Copper concentrate dual-band joint classification using reflectance hyperspectral images in the VIS-NIR and SWIR bands.

A study on the classification of copper concentrates relevant to the copper refining industry is performed by means of reflectance hyperspectral images in the visible and near infrared (VIS-NIR) bands (400-1000 nm) and in the short-wave infrared (SWIR) (900-1700 nm) band. A total of 82 copper concentrate samples were press compacted into 13-mm-diameter pellets, and their mineralogical composition was characterized via quantitative evaluation of minerals and scanning electron microscopy. The most representative minerals contained in these pellets are bornite, chalcopyrite, covelline, enargite, and pyrite. Three databases (VIS-NIR, SWIR, and VIS-NIR-SWIR) containing a collection of average reflectance spectra computed from 9×9p i x e l neighborhoods in each pellet hyperspectral image are compiled to train the classification models. The classification models tested in this work are a linear discriminant classifier and two non-linear classifiers, a quadratic discriminant classifier, and a fine K-nearest neighbor classifier (FKNNC). The results obtained show that the joint use of VIS-NIR and SWIR bands allows for the accurate classification of similar copper concentrates that contain only minor differences in their mineralogical composition. Specifically, among the three tested classification models, the FKNNC performs the best in terms of overall classification accuracy, achieving 93.4% accuracy in the test set when only VIS-NIR data are used to construct the classification model, up to 80.5% using only SWIR data, and up to 97.6% using both VIS-NIR and SWIR bands together.

A Radiometric Technique for Monitoring the Desulfurization Process of Blister Copper.

In this paper, a novel optical technique for following the progress of the blister copper desulfurization process is presented. The technique is based on the changes observed in the continuous spectrum of the visible-near-infrared (VIS-NIR) radiation that the blister melt emits while the chemical reactions of the sulfur elimination process are taking place. Specifically, the proposed technique uses an optical probe composed of an optical fiber, a collimating lens, and a quartz tube, which is immersed in the melt. This optical probe provides a field of view of the blowing zone where the desulfurization reaction occurs. The experimental results show that the melt VIS-NIR total irradiance evolves inversely to the SO2 concentration reported by a gas analyzer based on differential optical absorption spectroscopy. Furthermore, the blister copper spectral emissivity as well as the total emissivity observed throughout the process show strong correlation with the sulfur content during desulfurization reaction.

Improved Antibiotic Detection in Raw Milk Using Machine Learning Tools over the Absorption Spectra of a Problem-Specific Nanobiosensor.

In this article we present the development of a biosensor system that integrates nanotechnology, optomechanics and a spectral detection algorithm for sensitive quantification of antibiotic residues in raw milk of cow. Firstly, nanobiosensors were designed and synthesized by chemically bonding gold nanoparticles (AuNPs) with aptamer bioreceptors highly selective for four widely used antibiotics in the field of veterinary medicine, namely, Kanamycin, Ampicillin, Oxytetracycline and Sulfadimethoxine. When molecules of the antibiotics are present in the milk sample, the interaction with the aptamers induces random AuNP aggregation. This phenomenon modifies the initial absorption spectrum of the milk sample without antibiotics, producing spectral features that indicate both the presence of antibiotics and, to some extent, its concentration. Secondly, we designed and constructed an electro-opto-mechanic device that performs automatic high-resolution spectral data acquisition in a wavelength range of 400 to 800 nm. Thirdly, the acquired spectra were processed by a machine-learning algorithm that is embedded into the acquisition hardware to determine the presence and concentration ranges of the antibiotics. Our approach outperformed state-of-the-art standardized techniques (based on the 520/620 nm ratio) for antibiotic detection, both in speed and in sensitivity.

Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method.

Gold nanoparticles (AuNPs) are currently under intense investigation for biomedical and biotechnology applications, thanks to their ease in preparation, stability, biocompatibility, multiple surface functionalities, and size-dependent optical properties. The most commonly used method for AuNP synthesis in aqueous solution is the reduction of tetrachloroauric acid (HAuCl4) with trisodium citrate. We have observed variations in the pH and in the concentration of the gold colloidal suspension synthesized under standard conditions, verifying a reduction in the reaction yield by around 46% from pH 5.3 (2.4 nM) to pH 4.7 (1.29 nM). Citrate-capped AuNPs were characterized by UV-visible spectroscopy, TEM, EDS, and zeta-potential measurements, revealing a linear correlation between pH and the concentration of the generated AuNPs. This result can be attributed to the adverse effect of protons both on citrate oxidation and on citrate adsorption onto the gold surface, which is required to form the stabilization layer. Overall, this study provides insight into the effect of the pH over the synthesis performance of the method, which would be of particular interest from the point of view of large-scale manufacturing processes.

