C5 C7 Research Articles

Evaluation of the feasibility of equine in-vivo ultrasound technique for the medial branch of the dorsal ramus of the cervical spinal nerves

Ultrasound-guided local anaesthesia is commonly used in veterinary orthopaedics for horses. This study aimed to assess an in vivo ultrasound technique for the medial branch of the dorsal branch of the cervical spinal nerves (MB-DBCSNs) in horses and compare the performance of clinicians with different experience levels. Ten healthy, skeletally mature horses were examined using radiographic and ultrasound (US) techniques in the cervical area (C3–C7). Four operators with varying experience conducted US examinations using a 10 MHz linear and 6 MHz curvilinear transducer over ten training sessions. The number of cervical nerves visualized was recorded. A chi-square test was used to analyse the impact of training, anatomical location, and operator experience on the identification of facet joints. Operator agreement was evaluated with Cohen’s K test. The operators assessed 80 MB-DBCSNs, with radiographs and identified 70 healthy and 10 pathological facet joints. Training significantly improved visualization success, reaching 90% in later sessions. Cranial facet joints (C3–C5) were more frequently visualized (81%) than caudal ones (C5–C7) were (59%). US performance was influenced by the operator’s skill, and agreement among operators ranged from slight to fair. Overall, practice improved cervical nerve visualization in vivo, particularly for cranial nerves, but the technique requires a long learning curve because of low levels of operator agreement.

Influence of cranium orientation on cervical sagittal alignment during radiographic examination: a radiographic analysis

BACKGROUND CONTEXTDuring the radiographic examination, the cranium orientation varies not only individually but also within the same subject, in different imaging sessions. Knowing how changes in the orientation of the cranium influences cervical sagittal alignment during the radiographic examination of the cervical spine can aid clinicians in the accurate evaluation for cervical sagittal alignment in clinical practice. PURPOSETo radiographically examine the influence of cranium orientation on cervical sagittal alignment during radiographic examination in an asymptomatic cohort. STUDY DESIGNA prospective radiographic study. PATIENT SAMPLEEighty asymptomatic volunteers (mean age, 40.4 years; 50.0% male) were enrolled. OUTCOME MEASURESCervical sagittal parameters including the regional slope (C1 slope, C2 slope, C5 slope, C7 slope, and T1 slope), Cobb angle (O–C1 angle, C1–C2 angle, C2–C5 angle, C5–C7 angle, and C7–T1 angle), and cranial/cervical offset (sella turcica tilt [ST tilt] and C2 tilt). METHODSIn all participants, standing lateral radiographs of the cervical spine were taken in three forward-gazing positions: anteverted-cranium (AC) position; neutral-cranium (NC) position; and retroverted-cranium (RC) position. Cervical sagittal parameters, including the regional slope, Cobb angle, and cranial/cervical offset, in these three positions were statistically compared. RESULTSThe C1 and C2 slopes were anteverted and retroverted in the AC and RC positions, respectively, compared to those in the NC position. The C5 slope, C7 slope, and T1 slope were constant among the three positions. In O–C2 and C2–C5, statistically significant differences in the regional Cobb angles were identified among the three positions; however, there were no significant differences in the C5–C7 or C7–T1 segments. Cranial and cervical offsets of ST tilt and C2 tilt increased and decreased when the cranium was anteverted and retroverted, respectively. CONCLUSIONSThe current study suggests that the adjustment of the cranium orientation when taking cervical spine radiographs is mainly controlled at the upper cervical spine of the O–C2 segment in an asymptomatic cohort. On radiograph, alignment in the upper cervical segment of O–C2 changes; accordingly, the middle cervical segment of C2–C5 can change during the adjustment of cranium orientation. However, alignment in the lower cervical segment of C5–C7 and the cervicothoracic junction of C7–T1 remains constant. Further, cranial/cervical offset increases and decreases when the cranium is anteverted and retroverted, respectively. Our results can help the accurate evaluation of cervical sagittal alignment on plain radiographs in clinical practice.

