Scalable all-fiber coherent beam combination using digital control.

This paper describes a filled-aperture coherent beam combining (CBC) system based on locking of optical coherence via single-detector electronic-frequency tagging (LOCSET). The sensing and control architecture is implemented using a field-programmable gate array and high-bandwidth electro-optic phase modulators. The all-fiber optical configuration consists of a narrow linewidth 1560 nm seed laser separated into three channels, each containing 7 W erbium-doped fiber amplifiers. The system was demonstrated experimentally, achieving a total stabilized output power of 20 W, a combination efficiency greater than 95%, and an output RMS phase stability of λ/493. As this architecture employs an entirely digital sensing and control scheme based on LOCSET, it presents a highly scalable and cost-effective solution for CBC that is wavelength agnostic and can support an arbitrarily large number of channels.

High-Precision Quantum-Enhanced Gravimetry with a Bose-Einstein Condensate.

We show that the inherently large interatomic interactions of a Bose-Einstein condensate (BEC) can enhance the sensitivity of a high precision cold-atom gravimeter beyond the shot-noise limit (SNL). Through detailed numerical simulation, we demonstrate that our scheme produces spin-squeezed states with variances up to 14 dB below the SNL, and that absolute gravimetry measurement sensitivities between two and five times below the SNL are achievable with BECs between 10^{4} and 10^{6} in atom number. Our scheme is robust to phase diffusion, imperfect atom counting, and shot-to-shot variations in atom number and laser intensity. Our proposal is immediately achievable in current laboratories, since it needs only a small modification to existing state-of-the-art experiments and does not require additional guiding potentials or optical cavities.

All-optical low noise fiber Bragg grating microphone.

We present an all-fiber design for a microphone using a fiber Bragg grating Fabry-Perot resonator attached to a diaphragm transducer. We analytically model and verify the fiber-diaphragm mechanical interaction, using the Hänsch-Couillaud readout technique to provide necessary sensitivity. We achieved a noise-equivalent strain sensitivity of 7.1×10-12 ϵ/Hz, which corresponds to a sound pressure of 74 µPa/Hz at 1 kHz limited by laser frequency noise and yielding a signal-to-noise ratio of 47±2 dB with a 1 Pa drive at 1 kHz, in close agreement with modeled results.

External cavity diode lasers with 5kHz linewidth and 200nm tuning range at 1.55µm and methods for linewidth measurement.

Two simple external cavity diode laser designs using fibre pigtailed gain chips are tested and their properties compared with a high end DBR fibre laser. These ECDLs demonstrate a FWHM linewidth as low as 5.2kHz with a fitted Lorentzian FWHM linewidth as low as 1.6kHz. Tuning ranges of 200nm covering 1420nm to 1620nm were demonstrated. To the best of our knowledge these are the narrowest linewidth and most broadly tunable external cavity diode lasers reported to date. The improvement in linewidth is attributed to greatly enhanced acoustic isolation allowed by using fiber coupled gain chips and by replacing kinematic mounts with a pair of rotatable wedges for cavity alignment which eliminates acoustic resonances. A detailed description and discussion of techniques used to characterize the frequency noise and linewidths of these lasers is provided.

Poly(glycerol sebacate) elastomer: a novel material for mechanically loaded bone regeneration.

The selection criteria for potential bone engineering scaffolds are based chiefly on their relative mechanical comparability to mature bone. In this study, we challenge this notion by obtaining full regeneration of a rabbit ulna critical size defect by employing the elastomeric polymer, poly(glycerol sebacate) (PGS). We tested the regeneration facilitated by PGS alone, PGS in combination with hydroxyapatite particles, or PGS seeded with bone marrow stromal cells. We investigated the quantity and quality of the regenerated bone histologically, by microcomputed tomography and by four-point bending flexural mechanical testing at 8 weeks postimplantation. We conclude that the relatively lower stiffness of this biocompatible elastomer allows a load-transducing milieu in which osteogenesis, matrix deposition, and eventual bone maturation can take place. This study's results suggest that PGS elastomer is an auspicious osteoconductive material for the regeneration of bony defects. These results call for an innovative reassessment of the current art of selection for novel bone scaffold materials.