Effects of Implantation and Reimplantation of Cochlear Implant Electrodes in an In Vivo Animal Experimental Model (Macaca fascicularis).

OBJECTIVES: The objectives of this study were to evaluate the effect of reimplanting a cochlear implant electrode in animal normal-hearing cochlea to propose measures that may prevent cochlear injury and, given its close phylogenetic proximity to humans, to evaluate the macaque as a model for electroacoustic stimulation. DESIGN: Simultaneous, bilateral surgical procedures in a group of 5 normal-hearing specimens (Macaca fascicularis) took place in a total of 10 ears. Periodic bilateral auditory testing (distortion product otoacoustic emissions and auditory brainstem evoked responses [ABR]) took place during a 6-month follow-up period. Subsequently, unilateral explantation and reimplantation was performed. Auditory follow-up continued up to 12 months, after which animals were sacrificed and both temporal bones extracted for histological analysis. RESULTS: Implantation and reimplantation surgeries were performed without complications in 9 of 10 cases. Full insertion depth was achieved at reimplantation in four of five ears. Auditory evaluation: Statistically significant differences between implanted and reimplanted were observed for the frequencies 2000 and 11,000 Hz, the remaining frequencies showed no differences for distortion product otoacoustic emission. Before the procedure, average thresholds with click-stimuli ABR of the five animals were 40 dB SPL (implanted group) and 40 dB SPL (reimplanted group). One week after first implantation, average thresholds were 55 dB SPL and 60 dB, respectively. After 12 months of follow-up, the average thresholds were 72.5 dB SPL (implanted group) and 65 dB SPL (reimplanted group). Hearing loss appeared during the first weeks after the first implantation and no deterioration was observed thereafter. Differences for ABR under click stimulus were not significant between the two ear groups. Similar results were observed with tone-burst ABR. A 15 dB shift was observed for the implanted group preoperatively versus 1-week post surgery and an additional 17.5 dB shift was seen after 12-month follow-up. For the reimplanted group, a 20 dB shift was observed within the first week post reimplantation surgery and an additional 5 dB after 6 months follow-up. Statistical analysis revealed significant differences between the implanted and reimplanted ear groups for frequencies 4000 Hz (p = 0.034), 12000 Hz (p = 0.031), and 16,000 Hz (p = 0.031). The histological analysis revealed that the electrode insertion was minimally traumatic for the cochlea, mainly indicating rupture of the basilar membrane in the transition area between the basal turn and the first cochlear turn only in Mf1 left ear. CONCLUSIONS: With application of minimally traumatic surgical techniques, it is possible to maintain high rates of hearing preservation after implantation and even after reimplantation. Partial impairment of auditory thresholds may occur during the first weeks after surgery, which remains stable. Considering the tonotopic distribution of the cochlea, we found a correlation between the histological lesions sites and the auditory findings, suggesting that a rupture of the basilar membrane may impact hearing levels. The macaque was observed to be a functionally and anatomically an excellent animal model for cochlear implantation.

Hyperspectral Microscopy Technology to Detect Syrups Adulteration of Endemic Guindo Santo and Quillay Honey Using Machine-Learning Tools.

Honey adulteration is a common practice that affects food quality and sale prices, and certifying the origin of the honey using non-destructive methods is critical. Guindo Santo and Quillay are fundamental for the honey production of Biobío and the Ñuble region in Chile. Furthermore, Guindo Santo only exists in this area of the world. Therefore, certifying honey of this species is crucial for beekeeper communities-mostly natives-to give them advantages and competitiveness in the global market. To solve this necessity, we present a system for detecting adulterated endemic honey that combines different artificial intelligence networks with a confocal optical microscope and a tunable optical filter for hyperspectral data acquisition. Honey samples artificially adulterated with syrups at concentrations undetectable to the naked eye were used for validating different artificial intelligence models. Comparing Linear discriminant analysis (LDA), Support vector machine (SVM), and Neural Network (NN), we reach the best average accuracy value with SVM of 93% for all classes in both kinds of honey. We hope these results will be the starting point of a method for honey certification in Chile in an automated way and with high precision.

[Reconstruction of pharyngeal defects]. / Reconstrucción de defectos faríngeos.

Reconstruction of pharyngeal defects continues to present a clinical challenge for the Head and Neck surgeon. We have different reconstructive options to preserve speech, airway and swallowing functions. Reconstructive surgery implies a balance between oncologic cure, patient morbidity and quality of life. Classical reconstructive techniques include pedicled cervical cutaneous or myocutaneous flaps and distal myocutaneous flaps such as from the pectoralis major. Current microvascular technique options have a differing incidence of complications but always with high success rates. This article reviews the most current options on reconstructive techniques in pharyngeal defects.

