Extreme shifts in pyrite sulfur isotope compositions reveal the path to bonanza gold.

Pyrite is the most common sulfide mineral in hydrothermal ore-forming systems. The ubiquity and abundance of pyrite, combined with its ability to record and preserve a history of fluid evolution in crustal environments, make it an ideal mineral for studying the genesis of hydrothermal ore deposits, including those that host critical metals. However, with the exception of boiling, few studies have been able to directly link changes in pyrite chemistry to the processes responsible for bonanza-style gold mineralization. Here, we report the results of high-resolution secondary-ion mass spectrometry and electron microprobe analyses conducted on pyrite from the Brucejack epithermal gold deposit, British Columbia. Our δ34S and trace element results reveal that the Brucejack hydrothermal system experienced abrupt fluctuations in fluid chemistry, which preceded and ultimately coincided with the onset of ultra-high-grade mineralization. We argue that these fluctuations, which include the occurrence of extraordinarily negative δ34S values (e.g., -36.1‰) in zones of auriferous, arsenian pyrite, followed by sharp increases of δ34S values in syn-electrum zones of nonarsenian pyrite, were caused by vigorous, fault valve-induced episodic boiling (flashing) and subsequent inundation of the hydrothermal system by seawater. We conclude that the influx of seawater was the essential step to forming bonanza-grade electrum mineralization by triggering, through the addition of cationic flocculants and cooling, the aggregation of colloidal gold suspensions. Moreover, our study demonstrates the efficacy of employing high-resolution, in situ analytical techniques to map out individual ore-forming events in a hydrothermal system.

Automatic Detection of Dyspnea in Real Human-Robot Interaction Scenarios.

A respiratory distress estimation technique for telephony previously proposed by the authors is adapted and evaluated in real static and dynamic HRI scenarios. The system is evaluated with a telephone dataset re-recorded using the robotic platform designed and implemented for this study. In addition, the original telephone training data are modified using an environmental model that incorporates natural robot-generated and external noise sources and reverberant effects using room impulse responses (RIRs). The results indicate that the average accuracy and AUC are just 0.4% less than those obtained with matched training/testing conditions with simulated data. Quite surprisingly, there is not much difference in accuracy and AUC between static and dynamic HRI conditions. Moreover, the beamforming methods delay-and-sum and MVDR lead to average improvement in accuracy and AUC equal to 8% and 2%, respectively, when applied to training and testing data. Regarding the complementarity of time-dependent and time-independent features, the combination of both types of classifiers provides the best joint accuracy and AUC score.

Repairing attachment in families with depressed adolescents: A task analysis.

AIMS: This exploratory pilot study (N = 3 sessions, 793 speech units) used task analysis to refine an early model of the attachment task in attachment-based family therapy (ABFT). The attachment task aims to repair long-standing parent-adolescent relational ruptures that inhibit parents from being a resource for adolescents recovering from depression and/or suicidality. METHODS: Video recordings of three attachment task sessions with strong adherence to the model were selected for intensive study. Two sessions were rated as successful (i.e., attachment was repaired) and one as unsuccessful (i.e., attachment repair did not occur). Sessions were then coded using Structural Analysis of Social Behavior (SASB). RESULTS: The current SASB analysis provided empirical support for our previous clinical impression that the task involves three parts: (I) adolescent disclosure of attachment rupture, (II) parent disclosure, and (III) a more mutual conversation. SASB also provided insights into more subtle elements of the model. CONCLUSION: Successful attachment sessions were associated with high parent affiliation and autonomy-both while affirming the adolescent's story and when disclosing their own experience. Unsuccessful task attempts were associated with parental enmeshment and hostile belittling, blaming, and distancing. An enhanced model of ideal parent behaviors during the attachment task is offered, including space for parent disclosure-perhaps even apology-that is both warm and independent, leading to a more mutual parent-adolescent conversation. Clinically, the findings support the importance of the therapist focusing on the process and quality of parent-child interactions to facilitate attachment repair.

Speedy light focusing through scattering media by a cooperatively FPGA-parameterized genetic algorithm.

