5-Axis CNC Micromilling for Rapid, Cheap, and Background-Free NMR Microcoils.

The superior mass sensitivity of microcoil technology in nuclear magnetic resonance (NMR) spectroscopy provides potential for the analysis of extremely small-mass-limited samples such as eggs, cells, and tiny organisms. For optimal performance and efficiency, the size of the microcoil should be tailored to the size of the mass-limited sample of interest, which can be costly as mass-limited samples come in many shapes and sizes. Therefore, rapid and economic microcoil production methods are needed. One method with great potential is 5-axis computer numerical control (CNC) micromilling, commonly used in the jewelry industry. Most CNC milling machines are designed to process larger objects and commonly have a precision of >25 µm (making the machining of common spiral microcoils, for example, impossible). Here, a 5-axis MiRA6 CNC milling machine, specifically designed for the jewelry industry, with a 0.3 µm precision was used to produce working planar microcoils, microstrips, and novel microsensor designs, with some tested on the NMR in less than 24 h after the start of the design process. Sample wells could be built into the microsensor and could be machined at the same time as the sensors themselves, in some cases leaving a sheet of Teflon as thin as 10 µm between the sample and the sensor. This provides the freedom to produce a wide array of designs and demonstrates 5-axis CNC micromilling as a versatile tool for the rapid prototyping of NMR microsensors. This approach allowed the experimental optimization of a prototype microstrip for the analysis of two intact adult Daphnia magna organisms. In addition, a 3D volume slotted-tube resonator was produced that allowed for 2D 1H-13C NMR of D. magna neonates and exhibited 1H sensitivity (nLODω600 = 1.49 nmol s1/2) close to that of double strip lines, which themselves offer the best compromise between concentration and mass sensitivity published to date.

Cervical esophagotomy for foreign body extraction - Case report and comprehensive review of the literature.

INTRODUCTION: Esophageal foreign bodies are an important and serious cause of morbidity and mortality in both children and adults. Due to the possibility of serious complications, i.e. perforation, necrosis, mediastinitis, and fistulation, rapid and accurate diagnostic measures with subsequent therapy are necessary. CASE REPORT: We are reporting a case of a 55-year-old, mentally impaired patient that has swallowed a foreign body, which subsequently became lodged in his esophagus. Due to the fact that endoscopic removal was not possible and there was a high risk of complications such as esophageal perforation or mediastinitis in this case, we performed cervical esophagotomy and successfully extracted the foreign body. The patient showed an uneventful postoperative process and could be discharged on Day 11 after the operation. COMPREHENSIVE REVIEW: Furthermore, we performed a systematic review of the literature to identify all studies that described a surgical approach through esophagotomy in cases of foreign body ingestion and found 11 publications describing the cases of 29 patients. These studies reported an overall complication rate of 17.2% and a mortality rate of 0%. CONCLUSION: Our findings suggest that esophagotomy could be a viable approach for the extraction of foreign bodies especially in some cases when endoscopic removal was not successful and the risk of esophageal perforation is high.

Parallelizing acquisitions of solid-state NMR spectra with multi-channel probe and multi-receivers: applications to nanoporous solids.

A five-channel ((1)H, (19)F, (31)P, (27)Al, (13)C) 2.5 mm magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) probe is used in combination with three separate receivers for the parallel acquisitions of one (1D) and two-dimensional (2D) NMR spectra in model fluorinated aluminophosphate and porous Al-based metal-organic framework (MOF). Possible combinations to record simultaneously spectra using this set-up are presented, including (i) parallel acquisitions of quantitative 1D NMR spectra of solids containing nuclei with contrasted T1 relaxation rates and (ii) parallel acquisitions of 2D heteronuclear NMR spectra. In solids containing numerous different NMR-accessible nuclei, the number of NMR experiments that have to be acquired to get accurate structural information is high. The strategy we present here, i.e. the multiplication of both the number of irradiation channels in the probe and the number of parallel receivers, offers one possibility to optimize this measurement time.

The vital threat of an upper gastrointestinal bleeding: Risk factor analysis of 121 consecutive patients.

AIM: To analyze the importance in predicting patients risk of mortality due to upper gastrointestinal (UGI) bleeding under today's therapeutic regimen. METHODS: From 1998 to 2001, 121 patients with the diagnosis of UGI bleeding were treated in our hospital. Based on the patients' data, a retrospective multivariate data analysis with initially more than 270 single factors was performed. Subsequently, the following potential risk factors underwent a logistic regression analysis: age, gender, initial hemoglobin, coumarines, liver cirrhosis, prothrombin time (PT), gastric ulcer (small curvature), duodenal ulcer (bulbus back wall), Forrest classification, vascular stump, variceal bleeding, Mallory-Weiss syndrome, RBC substitution, recurrent bleeding, conservative and surgical therapy. RESULTS: Seventy male (58%) and 51 female (42%) patients with a median age of 70 (range: 21-96) years were treated. Their in-hospital mortality was 14%. While 12% (11/91) of the patients died after conservative therapy, 20% (6/30) died after undergoing surgical therapy. UGI bleeding occurred due to duodenal ulcer (n = 36; 30%), gastric ulcer (n = 35; 29%), esophageal varicosis (n = 12; 10%), Mallory-Weiss syndrome (n = 8; 7%), erosive lesions of the mucosa (n = 20; 17%), cancer (n = 5; 4%), coagulopathy (n = 4; 3%), lymphoma (n = 2; 2%), benign tumor (n = 2; 2%) and unknown reason (n = 1; 1%). A logistic regression analysis of all aforementioned factors revealed that liver cirrhosis and duodenal ulcer (bulbus back wall) were associated risk factors for a fatal course after UGI bleeding. Prior to endoscopy, only liver cirrhosis was an assessable risk factor. Thereafter, liver cirrhosis, the location of a bleeding ulcer (bulbus back wall) and patients' gender (male) were of prognostic importance for the clinical outcome (mortality) of patients with a bleeding ulcer. CONCLUSION: Most prognostic parameters used in clinical routine today are not reliable enough in predicting a patient's vital threat posed by an UGI bleeding. Liver cirrhosis, on the other hand, is significantly more frequently associated with an increased risk to die after bleeding of an ulcer located at the posterior duodenal wall.