Feature extraction and recognition of epileptiform activity in EEG by combining PCA with ApEn

This paper proposes a new method for feature extraction and recognition of epileptiform activity in EEG signals. The method improves feature extraction speed of epileptiform activity without reducing recognition rate. Firstly, Principal component analysis (PCA) is applied to the original EEG for dimension reduction and to the decorrelation of epileptic EEG and normal EEG. Then discrete wavelet transform (DWT) combined with approximate entropy (ApEn) is performed on epileptic EEG and normal EEG, respectively. At last, Neyman–Pearson criteria are applied to classify epileptic EEG and normal ones. The main procedure is that the principle component of EEG after PCA is decomposed into several sub-band signals using DWT, and ApEn algorithm is applied to the sub-band signals at different wavelet scales. Distinct difference is found between the ApEn values of epileptic and normal EEG. The method allows recognition of epileptiform activities and discriminates them from the normal EEG. The algorithm performs well at epileptiform activity recognition in the clinic EEG data and offers a flexible tool that is intended to be generalized to the simultaneous recognition of many waveforms in EEG.     

Changes in lower limb muscle activity after walking on a split-belt treadmill in individuals post-stroke

Background: There is growing evidence that stroke survivors can adapt and improve step length symmetry in the context of split-belt treadmill (SBT) walking. However, less knowledge exists about the strategies involved for such adaptations. This study analyzed lower limb muscle activity in individuals post-stroke related to SBT-induced changes in step length. Methods: Step length and surface EMG activity of six lower limb muscles were evaluated in individuals post-stroke (n = 16) during (adaptation) and after (after-effects) walking at unequal belt speeds. Results: During adaptation, significant increases in EMG activity were mainly found in proximal muscles (p ⩽ 0.023), whereas after-effects were observed particularly in the distal muscles. The plantarflexor EMG increased after walking on the slow belt (p ⩽ 0.023) and the dorsiflexors predominantly after walking on the fast belt (p ⩽ 0.017) for both, non-paretic and paretic-fast conditions. Correlation analysis revealed that after-effects in step length were mainly associated with changes in distal paretic muscle activity (0.522 ⩽ r ⩽ 0.663) but not with functional deficits. Based on our results, SBT walking could be relevant for training individuals post-stroke who present shorter paretic step length combined with dorsiflexor weakness, or individuals with shorter nonparetic step length and plantarflexor weakness.     

Estimation of muscle forces in gait using a simulation of the electromyographic activity and numerical optimization

Clinical gait analysis provides great contributions to the understanding of gait patterns. However, a complete distribution of muscle forces throughout the gait cycle is a current challenge for many researchers. Two techniques are often used to estimate muscle forces: inverse dynamics with static optimization and computer muscle control that uses forward dynamics to minimize tracking. The first method often involves limitations due to changing muscle dynamics and possible signal artefacts that depend on day-to-day variation in the position of electromyographic (EMG) electrodes. Nevertheless, in clinical gait analysis, the method of inverse dynamics is a fundamental and commonly used computational procedure to calculate the force and torque reactions at various body joints. Our aim was to develop a generic musculoskeletal model that could be able to be applied in the clinical setting. The musculoskeletal model of the lower limb presents a simulation for the EMG data to address the common limitations of these techniques. This model presents a new point of view from the inverse dynamics used on clinical gait analysis, including the EMG information, and shows a similar performance to another model available in the OpenSim software. The main problem of these methods to achieve a correct muscle coordination is the lack of complete EMG data for all muscles modelled. We present a technique that simulates the EMG activity and presents a good correlation with the muscle forces throughout the gait cycle. Also, this method showed great similarities whit the real EMG data recorded from the subjects doing the same movement.     

Electromyographic analysis of rectus femoris activity during seated to standing position and walking in water and on dry land in healthy children and children with cerebral palsy

Purpose: To analyze rectus femoris activity during seated to standing position and walking in water and on dry land comparing a group of children with the spastic diparesis type of cerebral palsy (CP) and a group of children without neurological disorders. Methods: This study included a group of nine children with CP and a control group of 11 children. The study compared the electromyographic activity of the rectus femoris during seated to standing position and walking, in water and on land. Results: A greater activation of the rectus femoris was observed in the group of children with CP compared with the control group when moving from a seated position to a standing position in water (p = 0.0039) and while walking on land (p = 0.0014) or in the pool (p = 0.007). Conclusion: This study demonstrated the activation of the rectus femoris while walking or standing up from a seated position in water was greater in the group of children with CP. Further studies should be performed to better understand the extent of muscular activation during body immersion in individuals with neurological disorders.     