We developed an accelerated Genetic Algorithm (GA) system based on the cooperation of a field-programmable gate array (FPGA) and the optimized parameters that enables fast light focusing through scattering media. Starting at the searching space, which influences the convergence of the optimization algorithms, we manipulated the mutation rate that defines the number of mutated pixels on the spatial light modulator to accelerate the GA process. We found that the enhanced decay ratio of the mutation rate leads to a much faster convergence of the GA. A convergence-efficiency function was defined to gauge the tradeoff between the processing time and the enhancement of the focal spot. This function allowed us to adopt the shorter iteration number of the GA that still achieves applicable light focusing. Furthermore, the accelerated GA configuration was programmed in FPGA to boost processing speed at the hardware level. It shows the ability to focus light through scattering media within a few seconds, 150 times faster than the PC-based GA. The processing cycle could be further promoted to a millisecond-level with the advanced FPGA processor chips. This study makes the evolution-based optimization approach adaptable in dynamic scattering media, showing the capability to tackle wavefront shaping in biological material.

Boron-oxygen complex yields n-type surface layer in semiconducting diamond.

Diamond is a wide-bandgap semiconductor possessing exceptional physical and chemical properties with the potential to miniaturize high-power electronics. Whereas boron-doped diamond (BDD) is a well-known p-type semiconductor, fabrication of practical diamond-based electronic devices awaits development of an effective n-type dopant with satisfactory electrical properties. Here we report the synthesis of n-type diamond, containing boron (B) and oxygen (O) complex defects. We obtain high carrier concentration (∼0.778 × 1021 cm-3) several orders of magnitude greater than previously obtained with sulfur or phosphorous, accompanied by high electrical conductivity. In high-pressure high-temperature (HPHT) boron-doped diamond single crystal we formed a boron-rich layer ∼1-1.5 µm thick in the {111} surface containing up to 1.4 atomic % B. We show that under certain HPHT conditions the boron dopants combine with oxygen defects to form B-O complexes that can be tuned by controlling the experimental parameters for diamond crystallization, thus giving rise to n-type conduction. First-principles calculations indicate that B3O and B4O complexes with low formation energies exhibit shallow donor levels, elucidating the mechanism of the n-type semiconducting behavior.

Additional muscular slip of the flexor digitorum longus muscle to the fifth toe.

Despite the fact that there are numerous reports on muscular variations in the sole of the foot, routine dissection in a formaldehyde-fixed cadaver revealed an accessory flexor digiti quinti muscle, which to the best of our knowledge is a very unusual variant. This was in the form of a slender, 38 mm long muscular slip, with a proximal and distal tendon extending from the common flexor digitorum longus tendinous plate out to the distal phalanx of the fifth toe. An associated finding was the absence of the musculotendinous portion of the flexor digitorum brevis to the same toe. A developmental explanation for this variation is presented. Clinical implications with regard to this anatomical condition may result in clawing of the fifth toe.

Technique tip: Simultaneous first metatarsal lengthening and metatarsophalangeal joint fusion for failed hallux valgus surgery with transfer metatarsalgia.

BACKGROUND: Failed hallux valgus surgery may result in residual or recurrent hallux valgus, and as well transfer metatarsalgia. The present technical tip concerns the combination of fusion of the first metatarsophalangeal (MTP) joint and lengthening of the first metatarsal (MT) through a scarf osteotomy. MATERIALS AND METHODS: Six patients underwent the presented technique, all for the indication of failed hallux valgus surgery with shortening of the first MT and degenerative changes in the 1st MTP joint. RESULTS: Follow-up at six months revealed all patients had complete healing of the osteotomy and arthrodesis sites. They were all asymptomatic and fully active, completely satisfied with the outcome. CONCLUSIONS: Combined fusion of the first MTP joint and lengthening of the first MT through a scarf osteotomy results in an excellent outcome in patients with failed hallux valgus surgery with shortening of the first MT and degenerative changes in the 1st MTP joint.

Treatment challenges associated with bone echinococcosis.