Hearing Impairment and Quality of Life in Adults with Asymmetric Hearing Loss: Benefits of Bimodal Stimulation.

OBJECTIVES: Bimodal stimulation for asymmetric hearing loss is an emerging treatment with proven audiometric outcomes. Our objectives are to assess the changes of the hearing impairment and the quality of life of patients treated with this type of stimulation, when compared to a unilateral Cochlear Implant (CI) stimulated condition. MATERIALS AND METHODS: 31 patients with asymmetric hearing loss (Group 1) were recruited for the study. They were divided into three groups, based on their hearing loss in the ear treated with the hearing aid: Group 1A (Pure Tone Audiometry (PTA) between 41 and 70 decibels (dB)); Group 1B, (PTA between 71 and 80 dB) and Group 1C (PTA between 81 and 90 dB). 30 patients had profound, bilateral hearing loss. Then, users of a unilateral cochlear implant were recruited for the control group. Their hearing impairment and quality of life were analyzed with questionnaires Abbreviated Profile of Hearing Aid Benefit (APHAB), Speech, Spatial and Qualities of Hearing Scale (SSQ) and the Health Utilities Index (HUI). They were followed up for at least 2 years. RESULTS: The group with the asymmetric hearing loss obtains a statistically significant clinical improvement in the APHAB under category "with hearing aid" compared to "without hearing aid". The group with the asymmetric hearing loss benefits more across basically all variables compared with the control group in the SSQ. Group 1A obtains the best outcome of the sample in the HUI. CONCLUSION: Bimodal stimulation and better hearing in the ear treated with the hearing aid reduce hearing impairment and improve the quality of life.

Bimodal Stimulation with Cochlear Implant and Hearing Aid in Cases of Highly Asymmetrical Hearing Loss.

OBJECTIVE: Bimodal stimulation is a possible treatment for asymmetrical hearing loss, wherein 1 ear is stimulated with a cochlear implant and the other is stimulated with a hearing aid. This emerging indication has gained significance over the last few years. However, little research has been conducted regarding the performance in different types of asymmetric Hearing loss. This study seeks to prove the bilateral-binaural advantage in a group of patients treated with bimodal stimulation (cochlear implant and hearing aid), with different degrees of hearing loss in their best ear. MATERIALS AND METHODS: In total, 31 patients were recruited for the study. They were divided into 3 groups on the basis of the ear with the hearing aid: Group A, pure tone average (PTA) between 41 and 70 dB HL; Group B, PTA between 71 and 80 dB HL; and Group C, PTA between 81 and 90 dB HL. The performance in PTA and disyllabic word recognition were analyzed separately in each ear and then bimodally. The minimum follow-up period was 2 years. RESULTS: There were statistically significant differences between bimodal and monaural conditions both in PTA and in disyllabic word recognition. The better the residual hearing in the ear with the hearing aid, the greater were the benefits obtained with bilateralism-binaurality. CONCLUSION: Bimodal stimulation provides better results than any monaural hearing mode, regardless of whether it involves the use of a hearing aid alone or a cochlear implant alone.

A new bone conduction implant: surgical technique and results.

OBJECTIVE: To describe the surgical technique under local or general anesthesia of 5 cases that have undergone this procedure and the audiologic results obtained with this new device. PATIENTS: Four patients with mixed hearing loss and 1 patient with single-sided deafness. INTERVENTION: Therapeutic. MAIN OUTCOME MEASURES: The surgery was planned beforehand with a 3D reconstruction of a CT scan. The procedure was documented and timed in every case. Air and bone conductive pure tone audiometry and disyllabic words discrimination were tested after and before the procedure. Results were statistically analyzed. RESULTS: All patients tolerated well the procedure. Four patients were intervened under local anesthesia and 1 under general anesthesia because of an associated procedure. All patients showed statistically significant difference between the presurgery and postsurgery audiologic tests. CONCLUSION: Implantation of the Bonebridge with local or general anesthesia is a safe and feasible procedure, with audiometric results that can come close with the ones provided by BAHD users.

Atraumaticity study of 2 cochlear implant electrode arrays.

