Small Instrument Research Articles

Adding Flexible Instrumentation to a Curved Videolaryngoscope: A Novel Tool for Laryngeal Surgery.

Transoral surgery of the larynx with rigid instruments is not always possible. This may result in insufficient therapy or in an increased need for open surgery. For these patients, alternative surgical systems are needed. Here, we demonstrate a curved prototype for laryngeal surgery equipped with flexible instruments. Pre-clinical user study in an ex vivo porcine laryngeal model. The prototype was built from established medical devices, namely a hyperangulated videolaryngoscope and modified flexible instruments as well as three-dimensional printed parts. Feasibility of laryngeal manipulation was evaluated in a user study (n = 19) with a porcine ex vivo laryngeal model. Using three different visualization technologies, the participants performed various fine motor skills tasks and rated the usability of the system on a 5-point Likert scale. Exposure, accessibility, and manipulation of important laryngeal structures were always possible using the new prototype. The participants needed considerably less time (mean, 96.4 seconds ± 6.4 seconds vs. 111.5 seconds ± 4.5 seconds, P = .18), reported significantly better general impression (mean score 3.0 vs. 3.8, P = .041) and significantly lower user head and neck strain (2.6 vs. 1.7, P = .022) using a 40-inch television screen as compared to a standard videolaryngoscope monitor. The results indicate that our curved prototype and large monitor visualization may provide a cost-effective minimally invasive alternative for difficult laryngeal exposure. Its special advantages include avoiding the need for a straight line of sight and a simple and cost-effective construction. The system could be further improved through advances in camera chip technology and smaller instruments. Laryngoscope, 131:E561-E568, 2021.

Simulation and experimental results of an unmanned towed system

This report investigates the flight dynamics of a small-scale (2 ft) towed system using a quadcopter and actively controlled payload. A towed system includes a main driver to propel the system forward connected to a payload via a tether. The towed system here is unique, and in that the driver is a scratch built quadcopter while the payload is also a scratch built actively controlled aircraft. The payload is designed to carry a small instrument that must be sufficiently far away from all interferences created by a quadcopter. A fully non-linear full state model is created and utilized to reveal that oscillations in the payload are decreased with the introduction of a PD controller on the payload. An experimental setup is built to validate simulation results. Experiments show that an actively controlled payload can decrease the attitude oscillations of the payload.

Electronic nose to distinguish bladder cancer by urinary odour feature: A pilot study.

No study has yet investigated the use of electronic nose (eNose) technology to reveal pattern recognition of urological diseases, including bladder cancer. We sought to determine the diagnostic performance of the eNose in recognizing urinary odour in patients with bladder cancer. The eNose is a commercially available model equipped with two sensors. The angle of the two sensors (θ) depends on the kinds of chemical substances, thus defining θ as the feature of odour. Quantity of odour is the number of θ detected during a measurement. Urine samples were from 36 untreated patients with bladder cancer, 29 with urolithiasis, 10 with urinary tract infection (UTI), and 27 healthy volunteers. Based on ROC analysis of the quantity in patients with bladder cancer, an optimal cut-off value for θ of 49, 48, and 55 was applied to compare with samples from the healthy volunteer, urolithiasis and UTI groups, respectively. There were significantly differences between bladder cancer and the other conditions using these specific points (p< 0.0001, respectively). The resulting diagnostic sensitivity was 61.4%, 45.6%, and 60.8%, and specificity was 52.8%, 68.4%, and 90.2%, respectively. The AUC for bladder cancer was 0.565, 0.548, and 0.909, respectively. The eNose is a small, portable, rapid, low cost, and noninvasive instrument for distinguishing bladder cancer from other benign conditions.