OBJECTIVES: In this literature review, we concentrate on epidemiology and therapy of osseous echinococcosis, with an emphasis on the recurrence risk. METHODS: Literature review 1930-2012. RESULTS: We retrieved 200 publications based upon single case reports or case series, mostly from resource-poor settings. Among the 721 rural patients (22% females; median age 37 years), 60% of all reported cases were from the Mediterranean region and almost all patients were immune competent. Echinococcus granulosus was identified as the most frequent species. Most infections involved a single bone (602/721; 83%) and often the spine (321 cases; 45%). In eight cases (8/702; 1%), a secondary bacterial surgical site infection was reported. Surgical intervention was performed in 702 cases (97%), with single intervention in 687 episodes (95%). Complete excision of the lesion was possible in only 117 episodes (16%). Albendazole was by far the most frequently used agent in monotherapy with various dosages, while mebendazole in monotherapy was less frequent (32 cases). The median duration of antihelminthic therapy was 6 months (range 0.7-144 months). There were 124 recurrences (17%) after a median delay of 2 years (range 0.4-17 years). In multivariate analysis, the presence of visceral organ involvement increased the odds of recurrence by 5.4 (95% CI 3.1-9.4), whereas the number of surgical interventions, the duration of antihelminthic therapy or the use of hypertonic saline did not influence recurrence. CONCLUSIONS: Bone echinococcosis is a rare parasitic disease. While treatment modalities vary considerably, combined surgical and medical approaches are the standard of care with a 17% risk of recurrence.

A unified beamforming and source separation model for static and dynamic human-robot interaction.

This paper presents a unified model for combining beamforming and blind source separation (BSS). The validity of the model's assumptions is confirmed by recovering target speech information in noise accurately using Oracle information. Using real static human-robot interaction (HRI) data, the proposed combination of BSS with the minimum-variance distortionless response beamformer provides a greater signal-to-noise ratio (SNR) than previous parallel and cascade systems that combine BSS and beamforming. In the difficult-to-model HRI dynamic environment, the system provides a SNR gain that was 2.8 dB greater than the results obtained with the cascade combination, where the parallel combination is infeasible.

Dense hydrated Mg-silicates in diamond: Implications for transport of H2O into the mantle.

Water in Earth's upper mantle is a minor and yet critically important component that dictates mantle properties such as strength and melting behavior. Minerals with stoichiometric water, such as those of the humite group, are important yet poorly characterized potential reservoirs for volatiles in the upper mantle. Here, we report observation of hydroxyl members of the humite group as inclusions in mantle-derived diamond. Hydroxylchondrodite and hydroxylclinohumite were found coexisting with olivine, magnesiochromite, Mg-bearing calcite, dolomite, quartz, mica, and a djerfisherite-group mineral in a diamond from Brazil. The olivine is highly forsteritic (Mg# 97), with non-mantle-like oxygen isotope composition (δ18O +6.2‰), and is associated with fluid inclusions and hydrous minerals-features that could be inherited from a serpentinite protolith. Our results constitute direct evidence for the presence of deserpentinized peridotitic protoliths in subcratonic mantle keels, placing important constraints on the stability of hydrous phases in the mantle and the origin of diamond-forming fluids.

Risk factors for dislocation arthropathy after Latarjet procedure: a long-term study.

PURPOSE: The purpose of this study was to analyse the long-term incidence of dislocation arthropathy after a modified Latarjet procedure for glenohumeral instability. METHODS: Long-term follow-up information was obtained from a consecutive series of patients who had undergone a modified Latarjet procedure by one surgeon between 1986 and 1999. Multivariable regression analysis was performed to examine the relation between the development of a dislocation arthropathy and patients and surgery-related factors. RESULTS: There were 117 patients (117 shoulders) for evaluation, (35 women and 82 men) with a mean age 28.4 ± 8.5 (range, 16-55). The mean follow-up was 16.2 years (range, ten to 22.2 years). Signs of dislocation arthropathy were found in 36 % of patients, graded as Samilson 1 in 30 %, Samilson 2 in 3 %, and 3 % Samilson 3 in 3 % of patients. Risk factors for dislocation arthropathy included surgery in patients older than 40 years of age (64.3 vs. 34.4 %; adjusted RR 2.2, 95 % CI 1.7-2.9) and lateral positioning of the transferred coracoid process in relation to the glenoid rim (82.4 vs. 30.4 %; adjusted RR 2.3, 95 % CI 1.7-3.2). Patients with hyperlaxity developed less dislocation arthropathy (15 vs. 42.5 %; adjusted RR 0.4, 95 % CI 0.1-0.95). CONCLUSION: The development of dislocation arthropathy after the Latarjet procedure remains a source of concern in the long term. It correlates with surgery after the age of 40 and lateral coracoid transfer in relation to the glenoid rim. On the other hand, hyperlaxity seems to have a protective effect on the development of dislocation arthropathy.