GC-MS analysis of the essential oils of Juniperus communis L. berries growing wild in the Molise region: Seasonal variability and in vitro antifungal activity

Juniperus communis L., also known as the common juniper, is a dioecious aromatic evergreen shrub and has been traditionally used in many countries as a diuretic, antiseptic, and digestive and as a flavor to aromatize certain alcoholic beverages. We analyzed the chemical variability in the volatile profiles from berries of J. communis, harvested in one of the oldest European parks, the National Park of Abruzzo, Lazio, and Molise (PNALM, Central Italy). We examined the berries in different phases of the biological cycle for 1 year (at six ripening stages). Hydrodistilled essential oils from the fresh berries were analyzed by gas chromatography–flame ionization detection (GC-FID), gas chromatography–mass spectrometry (GC-MS) and principal component analysis (PCA). A total of 90 components were detected, and remarkable qualitative and quantitative differences were observed in the chemical components during the ripening stages, from the green unripe berries to the bluish-black berries harvested at full maturity. The essential oils were an α-pinene (13.43–32.34%) chemotype. The monoterpene hydrocarbons decreased during the ripening with a progressive increase in sesquiterpenes such as germacrene D (12.29–17.59%) and β-caryophyllene (7.71–8.51%), which are the major components in ripe berry essential oils. The sesquiterpene hydrocarbon fraction (65.3–47.9%) also contained α-humulene, germacrene B, δ-cadinene, bicyclogermacrene, and eudesma 4(14),11 diene. Germacrene D and β-caryophyllene in high concentrations may be considered as marker components of the genus Juniperus from the Molise region. This particular chemical composition has been reported for the first time. It is interesting to note the presence of β-caryophyllene (7–11%), whose inhalation has been reported to affect anxiety and depression in a rat model. An in vitro antifungal assay showed that the essential oil from green and ripe berries inhibits the growth of Sclerotium rolfsii, a phytopathogen fungus that causes post-harvest diseases in many fruits and vegetables.     

Characterization and Distribution of the Selected Metals in the Scalp Hair of Cancer Patients in Comparison with Normal Donors

Eighteen metals were estimated in the scalp hair samples from cancer patients (n = 111) and normal donors (n = 113). Nitric acid–perchloric acid wet digestion procedure was used for the quantification of the selected metals by flame atomic absorption spectrophotometry. In the scalp hair of cancer patients, highest average levels were found for Ca (861 μg/g), followed by Na (672 μg/g), Zn (411 μg/g), Mg (348 μg/g), Fe (154 μg/g), Sr (129 μg/g), and K (116 μg/g), whereas in comparison, the dominant metals in the scalp hair of normal donors were Ca (568 μg/g), Zn (177 μg/g), Mg (154 μg/g), Fe (110 μg/g), and Na (103 μg/g). The concentrations of Ca, Cd, Co, Cr, Fe, K, Mg, Mn, Na, Ni, Pb, Sb, Sr, and Zn were notably higher in the hair of cancer patients as compared with normal donors, which may lead to a number of physiological disorders. Strong positive correlations were found in Mn–Pb (0.83), Cd–Cr (0.82), Cd–Li (0.57), Fe–Pb (0.56), and Fe–Mn (0.55) in the hair of cancer patients whereas Na–Cd, Li–Cr, Li–Co, Co–Cd, Li–Cd, Na–Co, Na–Li, Ca–Mg and Na–Cr exhibited strong relationships (r > 0.50) in the hair of normal donors. Principal Component Analysis (PCA) of the data revealed seven PCs, both for cancer patients and normal donors, but with significantly different loadings. Cluster Analysis (CA) was also used to support the PCA results. The study evidenced significantly different pattern of metal distribution in the hair of cancer patients in comparison with normal donors. The role of trace metals in carcinogenesis was also discussed.     