CHALLENGES IN SMALL KNEE ARTHROSCOPY: A QUALITATIVE AND QUANTITATIVE PEDIATRIC CADAVERIC EXPERIENCE

Background:Arthroscopy may be utilized for treatment of septic arthritis of the pediatric knee, with success reported in ages from 3 months to 12 years. There is limited data on the ability to arthroscopically assess articular structures and ensure adequate evaluation without arthrotomy.Hypothesis/Purpose:The purpose of this study is: (1) utilize arthroscopy in small cadaveric knees to improve qualitative and quantitative knowledge of pediatric articular structures and (2) to obtain pilot data for common procedures performed in pediatric patientsMethods:Five small pediatric cadaveric specimens (1-4 years) underwent arthroscopy (2.7 mm Stryker arthroscope). Medial and lateral compartments were assessed for meniscus size/mobility/height, compartmental joint space, ACL insertion, patellar chondral height and length, and position of the medial patellofemoral ligament were recorded. Utilizing standard anterior medial and lateral portals, the ability to visualize the structures of the posteromedial and posterolateral compartments was recorded. Procedures pertinent to immature ACL reconstruction and meniscal repair (unstable discoid) were critically evaluated to provide source data for future work.Results:Prior to arthroscopy, all specimens underwent volume-assessed knee insufflation (average 11.4 cc normal saline). Arthroscopic visualization of the menisco-capsular attachment was possible posteromedially in 4/6, and posterolaterally in 5/6 knees. Qualitative arthroscopic relationships were similar to adult references; including patellar-trochlear articulation and lateral meniscal positional relationship to the ACL insertion (see Figure 1). The ACL center was within 2 mm of the posterior aspect of the anterior horn of the lateral meniscus in all specimens. The average height of the medial compartment space under valgus load was 1.5 mm (1 – 2 mm), and lateral space under varus was 2.2 mm (2-3 mm); further emphasizing the need for small joint instruments. The width of the medial and lateral menisci are noted in Table 1. All-inside meniscal devices designed for skeletally mature specimens should be used with caution (Figure 1). Traditionally described inside-out technique for immature ACL reconstruction with an iliotibial band demonstrated significant proximity of the passing device to the neurovascular bundle (Figure 1).Conclusion:The entirety of the small knee is assessable via standard diagnostic arthroscopy, when a 2.7mm arthroscope is utilized. These findings suggest that intra-articular pathology can be reliably identified utilizing this surgical technique. However, the ability to work on the infant meniscus and cartilage with standard arthroscopic instruments is likely limited given the constraints of joint height.Table 1.Meniscal width of the medial and lateral meniscus as measure by a microprobe. Figure 1.Arthroscopic and gross images of an infant cadaveric knee 11 year old). (A) ACL insertion into the tibia. Note the relationship of the anterior horn of the lateral meniscus to the ACL Insertion. (B) The patellocrochiear articulation with a well formed troctilea, (C) Medial patellofemoral ligament as it inserts onto the patella. Marking in the ligament 1') indicates centroid of the ligament based on superficial anatomy. (D) Pilot study of placement of an all-inside meniscal repair device (Stryker AIR) The size of implant is 70% of the height of the lateral meniscus, .1E) Image of a dissected popliteal fossa of a small knee. Curved clamp )black arrow) was placed as if to facilitate passage of the !Thin a extra-articular ACL reconstruction with the dicta:fiat hand. Note the proximity to the posterior neurovascular structures (Yellow = artery; blue = nerve).

Study of the Microstructure Characteristics of Three Different Fine-grained Tailings Sand Samples during Penetration.

This paper explores the microstructural evolution characteristics of tailings sand samples of different types of infiltration failure during the infiltration failure process. The homemade small infiltration deformation instrument is used to test the infiltration failure characteristics of the tailings sand during the infiltration failure process. Evolutionary characteristics of the internal microstructure pores and particle distribution were also studied. Using CT (computerized tomography) technology to establish digital image information, the distribution of the microscopic characteristics of the particle distribution and pore structure after tailing sand infiltration were studied. Microscopic analysis was also performed to analyze the microscopic process of infiltration and destruction, as well as to see the microscopic structural characteristics of the infiltration and destruction of the total tailings. The test results show that there are obvious differences in the microstructure characterization of fluid soil and piping-type infiltration failures. Microstructure parameters have a certain functional relationship with macrofactors. Combining the relationship between macrophysical and mechanical parameters and microstructural parameters, new ideas for future research and the prevention of tailings sand infiltration and failure mechanisms is provided.

Complications after active stone removal.

Active stone removal has been entirely revolutionized in the past decades. Smaller instruments, scope and laser technology advancements and novel lithotripter modalities have entirely changed the way urological surgeons treat stones. Nevertheless novel technologies may lead to different and difficult to manage complications. Accurate knowledge of indications, limitations and technical details of these novel modalities can significantly decrease complication rates. The purpose of this review is to provide the most recently acquired knowledge to decrease patient's morbidity after active stone removal. Complications of active stone removal are well known for many years, nevertheless novel technologies in stone management can substantially differentiate their rates. Minimal invasive techniques are becoming even more minimal which reflects on the complications. Mastering the novel techniques in active stone removal and knowing their inherent limitations, in association with the recognition of predisposing factors and preventing measures have led to a highly acceptable low complication rate. Further refinements and technical improvement will reduce even more the complication incidence in the future.