Association of urine dicarboxylic acid levels with intracranial volume–normalized brain regions and with white matter hypo‐intensities

AbstractBackgroundNon‐invasive molecules related to AD imaging biomarkers can reveal disease mechanisms and may help in the mass screening of an aging population. Our study aims to determine if urine dicarboxylic acids (DCA) that changed in AD are coupled with brain volume changes.MethodStudy participants (> 65 years) were recruited in an ongoing HMRI Brain aging study, and MRI data were acquired and analyzed using NeuroQuant. The data were normalized to the intracranial volume (icv). DCAs were quantified using gas chromatography/mass spectrometry. We compared DCA and icv‐normalized brain region volumes in two ways: first, we used descriptive statistics to obtain the median (Q2) for short‐chain DCAs (C4+C5), medium‐chain DCAs (C7+C8+C9) and the ratio of short to medium chain DCAs ((C4+C5)/(C7+C8+C9)). Brain regions were then sorted to correspond to less than (<Q2) or greater than the DCA medians (>Q2). Differences were determined using two‐sample t‐tests and Wilcoxon rank‐sum tests with adjustment for multiple comparisons using FDR. Secondly, icv‐normalized brain regions and T1 hypo‐intensity were compared with DCA levels using a two‐tailed student’s t‐test.ResultThere was no significant difference in the DCA levels of participants with low (icv<Q2) or high icv (icv>Q2) (Fig.1A). In contrast, C4+C5 levels were higher, while C7+C8+C9 were lower in participants with higher whole brain volumes (WBV) (Fig. 1B). In addition, hippocampal volumes were greater when participants had a higher urine C4+C5 and lower C7+C8+C9. We identified 19 other icv‐normalized brain regions that were bigger when urine C4+C5 levels were high. In addition, participants with higher white matter hypo‐intensities had lower urine C4+C5 and a higher C7+C8+C9 DCA levels (Table 1).ConclusionThese data suggest that urine lipid composition is linked to icv‐normalized brain volumes. Higher mitochondrial‐associated lipids reflected larger brain volumes, while oxidized lipids indicated lower brain volumes. Thus, urine lipid levels can be used as surrogate biomarkers in clinical trials targeting brain volume changes. We will use a bigger sample size normalized for ApoE genotype, age, and sex to further examine lipids and brain volumes in participants with different cognitive states.

Stable carbon isotopic compositions of individual light hydrocarbons in the C5–C7 range in natural gas from the Qaidam Basin, China

C5–C7 light hydrocarbons are important components in petroleum and are extensively employed as an auxiliary approach in petroleum research. Consensus on the mechanism of light hydrocarbon generation has not yet been achieved. In this study, 20 gas samples were collected from the western part and northern margin of the Qaidam Basin. The molecular and carbon isotopic compositions of C1–C3 gaseous hydrocarbons and C5–C7 light hydrocarbons, as well as the carbon isotopes of oils were analyzed. Based on the relationships between carbon isotopes (13C) of individual light hydrocarbons and calculated vitrinite reflectance, it suggests that organic matters play a fundamental role in the carbon isotopes of light hydrocarbons, and maturity mainly affects the carbon isotopes of n-alkanes in light hydrocarbons. In addition, carbon isotopic differences between n-, iso- and cyclo-alkanes indicate that light hydrocarbons with different structures are produced from various biological precursors. Besides, carbon isotopes of individual light hydrocarbons can be used to estimate the δ13Ckerogen and distinguish cracked gas. On the one hand, small isotope fractionation between iso-alkanes and kerogen is observed. Average carbon isotopic compositions of iso-pentane ( i-C5), 2-methylpentane (2-MC5) and 3-methylpentane (3-MC5) can provide a similar δ13Ckerogen with actual values. On the other hand, the carbon isotopic difference between 2-MC5 and n-C6 generally decreases with increasing maturity. Combined with the parameter (2-MC6 + 3-MC6)/ n-C6, kerogen-cracked gases are characterized by high δ13C2MC5–δ13CnC6 and low (2-MC6 + 3-MC6)/ n-C6 values, whereas oil-cracked gases exhibit the opposite features.

Neurophysiological Evaluation of the Functional State of Muscular and Nervous Systems in High-Maneuvering Jet Fighters

