Forensic geoscience non-invasive detection and characterisation of underground clandestine complexes, bunkers, tunnels and firing ranges

Recent events in conflict zones have emphasized that the successful detection and characterisation of buried clandestine complexes, bunkers and tunnels is vitally important for forensic investigators globally, to reduce or solve criminal activities, address national security threats and avoid potential terrorist attacks. However, this can often prove very difficult, particularly in urban areas, with potentially both below-ground non target items and above-ground infrastructures present, that can interfere with detecting target(s). Here we provide selected successful case studies where forensic geoscience techniques were used to detect and characterise buried clandestine complexes, bunkers and tunnels using different geophysical techniques. Generally, desktop studies assessing pre-existing information, including local geology, soils, historical/modern remote sensing, maps and photographs inform appropriate geophysical survey technique(s) selection. Subsequent near-surface geophysical techniques are then employed to produce accurate plans of sub-surface targets, with numerical modelling and correction for the interfering effects of above ground infrastructure, enabling the calibration of geophysical datasets to provide confidence in their respective interpretations. All forensic investigations are, of course, unique to every site, and thus require an individual approach to their respective ground conditions. Investigations should be both phased and iterative, with techniques tailored to local conditions: the selection of geophysical method(s) is crucial to improve successful detection rates of such important buried targets.

Large rectangular cross-section tunnel undercrossing urban road by micro pipe jacking and joint assembly structure (MPJ & JAS) method in soft soils

With the continuous construction of urban traffic roads, more and more new roads are cut off by existing roads to form "dead end roads". There is an urgent need for a trenchless method suitable for urban ultra-shallow overburden to build the undercrossing tunnel. To solve this problem, this paper proposed the micro pipe jacking and joint assembly structure (MPJ & JAS) method, which has the characteristics of shallow burial depth, low cost, short construction time, flexible cross-section setting and high space utilization. The MPJ & JAS method construct a large cross-section tunnel through assembling small cross-section elements, quite different from traditional methods. Therefore, this paper designed a CT-shaped integrated joint, the mechanical performance of which was verified and clarified by tensile test. The bending test and finite element (FE) analysis proved the reliability of MPJ & JAS tunnel structure, and confirmed the structure performances such as the failure models, crack behaviors, load-deflection response and stress-strain distribution. Moreover, the influences of the steel plate thickness, concrete strength and shear connector spacing were determined by the FE analysis. On the basis of test results and reasonable assumptions, a theoretical design method considering the influence of the CT-shaped integrated joint was proposed, which can effectively predict the bending strength of the MPJ & JAS tunnel structure with an error of less than 10%. Finally, in view of the characteristics of the MPJ & JAS method, the suitable micro pipe jacking machine, soil reinforcement measure, hydraulic traction construction technology, high-precision guidance system and concrete construction quality detection method based on the phased array ultrasonic imaging technology were developed, supporting the accurate and efficient construction of the MPJ & JAS tunnel.

The catalytic mechanism of direction-dependent interactions for 2,3-dihydroxybenzoate decarboxylase

Benzoic acid decarboxylases offer an elegant alternative to CO2 fixation by reverse reaction-carboxylation, which is named the bio-Kolbe-Schmitt reaction, but they are unfavorable to carboxylation. Enhancing the carboxylation efficiency of reversible benzoic acid decarboxylases is restricted by the unexplained carboxylation mechanisms. The direction of reversible enzyme catalytic reactions depends on whether catalytic residues at the active center of the enzyme are protonated, which is subjected by the pH. Therefore, the forward and reverse reactions could be separated at different pH values. Reversible 2,3-dihydroxybenzoate acid decarboxylase undergoes decarboxylation at pH 5.0 and carboxylation at pH 8.6. However, it is unknown whether the interaction of enzymes with substrates and products in the forward and reverse reactions can be exploited to improve the catalytic activity of reversible enzymes in the unfavorable direction. Here, we identify a V-shaped tunnel of 2,3-dihydroxybenzoic acid decarboxylase from Aspergillus oryzae (2,3-DHBD_Ao) through which the substrate travels in the enzyme, and demonstrate that the side chain conformation of a tyrosine residue controls the entry and exit of substrate/product during reversible reactions. Together with the kinetic studies of the mutants, it is clarified that interactions between substrate/product traveling through the enzyme tunnel in 2,3-DHBD_Ao are direction-dependent. These results enrich the understanding of the interactions of substrates/products with macromolecular reversible enzymes in different reaction directions, thereby demonstrating a possible path for engineering decarboxylases with higher carboxylation efficiency. KEY POINTS: • The residue Trp23 of 2,3-DHBD_Ao served as a switch to control the entry and exit of catechol • A V-shaped tunnel of 2,3-DHBD_Ao for decarboxylation and carboxylation reactions was identified • The results provide a promising strategy for engineering decarboxylases with direction-dependent residues inside the substrate/product traveling tunnel of the enzyme.

The Incidence of Carpal Tunnel Syndrome Diagnosis Increases after Arthroscopic Shoulder Surgery

Purpose

Arthroscopic shoulder surgery has been identified as a potential risk factor for carpal tunnel syndrome (CTS). The purposes of this study were as follows: to (1) examine the percentage of patients who underwent arthroscopic shoulder procedures and later developed ipsilateral CTS within 1 year of the procedure, (2) determine the percentage of those patients with CTS who subsequently underwent an injection or release, and (3) examine comorbidities associated with developing CTS after surgery.

Methods

Patients who underwent arthroscopic rotator cuff repair (RCR), labral repair, or biceps tenodesis were retrospectively identified in a national database. Within 1 year, we compared the rates of ipsilateral CTS diagnoses versus the contralateral side. The rates of comorbidities between those who did and did not develop CTS were also compared.

Results

Within 1 year, arthroscopic RCR patients (1.47% vs 1.00%; odds ratio [OR], 1.48; P < .001) and arthroscopic labral repair patients (0.76% vs 0.52%; OR, 1.47; P < .001) had a significantly higher rate of ipsilateral carpal tunnel diagnosis versus contralateral side diagnosis. Arthroscopic RCR patients were also significantly more likely to have ipsilateral carpal tunnel injection (0.16% vs 0.11%; OR, 1.45; P < .001) and release (0.46% vs 0.37%; OR, 1.24; P < .001). Patients who had an ipsilateral carpal tunnel diagnosis following arthroscopic RCR and labral repair were both significantly older (both P < .001), a higher percentage of women (both P<.001), and more likely to have had a preoperative nerve block (both P < .05). Both cohorts had significantly higher mean Elixhauser comorbidity Index (P < .001) and more comorbidities.

Conclusions

This study demonstrated a significantly higher incidence of operative side CTS within 1 year following arthroscopic RCR and labral repairs. Arthroscopic RCR was also demonstrated to result in significantly higher rates of injections and carpal tunnel release. The cohort that developed ipsilateral CTS was older, had higher percentage of women, and had more comorbidities.

Type of study/level of evidence

Prognostic III.

Muscle interconnections in the anterior and posterior arm compartment: a cadaveric case series with possible clinical implications

PURPOSE

The report describes four cases of accessory bundles (ABs) or fibers connecting the muscles of the anterior with the posterior arm compartment. The ABs morphology (pure muscular or musculofascial or musculoaponeurotic) is described emphasizing their attachment points, characterized as muscles' interconnections.

MATERIALS AND METHODS

Four formalin-embalmed donated male cadavers were dissected.