Intentional Replantation to Treat Apical Periodontitis of Maxillary First Molar with Foreign Body Located Outside Apical Foramen Using CBCT: A Case Report

The recent use of cone beam computed tomography (CBCT) in the field of dentistry to obtain 3-dimensional (3D) images has enabled more effective examination and diagnosis in endodontic treatment. Such information has also been reported to be of benefit in surgical endodontic treatment such as intentional replantation. Here, we report a case of intentional replantation with the assistance of CBCT in which a good therapeutic outcome was achieved. The patient was a 30-year-old woman who visited our hospital with the chief complaint of spontaneous pain in the right maxillary first molar. Dental radiographs revealed a radiolucent area in the apical portion of the distal root, and a radiopaque area thought to be a broken shard from a small surgical instrument measuring approximately 1.5 mm in length. The shard was located outside the distal apical foramen. Based on these findings, the diagnosis was acute suppurative apical periodontitis of the right maxillary first molar. Infected root canal therapy was subsequently commenced. The patient's symptoms showed no improvement, however, and the pain persisted. Therefore, dental CBCT was performed to obtain 3D images, which confirmed a radiopaque area thought to be a broken shard from a small surgical instrument located outside the apical foramen of the distal root and facing in a direction that made it impossible to remove from the root canal. Because the patient's symptoms had shown no improvement and a foreign body was observed outside the apical foramen, intentional replantation combined with root resection was performed with informed consent. At a 1-year follow-up visit, progress was good, and there were no reported symptoms or signs. When reaching a diagnosis is difficult based on clinical findings and dental radiographs alone, the 3D images provided by CBCT offer a means of securing a more reliable diagnosis, allowing planning of treatment to be more effective.

Dermatosurgery Practice and Implications of COVID-19 Pandemic: Recommendations by IADVL SIG Dermatosurgery (IADVL Academy).

Dermatosurgery Practice and Implications of COVID-19 Pandemic: Recommendations by IADVL SIG Dermatosurgery (IADVL Academy).

Digital Microfluidic Platform to Maximize Diagnostic Tests with Low Sample Volumes from Newborns and Pediatric Patients.

“Children are not tiny adults” is an adage commonly used in pediatrics to emphasize the fact that children often have different physiological responses to sickness and trauma compared to adults. However, despite widespread acceptance of this concept, diagnostic blood testing is an excellent example of clinical care that is not yet customized to the needs of children, especially newborns. Cumulative blood loss resulting from clinical testing does not typically impact critically ill adult patients, but can quickly escalate in children, leading to iatrogenic anemia and related comorbidities. Moreover, the tests prioritized for rapid, near-patient testing in adults are not always the most clinically relevant tests for children or newborns. This report describes the development of a digital microfluidic testing platform and associated clinical assays purposely curated to address current shortcomings in pediatric laboratory testing by using microliter volumes (<50 µL) of samples. The automated platform consists of a small instrument and single-use cartridges, which contain all reagents necessary to prepare the sample and perform the assay. Electrowetting technology is used to precisely manipulate nanoliter-sized droplets of samples and reagents inside the cartridge. To date, we have automated three disparate types of assays (biochemical assays, immunoassays, and molecular assays) on the platform and have developed over two dozen unique tests, each with important clinical application to newborns and pediatric patients. Cell lysis, plasma preparation, magnetic bead washing, thermocycling, incubation, and many other essential functions were all performed on the cartridge without any user intervention. The resulting assays demonstrate performance comparable to standard clinical laboratory assays and are economical due to the reduced hands-on effort required for each assay and lower overall reagent consumption. These capabilities allow a wide range of assays to be run simultaneously on the same cartridge using significantly reduced sample volumes with results in minutes.