The present study aimed to assess the function of muscular and nervous systems in high-maneuvering jet fighters with the chosen method of clinical neurophysiology, which methodologically has not yet been presented in detail. Fifteen pilots with the experience of more than 1700 flying hours at 7G overloading on average and fifteen healthy subjects for the comparison of health status declared to participate in this study. The dermatomal perception from C4 to S1 was examined using von Frey’s filaments tactile method. Surface electromyography (sEMG) recordings examined the activity of proximal and distal muscles in the upper and lower extremities, the transmission of motor nerve impulses peripherally was diagnosed by electroneurography (ENG), the efferent transmission from C5–C7 and L4–L5 spinal centers to muscles was entirely verified with recordings of motor-evoked potentials induced oververtebrally with the magnetic field (MEP). The pilots estimated more lumbosacral than cervical pain at about 2 on the 10-point visual analog scale (VAS). Sensory perception studies did not reveal abnormal symptoms in the C2–S1 dermatomes innervation. Clinical neurophysiology studies indicated, in general, the lack of pathology during sEMG tests in comparison to healthy subjects or even better muscle motor unit contractile properties in pilots, both in the upper and lower extremities. In pilots, the parameters of ENG and MEP examinations show a statistically significant sensitivity for detecting the slight changes and their consequences in the transmission of neural impulses within L4–L5 ventral root fibers. The research results enable specifying the algorithm of future preventing rehabilitative treatment in high-maneuvering jet fighters with an average flight experience of 2000 h and working conditions at 7G on average. This study, for the first time, describes the application of a set of diagnostic neurophysiological methods with the particular importance of MEPs in the clinical evaluation of the jet fighters’ health status.

New insight into the mechanism of isomerization of C5–C7 alkanes over MoO3/FST

Molybdenum trioxide doped on fibrous silica-titania (MoO3/FST) has been synthesized and evaluated in the catalytic isomerization of C5–C7 for the first time. The structure characterization, functional group, and acid distribution of MoO3/FST were assessed via XRD, N2-physisorption, FTIR, and Py-IR analysis. The IR spectra revealed that MoO3/FST was occupied by a moderate-to-strong Brønsted and Lewis acid sites distribution. By adding MoO3, intense metal-support interactions were formed, lessening Brønsted acid sites' intensity in contrast to the increasing Lewis acid sites' intensity. The isomerization test demonstrated that maximum conversions of 50.0, 80.0, and 84.0% were acquired at 300 °C corresponding to n-C5, n-C6, and n-C7, respectively. As the isomerization temperature rose from 150 to 350 °C, the yield of n-C5 to n-C7 isomers increased to ∼70.0%. The high activity of MoO3/FST was ascribed to the effective interaction between MoO3 with perturbed silanol groups, which led to enrichment in protonic acid site formation via H2 spillover. This finding proves that the isomerization catalysts should possess great Lewis acid and Bronsted acid sites to enrich the protonic acid side, resulting in high performance in isomerization.

Biomarkers, light hydrocarbons, and diamondoids of petroleum in deep reservoirs of the southeast Tabei Uplift, Tarim Basin: Implication for its origin, alteration, and charging direction

The Atan Bulge in the southwestern Tabei Uplift of the Tarim Basin provides insights into the geochemistry of the oils and condensates in deep Ordovician reservoirs because its reservoir burial depth is generally greater than 6000 m. To investigate the oil origin, alteration, and migration pathways, the carbon isotopes, biomarkers, light hydrocarbons, and diamondoids of 16 oil and condensate samples from the Ordovician reservoirs in the Atan Bulge were analyzed. The results show that chain alkanes dominate the light hydrocarbons, followed by cycloalkanes and aromatic hydrocarbons. 1-methyladamantane (MA) dominates the diamondoids, followed by 1,3-dimethyldiamantane (DMD). The samples lacked biodegradation and thermochemical sulfate reduction signatures. Except for a few samples near the Manjiaer Depression, the evaporative fractionation caused by late natural gas charging is generally weak. The oil geochemistry suggests that the oils and condensates are primarily derived from lower Cambrian marine shale, and the organic matter is mainly type II. The equivalent vitrinite reflectance (Rc) calculated using thermal maturity indicators derived from methylphenanthrene, methyldiamantanes, and C5–C7 light hydrocarbons, respectively, is in the ranges of 0.78%–1.04%, 1.1%–1.5%, and 1.06%–1.48%. The samples' low (3-+4-)-methyldiamantane concentrations (36–76 μg/g) imply a low level of oil cracking. The carbon isotope distribution among oil fractions and different maturity ranges suggest that crude oil was generated and charged multiple times. The maturity of the samples decreases from SSE to NNE, indicating that the petroleum likely migrated from strike-slip faults during its primary charging period, with the Manjiaer Depression and its slope serving as the primary source kitchens.

