Three-dose vs extended-course clindamycin prophylaxis for free-flap reconstruction of the head and neck.

Background: Twenty-four hours of perioperative antibiotics provides effective prophylaxis for most head and neck cancer resections. Many reconstructive surgeons have been hesitant to apply this standard to free-flap reconstruction of the head and neck. This prospective clinical trial compared short-course and long-course clindamycin prophylaxis for wound infection in patients with head and neck cancer undergoing free-flap reconstruction.

Measurement of the frequency-dependent conductivity in sapphire.

Electron transport of photoexcited single-crystal sapphire (alpha-Al2O3) is characterized by terahertz time-domain spectroscopy. The complex conductivity displays a Drude-type frequency dependence, which yields carrier scattering rates and densities. Carrier scattering is dominated by interactions with acoustical and optical phonons at low and high temperatures, respectively, and follows Matthiessen's law over the measured temperature range of 40-350 K.

[Stabilization of proximal humeral fractures with the intramedullary dynamic titanium helix wire].

The implant Helix-Wire is a treatment device that is used since 1997. It provides minimally invasive stabilization of subcapital humeral fractures. The implant is inserted through a small lateral entrance and a cortical hole drilled into the intramedullary space of the proximal humeral shaft and drilled into the humeral head for fracture stabilization.

Direct NMR observation and DFT calculations of a hydrogen bond at the active site of a 44 kDa enzyme.

A hydrogen bond between the amide backbone of Arg7 and the remote imidazole side chain of HisIO6 has been directly observed by improved TROSY-NMR techniques in the 44 kDa trimeric enzyme chorismate mutase from Bacillus subtilis. The presence of this hydrogen bond in the free enzyme and its complexes with a transition state analog and the reaction product was demonstrated by measurement of 15N-15N and 1H-15N trans-hydrogen bond scalar couplings, (2h)J(NN) and (lh)J(HN), and by transfer of nuclear polarization across the hydrogen bond. The conformational dependences of these coupling constants were analyzed using sum-over-states density functional perturbation theory (SOS-DFPT).

Predictive geometric factors in a standardized model of femoral neck fracture. Experimental study of cadaveric human femurs.

An experimental study was performed on 20 cadaveric human proximal femurs to investigate both the reproducibility of their mechanical behavior under uniaxial compression and the correlation of mechanical properties with geometric dimensions and bone density. These variables were assessed by radiography, physical measurement, and dual-energy X-ray absorptiometry (DEXA). The specimens were immobilized, loaded to the point of fracture, and analyzed with the help of a materials testing machine.

Probing high-barrier pathways of surface reactions by scanning tunneling microscopy.

The ability of scanning tunneling microscopy to probe the pathways of thermally activated high-barrier surface processes is frequently limited by competing low-barrier processes that can confuse measurement of the true initial and final configuration. We introduce an approach to circumvent this difficulty by driving the surface process with nanosecond laser heating. The method is applied to determine the pathway of recombinative desorption in the H/Si(001) system.

Influence of controlled reaming on fat intravasation after femoral osteotomy in sheep.

This study assessed the influence of driving speed and revolution rate per minute of two reamers on femoral intramedullary pressure increases and fat intravasation. The AO and Howmedica reamers were tested in four groups with different combinations of driving speed and revolution rate per minute in both femurs in a sheep model. The 24 animals were exposed to hemorrhagic shock after midshaft osteotomy and were resuscitated before reaming of both femoral shafts.

Real-space study of the pathway for dissociative adsorption of H2 on Si(001).

Dissociative adsorption of molecular hydrogen on clean Si(001) surfaces has been investigated by means of scanning tunneling microscopy. The dissociated hydrogen atoms are found to occupy Si atoms of adjacent dimers. In addition to this interdimer configuration associated with the adsorption of isolated hydrogen molecules, pairs of adjacent doubly occupied dimers are readily formed.

Femoral neck fracture after removal of the standard gamma interlocking nail: a cadaveric study to determine factors influencing the biomechanical properties of the proximal femur.

We retrospectively analyzed 1334 patients who were implanted standard gamma interlocking nails (SGN) to stabilize trochanteric femoral fractures over the years 1992-1998. Reoperation to remove the nails was performed in 37 patients, in 9 of them purely because of pain. Three out of these 9 patients with removed SGN suffered femoral neck fractures in the early postoperative course after having been mobilized to full weight-bearing capacity.

The standard Gamma nail: a critical analysis of 1,000 cases.

Background: The continuous increase in the number of fractures of the proximal femur is directly attributable to the worldwide increase in life expectancy. The standard version of the Gamma Interlocking-Nail (standard Gamma nail [SGN], 200-mm length, 10-degree valgus curvature, two distal locking bolts) was designed because of the demands in orthopedic hip surgery to develop an implant stable enough to mobilize old patients as soon as possible to avoid further morbidity and mortality.

Methods: Between the years 1992 and 1998, 1,000 consecutive patients with peritrochanteric fractures were stabilized by using the SGN and included in this study.

Bedside hemoglobinometry in hemodialysis patients: lessons from point-of-care testing.

