Upper extremity kinematic and kinetic adaptations during a fatiguing repetitive task

Repetitive low-force contractions are common in the workplace and yet can lead to muscle fatigue and work-related musculoskeletal disorders. The current study aimed to investigate potential motion adaptations during a simulated repetitive light assembly work task designed to fatigue the shoulder region, focusing on changes over time and age-related group differences. Ten younger and ten older participants performed four 20-min task sessions separated by short breaks. Mean and variability of joint angles and scapular elevation, joint net moments for the shoulder, elbow, and wrist were calculated from upper extremity kinematics recorded by a motion tracking system. Results showed that joint angle and joint torque decreased across sessions and across multiple joints and segments. Increased kinematic variability over time was observed in the shoulder joint; however, decreased kinematic variability over time was seen in the more distal part of the upper limb. The changes of motion adaptations were sensitive to the task-break schedule. The results suggested that kinematic and kinetic adaptations occurred to reduce the biomechanical loading on the fatigued shoulder region. In addition, the kinematic and kinetic responses at the elbow and wrist joints also changed, possibly to compensate for the increased variability caused by the shoulder joint while still maintaining task requirements. These motion strategies in responses to muscle fatigue were similar between two age groups although the older group showed more effort in adaptation than the younger in terms of magnitude and affected body parts.     

Esophageal squamous cell carcinoma and adenocarcinoma in Malaysia – Pooled data from upper gastrointestinal centers in a multiethnic Asian population

BackgroundEsophageal cancer is the sixth leading cause of cancer death worldwide with considerable geographical histological variation There is a paucity of data in esophageal cancer in demographics, histology, and survival among the multi-ethnic Malaysian population. This paper is a review of esophageal cancer epidemiology and survival among esophageal cancer patients from data collected by the Malaysian Upper Gastrointestinal Surgical Society.MethodsThis is a multicenter retrospective observational study of esophageal cancer patients from six upper gastrointestinal surgical centers in Malaysia between 2005 and 2019. Patient characteristics, histological type and stage were compared and survival analyzed.ResultsThere were 820 patients with esophageal cancer included, where 442 (53.9 %) cases had squamous cell carcinoma (SCC) and 378 (46.1 %) had adenocarcinomas (AC). Malays were the predominant ethnicity with AC (66.7 %) while Indians were the ethnic majority (74.6 %) with SCC. Majority of patients (56.8 %) presented as stage IV disease. Overall, the 1-, 3-, and 5-years’ survival were 35.8 %, 13.8 % and 11.0 %, respectively. Surgical resection with curative intent yielded the best 5-year survival (29.4 %). Intervention in stage IV AC yielded superior survival when compared to SCC (median survival, 7.9 months vs 4.8 months; p, 0.018) Our series demonstrated an increase in AC to SCC over the last 15 years.ConclusionsThere was an ethnic preponderance seen between different histology in this region, not previously discussed. An increase in AC was observed over the last 15 years. Late diagnosis seen in most patients imparts poor prognosis as curative surgery affords the best outcome.     

Motor unit number estimation and quantitative needle electromyography in stroke patients

ObjectiveTo evaluate the effect of upper motor neuron damage upon motor units’ function by means of two separate and supplementary electrophysiological methods.MethodsThe abductor digiti minimi muscle of the non-paretic and the paretic side was studied in forty-six stroke patients with (a) motor unit number estimation (MUNE) – adapted multiple point stimulation method and (b) computerized quantitative needle electromyography (EMG) assessing the configuration of voluntary recruited motor unit potentials. Main outcome comparisons were focused on differences between non-paretic and paretic side.ResultsOn the affected hands mean MUNE value was significantly lower and mean area of the surface recorded single motor unit potentials was significantly larger than the corresponding ones on the non-paretic hands. EMG findings did not reveal remarkable differences between the two sides. Neither severity nor chronicity of stroke was related to MUNE or EMG parameters.DiscussionMUNE results, which suggested reduced motor unit numbers in stroke patients, in conjunction with the normal EMG features in these same muscles has given rise to different interpretations. In a clinical setting, reinnervation type changes in the EMG similar to that occurring in neuronopathies or axonal neuropathies should not be expected in muscles with central neurogenic lesion.     

Selection of the conodont Idiognathodus simulator (Ellison) as the event marker for the base of the global Gzhelian Stage (Upper Pennsylvanian, Carboniferous)

Studies carried out for more than 10 years by the Task Group to establish GSSPs at the base of the Moscovian–Kasimovian and Kasimovian–Gzhelian boundaries have resulted in the proposal that the level at which the conodont species Idiognathodus simulator (Ellison, 1941) first appears be selected to mark the base of the Gzhelian Stage. This expands this eastern European chronostratigraphic unit to a global scale.I. simulator (sensu Barrick et al., 2008) has been identified so far in Midcontinent and eastern North America, the Moscow and Donets basins and southern Urals of eastern Europe, and in south-central China. Correlation of this level based on this species and other conodont species can be reinforced in some areas by ammonoid and fusulinid data.     