A high-performance 8\u2009nV/\u221aHz 8-channel wearable and wireless system for real-time monitoring of bioelectrical signals

BackgroundIt is widely accepted by the scientific community that bioelectrical signals, which can be used for the identification of neurophysiological biomarkers indicative of a diseased or pathological state, could direct patient treatment towards more effective therapeutic strategies. However, the design and realisation of an instrument that can precisely record weak bioelectrical signals in the presence of strong interference stemming from a noisy clinical environment is one of the most difficult challenges associated with the strategy of monitoring bioelectrical signals for diagnostic purposes. Moreover, since patients often have to cope with the problem of limited mobility being connected to bulky and mains-powered instruments, there is a growing demand for small-sized, high-performance and ambulatory biopotential acquisition systems in the Intensive Care Unit (ICU) and in High-dependency wards. Finally, to the best of our knowledge, there are no commercial, small, battery-powered, wearable and wireless recording-only instruments that claim the capability of recording electrocorticographic (ECoG) signals.MethodsTo address this problem, we designed and developed a low-noise (8 nV/√Hz), eight-channel, battery-powered, wearable and wireless instrument (55 × 80 mm2). The performance of the realised instrument was assessed by conducting both ex vivo and in vivo experiments.ResultsTo provide ex vivo proof-of-function, a wide variety of high-quality bioelectrical signal recordings are reported, including electroencephalographic (EEG), electromyographic (EMG), electrocardiographic (ECG), acceleration signals, and muscle fasciculations. Low-noise in vivo recordings of weak local field potentials (LFPs), which were wirelessly acquired in real time using segmented deep brain stimulation (DBS) electrodes implanted in the thalamus of a non-human primate, are also presented.ConclusionsThe combination of desirable features and capabilities of this instrument, namely its small size (~one business card), its enhanced recording capabilities, its increased processing capabilities, its manufacturability (since it was designed using discrete off-the-shelf components), the wide bandwidth it offers (0.5–500 Hz) and the plurality of bioelectrical signals it can precisely record, render it a versatile and reliable tool to be utilized in a wide range of applications and environments.

ULTRA LIGHT UAV SYSTEMS FOR THE METRICAL DOCUMENTATION OF CULTURAL HERITAGE: APPLICATIONS FOR ARCHITECTURE AND ARCHAEOLOGY

Abstract. The Italian legislation on Remote Pilot Aircraft Systems (SAPR: Sistema Areomobile a Pilotaggio Remoto), as in 2012, regulates the use of drones in controlled and uncontrolled airspace. In 2016, the regulation introduced simplified procedures for the use of ultra-light drones. These instruments are particularly widespread in the field of Cultural Heritage survey. In fact, according to the Italian regulations currently in force it is possible to pilot a drone of less than 300 grams without the need of a flight license and without a specific training course and medical examination and it is not required a special permit to fly in populates areas (although without flying over groups of people). Another possible explanation is the limited cost of these aircrafts and their easy availability on the market, both on the shelves of all electronic shops and in online stores.Following the boom of drones under 300 g, and considering the new European regulations also pay particular attention to a similar segment of Unmanned Aerial Vehicle (UAV) (in the future for aircraft under 250 g), it is important to evaluate the results that can be obtained through these small instruments and above all to evaluate which are the fields of application compatible with the technical limitations imposed by the need to lighten the components onboard (think in particular of the sensors of digital cameras).The purpose of the study is linked to the documentation of Cultural Heritage, in particular, we want to investigate the quality and metric reliability of photogrammetric surveys carried out through ultra-light drone images. Some application of UAV photogrammetry by ultra-light drones are showed in this paper and they deal with archaeological and architectural survey.

Evaluation of fluoride and sodium hypochlorite solutions during the electrochemical dissolution of conventional NiTi instruments and Gold thermomechanically treated NiTi instruments.

To compare the dissolution time of two solutions, a fluoride solution and a sodium hypochlorite solution, both saturated with sodium chloride, during the electrochemical dissolution of instruments consisting of conventional nickel-titanium alloy and Gold thermomechanically treated nickel-titanium alloy. Two solutions, an NaF solution consisting of 12gL-1 NaF with 180gL-1 NaCl and an NaOCl solution consisting of 2.5% NaOCl with 180gL-1 NaCl, were evaluated in a polarization test of a sample of 48 ProTaper Universal F1 (PTU F1) and WaveOne Gold Small (WOGS) instruments. The electric potentials were 0.5V and 5V for the NaF and NaOCl solutions, respectively. The electrochemical cell consisted of three electrodes for the polarization test of the PTU F1 and WOGS instruments, which had 6mm of the tip immersed in the test solutions. The electric current was recorded for 540s. If complete dissolution of the immersed tip occurred in less than the expected time, the experiment was considered complete. The time variations (in seconds) of the instruments in the solutions were measured. Data were subjected to statistical analysis using the Mann-Whitney, Kruskal-Wallis and Dunn tests. The corrosion patterns of the instruments were evaluated by scanning electron microscopy (SEM). The NaF and NaOCl solutions were associated with significantly different (P=0.000) dissolution times of the instrument, with mean values of 12.96s and 83.63s, respectively. There was no significant difference (P=0.649) in dissolution time between the PTU F1 and WOGS instruments. NaF and NaOCl solutions were able to electrochemically dissolve PTU F1 and WOGS instruments. However, the NaF solution achieved dissolution in significantly less time.

