Atom Interferometry in a Warm Vapor.

We demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. This interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.

UHV STM I(V) and XPS studies of aryl diazonium molecules assembled on Si(111).

Molecular layers formed from 4-trifluoromethylbenzenediazonium tetrafluoroborate and 4-Methylbenzenediazonium tetrafluoroborate have been assembled on H-passivated Si(111) and studied by UHV STM and XPS. STM imaging shows well-developed Si(111) step edges and terraces both on Si(111):H and Si(111) substrates covered with a molecular layer. STM I(V) data acquired at different tip-substrate separations reveals a factor of approximately 10 enhancement in current for positive bias voltage when current flows through the 4-trifluoromethyl molecule when compared to the 4-methyl variant. The observed current enhancement in I(V) can be understood by comparing the projected density of states of the two molecule-Si systems calculated using a density functional theory local density approximation after geometry optimization was performed via the conjugate gradient method. XPS data independently confirm that H-passivated Si(111) remains oxygen free for short exposures to ambient conditions and provide evidence that the molecules chemically react with the silicon surface.

Respiratory control during independent lung ventilation.

We describe the case of a lung transplant patient with primary graft failure and an emphysematous native lung, who displayed different respiratory rates between the transplanted lung and the native lung. Inflation of the native lung delayed the next inspiratory effort relative to inflation of the denervated transplanted lung. Synchronous inflation of both lungs required more pressure in each lung than when that lung was inflated with the contralateral lung near functional residual capacity, suggesting the two lungs compete for space within the thoracic cavity.

Thermally responsive dendrons and dendrimers based on reversible furan-maleimide Diels-Alder adducts.

[reaction: see text]. Benzyl aryl ether dendrons and dendrimers containing thermally reversible furan-maleimide Diels-Alder adducts were prepared up to the third generation. The covalent cleavage and reassembly of the dendrons and dendrimers were evaluated by 1H NMR.

Early versus delayed treatment of enchondroma.

Enchondromata are among the most common primary neoplasms of the hand, which often present as pathologic fractures. The purpose of this study is to determine whether there are any differences between cases in which both fracture and tumor were treated primarily and those in which tumor treatment was delayed. We reviewed a total of 16 cases; six were treated immediately, 10 were delayed. The immediate treatment group had four complications, the delayed group had one. The theoretical advantages of immediate treatment include a decrease in both the period of disability and delay of definitive diagnosis. This study supports that supposition. However, we did note a significantly higher complication rate for the immediate treatment group (67% versus 10%). Our results indicate that while there is an apparent decreased disability period, there may be reason for caution in immediate treatment of both the fracture and the tumor in pathologic fractures through enchondromata.

Hand function following single ray amputation.

We retrospectively studied primary and reconstructive single ray resection at 16 to 150 months after surgery (median, 41 months) in 25 patients (18 males) whose average age was 28 years. Cases were reviewed 16 to 154 months after surgery (median, 41 months). The injuries involved 14 dominant and 11 nondominant hands. Twelve patients had primary ray resection (< or =2 weeks after injury) and 13 had secondary/reconstructive amputation of 18 border and 7 central digits. Examinations and functional testing by Minnesota rate of manipulation and timed grooved pegboard tests were done and x-rays were reviewed. The majority of patients were subjectively satisfied with the appearance and function of the hand. Patients lost an average of 13 weeks of work (range, 2-24 weeks); those with primary resection were out of work 9 weeks (range, 2-17 weeks) and patients who had secondary resection lost a total of 16 weeks of work (range, 7-24 weeks). Twenty-one of the 25 patients returned to their preinjury occupation. Evaluation of nonwork plus settled workers' compensation cases versus nonsettled compensation/litigation cases showed that there were statistically significant differences in grip strength, key pinch, oppositional pinch, and Minnesota rate of manipulation test results. Primary ray removal limits the total costs associated with injury and disability; unsettled compensation/litigation issues produce statistically disparate and otherwise physically inexplicable differences.

Pressure changes in Guyon's canal after carpal tunnel release.