Disc Space Involvement in Cervical Spondylotic Myelopathy: A Prospective Study

Introduction: Cervical spondylotic myelopathy (CSM) most frequently occur in old age because of degenerative change in the cervical vertebrate, intervertebral disc, and hypertrophy of ligamentum flava that create pressure on the spinal cord. Cervical spondylotic myelopathy manifests as long-tract clinical findings in the upper and lower extremities caused by spinal cord compression. Cervical myelopathy is a clinical syndrome that may result from cervical spondylosis. When cervical myelopathy is a result of spondylosis, it is referred to as cervical spondylotic myelopathy. The study aimed to analyze the involvement of the disc space of the vertebral column in cervical spondylotic myelopathy. Methods: This study was carried out at the department of orthopaedics, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. The study was conducted on 30 participants from March 2012 to September 2014. Result: Among the 30 cases, 24 (80%) cases were male and 6 (20%) cases were female. The age range was from 31-60 years. 15(50%) were manual workers, 12(40%) were sedentary workers and 3(10%) were housewives. the majority of the patients 15(50%) had suffered from the symptoms for 10 to 12 months. The most common level of myelopathy was the C5/6 level 13 (44.44%). Among the 30 patients, 27 (90%) cases were presented with myelopathy and the other 3(10%) cases were presented with myeloradiculopathy. Conclusion: Cervical spondylotic myelopathy is a progressive neurological disease that requires surgical intervention in most cases. In terms of interspace disc involvement, C5 C6 was the most frequent space which is 66.7%. C4 C5 and C6 C7 had the same frequency of involvement which was 10% indicating the second most common spaces concurrently.

Multimodal analgesic protocol for cervical disc replacement in the ambulatory setting: Clinical case series

BackgroundEffective pain management is paramount for outpatient surgical success. This study aims to report a case series of patients undergoing cervical disc replacement (CDR) in an ambulatory surgery center (ASC) with the use of an enhanced multimodal analgesic (MMA) protocol. MethodsPrimary, single-/2-level CDR procedures at an ASC with an enhanced MMA protocol were included. ASC patients were discharged day of surgery. Patient-reported outcome measures (PROMs) were administered at preoperative/6-week/12-week/6-month/1-year/2-year timepoints and included Visual Analogue Scale (VAS) neck, VAS arm, Neck Disability Index (NDI), Patient-Reported Outcomes Measurement Information System-Physical Function (PROMIS-PF), and 12-Item Short-Form Physical and Mental Composite Score (SF-12 PCS/SF-12 MCS). A t-test assessed postoperative PROM improvement from baseline. MCID achievement was determined by comparing ΔPROM scores to previously established thresholds. Results106 patients were included, 76 single-level and 30 2-level. Most single-levels occurred at C5–C6, most 2-levels at C5–C7. One 2-level patient developed a hematoma 5 days postoperatively and underwent revision for evacuation. Five patients reported postoperative dysphagia; all were quickly resolved. One patient had an episode of seizure secondary to serotonin syndrome from concealed drug use. Patient was reintubated, transferred, and treated for serotonin syndrome. Two patients experienced postoperative nausea/vomiting. Cohort significantly improved from baseline for all PROMS at all timepoints except SF-12 MCS at 1-year/2-years and SF-12 PCS at 2 years (p < 0.047, all). Overall MCID achievement rates were: VAS arm (48.7%), VAS neck (69.1%), NDI (98.9%), SF-12 MCS (50.0%), SF-12 PCS (54.6%), and PROMIS-PF (73.4%). ConclusionOutpatient CDR, incorporating an enhanced MMA protocol, can be safely and effectively performed with proper patient selection and surgical technique. Patients saw timely discharge, well-controlled postoperative pain, and favorable long-term outcomes.

Relationships between the Clinical Test Results and Neurophysiological Findings in Patients with Thoracic Outlet Syndrome.