Changes in relative work of the lower extremity joints and distal foot with walking speed

The modulation of walking speed results in adaptations to the lower limbs which can be quantified using mechanical work. A 6 degree-of-freedom (DOF) power analysis, which includes additional translations as compared to the 3 DOF (all rotational) approach, is a comprehensive approach for quantifying lower limb work during gait. The purpose of this study was to quantify the speed-related 6 DOF joint and distal foot work adaptations of all the lower extremity limb constituents (hip, knee, ankle, and distal foot) in healthy individuals. Relative constituent 6 DOF work, the amount of constituent work relative to absolute limb work, was calculated during the stance and swing phases of gait. Eight unimpaired adults walked on an instrumented split-belt treadmill at slow, moderate, and typical walking speeds (0.4, 0.6, and 0.8 statures/s, respectively). Using motion capture and force data, 6 DOF powers were calculated for each constituent. Contrary to previously published results, 6 DOF positive relative ankle work and negative relative distal foot work increased significantly with increased speed during stance phase (p < 0.05). Similar to previous rotational DOF results in the sagittal plane, negative relative ankle work decreased significantly with increased speed during stance phase (p < 0.05). Scientifically, these findings provide new insight into how healthy individuals adapt to increased walking speed and suggest limitations of the rotational DOF approach for quantifying limb work. Clinically, the data presented here for unimpaired limbs can be used to compare with speed-matched data from limbs with impairments.     

Carbon utilization profiles of bacteria colonizing the headbox water of two paper machines in a Canadian mill

Forty-one bacterial strains isolated from the headbox water of two machines in a Canadian paper mill were associated with the genera Asticcacaulis, Acidovorax, Bacillus, Exiguobacterium, Hydrogenophaga, Pseudomonas, Pseudoxanthomonas, Staphylococcus, Stenotrophomonas based on the sequence of their 16S rRNA genes. The metabolic profile of these strains were determined using Biolog EcoPlate, and the bacteria were divided into four metabolic groups. Metabolic profiles of the bacterial communities colonizing the headbox water of two paper machines was also determined weekly over a 1 year period. The only compound that was not reduced by the bacterial community was 2-hydroxybenzoic acid. Utilization frequency of the other carbon sources in the Biolog EcoPlate ranged from 3 to 100%. The metabolic profiles of the bacterial community did not vary considerably between the two paper machines. However, the metabolic profile varied among the sampling dates.     

Changes in the serum acid phosphatase activity of guinea pigs poisoned with C1 perfringens type A toxin and a mixture of toxin and a broth culture filtrate

It was shown in experiments on guinea pigs that the injection of C1. perfringens type A toxoid induced an increase in acid phosphatase activity of animal blood serum. The action of the toxoid increased under the effect of C1. butyricum cultural filtrate, which gave rise to an earlier enhancement of the specific activity of the enzyme as compared to the injection of the toxoid alone. Increased activity of acid phosphatase may play a pathogenetic role in cases of anaerobic infection caused by association of C1. perfringens and C1. butyricum.     

Cross training effects of non-paralytic dorsiflexion muscle strengthening exercise on paralytic dorsiflexor muscle activity,gait ability,and balancing ability in patients with chronic stroke: A randomized,controlled, pilot trial

Objective:To investigate the effects of non-paralytic dorsiflexion muscle strengthening exercise on functional abilities in chronic hemiplegic patients after stroke.Methods:A total of 21 patients with chronic stroke underwent dorsiflexion muscle strengthening exercise (MST) 5 times a week for 6 weeks (the experimental group, MST to non-paralytic dorsiflexion muscles, n=11; the control group, MST to paralytic dorsiflexion muscles; n=10). Paralytic dorsiflexor muscle activities (DFA) and 10 m walking tests (10MWT) and timed up and go tests (TUG) were measured before and after intervention.Results:A significant increase in DFA was observed after intervention in the experimental and control groups (p<0.05) (experimental 886.6% for reference voluntary contraction (RVC), control 931.6% for RVC). TUG and 10MWT results showed significant reductions post-intervention in the experimental and control groups (experimental group -5.6 sec, control -4.8 sec; experimental group -3.1 sec, control, -3.9 sec; respectively). No significant intergroup difference was observed between changes in DFA or between changes in TUG and 10MWT results after intervention (p>.05).Conclusion:Strengthening exercise performed on non-paralytic dorsiflexion muscles had positive cross-training effects on paralytic dorsiflexor muscle activities, balance abilities, and walking abilities in patients with chronic stroke.     