Comparison of four nanoparticle monitoring instruments relevant for occupational hygiene applications

BackgroundThe aim of this study is to make a comparison of a new small sized nanoparticle monitoring instrument, Nanoscan SMPS, with more traditional large size instruments, known to be precise and accurate [Scanning Mobility Particle Sampler (SMPS) and Fast Mobility Particle Sizer (FMPS)], and with an older small size instrument with bulk measurements of 10–1000 nm particles (CPC3007). The comparisons are made during simulated exposure scenarios relevant to occupational hygiene studies.MethodsFour scenarios were investigated: metal inert gas (MIG) welding, polyvinyl chloride (PVC) welding, cooking, and candle-burning. Ratios between results are compaed and Pearsson correlations analysis was performed.ResultsThe highest correlation between the results is found between Nanoscan and SMPS, with Pearsson correlation coefficients above 0.9 for all scenarios. However, Nanoscan tended to overestimate the results from the SMPS; the ratio between the UFP concentrations vary between 1.44 and 2.01, and ratios of total concentrations between 1.18 and 2.33. CPC 3007 did not show comparable results with the remaining instruments.ConclusionBased on the results of this study, the choice of measurement equipment may be crucial when evaluating measurement results against a reference value or a limit value for nanoparticle exposure. This stresses the need for method development, standardisation, and harmonisation of particle sampling protocols before reference values are introduced. Until this is established, the SMPS instruments are the most reliable for quantification of the concentrations of UFP, but in a more practical occupational hygiene context, the Nanoscan SMPS should be further tested.

Prediction of meat quality traits in the abattoir using portable and hand-held near-infrared spectrometers

The use of near-infrared spectrometers (NIRS) for predicting meat quality traits directly in the abattoir was tested with three trials. For the calibration trial, spectra were acquired from the cross-cut surface of the Longissimus thoracis muscle on 1166 carcasses of Piemontese young bulls with a portable visible-near-infrared spectrometer (Vis-NIRS) and with a small hand-held instrument (Micro-NIRS). A sample of the same muscle was analyzed to provide the reference. Validation statistics of the two instruments were similar. Predictabilities of meat color and purge loss were good, whereas for the other traits they were less promising. The repeatability trial showed that post-slaughter factors, not predictable by NIR spectra collected in the abattoir, affect reference meat quality values. A trial under operative conditions showed that both spectrometers were able to capture the major sources of variation in most of the meat quality traits. Overall, NIRS could be used to predict the animals' “native” characteristics exploitable for genetic improvement of meat quality traits.

Analysis and Experiment of Vibration Isolation Performance of a Magnetic Levitation Vibration Isolator with Rectangular Permanent Magnets

Magnetic levitation vibration isolator (MLVI) is an efficient method to suppress the external oscillations transmitted to some small instruments in the laboratories. This paper first presents a basic configuration of a kind of MLVI with four sets of the repulsive rectangular permanent magnets. Then, the parametric studies are carried out to discuss how the structure and air gap parameters influence the magnetic force, stiffness, and natural frequency of the MLVI. Moreover, as an MLVI case study, an operating point is set and the size dimensions of the MLVI are determined based on the parametric studies. The transmissibility of the MLVI is calculated by the dynamic equation at the operating point. An experimental table is constructed for the analytical validation. The experimental results proved the validity of the theoretical analysis and showed that there are good consistencies between the experiment results and the theoretical calculation, which obtains that the natural frequency of the MLVI is 4.75 Hz and the initial cut-off frequency of the MLVI is approximately 6 Hz at the operating point. When the frequency of the external oscillations reaches 16 Hz, the attenuation amplitude becomes − 20 dB. All of these show ability of the proposed MLVI to attain low-frequency vibration isolation, and provide a new type of basic passive MLVI to exploit an active MLVI for practical applications.