Practitioner and patient perceptions of orthodontic treatment: is the patient always right?

PURPOSE: As dentists embrace evidence-based clinical practice, we place increased emphasis on patient values. Standards like Angle Classification are not related to patient perceptions of the tangible benefits of treatment. This study quantifies the differences dentists and patients perceive in orthodontic treatment outcome. MATERIALS AND METHODS: A survey is used to quantify a patient's perception of orthodontic treatment. It was completed by 30 patients who completed treatment at the University of Pittsburgh School of Dental Medicine. Their responses were compared with the perceptions of five orthodontists, three general dentists, and two prosthodontists. RESULTS: Multivariate analysis of variance found the differences between and within the subjects to be significant at p < 0.004. Univariate analysis of variance of the initial scores showed the data to be significant at p < 0.002 and pairwise comparisons showed significant mean differences. Final score analysis of variance was significant at p < 0.001 and pairwise comparison showed significant mean differences. CONCLUSIONS: Patients and general dentists have a significantly less favorable initial perception of their dental esthetics and function when compared with orthodontists. Final scores of esthetic and functional perceptions between the patients and all three dentist groups showed significant differences, with patients perceiving the results of their treatment more favorably than practitioners. CLINICAL SIGNIFICANCE: The data herein elucidates differences in the value systems of professionals and patients. It is meant to encourage dentists to consider whether these differences justify the persistence of traditional orthodontic treatment goals or if treatment planning should incorporate consideration of each individual patient's preferences to maximize utility.

Human masseter muscle fiber type properties, skeletal malocclusions, and muscle growth factor expression.

PURPOSE: We identified masseter muscle fiber type property differences in subjects with dentofacial deformities. PATIENTS AND METHODS: Samples of masseter muscle were collected from 139 young adults during mandibular osteotomy procedures to assess mean fiber areas and percent tissue occupancies for the 4 fiber types that comprise the muscle. Subjects were classified into 1 of 6 malocclusion groups based on the presence of a skeletal Class II or III sagittal dimension malocclusion and either a skeletal open, deep, or normal bite vertical dimension malocclusion. In a subpopulation, relative quantities of the muscle growth factors IGF-I and GDF-8 gene expression were quantified by real-time polymerase chain reaction. RESULTS: Fiber properties were not different in the sagittal malocclusion groups, but were very different in the vertical malocclusion groups (P ≤ .0004). There were significant mean fiber area differences for type II (P ≤ .0004) and type neonatal-atrial (P = .001) fiber types and for fiber percent occupancy differences for both type I-II hybrid fibers and type II fibers (P ≤ .0004). Growth factor expression differed by gender for IGF-I (P = .02) and GDF-8 (P < .01). The ratio of IGF-I:GDF-8 expression associates with type I and II mean fiber areas. CONCLUSION: Fiber type properties are very closely associated with variations in vertical growth of the face, with statistical significance for overall comparisons at P ≤ .0004. An increase in masseter muscle type II fiber mean fiber areas and percent tissue occupancies is inversely related to increases in vertical facial dimension.

Self-report of latex allergy by patients visiting a dental clinic.

BACKGROUND: The prevalence of latex allergy among dental patients is not known, although it has been increasing in the population since 1982, when the use of gloves was expanded to prevent the transmission of infectious diseases. METHODS: A retrospective cross-sectional study was undertaken of 1,798 electronic health records (EHRs) of new clinic patients who registered at the University of Pittsburgh School of Dental Medicine (SDM) dental clinic between January and June 2010. Data extracted from the EHRs included age, gender, and a history of a previous latex reaction, asthma, or allergy to penicillin. RESULTS: A previous reaction to latex was reported by 59 patients (3.3%). Women were almost three times more likely to report this (4.7% versus 1.6%, P = 0.0005). Histories of asthma or penicillin allergy in women were significantly associated with latex allergy (P = 0.0005 and P = 0.0001, respectively). CONCLUSIONS: The reported rate of a previous reaction to latex in this patient sample was higher than that of the general population. This may, in part, be related to repeated exposures to latex-containing gloves. CLINICAL IMPLICATIONS: Practitioners are increasingly likely to encounter patients who have had a reaction to latex. Non-latex products must be available for these patients, who are more likely to be women and individuals with asthma or an allergy to penicillin.