Product formation and kinetic simulations in the pH range 1-14 account for a free-radical mechanism of peroxynitrite decomposition

The yields of nitrate and nitrite from decomposition of peroxynitrite in phosphate buffer at 37 degrees C were determined in the pH range 1-14. The NO(2)(-)/NO(3)(-) yields showed a stepwise variation with pH, with inflection points at approximately pH 3.1, 5.8, 6.8, 8.0, and 11.9. Nitrite formation increased strongly above pH 7 at the expense of nitrate, but above pH 12 nitrate again became the major product (80% at pH 14). At this pH, the Arrhenius parameters were E(a)=24.1+/-0.2kcal mol(-1) and A=(4.9+/-1.3)x10(12)s(-1). The yields of NO(2)(-), NO(3)(-), and O(2) measured at pH 5.8, 7.4, and 8.5 as a function of the initial peroxynitrite concentration (50-1000 microM) were linear only at pH 5.8. In the presence of carbon dioxide, oxygen production at pH 7.5 and pH 10 was found to be linear on the CO(2) concentration. The experimental observations were satisfactorily reproduced by kinetic simulations including principal component analyses. These data strongly suggest that the chemistry of peroxynitrite is exclusively mediated by z.rad;NO(2) and HO(z.rad;) radicals in the absence, and by z.rad;NO(2) and CO(3)(z.rad;-) radicals in the presence of CO(2).     

甬江干流浮游动物群落结构季节动态与水环境的关系

对采自2011年3月-2012年2月间甬江干流13个断面的水样, 按照国家标准测试了9项理化指标, 并应用浮游动物定性和定量方法, 研究了浮游物群落结构特点和季节变化. 研究共记录浮游动物95种, 其中轮虫24属72种、枝角类5属10种、桡足类11属13种和4种其他门类无脊椎动物幼虫; 优势种主要来自于轮虫动物的臂尾轮虫属(Brachionus)和龟甲轮虫属(Keratella), 前者占了浮游动物总丰度的22.1%, 后者占总丰度的20.2%. 浮游动物的丰度值在各断面均呈明显的季节变化, 从断面1至断面6, 最大峰值出现在春季, 从断面7至断面13, 最大峰值多出现在夏季; 全干流最大峰值出现在断面5 (3160 ind./L). 浮游动物群落生物多样性指数呈上游段低, 中、下游河段高的现象; 应用中度干扰假说(Intermediate disturbance hypothesis)对此结果给予了解释. Two-way ANOSIM相似性分析和Bray-Curtis相似性等级聚类分析显示: 不同断面上不同季节的浮游动物群落间均存在显著差异, 分别为R=0.264、P=0.1%和R=0.234、P=0.1%, 且季节性差异大于断面间差异. 在季节性差异中以春季和夏季间的差异性最大. 主成分分析(PCA)表明: 对不同断面浮游动物群落起作用的理化因子依次为CODCr、TN、DO和BOD5; 对不同季节浮游动物群落起作用的理化因子依次为pH、TN/TP、盐度和水温.       

寒潮过程中4个茶树品种光合特性和保护酶活性变化及品种间差异

以茶树品种龙井43号(Longjing No.43)、鸠坑(Jiukeng)、乌牛早(Wuniuzao)、福鼎大白茶(Fortin white tea)为试材,研究了一次寒潮过程对4个茶树品种叶片的光合特性、叶绿素荧光参数和保护酶活性的影响,并利用主成分分析方法确定4个茶树品种的抗寒性。结果表明:寒潮初期,随着气温的降低,4个茶树品种的叶绿素含量、最大光合速率(P_(max))、表观量子效率(AQY)、最大光化学量子产量(Fv/Fm)、非光化学淬灭(q N)均呈现下降趋势,在气温回升期间随气温升高而有所增加,且福鼎大白茶的叶绿素含量、P_(max)、AQY、Fv/Fm的值为4个品种中最大,q N的平均值以乌牛早为最小,鸠坑最大;4种茶树的过氧化物酶(POD)活性在寒潮及恢复期间持续增强;4种茶树POD活性的平均值以龙井43号最小,福鼎大白茶最大;叶片的气孔限制值(Ls)和丙二醛(MDA)含量在降温和气温回升过程中,表现出先增加后降低的趋势,整个期间的Ls和MDA含量的平均值以福鼎大白茶为最小,龙井43号最大;利用主成分分析法对4品种茶树的光合参数、荧光参数和抗氧化酶活性进行分析,得到4个品种茶树的抗寒性顺序为:福鼎大白茶乌牛早鸠坑龙井43号。研究结果为茶树的引种及茶叶生产布局提供理论依据。     