Behavior classification of goats using 9-axis multi sensors: The effect of imbalanced datasets on classification performance

Recent developments of small electronic instruments have enabled the classification of animal behavior using simultaneous measurements of various bio-logging data such as acceleration, magnetism, and angular velocity. Following technological progress, studies on the behavioral classification of ruminants combining measurements based on accelerometers, magnetometers, and gyroscopes have received attention. However, while the issue of class imbalance has recently become a serious challenge in classification by machine learning, few behavioral classification studies on livestock animals have focused on the effect of equalizing the prevalence of each behavior to improve the problem caused by the imbalance of data on classification performance. The aims of this study were to classify the behaviors of goats using a back-mounted 9-axis multi sensor (a tri-axial accelerometer, a tri-axial gyroscope, and a tri-axial magnetometer) with machine learning algorithms, and to evaluate changes in the predictive scores by equalizing the prevalence of each behavior. The behaviors of three goats grazing on an experimental pasture were logged for approximately 12 h with the multi sensors. The behaviors were recorded at 1-second intervals with time-lapse cameras throughout the experimental period. Three behaviors were classified: lying, standing, and grazing. Over 100 different variables were extracted from the raw sensor data, and classification was executed by inputting the variables into two supervised machine learning algorithms: K-nearest neighbors (KNN) and decision tree (DT). Moreover, because the prevalence of standing was low compared to that of grazing, the number of observations of each behavior in the training datasets for classification models was equalized by undersampling. As expected, the results indicated that the overall accuracies of both algorithms using all variables derived from the three sensors were higher than those using only variables from the acceleration data. Furthermore, both the algorithms using the variables from the acceleration and magnetism data could classify the behaviors as accurate as the algorithms using variables from all sensor data. Balancing the prevalence of each behavior resulted in a decrease in the F1 scores of the lying and grazing classifications but a slight increase in those of the standing classification by DT. In conclusion, our results suggest that, in addition to tri-axial acceleration, tri-axial magnetism is useful for classifying lying, standing, and grazing activities of ruminants and that equalizing the number of data for each behavior is important to correctly assess the predictive accuracy of behavioral classifications, particularly for the behavior with low prevalence.

Organ building in Lithuania in the 19th century

For Lithuania, the 19th century was marked by the symbol of the Russian Empire – Lithuania became a province of a foreign empire. Farming suffered a severe general downturn. As the Church’s powers began to be restricted, there was almost no opportunity for new significant instruments to emerge. The monasteries, which until then had been the initiators of the best organ building, were closed. Eastern Catholic (Unitarian) churches, which also had organs in Lithuania, became part of the Russian Orthodox Church, and the organs were ordered to be liquidated. The Catholic Church itself, unlike evangelicals, also had little regard for music and especially for organ matters. From the beginning of the 15th century, the development of Lithuanian organ culture was closely associated with Königsberg. Once the import customs were imposed, significant contacts which had taken place almost disappeared. The industrial revolution in Lithuania was delayed, and for half a century small artisan workshops still prevailed. Almost exclusively small, single-manual organs without pedals or positives were built. A large three-manual organ at Vilnius University St John’s Church was rather an exception. It was built by the Tiedemanns. This family, which originated in East Prussia, worked in the Baltic States throughout the first half of the 19th century. Only in the middle of the century did the new European organ building trend, the so-called organ romanticism, reach Lithuania. A particularly important role in this period was played by the experience of organ building of the neighbouring Curonia. Very few impressive examples were created, and in this respect Lithuania is hardly able to compete with the major countries of Central Europe. Lithuania is characterized by the fact that in the 19th century local masters and companies ( J. Rudavičius, M. Masalskis, F. Ostromensky), as well as masters from neighbouring Curonia (Herrmann, Weissenborn) and Poland (Blomberg) worked there. In western Lithuania, then part of Prussia, Terletzki was active. Meanwhile, large factories (Walcker, Rieger) reached Lithuania only in the first half of the twentieth century and only in a few instances. At that time, more work started to be focusing on the construction of two-manual with pedal instruments. At the end of the century, J. Rudavicius built some three-manual organs. His 63-stop organ built in 1896 for a long time was the largest in Lithuania. Although the 19th century Lithuanian organs are relatively modest compared to other countries, they have the value that is only growing in the context of present-day Europe, since the “progressive ideology” of more economically powerful European countries affected the art of organ building and few small romantic instruments are left.