RESULTS

The muscles' interconnections were unilaterally identified. In the first case, the two ABs originated from the coracobrachialis muscle (CB), received fibers from the biceps brachii (BB), and were inserted into the triceps brachii (TB) medial head. The ABs created an arch over the brachial vessels and the median nerve (MN). In the second case, an accessory musculoaponeurotic structure was identified between CB and TB medial head and extended over the brachial vessels. In the third case, the myofascial ABs between the BB short head and the upper arm fascia, coursed anterior to the MN, the brachial artery, and the ulnar nerve, with direction to the TB medial head. In the fourth case, the three muscular ABs originating from the CB superficial and deep heads, in common with the BB short head, joined the upper arm fascia and the TB medial head and possibly entrapped the musculocutaneous nerve, the MN, and the brachial artery.

CONCLUSION

ABs or musculoaponeurotic extensions may predispose to complications due to their potential compression on nerves and vessels. Clinicians should consider the possible existence of such bridging variants between muscles, in the differential diagnosis of a patient presenting with ischemia, edema, or MN palsy symptoms.

Genetic mechanism of high geotemperature in tunnels in consideration of temperature monitoring and hydrogeochemical analysis

During the tunnel construction, high geotemperature is a recurrent phenomenon in geothermal anomalous zones, significantly affecting both human resources and equipment involved in the process. The current study takes the Nige tunnel, the tunnel with the highest known geotemperature in China, as a case study to analyze the underlying dynamics of this phenomenon. The geotemperature within the tunnel is monitored during excavation before delving into a detailed analysis of the basic characteristics of the high geotemperatures measured. Subsequently, an investigation is conducted into the hot springs in close proximity to the Nige tunnel, which serves to reveal potential heat sources contributing to the high geotemperature. To further reveal the hydrochemical and geothermal reservoir characteristics of the area surrounding the tunnel and hot spring, a water quality test is performed. Lastly, the study situates its findings regarding the geological genesis of high geotemperature within the context of investigating heat conduction channels. Results demonstrate the coexistence of high water temperature (Water T) and rock temperature (Rock T) in the Nige tunnel, with maximum temperatures recorded as 63.4 °C and 88.8 °C, respectively. This study concludes that the source of deep circulating hot water likely stems from infiltration and combination of atmospheric precipitation and shallow water from the continental environment. Additionally, the geotemperature within tunnels primarily stems from thermal anomalous bodies in the deep crust. The performances may be used as guidance to address similar issues that arise in regions with high geotemperature.

Emission profiles, source identifications, and health risk of polycyclic aromatic hydrocarbons (PAHs) in a road tunnel located in Xi'an, China

Understanding the sources and characteristics of PM2.5-bound PAHs from traffic-related pollution can provide valuable data for mitigating air contamination from traffic in local urban regions. However, little information on PAHs is available regarding the typical arterial highway-Qinling Mountains No.1 tunnel in Xi'an. We estimated the profiles, sources, and emission factors of PM2.5-bound PAHs in this tunnel. The total PAH concentrations were 22.78 ng·m-3 and 52.80 ng·m-3 at the tunnel middle and exit, which were 1.09 and 3.84 times higher than that at the tunnel entrance. Pyr, Flt, Phe, Chr, BaP, and BbF were the dominant PAH species (representing approximately 78.01% of total PAHs). The four rings PAHs were dominant (58%) among the total PAH concentrations in PM2.5. The results demonstrated that diesel and gasoline vehicles exhaust emissions contributed 56.81% and 22.60% to the PAHs, respectively, while the corresponding value for together brakes, tyre wear, and road dust was 20.59%. The emission factors of total PAHs were 29.35 μg·veh-1·km-1, and emission factors of 4 rings PAHs were significantly higher than those of the other PAHs. The sum of ILCR was estimated to be 1.41×10-4, which accorded with acceptable level of cancer risk (10-6-10-4), PAHs should not ignored as they still affect the public health of inhabitants. This study shed light on PAH profiles and traffic-related sources in the tunnel, thereby facilitating the assessment of control measures targeting PAHs in local areas.

The evaluation analysis on the airborne dust regional pollution of the anchor drilling operation in the tunnel

The anchor drilling operations generate massive airborne dust particles in the tunnel heading face that raises the pneumoconiosis morbidity and explosion risk. In this paper, a full-scale tunnel physical model is constructed to study the effect of the wind velocity and drilling site position on the airborne dust regional pollution scope based on the actual anchor drilling craft. The research indicates that the four extensive vortex areas keep the dust suspension at 14 m from the heading face and make the deposition dust particle refloat. The average respirable dust rate reaches the maximum value at section 5 m and presents a gradual decline as the dust particle migrates along the outlet direction. Raising the wind velocity contributes to alleviating the airborne dust pollution in the anchor drilling operation. As the wind velocity increases from 3 to 24 m/s, the high dust concentration area and number higher than 200 mg/m³ pose overall decrease trends, and the average dust concentration displays a linear decrease until 26.14-58.65 mg/m³ around the anchor worker head. Moving the drilling site positions closer to the exhaust air duct aggravates the airborne dust pollution in the front breathing zone. As the anchor drilling operation switches from the return air side to the supply air side, the dust concentration area ascends by 59.4-84.4% in the personnel respiratory space.

Preparation and performance of photocatalytic NO degradation superhydrophobic coatings for tunnel

Due to the semi-closed structure of the tunnel, serious air pollution in tunnels from vehicle exhaust becomes an issue which needed to be addressed. Among the exhaust, nitric oxide (NO) is typically considered as one of the main pollutants. In this paper, a superhydrophobic photocatalytic coating was fabricated by a spraying method by airbrush with a WO₃/TiO₂ photocatalysis for NO degradation. The water advanced contact angle (WACA) of the coating reached 166.32°, and the WACA was still above 145° after the 30 times abrasion test. The coating exhibited an excellent ability to remove inorganic and organic pollutants. Also, the NO degradation efficiency of this superhydrophobic coating under ultraviolet and visible light sources and humid environments was tested. When the relative humidity reached 98%, the NO degradation efficiency of the coating remained unchanged under visible light irradiation compared with the relative humidity of 45%. In addition, the coating exhibited prominent stability of NO degradation during the cyclic test. Furthermore, the WT coating showed stability and synergy of self-cleaning and photocatalysis toward NO degradation, which ensured the long-term use of the coating. Finally, a synergistic mechanism for self-cleaning and photocatalysis was proposed. This may provide a new idea and support for the application of photocatalytic technology in the degradation of NO in the tunnel.

Fast approximative methods for study of ligand transport and rational design of improved enzymes for biotechnologies

Acceleration of chemical reactions by the enzymes optimized using protein engineering represents one of the key pillars of the contribution of biotechnology towards sustainability. Tunnels and channels of enzymes with buried active sites enable the exchange of ligands, ions, and water molecules between the outer environment and active site pockets. The efficient exchange of ligands is a fundamental process of biocatalysis. Therefore, enzymes have evolved a wide range of mechanisms for repetitive conformational changes that enable periodic opening and closing. Protein-ligand interactions are traditionally studied by molecular docking, whereas molecular dynamics is the method of choice for studying conformational changes and ligand transport. However, computational demands make molecular dynamics impractical for screening purposes. Thus, several approximative methods have been recently developed to study interactions between a protein and ligand during the ligand transport process. Apart from identifying the best binding modes, these methods also provide information on the energetics of the transport and identify problematic regions limiting the ligand passage. These methods use approximations to simulate binding or unbinding events rapidly (calculation times from minutes to hours) and provide energy profiles that can be used to rank ligands or pathways. Here we provide a critical comparison of available methods, showcase their results on sample systems, discuss their practical applications in molecular biotechnologies and outline possible future developments.