Remission rate of implant-related infections following revision surgery after fractures.

PURPOSE: In contrast to a large amount of epidemiological data regarding the incidence of implant infections after fracture management, surprisingly few have been published concerning the success of their treatment. METHODS: This was a single-centre cohort study at Geneva University Hospitals from 2000 to 2012 investigating the remission rates of orthopaedic implant infections after fracture repair and associated variables. RESULTS: A total of 139 episodes were included: There were 51 women (37%) and 28 immunosuppressed (20%) patients with a median age and American Society of Anaesthesiologists (ASA) score of 51 years and 2 points, respectively. The infected implants were plates (n = 75, 54 %), nails (24, 17%), wires (20), screws (10), cerclage cables or wires (3), hip screws (4) or material for spondylodesis (3). A pathogen was identified in 135 (97%) cases, including Staphylococcus aureus (73, 52%), coagulase-negative staphylococci (20), streptococci (7) and 19 Gram-negative rods. All patients underwent antibiotic treatment, and 128 (92%) remained in remission at a median follow-up time of 2.6 years (range one to 13 years). In multivariate logistic regression analysis, the plate infections were significantly associated with lower remission rates [65/75, 87%, odds ratio (OR) 0.1, 95% confidence interval (CI) 0.01-0.90]. No associations were found for gender, age, immune status, ASA score, additional surgical interventions (OR 0.4, 95% CI 0.1-4.1) or duration of antibiotic treatment (OR 1.0, 95% CI 0.98-1.01). CONCLUSIONS: Among all infected and removed orthopaedic implants, plates were associated with slightly lower remission rates, while the overall treatment success exceeded 90%. The duration of antibiotic therapy did not alter the outcome.

Risk factors for post-traumatic osteoarthritis of the ankle: an eighteen year follow-up study.

PURPOSE: Long-term studies evaluating risk factors for development of ankle osteoarthritis (OA) following malleolar fractures are sparse. METHODS: We conducted a retrospective cohort study including consecutive patients treated by open reduction and internal fixation for malleolar fracture between January 1988 and December 1997. Perioperative information was obtained retrospectively. Patients were evaluated clinically and radiographically 12-22 years postoperatively. Radiographic ankle OA was determined on standardised radiographs using the Kellgren and Lawrence scale (grade 3-4=advanced OA). Uni- and multivariate regression analyses were performed to determine risk factors for OA. RESULTS: During the inclusion period, 373 fractures (372 patients; 9% Weber A, 58% Weber B, 33% Weber C) were operated upon. The mean age at operation was 42.9 years. There were 102 patients seen at follow-up (mean follow-up 17.9 years). Those not available did not differ in demographics and fracture type from those seen. Advanced radiographic OA was present in 37 patients (36.3%). Significant risk factors were: Weber C fracture, associated medial malleolar fracture, fracture-dislocation, increasing body mass index, age 30 years or more and length of time since surgery. CONCLUSIONS: Advanced radiographic OA was common 12-22 years after malleolar fracture. The probability of developing post-traumatic OA among patients having three or more risk factors was 60-70%.

Effect of Titrated Exposure to Non-Traumatic Noise on Unvoiced Speech Recognition in Human Listeners with Normal Audiological Profiles.

Non-traumatic noise exposure has been shown in animal models to impact the processing of envelope cues. However, evidence in human studies has been conflicting, possibly because the measures have not been specifically parameterized based on listeners' exposure profiles. The current study examined young dental-school students, whose exposure to high-frequency non-traumatic dental-drill noise during their course of study is systematic and precisely quantifiable. Twenty-five dental students and twenty-seven non-dental participants were recruited. The listeners were asked to recognize unvoiced sentences that were processed to contain only envelope cues useful for recognition and have been filtered to frequency regions inside or outside the dental noise spectrum. The sentences were presented either in quiet or in one of the noise maskers, including a steady-state noise, a 16-Hz or 32-Hz temporally modulated noise, or a spectrally modulated noise. The dental students showed no difference from the control group in demographic information, audiological screening outcomes, extended high-frequency thresholds, or unvoiced speech in quiet, but consistently performed more poorly for unvoiced speech recognition in modulated noise. The group difference in noise depended on the filtering conditions. The dental group's degraded performances were observed in temporally modulated noise for high-pass filtered condition only and in spectrally modulated noise for low-pass filtered condition only. The current findings provide the most direct evidence to date of a link between non-traumatic noise exposure and supra-threshold envelope processing issues in human listeners despite the normal audiological profiles.