A thoracic outlet syndrome (TOS) is the type of brachial plexus disorder most difficult to objectively assess using a clinical examination and differential diagnosis. Its symptoms can be frequently misdiagnosed, especially among others with cervical disc-root conflicts, plexopathies, and peripheral neuropathies. In this study, we aim to identify the correlations between positive Doppler ultrasonography results indicating pathological changes in the subclavian flow velocity, clinical tests, and chosen clinical neurophysiology recordings as proposed alternative or supplementary diagnostic tools for evaluating TOS patients. Sixty TOS patients with positive Doppler ultrasonography and Roos test results and sixty healthy people as a control group were bilaterally examined, and the results were compared. Pain intensity was assessed using a visual analogue scale (VAS). Sensory perceptions within C4–C8 dermatomes were assessed with Von Frey filament (FvF) tests. The activity of motor units in the proximal and distal muscles of the upper extremities was evaluated using surface electromyography (sEMG) during maximal contractions before and after a provocative raised hands test (RHT). An electroneurography (ENG) was used to evaluate the transmission of nerve impulses peripherally. Motor evoked potential (MEP) recordings, induced by the over-vertebral magnetic stimulation of the C5–C7 neuromeres, were used to examine motor transmissions from the cervical motor centres to the upper extremities muscles. The results revealed a relationship between positive Doppler test scores and pathological changes in the subclavian flow velocity through the results of the following diagnostic tools: a VAS score of 1.9 was detected on average, superficial sensory perception abnormalities were found in the innervation areas of the ulnar nerves detected by FvF tests, a decrease in the amplitudes of sEMG recordings was seen in distal rather than proximal muscles (especially following the RHT), a decrease in the motor and sensory peripheral transmissions of nerve impulses in the median, ulnar and cutaneous anterobrachial median nerves was seen, as well as MEP amplitudes recorded from the abductor pollicis brevis muscle. The provocative RHT combined with sEMG and MEP recordings can be considered accurate and objective clinical neurophysiology tools that could supplement the commonly used clinical tests. Such an approach may result in a more precise neurogenic TOS diagnostic algorithm.

Incorporating strategy in hybrid surgery for continuous two-level cervical spondylosis from a biomechanical perspective

Background and objectiveHybrid surgery, incorporating cervical disc replacement and anterior cervical discectomy and fusion, has shown good clinical results in the treatment of multilevel cervical spondylosis according to early follow-ups. This study investigated the surgical strategy of hybrid surgery for two-level cervical spondylosis by distinguishing the biomechanical characteristics with different incorporating modes. MethodA finite element model of a healthy cervical spine including C2-T1 was developed, and hybrid surgery was simulated by replacing at one level with Prestige-LP and fusion at another level with the anterior plate in C3–C5 (Hybrid-S1: replaced at C3–C4, Hybrid-S2: replaced at C4–C5), and in C4–C6 (Hybrid-M1: replaced at C4–C5, Hybrid-M2: replaced at C5–C6) and in C5–C7 (Hybrid-U1: replaced at C5–C6, Hybrid-U2: replaced at C6–C7). The motion of C2 vertebrae in flexion, extension, axial rotation, and lateral bending was imposed on all hybrid models following the displacement control testing protocol. ResultsThe largest range of motion (ROM) in a healthy spine was observed at C5-C6, followed by C3-C4, C4-C5 and C6-C7. On average, the ROM at the replaced segment increased by 175.7%, 202.7%, 176.3%, 117.1%, 139.4%, and 236.0% in Hybrid-S1, Hybrid-S2, Hybrid-M1, Hybrid-M2, Hybrid-U1, and Hybrid-U2, respectively. The facet joint stress at the replaced segment increased by 186.9%, 124.4%, 111.1%, 60.3%, 62.7%, and 144.7%, and the adjacent intradiscal pressure (IDP) increased by 45.2%, 38.7%, 2.7%, 2.1%, 13.9%, and 20.1%. ConclusionsIncorporating mode in hybrid surgery affects cervical biomechanics. Hybrid surgery with replacement at a segment with a greater ROM and fusion at a segment with a lower ROM can results in fewer changes in terms of overall cervical stiffness, ROM at the operative level, facet joint stress, and adjacent IDP. In hybrid surgery, it is better to implement disc replacement at a level with a greater ROM and fusion of another segment.

Clinical Assessment of Functional Recovery Following Nerve Transfer for Traumatic Brachial Plexus Injuries.

Surgical reconstruction and postoperative rehabilitation are both important for restoring function in patients with traumatic brachial plexus injuries (BPIs). The current study aimed to understand variations in recovery progression among patients with different injury levels after receiving the nerve transfer methods. A total of 26 patients with BPIs participated in a rehabilitation training program over 6 months after nerve reconstruction. The differences between the first and second evaluations and between C5–C6 and C5–C7 BPIs were compared. Results showed significant improvements in elbow flexion range (p = 0.001), British Medical Research Council’s score of shoulder flexion (p = 0.046), shoulder abduction (p = 0.013), shoulder external rotation (p = 0.020), quantitative muscle strength, and grip strength at the second evaluation for both groups. C5–C6 BPIs patients showed a larger shoulder flexion range (p = 0.022) and greater strength of the shoulder rotator (p = 0.004), elbow flexor (p = 0.028), elbow extensor (p = 0.041), wrist extensor (p = 0.001), and grip force (p = 0.045) than C5–C7 BPIs patients at the second evaluation. Our results indicated different improvements among patients according to injury levels, with quantitative values assisting in establishing goals for interventions.