Design and application of a dust suppression technology of the forcing air curtain in fully mechanized rock tunnelling faces

To effectively reduce high dust concentrations and keep clean air in fully mechanized rock tunnelling faces in coal mine, this study carried out a research of dust suppression technology of the forcing air curtain. First, the mechanism of dust diffusion controlled by the forcing air curtain was introduced in this study. Then, numerical simulations of the formation of the forcing air curtain as well as the influence for dust diffusion under the different distance between forcing air duct outlet and heading end were carried out. Moreover, a dust suppression technology of the forcing air curtain was designed and tested in a fully mechanized rock tunnelling face of southern return air tunnel which was located in the Tangkou coal mine of China. It shows that the numerical simulation results were in good agreement with the in situ tests. The average removal rate of total and respirable dust could reach up to 95.1% and 96.1%, respectively, at manned working areas in the tunnel. Research results show that the dust suppression technology of the forcing air curtain is an effective method of dust control in fully mechanized rock tunnelling faces.

Environmental and health risks of VOCs in the longest inner-city tunnel in Xi'an, Northwest China: Implication of impact from new energy vehicles

Traffic source-dominated volatile organic compound (VOC) samples were collected during four time-intervals in a day (Ⅰ: 7:30-10:30, Ⅱ: 11:00-14:00, Ⅲ: 16:30-19:30, and Ⅳ: 20:00-23:00) in a tunnel in summer, 2019, in Xi'an, China. The total measured VOC (TVOC) in periods Ⅰ and Ⅲ (rush hours, 107.2 ± 8.2 parts per billion by volume [ppbv]) was 1.8 times that in periods Ⅱ and Ⅳ (non-rush hours, 58.6 ± 13.8 ppbv), consistent with the variation in vehicle numbers in the tunnel. The considerably elevated ethane and ethylbenzene levels could have been attributed to emissions from compressed natural gas vehicles and the rapid development of methanol-fueled taxis in Xi'an in 2019. The mixing ratios of benzene, toluene, ethylbenzene, and xylenes (BTEX) contributed 9.4%-12.7% to TVOCs, and the contributions were nearly 40% higher in periods Ⅰ and Ⅲ than in Ⅱ and Ⅳ, indicating that BTEX levels were strongly affected by vehicle emissions. The indicators of motor vehicle emission, namely ethylene, propylene, toluene, m/p-xylenes, o-xylene, and propane, contributed to more than half of the ozone formation potential in this study. The noncarcinogenic risks of VOCs in this study were within the international safety standard, whereas the carcinogenic risks exceeded the standard by 2.3-4.6 times, suggesting that carcinogenic risks were more serious than noncarcinogenic risks. VOCs presented 2.2 and 1.4 times noncarcinogenic and carcinogenic risks during rush hours than during non-rush hours, respectively. Notably, the carcinogenic risk in period Ⅳ was comparable with that in period Ⅲ; however, the vehicle numbers and VOC mixing ratios were the lowest at night, which may have attributed to the increasing number and proportion of methanol M100-fueled vehicles in the tunnel. Therefore, VOCs emitted by new energy vehicles should also be seriously considered while evaluating fossil fuel vehicle emissions.

Screening of world approved drugs against highly dynamical spike glycoprotein of SARS-CoV-2 using CaverDock and machine learning

The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes pathological pulmonary symptoms. Most efforts to develop vaccines and drugs against this virus target the spike glycoprotein, particularly its S1 subunit, which is recognised by angiotensin-converting enzyme 2. Here we use the in-house developed tool CaverDock to perform virtual screening against spike glycoprotein using a cryogenic electron microscopy structure (PDB-ID: 6VXX) and the representative structures of five most populated clusters from a previously published molecular dynamics simulation. The dataset of ligands was obtained from the ZINC database and consists of drugs approved for clinical use worldwide. Trajectories for the passage of individual drugs through the tunnel of the spike glycoprotein homotrimer, their binding energies within the tunnel, and the duration of their contacts with the trimer's three subunits were computed for the full dataset. Multivariate statistical methods were then used to establish structure-activity relationships and select top candidate for movement inhibition. This new protocol for the rapid screening of globally approved drugs (4359 ligands) in a multi-state protein structure (6 states) showed high robustness in the rate of finished calculations. The protocol is universal and can be applied to any target protein with an experimental tertiary structure containing protein tunnels or channels. The protocol will be implemented in the next version of CaverWeb (https://loschmidt.chemi.muni.cz/caverweb/) to make it accessible to the wider scientific community.

Anterior cruciate ligament reconstruction femoral tunnel drilling preference among orthopaedic surgeons

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) technique for femoral tunnel drilling varies substantially, each with advantages and disadvantages. The purpose of this study was to define ACLR femoral tunnel technique predilection among surgeons and to explore factors associated with their preference.

METHODS

An 11-question survey regarding ACLR femoral tunnel technique was completed by 560 AANA/AOSSM members. Surgeon and practice demographics and residency and fellowship experiences were evaluated with bivariate and multivariable models for association with surgeon preference.

RESULTS

In current practice, 55% of surgeons prefer anteromedial (AM) portal drilling, 32% retrograde, and 14% transtibial (TT). Sports Medicine fellowship experience was the strongest predictor of current practice (p < 0.001), followed by residency technique (p = 0.014). A significant increase in TT drilling was noted for those practicing >15 years TT (29% vs 3%, p < 0.001), with an inverse relationship for retrograde drilling (38% vs 21%, p < 0.001). Number of ACLRs/year and percent Sports specific practice were significant predictors for AM drilling (p < 0.001). Though less than AM and retrograde, TT was more common for those in private practice (17% vs 8%, p < 0.001), and more prevalent in the Midwest/Southeast (19% vs 10%, p = 0.003). Non-significant predictors included highest level of athlete for whom an ACLR had been performed, level of athlete serving as team physician, and Certificate of Added Qualifications status.

CONCLUSION

Surgeon training, practice setting, and years in practice significantly predict preference for femoral tunnel drilling technique. Surgeon comfort and confidence in attaining an anatomic reconstruction should drive choice of technique.

Human liver umbilical fissure variants: pons hepatis (ligamentum teres tunnel)

PURPOSE

In the classical description of normal liver anatomy, the umbilical fissure is a long, narrow groove that receives the ligamentum teres hepatis. The pons hepatis is an anatomic variant, where the umbilical fissure is converted into a tunnel by an overlying bridge of liver parenchyma. We carried out a study to evaluate the existing variations of the umbilical fissure in a Caribbean population.

METHODS

We observed all consecutive autopsies performed at a facility in Jamaica and selected cadavers with a pons hepatis for detailed study. A pons hepatis was considered present when the umbilical fissure was covered by hepatic parenchyma. We recognized two variants: an open-type (incomplete) pons hepatis in which the umbilical fissure was incompletely covered by parenchyma ≤ 2 cm in length and a closed type (complete) pons hepatis in which the umbilical fissure was covered by a parenchymal bridge > 2 cm and thus converted into a tunnel. We measured the length (distance from transverse fissure to anterior margin of the parenchymatous bridge), width (extension across the umbilical fissure in a coronal plane) and thickness (distance from the visceral surface to the hepatic surface measured at the mid-point of the parenchymal bridge in a sagittal plane) of each pons hepatis. A systematic literature review was also performed to retrieve data from relevant studies. The raw data from these retrieved studies was used to calculate the global point prevalence of pons hepatis and compared the prevalence in our population.