Acromioclavicular and coracoclavicular cerclage reconstruction for acute acromioclavicular joint dislocations.

BACKGROUND: Little information is available on the results of the different stabilization techniques described for treatment of acute acromioclavicular (AC) joint injuries. Additionally, no studies have analyzed isometric performance of the shoulder after AC stabilization. The objective of our study was to present functional outcome including isokinetic testing and radiographic evaluation of patients treated with stabilization of AC joint dislocations. PATIENTS AND METHODS: Thirty-seven patients with acute type III to V AC joint disruption underwent open coracoclavicular (CC) and AC stabilization with nonabsorbable sutures. RESULTS: The mean follow-up was 4.5 ± 2.5 years (range, 2-10.5). The mean Constant score (CS) was 96. There were 34 (91.9%) excellent results, 1 good (2.7%), 1 satisfactory (2.7%), and 1 fair (2.7%). The disabilities of the arm, shoulder, and hand (DASH) questionnaire revealed good overall subjective evaluation with a mean of 7 points. The mean visual analog scale (VAS) pain score was 0.8. Patients with a CC distance <5 mm, or an anterosuperior AC reduction less than 50%, showed significantly better results in CS and DASH score in comparison to patients with a subluxated AC joint (P < .005). Twenty-two patients agreed to undergo isokinetic evaluation. We were unable to demonstrate any clinically significant difference between the involved and the uninvolved side. DISCUSSION: The described technique of cerclage augmentation offers an attractive alternative in AC joint stabilization, with good to excellent results. In comparison to other techniques, there were no complications related to any implants, no graft donor site morbidity, or need for implant removal.

Cup size and risk of dislocation after primary total hip arthroplasty.

We evaluated the relationship between cup diameter and dislocation risk in patients undergoing primary total hip arthroplasty (THA) with a 28-mm head. There were 50 dislocations, 28 of which occurred in 2221 (1.3%) THAs with a cup diameter smaller than 56 mm and 22 in 513 (4.3%) with a cup diameter of 56 mm or larger. Dislocation risk varied between 0.6% and 2.4% in the smaller cup group and between 4.1% and 5.2% in the larger cup group. The risk was substantially higher in the large cup group (unadjusted odds ratio, 3.5; 95% confidence interval, 2.0-6.2). Multivariable logistic regression revealed an adjusted odds ratio of 2.4 (95% confidence interval, 1.2-4.9). Patients with THA (28-mm head) had more than twice the risk of dislocation with cup size of 56 mm or higher compared to patients with smaller cups.

Noninsertional Achilles tendinopathy treated with gastrocnemius lengthening.

BACKGROUND: Surgery is frequently considered an option for refractory, symptomatic noninsertional Achilles tendinopathy. Gastrocnemius equinus can result in mechanical overload of the Achilles tendon and may be a factor in its etiology. Our hypothesis was that reducing load transmission to the Achilles tendon by gastrocnemius lengthening (Strayer procedure) may be an effective treatment. MATERIALS AND METHODS: A prospective case series of all patients with a minimum 1-year symptomatic noninsertional Achilles tendinopathy who underwent gastrocnemius lengthening was evaluated before surgery, and at 1 and 2 years after surgery. There were 14 patients (17 tendons). RESULTS: One year after surgery, the median American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score was 100 points, as compared to 71 points preoperatively (p < 0.001). The median total Foot Function Index (FFI) decreased significantly from 39 to 12 points at 1 year (p < 0.001) and remained stable (12 points) at 2 years. An electronic goniometer recorded a mean gain in ankle dorsiflexion of 13 degrees. At 1 year after surgery the MRI in all eight patients (ten tendons) with a preoperative MRI demonstrated a decrease in signal hyperintensity and tendon size, signifying an improvement of the tendinopathy. At 2 years after surgery, patient satisfaction assessment revealed that all but one patient was satisfied with the result and 11 of the 14 (79%) patients were able to resume their previous sporting activities. There were no complications. CONCLUSION: Gastrocnemius lengthening was an effective treatment for chronic Achilles noninsertional tendinopathy. Two-year results show good to excellent clinical outcome.