The HemoCue B-hemoglobin test system (HemoCue, Inc., Mission Viejo, CA) is a photometric method for rapid bedside determination of hemoglobin (Hb). We compared the performance of HemoCue measured Hb against Coulter STK-S (CSTK) measured Hb in chronic hemodialysis (HD) patients in two different settings.

Novel surface vibrational spectroscopy: infrared-infrared-visible sum-frequency generation.

A novel type of surface vibrational sum-frequency generation spectroscopy is presented that enables a highly specific measurement of the coupling of molecules on surfaces. With this doubly vibrationally resonant technique, two-dimensional vibrational spectroscopy of molecules on surfaces becomes possible. The technique is demonstrated for the C-O stretch vibration of CO on a ruthenium (001) surface.

Charge transport and carrier dynamics in liquids probed by THz time-domain spectroscopy.

We examine the transport properties and the dynamics of free electrons in n-hexane by means of femtosecond spectroscopy using an ultraviolet pump pulse to create the electrons and a THz electromagnetic pulse as a probe. The complex dielectric response of the photogenerated electrons is determined over a broad range of frequencies, from which we infer the electron scattering time and density through the Drude model. The time evolution of the carrier density reveals nongeminate electron-ion recombination within hundreds of picoseconds at high ion concentration.

Treatment of talar neck fractures: clinical results of 50 patients.

Fractures of the neck and body of the talus present as one of the most challenging and rare injuries. These fractures are often associated with other ankle, foot, and skeletal injuries, which complicate their treatment. The clinical course of 50 patients with a mean age of 29 years with a severe talus fracture between 1992 and 1997 is presented.

Treatment of sternal nonunion with the Dall-Miles cable system.

We have used this technique in two patients. One had early sternal dehiscence with presternal infection, and the other had late sternal nonunion. Uncomplicated sternal union was achieved in both patients.

A self-assembled cylindrical capsule: new supramolecular phenomena through encapsulation.

The synthesis and spectroscopic characterization of self-assembled cylindrical capsule 1a x 1a of nanometer dimensions is described. Encapsulation studies of large organic guest molecules were performed by using 1H NMR sprectroscopy in [D12]mesitylene solution. In addition to the computational (MacroModel 5.

Microsurgery costs and outcome.

Reliable information on cost and value in microsurgery is not readily available in the literature. Driving factors for cost, determinants of complications, and cost-reduction strategies have not been elucidated in this population, despite such progress in other areas of medicine. Clearly, the time-consuming and costly nature of this endeavor demands that appropriate indications and patient management be delineated; to operate proactively in this cost-conscious time, financial and outcome determinations are critical.

Implant failure of the gamma nail.

The gamma nail is a temporary implant characterised by a limited life expectancy under continuous dynamic stress. We reviewed a series of 839 patients with gamma nail stabilisation and found two fatigue fractures (0.2%) at the aperture of the distal locking holes.

Postoperative pain and subcutaneous oxygen tension.

Surgical patients randomly assigned to standard pain control had postoperative subcutaneous oxygen partial pressures that were significantly less than patients given better pain treatment. Our data suggest that control of postoperative pain is a major determinant of surgical-wound infection and should be given the same consideration as maintaining adequate vascular volume and normothermia.

Molecular Recognition within a Self-Assembled Cylindrical Host.

A change in geometry is necessary on entry into the capsule: a supramolecular associate approximately 1.8 nm long (see schematic representation), which consists of two halves stabilized by hydrogen bonds, influences the intra- and intermolecular interactions of the guest molecules encapsulated. Thus tertiary amides and anilides such as 1, which exist in solution preferably as E rotamers, are fixed in the Z conformation inside the capsule for steric reasons.

Unreamed nailing of tibial fractures with the solid tibial nail.

In 1993 a solid 7.5-mm tibial nail was developed and is composed of a wrought stainless steel alloy. In a preclinical testing series its static and dynamic mechanical properties proved to be superior to other small diameter nails.

Development and implementation of an extremity free-tissue-transfer database.

Rigorous clinical outcomes research requires accurate, complete, and standardized data. No such system is currently being used by reconstructive microsurgeons to evaluate free-tissue-transfer procedures. To facilitate collection of relevant and complete data, the authors propose a standardized format for data collection regarding these procedures.

[Borderline indications for locked intramedullary nailing of femur and tibia].

The borderline indications of locked intramedullary nailing of the femur and the tibia, based on Küntscher nailing, are defined by the location of the fracture, the associated soft tissue injury, the appearance of infection and the patient's pulmonary status. From 1975 to 1995 at the Department of Traumatology, Vienna University School of Medicine, 551 patients with 559 femoral fractures and 536 patients with 548 tibial fractures were stabilized using locked intramedullary nailing. A total of 135 (24%) proximal femoral fractures were stabilized using intramedullary locking nails in 54 cases, and using long gamma nails in 81 cases.

Soft-tissue fungal infections: surgical management of 12 immunocompromised patients.

Isolated fungal soft-tissue infections are uncommon but may cause severe morbidity or mortality among transplant recipients and other immunosuppressed patients. Twelve immunocompromised patients illustrating three patterns of infection were treated recently at the Duke University Medical Center. These groups comprised (I) locally aggressive infections, (II) indolent infections, and (III) cutaneous manifestations of systemic infection.