Intracellular trafficking pathways involved in the gene transfer of nano-structured calcium phosphate-DNA particles.

Nano-structured calcium phosphate (NanoCaP) particles have been proven to be a powerful means of non-viral gene delivery. In order to better understand the mechanisms through which NanoCaPs-mediated mammalian cell transfection is achieved, we have sought to define the intracellular trafficking pathways involved in the cellular uptake and intracellular processing of these particles. Previous work has indicated that NanoCaP-DNA complexes are most likely internalized via endocytosis, however the subsequent pathways involved have not been determined. Through the use of specific inhibitors, we show that endocytosis of NanoCaP particles is both clathrin- and caveolae-dependent, and suggest that the caveolaer mechanism is the major contributor. We demonstrate colocalization of NanoCaP-pDNA complexes with known markers of both clathrin-coated and caveolar vesicles. Furthermore, through the use of quantitative flow cytometry, we present the first work in which the percent internalization of CaP-DNA complexes into cells is quantified. The overall goal of this research is to foster the continued improvement of NanoCaP-based gene delivery strategies.

Dentin matrix protein 1 (DMP1) signals via cell surface integrin.

Dentin matrix phosphoprotein 1 (DMP1) is a non-collagenous, acidic extracellular matrix protein expressed chiefly in bone and dentin. We examined the DMP1 ability to engage cell-surface receptors and subsequently activate intracellular signaling pathways. Our data indeed show that the presence of extracellular DMP1 triggers focal adhesion point formation in human mesenchymal stem cells and osteoblast-like cells. We determine that DMP1 acts via interaction with αvß3 integrin and stimulates phosphorylation of focal adhesion kinase. Further biochemical characterization confirms the activation of downstream effectors of the MAPK pathways, namely ERK and JNK, after DMP1 treatment. This activation is specifically inhibitable and can also be blocked by the addition of anti-αvß3 integrin antibody. Furthermore, we show that extracellular treatment with DMP1 stimulates the translocation of phosphorylated JNK to the nucleus and a concomitant up-regulation of transcriptional activation by phosphorylated c-Jun. The evidence presented here indicates that DMP1 is specifically involved in signaling via extracellular matrix-cell surface interaction. Combined with the published DMP1-null data (Feng, J. Q., Ward, L. M., Liu, S., Lu, Y., Xie, Y., Yuan, B., Yu, X., Rauch, F., Davis, S. I., Zhang, S., Rios, H., Drezner, M. K., Quarles, L. D., Bonewald, L. F., and White, K. E. (2006) Nat. Genet. 38, 1310-1315) it can be hypothesized that DMP1 could be a key effector of ECM-osteocyte signaling.

Effect of a simulation educational intervention on knowledge, attitude, and patient transfer skills: from the simulation laboratory to the clinical setting.