RESULTS

Of 66 autopsies observed, a pons hepatis was present in 27 (40.9%) cadavers. There were 15 complete variants, with a mean length of 34.66 mm, mean width of 16.98 mm and mean thickness of 10.98 mm. There were 12 incomplete variants, with a mean length of 17.02 mm, width of 17.03 mm and thickness of 9.56 mm. The global point prevalence of the pons hepatis (190/5515) was calculated to be or 3.45% of the global population.

CONCLUSIONS

We have proposed a classification of the pons hepatis that is reproducible and clinically relevant. This allowed us to identify a high prevalence of pons hepatis (41%) in this Afro-Caribbean population that is significantly greater than the global prevalence (3.45%; P < 0.0001).

The Anatomy, Presentation and Management Options of Cubital Tunnel Syndrome

Cubital tunnel syndrome is the second most common nerve compression syndrome seen in the upper limb. Paresthesia and weakness are the two most common presentations in the hand. If left untreated, compression can lead to irreversible nerve damage, resulting in a loss of function of the forearm and hand. Therefore, recognizing the various clinical presentations of cubital tunnel syndrome can lead to early detection and prevention of nerve damage. Conservative management is usually tried first and involves supporting the elbow using a splint. If this fails and symptoms do not improve, surgical management is indicated. There are 3 main surgical techniques used to relieve compression of the nerve. These are simple decompression, anterior transposition and medial epicondylectomy. Studies comparing the techniques have demonstrated particular advantages to using one or another. However, the overall technique of choice is based on both the clinical scenario and the surgeon's digression. Following primary cubital tunnel surgery, recurrent symptoms can often occur due to a variety of pathological and non-pathological causes and revision surgery is usually warranted. This article provides a complete review of cubital tunnel syndrome.

Regional transport and urban emissions are important ammonia contributors in Beijing, China

Measuring ammonia (NH₃) is important for understanding the role of NH₃ in secondary aerosol formation and the atmospheric deposition of reactive N. In this study, NH₃ was measured in an urban area, a background region, and a tunnel in Beijing. The average NH₃ concentrations between September 2017 and August 2018 were 24.8 ± 14.8 ppb and 11.6 ± 10.3 ppb in the urban area and background region, respectively. Higher NH₃ concentrations at both the urban and background sites, relative to some earlier measurements indicated a likely increase in the NH₃ concentrations in these regions. The urban NH₃ level in Beijing was much higher than that typically observed at urban and industrial sites in other domestic and foreign cities, suggesting that the Beijing urban area was affected by greater NH₃ emissions than other regions. Based on the relationship among NH₃, wind direction, and wind speed, the urban area was affected by both local emissions and air transported from North China Plain (NCP). Potential source contribution function analyses suggested that regional transport from the NCP could greatly affect local concentrations of NH₃ in both urban and background areas in spring and autumn; however, in addition to the NCP, urban emissions could also affect NH₃ levels in the background region in summer and winter. The average NH₃ concentration at the Fenshuiling Tunnel was 8.5 ± 7.7 ppb from December 2017 to February 2018. The NH₃:CO emission ratio measured in the tunnel test was 0.022 ± 0.038 ppb/ppb, which was lower than values in the USA and South Korea. The contribution of traffic to NH₃ in Beijing did not agree well with the available emission inventories, suggesting that vehicular emissions were underestimated and further evaluation is necessary.

"Suprascapular canal": Anatomical and topographical description and its clinical implication in entrapment syndrome

BACKGROUND

Suprascapular nerve (SN) entrapment syndrome accounts for 1-2% of all shoulder pain. The SN travels within a space between the suprascapular notch (SSN) and the spinoglenoid notch (SGN).

PURPOSE

To report a detailed topographical study of the suprascapular canal (SSC) and ultimately sort the different types of SN entrapment by its anatomical localization within the canal.

BASIC PROCEDURES

Observational study on 30 free dissected limbs of formaldehyde-fixed cadavers. The SN and vessels were traced as they passed through the SSC and the boundaries of the SSC were observed and documented. The SSC was then exposed by reflecting away the bordering muscles. Dimensions of the SSC as well as parameters of the SSN and SGN were measured using a digital caliper. Finally, a thorough literature review was made to survey the SN entrapment occurrence by site.

MAIN FINDINGS

The SSC is situated in the spinoglenoid fossa, has an average width of 13 mm, and runs underneath the supraspinatus muscle with an average distance of 25 mm between the SSN and SGN sloping in an infero-postero-lateral direction. The first segment represents the SSC entrance site and is composed of two spaces: osteofibrous and musculofibrous. The second segment is bordered by the supraspinatus muscle fascia, lateral margin of the supraspinous fossa, glenohumeral joint capsule, and the bony surface of the scapula (spinoglenoid fossa). This represents the SSC passage site. The third segment represents the SSC exit site around the spinoacromial arch at the SGN.

PRINCIPAL CONCLUSIONS

The SSC is defined as an osteofibrous canal running between the SSN and SGN enclosed by the supraspinatus fascia. It is anatomically composed of three segments: an entrance, a passage, and an exit. The distal SN passes through the SSC via five intervals that correspond to five potential sites of anatomical nerve entrapment: at the pre-entrance site, entrance site, passage site, exit site, and post-exit site. Each of those sites was found to be associated with specific causes and forms of entrapment.

Revisiting freeway single tunnel crash characteristics analysis: A six-zone analytic approach

Considerable studies have been conducted to investigate the tunnels' traffic safety. However, the entrance and exit parts of a tunnel are mostly considered symmetrical in previous studies, and the different lengths (long, medium, and short) of tunnels have not been separately studied. This study aims to investigate the characteristics of traffic crashes in freeway single tunnels by separately considering the entrance and exit of the tunnel as well as the different lengths of tunnels. A six-zone approach is proposed, and the data from 156 single tunnels in Hunan province, China, are applied for safety analysis. The crash rate, crash type, and contributing crash factors are compared between the conventional four-zone approach and the proposed method, and the three types of tunnels with different lengths are also compared for in-depth analysis. Results show that the proposed six-zone method provides a better understanding of the tunnels crash characteristics. The most crash-prone zones for long, medium, and short tunnels are the mid-zone, the entrance zone, and the access zone, respectively. Furthermore, at the tunnel entrance, drivers usually fail to maintain safe distance, which results in the high proportion of rear-end crashes, while at the tunnel exit, they do speeding and improper lane change that increases the risk of sideswipe, rollover, and collision with fixed objects. The study also discusses the crash occurrence mechanism for different types of tunnels. Findings of this study shed some light on the engineering and policy implications for improving traffic safety of the freeway tunnels.