Changes in serum dipeptidyl-aminopeptidase IV (glycylprolyl dipeptidyl-aminopeptidase) activity of patients with gastric carcinoma after surgical excision and the enzyme activity in the carcinoma tissue

Serum dipeptidyl-aminopeptidase IV (glycylprolyl dipeptidyl-aminopeptidase, GP-DAP) activity was found to be significantly decreased in patients with gastric carcinoma. The patients with advanced carcinoma showed more significant reduction of serum enzyme activity. After successful surgical removal of gastric carcinoma, serum enzyme activity tended to return to the normal level. In cases of recurring carcinoma serum activity decreased progressively. When hepatitis or liver metastasis was complicated, serum activity was significantly increased. Gastric carcinoma tissue itself had lower GP-DAP activity than normal gastric tissue of the same patients.     

Changes with time after capture in the metabolic activity of the carnivorous copepod Euchaeta norvegica Boeck

The rates of respiration and ammonium excretion of the carnivorous copepod Euchaeta norvegica Boeck decreased by 40 and 70%, respectively, during the first ≈10 h after capture. ETS (electron transport system) activity decreased in parallel with the rate of respiration. Increasing O/N and decreasing N/P atomic ratios during incubation indicated a change from protein to lipid metabolism, suggesting that starvation was the major factor responsible for the depression of the metabolic rates after capture. The adenylate energy charge (EC) ratio was significantly lower during the initial 13 h after capture than subsequently, caused mainly by an elevated AMP level. The total content of adenine nucleotides increased during this period of lowered EC. Starvation could also have been responsible for these changes in the adenine nucleotide levels through degradation of RNA. Our earlier interpretation that the lowered EC values after capture reflected capture stress has not been confirmed. The lactate level of E. norvegica just after capture was low (≈0.1 μg·mg dry wt^?1) and thus not indicative of any oxygen debt.     

An investigation of the simultaneously recorded occlusal contact and surface electromyographic activity of jaw-closing muscles for patients with temporomandibular disorders and a scissors-bite relationship

Surface electromyographic (SEMG) activity of the masseter and anterior temporalis (TA) muscles has been reported to be associated with occlusion and orofacial pain. However, our recent report did not reveal an association between the side of orofacial pain and the side showing higher or lower level of SEMG activity of masseter or TA. The present purpose was to re-test this association in patients who had unilateral scissors-bite relationship. Thirty-two unilateral scissors-bite femalepatients complaining of unilateral orofacial pain (n = 15) or TMJ sounds (n = 17) were enrolled to simultaneously record contacts, force distribution of occlusion, and SEMG activity of masseter and TA during centric maximal voluntary clenching (MVC). The results indicated that neither orofacial pain nor the TMJ sounds had an association with the masseter’s SEMG values, while scissors-bite had (P < 0.05). A lower SEMG value for masseter was found on the scissors-bite side where there was a smaller number of contacts and a lower biting force distribution (P < 0.05). No such association was revealed in TA. In conclusion, in patients with unilateral TMD symptom(s) and scissors-bite, the jawclosing muscles’ SEMG activity during centric MVC was associated with the scissors-bite rather than the symptoms of orofacial pain or TMJ sounds.     

Inertial motion capture in conjunction with an artificial neural network can differentiate the gait patterns of hemiparetic stroke patients compared with able-bodied counterparts

Clinical gait analysis has proven to reduce uncertainties in selecting the appropriate quantity and type of treatment for patients with neuromuscular disorders. However, gait analysis as a clinical tool is under-utilised due to the limitations and cost of acquiring and managing data. To overcome these obstacles, inertial motion capture (IMC) recently emerged to counter the limitations attributed to other methods. This paper investigates the use of IMC for training and testing a back-propagation artificial neural network (ANN) for the purpose of distinguishing between hemiparetic stroke and able-bodied ambulation. Routine gait analysis was performed on 30 able-bodied control subjects and 28 hemiparetic stroke patients using an IMC system. An ANN was optimised to classify the two groups, achieving a repeatable network accuracy of 99.4%. It is concluded that an IMC system and appropriate computer methods may be useful for the planning and monitoring of gait rehabilitation therapy of stroke victims.