We measured pressure changes in Guyon's canal and the carpal tunnel before and after endoscopic (11 cases) and open (10) carpal tunnel release. We found that release of the flexor retinaculum by endoscopic and open techniques measurably decreased pressure in both the carpal tunnel and Guyon's canal. This study provides an explanation for relief of ulnar tunnel syndrome symptoms following carpal tunnel release and may indicate that carpal tunnel release alone may be sufficient to provide symptomatic relief for most patients with carpal and ulnar tunnel syndromes.

Long-term results of carpal tunnel release.

To determine the long-term results of carpal tunnel release, we retrospectively reviewed 60 cases, an average of 5.5 years after surgery. 87% reported a good or excellent overall outcome; the average time to maximum improvement of symptoms was 9.8 months. However, 30% reported poor to fair strength and long-term scar discomfort, and 57% noted a return of some pre-operative symptoms, most commonly pain, beginning an average of 2 years after surgery. We found no correlation between pre-operative symptoms or extent of surgical dissection (internal neurolysis) and outcome. Carpal tunnel syndrome was job related in 42%; of these, 26% changed from heavy to lighter work following surgery. Although occupational cases were slower to improve and remained off work longer, the long-term subjective results were the same for both groups. We found significant morbidity from the surgical scar and decreased strength, and often considerable delay until ultimate improvement, especially in patients with job-related carpal tunnel syndrome.

Severe fractures of the distal radius: effect of amount and duration of external fixator distraction on outcome.

Although severe intra-articular fractures of the distal radius are often treated with external fixation/distraction, little attention has been devoted to the amount and duration of fixator distraction required to maximize outcome. To determine these effects, we conducted a retrospective study of 26 patients whose primary treatment was external fixation/distraction. Patients were evaluated by chart review, questionnaire, x-ray films, and physical examination an average of 104 weeks after injury. The carpal height index was used to quantify distraction. Scores for pain, function, wrist motion, and grip strength and the total score were adversely affected in proportion to the increase in carpal height index by distraction. Outcome was adversely affected as the duration of distraction increased. Motion scores were affected most. Overall, patients recovered at least 75% of motion and grip strength, and 85% attained New York Orthopedic Hospital grades of good or excellent. These are the first data to show that there are potential adverse effects from increasing amounts of distraction and prolonged use of the external fixator.

Tenosynovial injection for carpal tunnel syndrome.

Although local steroid injection into the tenosynovium is a frequent treatment for carpal tunnel syndrome, it involves some risk and is not always effective. We simulated injection on 16 fresh cadaver forearms, instilling 1 ml (group 1) or 2 ml (group 2) of methylene blue at 1 cm or 3 cm proximal to the most distal wrist crease. Passive flexion and extension were simulated 2 minutes after injection by application of traction to the appropriate digital tendons. Specimens were dissected under loupe magnification from midpalm to midforearm, dye diffusion was quantified and photographed, sections of the carpal tunnel and contents were graded for presence of dye, and average values were determined for each of the four groups. Diffusion of dye was best in group 2B in which 2 ml was injected 3 cm proximal to the distal wrist flexion crease.

Scaphocapitate intercarpal arthrodesis.

We reexamined 17 patients at 16 to 57 months (average, 23.4 months) after scaphocapitate arthrodesis. Surgery was performed for treatment of rotary scaphoid instability, isolated arthrosis, resistant scaphoid nonunion, and prevention of carpal collapse in Kienböck's disease. Scaphocapitate fusion with autogenous bone grafting was used to bridge carpal spaces. Two patients had nonunion of the scaphocapitate arthrodesis, which required reoperation. Seven patients experience persistent pain with heavy use; of these, two changed occupations and one remains disabled. Compared with the nonoperated side, scaphocapitate fusion reduced wrist extension an average of 28 degrees, flexion 40 degrees, radial deviation 14 degrees, and ulnar deviation 14 degrees. The greatest loss was of radial deviation. Static grip reached a average of 74% of the nonoperated side. Dynamic power regained 73%, and dynamic endurance measured 105% of the nonoperated side. Motion peaked after six months on average, and then reached a plateau. Static strength peaked at 11 months and then stabilized.