HYPOTHESIS: Evaluate, based on morphologic and histologic parameters, the atraumaticity of 2 electrode arrays implanted in 10 human temporal bones. BACKGROUND: Atraumatic surgery and electrode arrays are current topics in otologic surgery. The preservation of cochlear anatomy and its functions is a priority and morphologic evaluation of the surgical trauma is essential to continue improving in this field. METHODS: Ten preserved human temporal bones (TB) without anatomic alterations were used in this study. They were divided into 2 groups of 5, and atraumatic surgery was performed to insert HiFocus 1J (group A) and HiFocus Helix (group B) electrode arrays. Anatomic comparisons were performed using computed tomography and histologic analysis. RESULTS: Group A: the mean length for the cochlear longitudinal axis was 10.30 mm, and the cochlear transversal axis was 7.2 mm. Scala tympani insertion was achieved in 4/5 TB studied, with a mean depth and angle of insertion of 19.2 mm and 325.5°, respectively. Lateral location of the electrode array was achieved in all specimens. No significant correlation was observed between these dimensions and depth of insertion. Group B: the mean length for the cochlear longitudinal axis was 9.52 mm, and cochlear transversal axis was 6.38 mm. Scala tympani insertion was achieved in 4/5 TB studied, with a mean depth and angle of insertion of 17.5 mm and 352°, respectively. Modiolar location of the electrode array was achieved in all specimens. A positive correlation was established between the linear and angular insertion depths (p = 0.044). CONCLUSION: In summary, it is safe to state that neither electrode array shows significant insertion trauma.

[Attic exposure-antrum exclusion as an on demand surgical technique for cholesteatoma]. / Aticoexposición-antroexclusión como técnica quirúrgica a la demanda para el tratamiento del colesteatoma.

INTRODUCTION AND OBJECTIVE: Attic exposure and antrum exclusion (AE-AE) is an on demand surgical technique for the treatment of cholesteatoma. Several techniques have been described with variable recurrence rates. The aim of the study was to describe this surgical technique and its indications and to analyse long-term outcomes. MATERIALS AND METHODS: Forty-two patients were included. They received AE-AE in a tertiary centre and were followed-up from 6 months to 7 years. The surgical technique exposes the attic by drilling the superior wall of the external auditory canal and excludes the antrum and the mastoid cells by closing the aditus with a cartilage graft. It is indicated if the lesion does not go beyond the aditus or, if it does, it is a delimited cholesteatoma not damaging the labyrinth. The patients were followed-up by physical examination and radiology (CT scan and Non-EPI diffusion-weighted MRI since 2009). RESULTS: The recurrence rate of the cholesteatoma was 4.8%. At recurrence, an open canal-wall-down mastoidectomy technique was performed. The rate of otorrhea (2/42 cases), serous otitis (2/42) and other complications was low, so aquatic activities were not contraindicated. The AE-AE did not modify ossicular chain reconstruction with respect to the rest of surgical techniques. CONCLUSIONS: AE-AE is a canal-wall-down technique. Its purpose is to remove the lesion and to reduce the recurrence of cholesteatoma. In addition, it allows the entrance of water and reduces the need for 2(nd) look surgery. Non-EPI diffusion-weighted MRI is a reliable technique for follow-up, especially for the excluded mastoid.

Experience with the active middle ear implant in patients with moderate-to-severe mixed hearing loss: indications and results.

OBJECTIVE: Quantify the improvement and impact of the active middle ear implants (AMEIs) on a moderate-to-severe mixed hearing loss population. STUDY DESIGN: Retrospective study on the indications and results obtained by individuals implanted with the AMEI. SETTINGS: Tertiary referral center. PATIENTS: Thirteen adult patients with moderate-to-severe hearing loss were evaluated. Air and bone conductive pure tone audiometry and disyllabic word discrimination was performed before and after surgery. The follow-up period was from 5 to 64 months. INTERVENTION: Surgical implantation of the AMEI. MAIN OUTCOME MEASUREMENT: Auditory performance analyzed using pure tone and speech audiometry with AMEI off and on. RESULTS: The average auditory gain in the frequency range 0.5 of 6 kHz was 44.07 dB. The average AC audiometric performance after activating the device is significantly better than the preoperative BC performance in 10 of 13 patients, with an average gain of 11.3 dB. Speech audiometry performance using disyllabic words showed a significant improvement. The detection threshold reduced significantly, from 65 to 24 dB (p = 0.012) with the AMEI. The speech recognition score at 65 dB SPL also showed a significant improvement from 28% to 90% post surgery (p = 0.004). The maximum speech recognition score also improved post surgery, from 56% to 93% with the AMEI (p = 0.023). CONCLUSION: The AMEI is considered an appropriate device to be used by patients with BC losses up to 70 dB, provided that hearing levels are present in all frequencies between 0.5 and 4 KHz, and the speech recognition percentage is above 60% in the ear chosen for implantation.