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and their derivatives (nitrated-PAHs and oxygenated-PAHs) in a road tunnel located in Qingdao, China: Characteristics, sources and emission factors

Daytime and nighttime PM_2.5 samples were collected at a road tunnel located in Qingdao, China. The mass concentrations and chemical compositions of polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated-PAHs (OPAHs) were analysed to determine the variation characteristics and sources. The concentrations in exit were obviously higher than those of entrance in the tunnel. Fluoranthene (FLT) and Pyrene (PYR) were the most abundant PAHs, 2 + 3-nitrofluoranthene (2 + 3N-FLA), 1-nitropyrene (1N-PYR) and 2-nitropyrene (2N-PYR) were the dominant NPAHs, and 9-fluorenone (9-FO) and 9,10-anthraquinone (9,10-ANQ) were the most abundant OPAHs. The high rings (4-6 rings) PAHs accounted for over 90% of the total PM_2.5-bound PAH concentrations, most of which were considered as motor vehicle emissions. Based on the diagnostics ratios and PCA results, the most important sources of PAHs and NPAHs were estimated as gasoline and diesel vehicles emissions in the tunnel. In addition, non-exhausts (such as road dust, brake line, asphalt and tires wear) also had some contributions to PAHs and NPAHs. The average emission factors were 60.98, 9.02 and 8.47 μg veh^-1 km^-1 for total PM_2.5-bound PAHs, NPAHs and OPAHs, respectively. The emission factors of high rings (4-6 rings) PAHs were greater than those with low rings (2-3 rings). 1N-PYR had the highest emission factor in all measured NPAHs, while the emission factors for the two highest OPAHs were 9-FO and 9,10-ANQ in this tunnel.

Scale deposits in tunnel drainage systems - A study on fabrics and formation mechanisms

Rapid deposition of chemical sediments, particularly calcium carbonate, is a widespread phenomenon in tunnel constructions, which can significantly disturb water draining. The removal of the scale deposits in the drainage setting is labor and cost intensive. Prediction or prevention of these unwanted scale deposits are challenging and require detailed knowledge on their site-specific source, formation mechanisms and environmental dependencies. This case study combines a mineralogical, (micro)structural, isotopic, microbiological, and hydrochemical approach to understand the formation of scale deposits in an Austrian motorway tunnel. Chemical and isotopic results revealed that all investigated solutions originate from a distinct local aquifer. High pH (11), indicative high alkaline element concentrations (Na 26 mg/l; K 67 mg/l), originated from concrete leaching, and a strong supersaturation in respect to calcite (SI > 1) are representative for the environmental setting of scaling type 1. This type is characterized by the formation of calcite, aragonite, and rarely documented dypingite (Mg₅(CO₃)₄(OH)₂*5H₂O), and yields in a highly porous material showing minor indications of microbial presence. In contrast, scale deposits of type 2 are strongly microbially influenced, yielding dense and layered mineral deposits, typically consisting of calcite. The corresponding aqueous solution revealed elevated Mg concentration (38 mg/l) and a high molar Mg/Ca ratio (0.8). Scale deposits containing distinct aragonite precipitates next to calcite, mostly growing in pore spaces of the scale fabric, are accounted as type 3. Therein, dypingite is always growing on top of aragonite needles, indicative for prior CaCO₃ precipitation. The composition of corresponding solutions shows the highest Mg/Ca ratio (1.1). Scale type 4 is characterized as a compact deposit consisting entirely of calcite. Its corresponding solution exhibits a molar Mg/Ca ratio of 0.6. From the obtained data sets a conceptual model was developed describing the distinct operative and (micro)environmental conditions responsible for the distinct diversity of scale deposits.

Structural basis for differentiation between two classes of thiolase: Degradative vs biosynthetic thiolase

Thiolases are a well characterized family of enzymes with two distinct categories: degradative, β-ketoadipyl-CoA thiolases and biosynthetic, acetoacetyl-CoA thiolases. Both classes share an identical catalytic triad but catalyze reactions in opposite directions. Moreover, it is established that in contrast to the biosynthetic thiolases the degradative thiolases can accept substrates with broad chain lengths. Hitherto, no residue or structural pattern has been recognized that might help to discern the two thiolases, here we exploit, a tetrameric degradative thiolase from Pseudomonas putida KT2440 annotated as PcaF, as a model system to understand features which distinguishes the two classes using structural studies and bioinformatics analyses. Degradative thiolases have different active site architecture when compared to biosynthetic thiolases, demonstrating the dissimilar chemical nature of the active site architecture. Both thiolases deploy different "anchoring residues" to tether the large Coenzyme A (CoA) or CoA derivatives. Interestingly, the H356 of the catalytic triad in PcaF is directly involved in tethering the CoA/CoA derivatives into the active site and we were able to trap a gridlocked thiolase structure of the H356A mutant, where the CoA was found to be covalently linked to the catalytic cysteine residue, inhibiting the overall reaction. Further, X-ray structures with two long chain CoA derivatives, hexanal-CoA and octanal-CoA helped in delineating the long tunnel of 235 Å² surface area in PcaF and led to identification of a unique covering loop exclusive to degradative thiolases that plays an active role in determining the tunnel length and the nature of the binding substrate.

The medial safe zone for treating intraneural ganglion cysts in the tarsal tunnel: a technical note

INTRODUCTION

Intraneural ganglion cysts in the tarsal tunnel are rare but are being increasingly reported. The cysts involve the tibial or plantar nerves and are most commonly derived from a neighboring (degenerative) joint, (i.e., the tibiotalar or subtalar) via an articular branch arising from the medial aspect of the nerve. We describe a safe zone for approaching these cysts in the tarsal tunnel that allows for identification of the joint connection without injury to important distal branches.

METHODS

We present a case of an intraneural ganglion cyst within the tarsal tunnel in a patient with symptoms consistent with tarsal tunnel syndrome. Using intraoperative photographs and artist rendering, we describe a technique to safely disconnect the abnormal joint connection while preserving the important distal branches of the tibial nerve.

CONCLUSION

The safe zone for the tibial nerve in the tarsal tunnel can be exposed by mobilization and gentle retraction of the vascular bundle. In cases of intraneural ganglion cysts, all apparent connections between the nerve and degenerative joints within this safe zone can be resected without injury to important distal nerve branches.

Carpal Tunnel Syndrome Associated with Bifid Median Nerve and Palmaris Profundus - Case Report and Literature Review

The anatomic variations of the median nerve and of the muscles of the wrist have been widely reported in literature. It is essential for the surgeon to be familiar with these variations in order to avoid accidental injury to the nerve during surgery. We report a rare case of bifid median nerve accompanied by an anomalous tendon of palmaris profundus discovered during the surgical release of carpal tunnel. The transverse carpal ligament was dissected and the anomalous tendon was left in situ because any direct compression over the median nerve was noticed intraoperatively. The patient was evaluated one year postoperatively clinically and radiologically (with MRI). At the follow up the resolution of symptoms was complete and the sleep disturbance was solved. The patient achieved a postoperative QuickDASH score of 9.1 and a Michigan Hand Questionnaire outcome score of 90 points.

High prevalence of hidradenitis suppurativa in patients with perianal fistula

BACKGROUND

Perianal fistula is an abnormal communication between the anal canal and perianal skin. Hidradenitis suppurativa (HS) is a chronic, auto-inflammatory skin disease in the intertriginous body areas, presenting with recurring abscesses, inflammatory nodules, and sinus tracts. The aim of this study was to determine the prevalence of HS in patients with a perianal fistula.

METHODS

All patients with perianal fistula visiting a specialized proctology clinic between July and September 2017 were included and asked a validated diagnostic question for HS. Subsequently, physical examination was performed to objectively assess the diagnosis and relevant patient characteristics.

RESULTS

In 6.6% (8/122) of patients, HS was diagnosed outside the perianal region. Four of these patients were newly diagnosed. The fistulas in HS patients were classified as a superficial fistula (three), a blind ending fistula (two), and a transsphincteric fistula (two). One patient had more than one type of fistula.