Prospective randomised study comparing screw versus helical blade in the treatment of low-energy trochanteric fractures.

PURPOSE: The purpose of this study was to compare femoral head placement, rates of reoperation and cephalic implant cut-out of a screw versus a blade for patients over age 60 with low energy trochanteric fractures (AO/OTA 31-A1, A2, and A3) treated either with sliding hip screw or cephalomedullary nail. METHODS: After surgeon selection of either hip screw or nail, hip screw patients were randomised to either a DHS (dynamic hip system screw) or DHS blade (dynamic hip system blade), while nail patients were randomised to either a Gamma3 Trochanteric Nail or a PFNA (proximal femoral nail antirotation). This resulted in a screw group (DHS and Gamma nail), and a blade group (DHS blade and PFNA). Outcome measures included tip-apex distance and zone location of the cephalic implant, as well as reoperation and implant cut-out within the first postoperative year. RESULTS: A total of 335 patients were randomised, 172 to a screw and 163 to a blade. There was no significant difference concerning mean tip-apex distance, percentage of patients with a tip-apex distance >25 mm, and patients with a centre-centre position of the cephalic implant. There were 137 patients in the screw group and 132 in the blade group available for follow-up. They did not differ regarding rates of reoperation or cut-out (screw group = 2.9%; blade group = 1.5%). CONCLUSIONS: Both a screw and a blade performed equally well in terms of implant placement in the femoral head and outcome.

Occurrence of fever in the first postoperative week does not help to diagnose infection in clean orthopaedic surgery.

Postoperative fever is often misinterpreted as a sign of infection, especially when occurring after the third postoperative day. We assessed the epidemiology of postoperative fever in adult orthopaedic patients and its association with infection. Among 1,073 patients participating in a prospective observational study, 198 (19%) had a postoperative fever (>38°C). Thirteen patients (1.2%) had a surgical site infection and 78 patients (7.3%) had remote bacterial infections during their hospital stay. Including asymptomatic bacteriuria, 174 patients were given antibiotic therapy for a median duration of six days. In multivariate analysis, no clinical parameter was associated with fever, including haematoma (odds ratio 0.9, 95%CI 0.6-1.3), infection (1.6, 0.7-3.7), or antibiotic use (1.6, 0.9-3.0). The maximum temperature on each of the first seven postoperative days did not differ between infected and uninfected patients (Wilcoxon rank-sum tests; p > 0.10). We conclude that fever, even up to the seventh postoperative day, is not substantially helpful to distinguish infection from general inflammation in clean orthopaedic surgery.

Transverse fractures of the olecranon: a biomechanical comparison of three fixation techniques.

INTRODUCTION: The gold standard for treating transverse olecranon fractures is tension band fixation. A problem with this technique is migration of the K-wires leading to premature hardware removal. The aim of this study is to compare stability provided by two new techniques designed to eliminate the problem with backing out of K-wires, with that of the recommended tension band technique, performed with a biomechanical in vitro investigation. Our hypothesis was that the two new techniques would provide at least equal stability as the traditional tension band fixation. METHODS: Transverse olecranon osteotomies were created in human cadaveric elbows to simulate a type 21-B1.1 fracture. Three groups of 8 specimens were instrumented with: (1) recommended AO tension band technique; (2) modified K-wires with eyelets and tension band; (3) staples across the fracture with tension band. Each elbow was tested in a 90° flexed position. The triceps tendon was sinusoidally loaded by applying two load steps at 500 and 700 N for 4000 cycles each. Relative movements between the fragments were determined. RESULTS: At the end of the first and second load step the displacement of the osteotomy at the posterior ulnar side was significantly less for the staples across the fracture with tension band as compared to both other groups. There were no significant differences between groups 1 and 2. CONCLUSION: Since clinical results depend partly on stable fixation, it is concluded that using staples in the clinical situation might provide better results than the currently recommended tension band technique.