Использование большой грудной мышцы для восстановления активного сгибания предплечья у детей с амиоплазией

Introduction Amyoplasia is the most common type of arthrogryposis multiplex congenita. Some patients may lack active elbow flexion due to aplasia of the forearm flexor muscles. The objective was to identify the optimal age for pectoralis major muscle transfer to improve elbow flexion in children with amyoplasia and estimate outcomes of the procedure depending on the level of spinal cord injury. Material and methods Restoration of active elbow flexion was performed for 34 children with amyoplasia (39 upper limbs) between 2011 and 2020 using partial monopolar pectoralis major muscle transfer. The age of patients ranged between 1.5 and 15.5 years (6.24 ± 4.24 years). The patients were divided into 3 groups depending on the level of spinal cord injury: C6–C7 (n = 4; 11.8 %), C5–C7 (n = 24; 70.6 %), C5–Th1 (n = 6; 17.6 %). The outcomes were estimated at 6 to 99 months (44.53 ± 31.72 months). The patients underwent preoperative and postoperative clinical and neurological examination. The results were statistically analyzed. Results Active elbow flexion improved by 56.8 degrees (p &lt; 0.0001), forearm flexor muscles strengthened by 2.0 points (p &lt; 0.0001) and extension deficit improved by 14.5 degrees (p &lt; 0.0001) were postoperatively statistically significant. Results were rated as good in 15 (38.5 %); as fair, in 8 (20.5 %) and poor in 16 (41 %) cases. Greater differences were found between the group of patients with the level of C6-C7 spinal cord injury in relation to the group of patients with the level of C5-Th1 (p &lt; 0.05). There were no statistically significant differences between patients with C6–C7 and C5–C7 lesion levels (p &gt; 0.05). Children of different age groups showed no differences in the results of treatment (p &gt; 0.05). Conclusion Pectoralis major muscle could be used for active elbow flexion restoration in patients with amyoplasia. The best results were observed in patients with C6–C7, C5–C7 segmental lesions of the spinal cord. There was no correlation between age of patient at the time of surgery and the effectiveness of operation.

Occurrence, distribution, and input pathways of per- and polyfluoroalkyl substances in soils near different sources in Shanghai

Per- and polyfluoroalkyl substances (PFAS) are complex emerging pollutants that are widely distributed in soils. The compositions of PFAS vary according to the emission sources. However, the soil distributions of PFAS from different sources are still poorly understood. In this study, the concentrations and compositions of 18 PFAS in soils close to potential sources (industrial areas, airports, landfills, fire stations and agricultural areas) were investigated in Shanghai. The total PFAS concentrations varied from 0.64 to 294 μg kg−1d.w.. Among the sites, the highest PFAS concentration was found near the fire station (average = 57.9 μg kg−1d.w.), followed by the industrial area (average = 8.53 μg kg−1d.w.). The detection frequencies of the 18 PFAS ranged from 47.5% to 100%. Perfluorooctanoic acid (PFOA) and perfluoroheptanoic acid (PFHpA) were detected in all samples. The detection frequencies of PFAS near the fire station were higher than those near other sources. The PFAS in soils were mainly composed of short-chain perfluoroalkyl carboxylic acids (C ≤ 8). Elevated concentrations of long-chain perfluoroalkyl carboxylic acids (C > 12) were found in industrial area. Principal component analysis revealed that long-chain PFAS had different factor loadings compared to short-chain PFAS. With the exception of agricultural soils, the correlations between individual PFAS were more positive than negative. Strong positive correlations were found within three groups of perfluoroalkyl carboxylic acids (C5–C7, C9–C12, and C14–C18), suggesting their similar inputs and transportation pathways. The PFAS in soils around the fire station were likely directly emitted from a point source. In contrast, the PFAS in soils near the other sites had multiple input pathways, including both direct emission and precursor degradation.

Ultrasound-guided selective trunk block (SeTB): a cadaver anatomic study to evaluate the spread of dye after a simulated injection

Background and objectivesRecent reports suggest that a selective trunk block (SeTB) can produce sensorimotor blockade of the entire upper extremity, except for the T2 dermatome. There are no data demonstrating...