CONCLUSION

The prevalence of HS in patients with a perianal fistula is at least 6.6%. This is higher than the prevalence reported in the general European population (1%) suggesting an association between perianal fistulas and HS. We stress the importance to screen for HS in patients with perianal fistulas in order to start appropriate anti-inflammatory treatment to reduce symptoms and disease progression.

Engineering enzyme access tunnels

Enzymes are efficient and specific catalysts for many essential reactions in biotechnological and pharmaceutical industries. Many times, the natural enzymes do not display the catalytic efficiency, stability or specificity required for these industrial processes. The current enzyme engineering methods offer solutions to this problem, but they mainly target the buried active site where the chemical reaction takes place. Despite being many times ignored, the tunnels and channels connecting the environment with the active site are equally important for the catalytic properties of enzymes. Changes in the enzymatic tunnels and channels affect enzyme activity, specificity, promiscuity, enantioselectivity and stability. This review provides an overview of the emerging field of enzyme access tunnel engineering with case studies describing design of all the aforementioned properties. The software tools for the analysis of geometry and function of the enzymatic tunnels and channels and for the rational design of tunnel modifications will also be discussed. The combination of new software tools and enzyme engineering strategies will provide enzymes with access tunnels and channels specifically tailored for individual industrial processes.

Developing air exchange rate models by evaluating vehicle in-cabin air pollutant exposures in a highway and tunnel setting: case study of Tehran, Iran

The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM₁₀ for the open windows condition was seven times greater when compared to closed windows and air conditioning on. When the vehicle was passing through the tunnel, in-cabin CO and particle number increased 100 and 30%, respectively, compared to driving on highway. Air exchange rate (AER) is a significant factor when evaluating in-cabin air pollutants level. AER was measured and simulated by a model developed through a Monte Carlo analysis of uncertainty and considering two main affecting variables, vehicle speed and fan speed. The lowest AER was 7 h^-1 for the closed window and AC on conditions, whereas the highest AER was measured 70 h^-1 for an open window condition and speed of 90 km h^-1. The results of our study can assist policy makers in controlling in-cabin pollutant exposure and in planning effective strategies for the protection of public health.

Does Second-Generation Suspensory Implant Negate Tunnel Widening of First-Generation Implant Following Anterior Cruciate Ligament Reconstruction?

Purpose

Tunnel widening following anterior cruciate ligament (ACL) reconstruction is commonly observed. Graft micromotion is an important contributing factor. Unlike fixed-loop devices that require a turning space, adjustable-loop devices fit the graft snugly in the tunnel. The purpose of this study is to compare tunnel widening between these devices. Our hypothesis is that the adjustable-loop device will create lesser tunnel widening.

Materials and Methods

Ninety-eight patients underwent ACL reconstruction from January 2013 to December 2014. An adjustable-loop device was used in 54 patients (group 1) and a fixed-loop device was used in 44 patients (group 2). Maximum tunnel widening at 1 year was measured by the L’Insalata’s method. Functional outcome was measured at 2-year follow-up.

Results

The mean widening was 4.37 mm (standard deviation [SD], 2.01) in group 1 and 4.09 mm (SD, 1.98) in group 2 (p=0.511). The average International Knee Documentation Committee score was 78.40 (SD, 9.99) in group 1 and 77.11 (SD, 12.31) in group 2 (p=0.563). The average Tegner-Lysholm score was 87.25 (SD, 3.97) in group 1 and 87.29 in group 2 (SD, 4.36) (p=0.987). There was no significant difference in tunnel widening and functional outcome between the groups.

Conclusions

The adjustable-loop device did not decrease the amount of tunnel widening when compared to the fixed-loop device. There was no significant difference in outcome between the two fixation devices.

Level of Evidence

Level 3, Retrospective Cohort

Determination of real-world emission factors of trace metals, EC, OC, BTEX, and semivolatile organic compounds (PAHs, PCBs and PCNs) in a rural tunnel in Bilecik, Turkey

A field study was performed in a rural tunnel to determine pollutant concentrations, sources and on road vehicle emission factors (EFs) of particulate matter, trace metals, elemental carbon (EC), organic carbon (OC), benzene, toluene, ethyl benzene and xylenes (BTEX), and polycyclic aromatic hydrocarbons (PAHs). Emission factors (EFs) for polychlorinated naphthalenes (PCNs) and polychlorinated biphenyls (PCBs) were also determined. A 12-day extensive sampling campaign during morning and afternoon periods at inlet and exit stations of the tunnel was conducted. Morphology of the particles was also investigated by Scanning Electron Microcopy (SEM). Correlation analysis, factor analysis and diagnostic PAH ratios were utilized to identify emission sources of trace metals. Identified sources include brake wear (33%), resuspension of road dust (15%), tyre wear (12%), exhaust emissions (10%), and lubricants (9%). Based on the PAH diagnostic ratios, major sources of PAHs were estimated as diesel emissions. EFs were comparable with the literature and varied from 31.5 to 295.4 mg vehicle^-1 km^-1 with an average of 129.2 ± 80 mg vehicle^-1 km^-1 for PM_2.5. PM_2.5-10 EFs varied between 15.9 and 236.1 mg vehicle^-1 km^-1 with an average of 96 ± 30 mg vehicle^-1 km^-1. Average EC EFs were 40.3 ± 9.8 mg vehicle^-1 km^-1 for PM_2.5 samples and 19.5 ± 0.5 mg vehicle^-1 km^-1 for PM_2.5-10 samples while OC EFs were 33.7 ± 18 and 15.5 ± 8.4 mg vehicle^-1 km^-1 for fine and coarse particles, respectively. EFs of elements were generally 2 (Al) to 59 (Mg) times higher than those previously reported in the literature. Compared to literature, relatively higher EFs for Σ₁₃PAHs (range: 48.1-168 μg vehicle^-1 km^-1, average: 84.3 ± 46.4 μg vehicle^-1 km^-1) were obtained. BTEX emission factors were in the range of 4.2 ± 4.7 mg vehicle^-1 km^-1 (m + p-xylene) and 16.7 ± 10.5 mg vehicle^-1 km^-1 (toluene). Average EFs for ΣPCBs and ΣPCNs were 12.06 ± 5.3 μg vehicle^-1 km^-1 and 88.9 ± 70.4 ng vehicle^-1 km^-1, respectively.

Characteristics of the pollutant emissions in a tunnel of Shanghai on a weekday

Tunnel displays a typical semi-closed environment, and multitudes of the pollutants tend to accumulate. The samples of gaseous pollutants and particulate matter (PM) were collected from the Xiangyin tunnel at Shanghai to investigate the characteristics of the pollutant emissions. The results indicated that both gaseous pollutants and PM exhibited much higher concentrations during the rush hours in the morning and at night due to vehicle emission. Two peaks of the PM concentration were observed in the scope of 0.7-1.1 and 3.3-4.7 μm, accounting for 14.6% and 20.3% of the total concentrations, respectively. Organic matter (OM), EC, and many water-soluble ions were markedly higher at the rush hours in the morning than those at night, implicating comprehensive effects of vehicle types and traffic volume. The particle number concentrations exhibited two peaks at Aitken mode (25 nm and 100 nm) and accumulation mode (600 nm), while the particle volume concentration displayed high values at the accumulation mode (100-500 nm) and coarse mode (2.5-4.0 μm). The peak around 100 nm was detected in the morning rush hours, but it diminished with the decrease of the traffic volume. Individual-particle analysis revealed that main particles in the tunnel were Fe-rich particles, K-rich particles, mineral particles, Ca-S rich particles and Al-Si particles. The particles collected at the rush hours displayed marked different morphologies, element concentrations and particle sizes compared to the ones collected at the non-rush period. The data presented herein could shed a light on the feature of vehicle emissions.