INTRODUCTION: Musculoskeletal injury in the workplace is the primary work-related factor in loss of nursing personnel from the workforce. Moving or transferring patients is the dominant contributing event. A simulation educational approach has not been closely studied in this area but may have advantages over traditional approaches. Specific aims were to (1) evaluate the effect of a simulation intervention on success of patient transfers in a clinical setting and (2) measure change in participants' knowledge and attitude as a result of the intervention. METHODS: A prospective, observational, longitudinal design was used. Baseline patient transfer observations were conducted on control and intervention units. An optimum task set was developed using hierarchical task analysis methods. Subjects (N = 71) completed pre- and postintervention knowledge and attitude assessments. The intervention consisted of simulated patient transfers using a mannequin, education, and training, followed by repeated simulated transfers using a mannequin with debriefing. Observations of patient transfers in patient care areas were repeated at 4 and 12 weeks. RESULTS: Patient transfer success improved from 66% at baseline to 88% at the 4-week measurement point (t = 7.447, P ≤ 0.0004). At 12 weeks, transfer success had decreased to 71%, with addition of new employees between weeks 4 and 12 confounding the 12-week measurement. Knowledge improved from a baseline of 65% to 95% postsimulation intervention (z = -6.634, P ≤ 0.0004). Attitude change was also evaluated with significance seen with 12 of 15 items (P ≤ 0.05). CONCLUSIONS: A simulation intervention was successful in significantly improving knowledge and changing subject perceptions with regard to this task. Skills acquired through simulation successfully transferred to the clinical setting. Improvement in success for patient moves not trained in the simulation laboratory suggests that acquired skills were generalizable and supports application to different settings.

Impact of angiolymphatic and pleural invasion on surgical outcomes for stage I non-small cell lung cancer.

BACKGROUND: In the current study, we analyze the impact of pathologic variables (angiolymphatic invasion, visceral pleural invasion, and tumor inflammation) upon survival outcomes after segmentectomy or lobectomy for stage I non-small cell lung cancer. METHODS: A retrospective review was made of 524 patients undergoing resection of stage I non-small cell lung cancer through either lobectomy (n = 285) or anatomic segmentectomy (n = 239). Primary outcome variables include recurrence-free and overall survival. Statistical comparisons were performed with the t test and Fisher's exact test. Recurrence-free and overall survival was estimated utilizing the Kaplan-Maier method, with statistical significance being assessed by the log rank test. RESULTS: The incidence of angiolymphatic invasion, visceral pleural invasion, and degree of tumor inflammation, as well as morbidity, mortality, and length of stay were similar between segmentectomy and lobectomy. The presence of angiolymphatic invasion or visceral pleural invasion was associated with a significant decrease in recurrence-free survival (p < 0.01) and overall survival (p < 0.01). There was a trend for decreased recurrence with increasing tumor inflammation (mild versus severe, p = 0.066). There was no difference in rates of local recurrence (5.6% versus 7.9%, p = 0.59) or survival (p = 0.455) between segmentectomy and lobectomy, respectively. CONCLUSIONS: Angiolymphatic and visceral pleural invasion appear to be strong adverse prognostic factors after anatomic resection by segmentectomy or lobectomy for stage I non-small cell lung cancer. Overall survival is not affected by the extent of anatomical surgical resection. These data may have implications regarding the role of adjuvant systemic therapy after surgical resection for tumors with these pathologic characteristics.

Cytochrome c oxidase deficiency in human posterior cricoarytenoid muscle.

BACKGROUND: Mitochondrial alterations occur in skeletal muscle fibers throughout the normal aging process, resulting from increased accumulation of reactive oxide species (ROS). These result in respiratory chain abnormalities, which decrease the oxidative capacity of muscle fibers, leading to decreased contractile force, sarcopenia, or fiber necrosis. Intrinsic laryngeal muscles are a cranial muscle group that possesses some distinctive genotypic, phenotypic, and physiologic properties. Their susceptibility to mitochondrial alterations resulting from biological processes that increase levels of oxidative stress may be one of these distinctive characteristics. OBJECTIVES: The incidence of cytochrome c oxidase (COX) deficiency (COX(-)) was determined in human posterior cricoarytenoid (PCA) muscle when compared with the human thyrohyoid (TH) muscle, an extrinsic laryngeal muscle that served as "control" muscle. Ten PCA and 10 TH muscles were harvested postlaryngectomy from 10 subjects ranging in age from 55 to 86 years. Differences in COX(-) were compared within and between muscle types using tissue section staining and standard morphometric analysis. RESULTS AND CONCLUSIONS: COX(-) fibers were identified in both the PCA and TH muscles. The PCA muscle had 10 times as may affected fibers as the TH muscle, with significant differences in COX(-) found between muscle type and fiber type (P=0.003). Almost all of this effect was the result of elevated levels of COX(-) in type I fibers from the PCA muscle (P=0.002) that showed a strong positive correlation with increased age. These results suggest that increased mitochondrial alterations may occur in the PCA muscle during normal aging.