Estimation of Measurement Error of the Seawater Beam Attenuation Coefficient in Turbid Water of Arctic Seas

The article describes the estimation of measurement error of seawater beam attenuation coefficient using the Monte Carlo method. Measurements of the beam attenuation coefficient and its vertical distribution are the most common type of hydro-optical investigations since it is widely used for the research of light distribution in sea medium. Moreover, the beam attenuation coefficient is closely related to the concentration of the suspended substance and may be used for its estimation. Usually, the measurements of beam attenuation coefficient are conducted with small instrument base in rather transparent waters. In this case, the method errors of the beam attenuation coefficient measurement are low. However, in practice, cases of very turbid waters (near-bottom nepheloid layers), where measurement errors of beam attenuation coefficient significantly increase due to multiple scattering within the instrument base, are often encountered. The estimation of such errors is reviewed in this work. The effect of scattering phase function on the considered errors is described to the greatest extent. Moreover, the effect of the instrument base length and angle of view of the receiving system on measurement errors of beam attenuation coefficient is studied. Corresponding estimations are provided.

Efficacy and safety of Tramadol as an analgesic in women undergoing vaginoscopic hysteroscopy: a randomized placebo-controlled trial

Pain or discomfort during the hysteroscopy remains a challenge even after the introduction of small calibre instruments and vaginoscopic techniques. Tramadol, a centrally acting analgesic, is one among the medications used to reduce pain; however, the experience with its use in the vaginoscopic technique is limited. This was a randomised double-blind placebo-controlled trial conducted to study the effectiveness of oral Tramadol as an analgesic in 100 women undergoing diagnostic vaginoscopic hysteroscopy. Median pain score assessed by the Visual Analogue Scale was lower in the study group compared to the placebo group during the procedure (7 versus 8; p < .001) and immediately after the procedure (6 versus 7; p < .001) Ease of entry, procedure entry time and the adverse effects were similar in both the groups. Administration of oral Tramadol 50 mg, 1 h prior to the procedure may be a safe and effective analgesic in women undergoing diagnostic vaginoscopic hysteroscopy.Impact statementWhat is already known on this subject? Even with the use of newer hysteroscopes with small calibres and vaginoscopic techniques, pain and discomfort to the patient during negotiation through the cervix remain the main challenge to the surgeon. Among the several medications reported to reduce pain during the procedure, Tramadol a centrally acting drug with dual analgesic action, both by the µ opioid receptor agonist action and by the inhibiting uptake of serotonin and norepinephrine, can be used. However, studies using oral Tramadol during vaginoscopic hysteroscopy are limited.What do the results of this study add? The median pain score assessed by the Visual Analogue Scale was lower in the study group compared to the placebo group during the procedure (7 versus 8; p < .001) and immediately after the procedure (6 versus 7; p < .001). Ease of entry, procedure entry time and the adverse effects were similar in both the groups.What are the implications of these findings for clinical practice and/or further research? This study suggests that administration of oral Tramadol 50 mg, 1 h prior to the procedure, may be used as a safe and effective analgesic in women undergoing diagnostic vaginoscopic hysteroscopy. Future trial with a larger sample size is required to confirm the tolerability of its use, as the incidence of adverse effects was low in the study.

Influence of different loupe systems and their light source on the vision in endodontics

The aim of this study was to evaluate the performance of Galilean and Keplerian loupes in the endodontic lumen with and without integrated light. Although the use of an operating microscope is widely recommended in endodontics it is uncertain whether an adequate loupe system with coaxial light source might replace the microscope for some endodontic work. Twenty-four dentists (age 27–64 years) underwent a miniaturized visual test inside the endodontic lumen of a natural molar: at the canal entrance, 5 mm inside the canal, and at the apex. The tooth was mounted in a phantom head in a simulated clinical setting. The naked eye (negative) and the microscope 6× (positive) served as control groups, and Galilean loupes 2.5× and Keplerian loupes 4.3× with and without a coaxial light source as experimental groups. A structure of 0.05 mm corresponding to the smallest instrument (06) was the threshold for sufficient vision. The loupe type, coaxial light source and the dentists’ age had a statistically significant influence at all locations. None of the loupes helped to visualize structures at the apex. At the canal entrance, the visual threshold was reached by dentists < 40 years with Galilean loupes, by dentists ≥ 40 years with Keplerian loupes, with and without coaxial light. Dentists < 40 years detected structures < 0.05 mm inside the root canal with Keplerian loupes and coaxial light. The microscope offered highly superior results. The naked eye was insufficient to reach the visual threshold at any location.