Drilling through anteromedial portal with a femoral aiming device ensures a sufficient length and a proper graft position, and prevents posterior wall breakage during anterior cruciate ligament reconstruction

OBJECTIVE

The aim of this study was to evaluate the characteristics of the femoral tunnel (FT) which was drilled through the AM portal by using a femoral aimer device and AP stability of the knee.

METHODS

Thirty-eight patients, with the mean age 29.6 (range: 20-43) years, were evaluated after ACL reconstruction. The mean follow-up time was 31.9 (range: 16-57) months. The FT was drilled using a femoral aimer with different offset according to the graft size measured, through the AM portal. The semitendinous and gracilis tendon autograft was used for reconstruction. The angles of FT and the exit point on the lateral condyle were measured on AP views of the knee. AP stability of the knee was measured with the KT-2000.

RESULTS

The mean angle of FT was 46.5° (± 8.4°), on the AP view. The mean distance between the exit point of FT and the most distal end of the femoral condyles was 46.7 (± 4.9) mm. The mean FT length was 36.1 (± 3.1) mm. The mean difference of anterior translation compared to the intact knee was 1.9 (± 1.6) mm. Except the three patients, with "one positive" pivot shift test, in the remaining 35 knees stability was equal to the healthy knee.

CONCLUSIONS

Femoral drilling by using a femoral aimer device through AM portal provided long enough FT for safe graft fixation and appropriate coronal plan obliquity. The exit point was far proximal from the insertion site of the popliteus tendon and lateral collateral ligament. Furthermore, the AM portal technique significantly improved AP stability of the knee.

Computational Analysis of Protein Tunnels and Channels

Protein tunnels connecting the functional buried cavities with bulk solvent and protein channels, enabling the transport through biological membranes, represent the structural features that govern the exchange rates of ligands, ions, and water solvent. Tunnels and channels are present in a vast number of known proteins and provide control over their function. Modification of these structural features by protein engineering frequently provides proteins with improved properties. Here we present a detailed computational protocol employing the CAVER software that is applicable for: (1) the analysis of tunnels and channels in protein structures, and (2) the selection of hot-spot residues in tunnels or channels that can be mutagenized for improved activity, specificity, enantioselectivity, or stability.

The effect of ventilation protocols on airborne particulate matter in subway systems

As part of the European-funded IMPROVE LIFE project work programme experiments were performed in the Barcelona Metro system with the objective of better understanding the relationship between ventilation and air quality. The results demonstrate that tunnel ventilation plays an extremely important role in maintaining cleaner air and is capable of reducing both inhalable particulate matter (PM) mass and particle number concentration (>0.3μm) on platforms by over 50%, even in the presence of full-length platform screen doors. Another key influence on platform air quality is the chosen combination of fan power and forced air flow direction (impulsion of outdoor ambient air or extraction of subway indoor air): cleaner platform air was achieved using platform impulsion at higher power settings designed to ameliorate high summer temperatures underground. Reversing platform air flow from impulsion to extraction produced an immediate deterioration in PM air quality, most notably if the higher power setting was maintained, when an especially marked increase in numbers of very fine (submicron) particles was observed and attributed to tunnel air being drawn into the platform. At night, in the absence of trains and platform ventilation, platform air quality improves when tunnel fans are working at reduced power, whatever the flow direction (impulsion/extraction). Inside the air conditioned Barcelona Metro trains (where underground commuters spend most of their time) air quality is markedly better than on the platform, and unchanged A/C filters were observed capable of maintaining a similar reduction in inside train PM for at least three months.

Magnetic resonance imaging after anterior cruciate ligament reconstruction: A practical guide

Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopedic procedures performed worldwide. In this regard, magnetic resonance imaging (MRI) represents a useful pre-operative tool to confirm a disruption of the ACL and to assess for potential associated injuries. However, MRI is also valuable post-operatively, as it is able to identify, in a non-invasive way, a number of aspects and situations that could suggest potential problems to clinicians. Graft signal and integrity, correct tunnel placement, tunnel widening, and problems with fixation devices or the donor site could all compromise the surgical outcomes and potentially predict the failure of the ACL reconstruction. Furthermore, several anatomical features of the knee could be associated to worst outcomes or higher risk of failure. This review provides a practical guide for the clinician to evaluate the post-surgical ACL through MRI, and to analyze all the parameters and features directly or indirectly related to ACL reconstruction, in order to assess for normal or pathologic conditions.

Evaluating near highway air pollutant levels and estimating emission factors: Case study of Tehran, Iran

A field sampling campaign was implemented to evaluate the variation in air pollutants levels near a highway in Tehran, Iran (Hemmat highway). The field measurements were used to estimate road link-based emission factors for average vehicle fleet. These factors were compared with results of an in tunnel measurement campaign (in Resalat tunnel). Roadside and in-tunnel measurements of carbon monoxide (CO) and size-fractionated particulate matter (PM) were conducted during the field campaign. The concentration gradient diagrams showed exponential decay, which represented a substantial decay, more than 50-80%, in air pollutants level in a distance between 100 and 150meters (m) of the highway. The changes in particle size distribution by distancing from highway were also captured and evaluated. The results showed particle size distribution shifted to larger size particles by distancing from highway. The empirical emission factors were obtained by using the roadside and in tunnel measurements with a hypothetical box model, floating machine model, CALINE4, CT-EMFAC or COPERT. Average CO emission factors were estimated to be in a range of 4 to 12g/km, and those of PM10 were 0.1 to 0.2g/km, depending on traffic conditions. Variations of these emission factors under real working condition with speeds were determined.

PrinCCes: Continuity-based geometric decomposition and systematic visualization of the void repertoire of proteins

Grooves and pockets on the surface, channels through the protein, the chambers or cavities, and the tunnels connecting the internal points to each other or to the external fluid environment are fundamental determinants of a wide range of biological functions. PrinCCes (Protein internal Channel & Cavity estimation) is a computer program supporting the visualization of voids. It includes a novel algorithm for the decomposition of the entire void volume of the protein or protein complex to individual entities. The decomposition is based on continuity. An individual void is defined by uninterrupted extension in space: a spherical probe can freely move between any two internal locations of a continuous void. Continuous voids are detected irrespective of their topological complexity, they may contain any number of holes and bifurcations. The voids of a protein can be visualized one by one or in combinations as triangulated surfaces. The output is automatically exported to free VMD (Visual Molecular Dynamics) or Chimera software, allowing the 3D rotation of the surfaces and the production of publication quality images. PrinCCes with graphic user interface and command line versions are available for MS Windows and Linux. The source code and executable can be downloaded at any of the following links: http://scholar.semmelweis.hu/czirjakgabor/s/princces/#t1 https://github.com/CzirjakGabor/PrinCCes http://1drv.ms/1bP9iJ3.