Evaporative emission from China 5 and China 6 gasoline vehicles: Emission factors, profiles and future perspective

Vehicular evaporative emission is a major source of atmospheric volatile organic compounds (VOCs), while quantification and characterization of the evaporative emission in China, particularly for the vehicles meeting the latest emission standards, are rarely reported. In this study, we performed evaporative emission experiments in a sealed housing evaporative determination (SHED) using eleven new and in-use light-duty gasoline vehicles to investigate the evaporative VOCs emission from the China 5 and China 6 vehicles and unravel the deterioration of evaporation control system of in-use ones. The total hydrocarbon (THC) emission factors (EFs) of 24-h diurnal breathing loss from the new China 6, new China 5 and in-use China 5 vehicles are 0.25, 0.81 and 5.27 g/d respectively. Compared with headspace vapor, the emission profiles of both hot soak loss (HSL) and diurnal breathing loss (DBL) from all new tested vehicles contain more C7–C9 aromatics, particularly for the China 6 vehicles. C4–C5 alkanes and C7–C9 aromatics account for most of total VOCs mass for all China 5 vehicles, while emissions from the China 6 vehicles exhibit no strongly prevailing species for both HSL and DBL emission. Typical ratios like normalized ratios of benzene, toluene and ethylbenzene can be used to distinguish evaporative emission from vehicular exhaust. Ozone formation potentials (OFPs) of the in-use China 5 vehicles are 5.35 and 7.16 times higher than that of China 5 new ones in DBL and HSL experiments respectively. Secondary organic aerosol formation potential of all tests ranged from 17.30 to 29.76, with aromatics contributing the largest proportion (over 90.0%). With the implementation of China 6's standard, the evaporative THC emission in China may peak in 2022 and will be cut down by 76% until 2030. Also, the underestimation of evaporative emission was estimated when neglecting the difference of EFs between new and in-use vehicles.

The geochemical characteristics and origin of Ordovician ultra-deep natural gas in the North Shuntuoguole area, Tarim Basin, NW China

Ultra-deep Ordovician in Shuntuoguole area, Tarim Basin, NW China, has complex oil & gas phases, in which light oil, volatile oil, condensate and dry gas phases coexisting. The study compares the geochemical characteristics and origin of Ordovician ultra-deep natural gas in the North Shuntuoguole (SB) area to that of gas in the Shuntuo (ST), South Shuntuoguole (SN), Gulong (GL), and Gucheng (GC) areas using natural gas composition, carbon isotope and hydrogen isotope data and light hydrocarbon data. The Ordovician ultra-deep natural gas in the SB area is wet gas, with dryness indexes ranging from 0.52 to 0.88 and minimal H2S content. The carbon isotopes of natural gas are relatively low, with δ13C1 and δ13C2 values ranging from −49.6‰ to −44.7‰ and −39.3‰ to −32.7‰, respectively. All the natural gas shows positive carbon and hydrogen isotope series. The n-alkane and iso-alkane dominate the C5–C7 light hydrocarbon, with the methylcyclohexane index of light hydrocarbon lower than 35%. All of the Ordovician natural gas in the Shuntuogule area is oil-type gas. The Ordovician natural gas in the SB area is dominated by kerogen cracking gas, with a small fraction of wet gas from the early stages of oil cracking, whereas, all of the gas in the ST, SN, GL and GC areas comes from oil cracking. The Cambrian source rocks led directly to both types of cracking gases. The distribution of two types of cracking gas in the Shuntuogule area is correlated with the maximum paleogeothermal temperature and (or) present temperature of the Ordovician. The maximum paleogeothermal temperature and present Ordovician temperature in the SB area are 170–180 °C and 150–160 °C, respectively, which are lower than those in ST and SN areas, and have not yet achieved the temperature of large amount oil cracking. As a result, light oil and volatile oil phases were preserved in the SB area, which was dominated by kerogen cracking gas, whereas reservoir phases varied from condensate to dry gas phases, and natural gas is oil-cracking gas, from ST to SN to GL to GC areas, due to large scale oil cracking caused by high present temperature and (or) paleo-geothermal temperature of the Ordovician.