Who will manage American patients with diabetes? Residents' career preferences and perceptions of diabetes care.

OBJECTIVE: To identify the factors that encourage or discourage internal medicine and pediatric residents regarding specializing in endocrinology with a focus on diabetes. METHODS: We conducted an electronic survey of internal medicine and pediatric residents using a $10 participation incentive. A total of 653 residents responded to the survey (estimated response rate of 9.2%)-626 from residency programs that were contacted for our survey and 27 from referrals. RESULTS: Among internal medicine and pediatric residents surveyed, 39 respondents (6.0%) planned to specialize in endocrinology, and 27 of these (4.1% of total respondents) planned to focus on diabetes. "Intellectual satisfaction," "emotional satisfaction," and "work-life balance" were identified by respondents as the most important factors in their choice of a specialty, with ratings of 5.5, 5.4, and 5.3 on a 6-point Likert scale. Among these factors identified as most important to a medical career, endocrinology with a focus on diabetes scored poorly with regard to intellectual and emotional satisfaction but received high ranking with regard to lifestyle. With regard to other factors, endocrinology was rated negatively on "compensation," "number of procedures," and "patient adherence to prescribed treatment." Exposure to diabetes during training had no major influence on the decision to enter endocrinology. CONCLUSION: Endocrinology with a focus on diabetes care is not an attractive specialty for most internal medicine and pediatric residents. Therefore, new strategies to attract residents to the field of diabetes care are needed.

Assessing the need for anesthesia and sedation services in Kuwaiti dental practice.

The objective of this study was to examine the public health relevance of the prevalence of dental fear in Kuwait and the resultant barrier that it creates regarding access to dental care. The study analysis demonstrated a high prevalence of dental fear and anxiety in the Kuwaiti population and a perceived need for anesthesia services by dental care providers. The telephone survey of the general population showed nearly 35% of respondents reported being somewhat nervous, very nervous, or terrified about going to the dentist. In addition, about 36% of the population postponed their dental treatment because of fear. Respondents showed a preference to receive sedation and anesthesia services as a means of anxiety relief, and they were willing to go to the dentist more often when such services were available. People with high fear and anxiety preferred to receive some type of medication to relieve their anxiety. In conclusion, the significance and importance of the need for anesthesia services to enhance the public health of dental patients in Kuwait has been demonstrated, and improvements are needed in anesthesia and sedation training of Kuwaiti dental care providers.

Overcoming barriers to tobacco cessation counselling in dental students.

PURPOSE: Tobacco use screening and brief intervention is recognised as an effective available preventive health service; yet, this service is still not routinely offered to dental patients by clinicians, despite dental schools generally providing some form of tobacco cessation counselling (TCC) by including it in their dental curriculum. A pilot study was therefore carried out to more clearly identify barriers that prevented the delivery of this service to tobacco-using patients at the University of Pittsburgh School of Dental Medicine and educational initiatives that might overcome these barriers. MATERIALS AND METHODS: A survey of faculty and students asked participants to rank their knowledge, preparation and comfort levels in performing TCC as well as their belief as to the importance of such training in the dental curriculum. Six months following training and practice opportunities, surveys were again administered to participants. Each individual's pre- and post-TCC training surveys were reviewed and difference in response to each item was calculated. RESULTS: The results of the present study show that students feel more prepared, that the time required to provide TCC was less than anticipated and that training in TCC is an important part of dental education to a greater extent after the pilot study than before. CONCLUSIONS: TCC training and practice opportunities for clinical application were effective in this pilot study in improving students' attitudes towards cited barriers.