Aticoexposición-antroexclusión como técnica quirúrgica a la demanda para el tratamiento del colesteatoma / Attic exposure-antrum exclusion as an on demand surgical technique for cholesteatoma

Introducción: La aticoexposición-antroexclusión (AE-AE) simple o ampliada, es una técnica a la demanda para el tratamiento del colesteatoma. Las tasas de recurrencia/recidiva descritas con diferentes técnicas quirúrgicas son variables. El objetivo de este estudio es describir la técnica quirúrgica, sus indicaciones y analizar los resultados a largo plazo. Material y métodos: Se incluyen 42 pacientes intervenidos de AE-AE en un centro terciario con un seguimiento de 6 meses-7 años. Esta técnica expone completamente el ático fresando la pared superior del conducto auditivo externo y excluye el antro y mastoides cerrando el additus con injertos de cartílago. Se indica en pacientes con colesteatoma localizado en la caja timpánica sin sobrepasar el additus o en caso de hacerlo estar encapsulado sin erosionar la cápsula laberíntica. El seguimiento es clínico y radiológico (TC de peñascos y RM con secuencias de difusión desde 2009). Resultados: El 4,8% de los casos presentó una recidiva, los cuales fueron rescatados en un segundo tiempo quirúrgico. En el seguimiento la tasa de otorrea (2/42), otitis serosa (2/42) u otras complicaciones fue baja, no contraindicando las actividades acuáticas. La AE-AE no modificó el tipo de reconstrucción osicular respecto a otras técnicas. Conclusiones: La AE-AE es una técnica abierta. Pretende eliminar totalmente la lesión y reducir la recidiva de colesteatoma, facilitando una normalización en los baños y una disminución de revisiones posquirúrgicas. La RM en secuencias de difusión es una técnica fiable en el despistaje y seguimiento, especialmente para el control de los espacios mastoideos tras la AE-AE (AU)

Introduction and objective: Attic exposure and antrum exclusion (AE-AE) is an on demand surgical technique for the treatment of cholesteatoma. Several techniques have been described with variable recurrence rates. The aim of the study was to describe this surgical technique and its indications and to analyse long-term outcomes. Materials and methods: Forty-two patients were included. They received AE-AE in a tertiary centre and were followed-up from 6 months to 7 years. The surgical technique exposes the attic by drilling the superior wall of the external auditory canal and excludes the antrum and the mastoid cells by closing the aditus with a cartilage graft. It is indicated if the lesion does not go beyond the aditus or, if it does, it is a delimited cholesteatoma not damaging the labyrinth. The patients were followed-up by physical examination and radiology (CT scan and Non-EPI diffusion-weighted MRI since 2009). Results: The recurrence rate of the cholesteatoma was 4.8%. At recurrence, an open canal-wall-down mastoidectomy technique was performed. The rate of otorrhea (2/42 cases), serous otitis (2/42) and other complications was low, so aquatic activities were not contraindicated. The AE-AE did not modify ossicular chain reconstruction with respect to the rest of surgical techniques. Conclusions: AE-AE is a canal-wall-down technique. Its purpose is to remove the lesion and to reduce the recurrence of cholesteatoma. In addition, it allows the entrance of water and reduces the need for 2nd look surgery. Non-EPI diffusion-weighted MRI is a reliable technique for follow-up, especially for the excluded mastoid (AU)

Reconstrucción de defectos faríngeos / Reconstruction of pharyngeal defects

La reconstrucción de defectos faríngeos sigue siendo un reto para el cirujano de cabeza y cuello. Las diferentes opciones reconstructivas van orientadas a mantener la función vocal, la vía aérea y la deglución. La técnica de reconstucción supone un equilibrio entre la curación oncológica, la morbilidad del paciente y la calidad de vida. Las técnicas reconstructivas clásicas incluyen los colgajos pediculados cutáneos y miocutáneos cervicales y los colgajos miocutáneos distales, como el de pectoral mayor. Actualmente, las técnicas de reconstrucción microvascular difieren en la incidencia de complicaciones, pero siempre con un alto nivel de viabilidad. Este trabajo tiene como objetivo revisar las opciones actuales en técnicas reconstructivas de defectos faríngeos (AU)

Reconstruction of pharyngeal defects continues to present a clinical challenge for the Head and Neck surgeon. We have different reconstructive options to preserve speech, airway and swallowing functions. Reconstructive surgery implies a balance between oncologic cure, patient morbidity and quality of life. Classical reconstructive techniques include pedicled cervical cutaneous or myocutaneous flaps and distal myocutaneous flaps such as from the pectoralis major. Current microvascular technique options have a differing incidence of complications but always with high success rates. This article reviews the most current options on reconstructive techniques in pharyngeal defects (AU)