Twenty-Year Experience of a Double-Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a four-strand semitendinosus tendon was started in our department in July 1994. The motivation for starting the procedure was that the EndoButton with an inside-out procedure instrument became available in Japan. A review article of our DB ACL reconstruction procedure was summarized for the twentieth anniversary of the surgical procedure. Initial tension setting of the two grafts was changed in the first 8 years to achieve better stability during DB ACL reconstruction. A randomized clinical trial (RCT) was started in July 2002 to clarify superiority of the DB procedure to single-bundle (SB) reconstruction under the concept of anatomic reconstruction. Several anatomic studies were performed to describe normal ACL anatomy, which is essential for realizing anatomic reconstruction. A remnant-preserving technique would be an additional option for our DB procedure to improve reconstruction outcomes. Thus, a new remnant-preserving DB procedure was started in 2012. The reproducibility of the new procedure was investigated using three-dimensional computed tomography images. More complex procedures were performed using a transtibial technique and EndoButtons. Initial tension balancing between the two grafts was important for a better outcome. Superiority of knee stability after the DB compared to that after the SB procedure was clarified by the RCT. However, no patient consensus has been reached on any subjective advantage to the DB procedure. Studies of normal ACL anatomy have left questions unresolved regarding where the two tunnels should be created for direct and indirect insertions based on normal anatomy. A new remnant-preserving DB ACL procedure has been practiced. The procedure was more reproducible with respect to creating the femoral tunnel. DB ACL reconstruction using a semitendinosus tendon is an attractive option when pursuing a better outcome for patients.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.

PCDD and PCDF concentrations in a traffic tunnel environment

In an effort to understand the fundamental aspects of air quality in traffic tunnel environments, field campaigns were conducted to measure polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and other important pollutants within two traffic tunnels in Nam San (NS) and Hong Ji (HJ) in Korea in 2009 and 2010. The mean concentrations of ∑PCDD/Fs (in fg/m(3)) at the two tunnel sites were 1270 (± 880) and 1200 (± 810), respectively. These values were moderately lower than those measured at a non-tunnel urban background site (1350 (± 780) fg/m(3))--selected as a reference in this study. In addition, seasonal patterns of dioxin concentrations were clearly evident at the traffic tunnels like the urban reference site, showing higher levels during the winter (and spring) than the summer (and fall). The observed seasonal variations were driven by changes in the concentrations of ∑PCDF congeners, while ∑PCDD concentrations showed little seasonality. The results of our study suggest that there is no significant difference in source characteristics between the two investigated tunnel sites and urban location, although the role of gasoline and diesel fueled vehicles are considered as the major source in determining the PCDDs and PCDF levels in a tunnel environment. However, given the relative increase in other important ambient pollutant (e.g. PM10) concentrations over ∑PCDD/Fs in tunnel air (compared to urban background air), the balance of sources in tunnels is clearly different from those in urban air overall.

Volume and contact surface area analysis of bony tunnels in single and double bundle anterior cruciate ligament reconstruction using autograft tendons: in vivo three-dimensional imaging analysis

Background

Regarding reconstruction surgery of the anterior cruciate ligament (ACL), there is still a debate whether to perform a single bundle (SB) or double bundle (DB) reconstruction. The purpose of this study was to analyze and compare the volume and surface area of femoral and tibial tunnels during transtibial SB versus transportal DB ACL reconstruction.

Methods

A consecutive series of 26 patients who underwent trantibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft from January 2010 to October 2010 were included in this study. Three-dimensional computed tomography (3D-CT) was taken within one week after operation. The CT bone images were segmented with use of Mimics software v14.0. The obtained digital images were then imported in the commercial package Geomagic Studio v10.0 and SketchUp Pro v8.0 for processing. The femoral and tibial tunnel lengths, diameters, volumes and surface areas were evaluated. A comparison between the two groups was performed using the independent-samples t-test. A p-value less than the significance value of 5% (p < 0.05) was considered statistically significant.

Results

Regarding femur tunnels, a significant difference was not found between the tunnel volume for SB technique (1,496.51 ± 396.72 mm³) and the total tunnel volume for DB technique (1,593.81 ± 469.42 mm³; p = 0.366). However, the total surface area for femoral tunnels was larger in DB technique (919.65 ± 201.79 mm²) compared to SB technique (810.02 ± 117.98 mm²; p = 0.004). For tibia tunnels, there was a significant difference between tunnel volume for the SB technique (2,070.43 ± 565.07 mm³) and the total tunnel volume for the DB technique (2,681.93 ± 668.09 mm³; p ≤ 0.001). The tibial tunnel surface area for the SB technique (958.84 ± 147.50 mm²) was smaller than the total tunnel surface area for the DB technique (1,493.31 ± 220.79 mm²; p ≤ 0.001).

Conclusions

Although the total femoral tunnel volume was similar between two techniques, the total surface area was larger in the DB technique. For the tibia, both total tunnel volume and the surface area were larger in DB technique.

Fascial entrapment of the sural nerve and its clinical relevance

Sural nerve presents great topographic variability and it is responsible for sensory innervation of the posterolateral side of the distal third of the leg and lateral aspect of the foot. Entrapment of the nerve could be caused by compression due to fascial thickening, while the symptomatology includes sensory alterations and deficits at the nerve distribution area. We report a cadaveric case of a variant sural nerve that presented a distinct entrapment site. A supernumerary sensory branch was encountered originating from the common peroneal nerve, while the peroneal component of the sural nerve was observed to take a course within a fibrous fascial tunnel 3.1 cm in length that caused nerve fixation and flattening. The tension applied to the aforementioned branch was shown to worsen during passive forcible foot plantaflexion and inversion. The etiology, diagnosis and the treatment options are discussed comprehensively.

In vivo three-dimensional imaging analysis of femoral and tibial tunnel locations in single and double bundle anterior cruciate ligament reconstructions

BACKGROUND

Anatomic footprint restoration of anterior cruciate ligament (ACL) is recommended during reconstruction surgery. The purpose of this study was to compare and analyze the femoral and tibial tunnel positions of transtibial single bundle (SB) and transportal double bundle (DB) ACL reconstruction using three-dimensional computed tomography (3D-CT).

METHODS

In this study, 26 patients who underwent transtibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft. 3D-CTs were taken within 1 week after the operation. The obtained digital images were then imported into the commercial package Geomagic Studio v10.0. The femoral tunnel positions were evaluated using the quadrant method. The mean, standard deviation, standard error, minimum, maximum, and 95% confidence interval values were determined for each measurement.

RESULTS

The femoral tunnel for the SB technique was located 35.07% ± 5.33% in depth and 16.62% ± 4.99% in height. The anteromedial (AM) and posterolateral (PL) tunnel of DB technique was located 30.48% ± 5.02% in depth, 17.12% ± 5.84% in height and 34.76% ± 5.87% in depth, 45.55% ± 6.88% in height, respectively. The tibial tunnel with the SB technique was located 45.43% ± 4.81% from the anterior margin and 47.62% ± 2.51% from the medial tibial articular margin. The AM and PL tunnel of the DB technique was located 33.76% ± 7.83% from the anterior margin, 45.56% ± 2.71% from the medial tibial articular margin and 53.19% ± 3.74% from the anterior margin, 46.00% ± 2.48% from the medial tibial articular margin, respectively. The tibial tunnel position with the transtibial SB technique was located between the AM and PL tunnel positions formed with the transportal DB technique.

CONCLUSIONS

Using the 3D-CT measuring method, the location of the tibia tunnel was between the AM and PL footprints, but the center of the femoral tunnel was at more shallow position from the AM bundle footprint when ACL reconstruction was performed by the transtibial SB technique.

Aortocaval tunnel to the superior vena cava: a case report

A 20-year old female with a rare anomaly of aortocaval tunnel to superior vena cava is presented. Rare cases of congenital communications between aorta and right sided of the heart has been reported previously. The patient underwent surgical repair and had uneventful recovery.