In-vitro evaluation of frictional resistance with 5 ligation methods and Gianelly-type working wires.

INTRODUCTION: Numerous in-vitro studies have been conducted with various archwire-ligation combinations to evaluate the effect of wire size and ligation method on frictional resistance. The aim of this in-vitro study was to compare the frictional resistance during sliding mechanics with Gianelly-type stainless steel working wires, Leone slide ligature, conventional elastic ligature, and stainless steel (SS) ligature, and a conventional bracket and active and passive self-ligating brackets. METHODS: Three ligation methods with Victory (V) brackets--Leone (VLeone), conventional (regular) elastic (VReg), and SS (VSS)--were used with standard SS brackets, and 2 self-ligating brackets--Damon MX (Ormco/"A", St. Paul, Minn) (DMX) and In-Ovation R (GAC Intl., Bohemia, NY)--were used with 2 rectangular SS wires (0.016 x 0.022 and 0.018 x 0.022 in). Therefore, 5 ligation methods and 2 wire sizes were evaluated with respect to their effects on frictional resistance. RESULTS: No statistically significant differences were found between the SS ligation method and DMX (neither produced measurable static friction). For the wire size 0.016 x 0.022-in SS, the DMX and SS produced significantly less static friction than the In-Ovation R, VLeone, and VReg. The In-Ovation R produced significantly less friction than both the VLeone and VReg, whereas the VLeone produced significantly less friction than the VReg. For the wire size 0.018 x 0.022-in SS, the overall results were the same, except that the In-Ovation R produced significantly more friction than the VLeone. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (except DMX and VSS, which showed no measurable friction at either wire size). CONCLUSIONS: The Leone slide ligature showed less friction at both wire sizes than VReg; however, it showed significantly more friction than both DMX and VSS. DMX and VSS brackets produced no measurable friction with either 0.016 x 0.022-in or 0.018 x 0.022-in wires. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (excluding DMX and VSS, which showed no measurable friction at either wire size).

Complications associated with anesthesia administered for dental treatment.

This assessment sought to identify and quantify complications that occur with anesthesia administration during dental treatment of consecutive patients who received care through the University of Pittsburgh School of Dental Medicine's (UPSDM) Department of Anesthesiology. This prospective study was completed by participating anesthesia caregivers at the UPSDM as a case-by-case evaluation. A standardized form delineating possible complications was used to collect data following 286 consecutive outpatient anesthetic cases administered within the UPSDM. After statistical analysis of five types of administered anesthesia, the overall complication rate was 22.4% in 286 cases. All of the complications were considered to be mild (90.6%) or moderate (9.4%); there were no reports of severe complications. The complications encountered most frequently were airway obstruction (18 reports) and occurrence of nausea/vomiting (12 reports). ASA classification, anesthetic technique, pre-existing medical findings, and the type of dental procedure performed all were variables that were found to affect the incidence of anesthesia-related complications. The overall complication rate from anesthesia administered during dental care is similar to or less than that reported within the hospital operating system environment.

Complications associated with anesthesia administration for dental treatment in a special needs clinic.

The goal of this study was to identify and quantify complications occurring with the administration of anesthesia for the dental treatment of patients with special needs. Anesthesia providers completed a standardized evaluation form, delineating possible complications for 202 consecutive ambulatory patients receiving anesthesia in a special needs clinic. Statistical analysis of four types of administered anesthesia showed that the overall complication rate was 23.8%. Evaluation of the data showed complications that were considered either mild (95.8%), or moderate (4.2%), while no reports of severe complications occurred. Airway obstruction and nausea/vomiting were the most frequently encountered complications. Variables found to affect the incidence of anesthetic complications included ASA classification, anesthetic technique, Mallampati airway classification, and type of dental procedure performed. An evaluation of the results of the study showed that the majority of complications that occurred with anesthesia during care of patients with special needs were mild and did not lead to severe adverse events. Our findings show that anesthesia administered during dental treatment for patients with special needs is safe and effective.