compared with the chronic pain patients. Therefore, premedication visits should be focussed more on adequate information exchange and involvement of the patient in the shared decision making process.