Lipase-active heterogeneous biocatalysts for enzymatic synthesis of short-chain aroma esters

The lipase-active heterogeneous biocatalysts were prepared by adsorptive immobilization of Thermomyces lanuginosus lipase (designated as rPichia/lip) produced by authoring recombinant Pichia pastoris strain. Biocatalysts of LipoCarb type were prepared by spontaneous adsorption of rPichia/lip on the authoring macroporous carbon aerogel. Biocatalysts of LipoSil type were prepared by forced adsorption of rPichia/lip on mesoporous silica. The prepared biocatalysts were studied carefully in the esterification of short-chain fatty acids (butyric C4, C5–C7) and aliphatic alcohols (ethanol C2, C3–C5, C8) in order to produce valuable fruity-smelling esters. Biocatalytic properties, such as enzymatic activity, substrates specificity, and operational stability, were found to depend on chemical nature of both the adsorbents and organic solvents, primarily on their polarity. When comparing the activity in the synthesis of n-butyl heptanoate, it was found that the LipoCarb biocatalysts demonstrated activity an order of magnitude higher than LipoSil type. The Michaelis-Menten kinetic constants differed by a factor of 30, e.g. 1.1·102 s−1 and 3.7 s−1, respectively. The operational stability of the lipase-active biocatalysts was sufficiently high; rPichia/lip adsorbed on carbon aerogel retained till 96% of the initial activity after 29 reaction cycles, whereas rPichia/lip adsorbed on silica completely retained the activity after 38 reaction cycles of esterification under optimal reaction conditions selected. The prepared biocatalysts of LipoCarb and LipoSil types were promising for the Green enzymatic synthesis of fragrance and aroma esters under very mild ambient conditions (20±2 °C, 1 bar).

Long-term functional recovery in C5-C6 avulsions treated with distal nerve transfers

ABSTRACT Background In patients suffering from traction lesions of the brachial plexus, complete C5 and/or C6 root avulsion patients with C7 root preservation are relatively uncommon occurrences, but represent excellent candidates for surgical treatment, with satisfactory results. Shoulder abduction and extra-rotation, elbow flexion and forearm supination are lost functions restorable with surgical treatment. Methods This single-center, prospective observational study involved a series of 27 young adults with C5 and/or C6 root complete avulsion and C7 preservation, which underwent surgical repair with double or triple nerve transfer. Results Patients recovered a useful elbow flexion. Electromyographic and clinical signs of biceps reinnervation were observed in each UN-MC nerve transfer. The abduction strength recovery was M5 in 10 patients, M4 in 14 patients and M3 in 3 patients. The external rotation strength recovery was M5 in 4 patients, M4 in 18 patients, M3 in 3 patients and M2 in 2 patients. The elbow flection strength was M5 in 5 patients, M4 in 15 patients and M3 in 7 patients. Elbow extension was preserved in all cases. Conclusions The concept of ‘peripheral rewiring procedures’ represents an advance in the repair of the peripheral nerve injuries. Triple nerve transfer can be nowadays considered a standard treatment for isolated C5-C6 avulsions. We report our experience with the second-biggest casuistry in the literature on patients treated with this technique. We consider our outcome concerning functional recovery to be satisfying and comparable to data reported in the literature.

Heterogeneous photooxidation of 6:2 polyfluoroalkyl phosphoric acid diester on dust mineral components under simulated sunlight and the influence of relative humidity and oxygen

Polyfluoroalkyl phosphoric acid diesters (diPAPs) have been widely and increasingly detected in various environmental mediums. The degradation of diPAPs brings perfluoroalkyl carboxylic acids (PFCAs) concerned of adverse health effects. DiPAPs mainly occur in particulate matter in ambient air and their photo-degradation behaviors have not been investigated. In this study, heterogeneous photo-degradation of 6:2 diPAP was studied on four model mineral components in ambient dust. 6:2 diPAP was found to undergo a fast degradation on titanium dioxide (TiO2) particles as well as on artificial mineral dust containing TiO2 (2.67% in mass) to produce C5–C7 PFCAs and other intermediates. Based on monitored intermediates and further degradation tests on important intermediates, thermodynamic calculation of energy barrier and Gibbs Free Energy was used to explain the observed degradation patterns and accordingly the degradation pathways of diPAPs were proposed. The increase in relative humidity promotes the production of hydroxyl radicals, which enhances the hydrolysis of 6:2 mono- and di-PAPs and the yield of C5 and C7 PFCAs. Oxygen is critical for radical formation, which bypasses the production of fluorotelomer carboxylic acid. Results of this study for the first time demonstrate that diPAP may account for additional PFCA sources in both indoor and outdoor environments and the heterogeneous degradation pathways were different from those of volatile fluorotelomer alcohols.