Miospore stratigraphy of Lower and early Middle Devonian deposits from Tidikelt, Central Sahara, Algeria

The Tidikelt region forms an outstanding area for subsurface Lower Devonian stratigraphy in the central Algerian Sahara. Sediments from five boreholes have revealed abundant and diverse assemblages of miospores, acritarchs, chitinozoa, scolecodont and microplant remains. The miospores are moderately well preserved. Three new miospore species (Dibolisporites saharansis nov. sp. Hassan Kermandji, Acinosporites conatus nov. sp. Hassan Kermandji and Scylaspora tidikeltense nov. sp. Hassan Kermandji) are described. Miospore assemblages vary through the regressive and transgressive sequences. Seven miospore assemblage biozones, including six new miospore assemblage biozones (Scylaspora tidikeltense-Perotrilites microbaculatus, Dictyotriletes emsiensis-Emphanisporites spinaeformis, Apiculiretusispora arenorugosa-Camptozonotriletes caperatus, Verrucosisporites polygonalis-Dictyotriletes subgranifer, Emphanisporites annulatus-Geminospora svalbardiae, Hystricosporites microancyreus-Grandispora protea, Calyptosporites velatus-Rhabdosporites langii) are proposed for the Lower and early Middle Devonian rocks of Tidikelt Plateau. The combined use of distinctive, wide distribution cosmopolitan and Gondwanan forms as biozonal and species characteristics permits accurate subdivision, dating and correlation of Tidikelt successions with other similar miospore zones of the Lower Devonian of Europe, Canada and other parts of Gondwana plate. The miospore data provide new explanations to stratigraphic relationships of regional rock units, sedimentary cycles and stratigraphic hiatus. The miospore biozones are proposed as a provincial biozonation, which may also be applied to other Palaeozoic rocks of similar miospore content.     

Discovery of the oldest known Pterygota in the Lower Carboniferous of the Upper Silesian Basin in the Czech Republic (Insecta: Archaeorthoptera)

The earliest pterygote (winged insect), dated from the Lower Carboniferous (Namurian A/E1, circa 324 millions years ago) is described from the Upper Silesian Basin in the Czech Republic. On the basis of its wing venation, it is attributed to the Archaeorthoptera Béthoux and Nel, 2002, crown group of the “Orthoptera”. Besides Apterygota (Collembola and Archaeognatha) known from the Lower Devonian, extremely rare pterygote insects are known from Lower Carboniferous deposits when they first appeared. The present discovery supports the hypothesis of the presence of the ancestor lineage of the orthopteroid in the Lower Carboniferous ecosystems.     

Bryozoans as substratum of fossil fistulose Foraminifera (Fam. Polymorphinidae)

In the Upper Cretaceous-Lower Tertiary sections exposed in the Curfs quarries at Berg (munic. Berg en Terblijt - also known as Geulhem, southern Netherlands) and some other localities, numerous foraminifers of the family Polymorphinidae with complete fistulose apertures have been found. These apertures, which are equipped with circular openings and auxiliary apertural chambers, branching and numerous narrow projecting tubes or stolons, have been widely reported, but their role has been the subject of controversy. The Dutch material shows the foraminifers attached with the apertural tubes to fragments of bryozoan colonies or molluscan shells, suggesting that the tubes could perhaps act as holdfast organs. Most specimens were found in calcarenites of the nearshore facies. The foraminifers cannot be treated as symbiotic organisms nor parasites but as epifauna in search of protection from mechanical destruction by waves and current action. The present case may be best explained as an adaptation of sessile foraminifers with fragile hyaline tests to live in highly disadvantageous, high-energy conditions.     

The oldest illustration of Chinese crinoid calyx: Annotated translation of “Cupressocrinus abbreviatus” reported by Fritz Frech in 1911

The early history on the discovery of the first Chinese crinoid calyx of “Cupressocrinus abbreviatus” (now Halocrinites schlotheimii Steininger, 1831) remains unclear. The first record of “C. abbreviatus” was reported by Fritz Frech in 1911. It was included in the fifth and the last volume of the series titled China by the German traveler and explorer Ferdinand Freiherr von Richthofen. The cover page, title page, and prologue are informative; thus, they are explained and translated in detail. Richthofen's specimen is still the oldest documented cupressocrinitid calyx known in China today. Discovery of a second cupressocrinitid specimen confirms the existence of this family in China. Current taxonomic positions of the Chinese specimens are discussed.     

内镜黏膜下剥离术和挖除术治疗上消化道肿瘤的疗效及安全性分析

目的:分析内镜黏膜下剥离术(ESD)和黏膜下挖除术(ESE)治疗上消化道肿瘤的疗效及安全性。方法:回顾性分析2017年1月至2019年4月我院消化内科接受ESD或ESE治疗的68例上消化道肿瘤住院患者的临床资料,收集患者基础疾病、手术时间、病变部位大小、整块切除率、并发症等资料,同时采用Logistic回归分析对术中穿孔进行危险因素分析。结果:64例患者完整切除瘤体(94.12%),肿瘤平均直径(16.98±8.29)mm。食管病灶病理类型以高级别上皮内瘤变为主,有15例(22.06%);胃部病灶分布以胃体、胃底和胃窦居多,分别有18例(26.47%)、16例(23.53%)和12例(17.65%),病理类型以间质瘤最多,占36.76%;11例患者发生并发症(16.18%),4例患者出现术后出血(5.88%),经过内镜下止血后好转,8例患术中穿孔(11.76%),均行内镜下尼龙绳联合钛夹行荷包缝合,其中1例患者术中穿孔合并术后迟发性出血;病灶最大直径(≥25 mm,P=0.036)和病灶部位(胃底,P=0.015)是导致ESD或ESE术中穿孔的独立危险因素。结论:ESD和ESE治疗上消化道肿瘤安全有效,但需注意病灶大小和胃底病变,因其是导致术中穿孔的独立危险因素。