Short-term Observations Research Articles

Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets) and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus), in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m) in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low) were sampled for two years. We found that ramets under the high sedimentation regime (HSR) were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR). The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR) to phalanx (in HSR). Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80) as compared to the LSR (R = 0.48). Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

东北镜泊湖硅藻对近现代气候变化和人类干扰的响应过程

PDF HTML阅读 XML下载 导出引用 引用提醒 东北镜泊湖硅藻对近现代气候变化和人类干扰的响应过程 DOI: 10.5846/stxb201610272185 作者: 作者单位: 浙江师范大学,中科院南京地理与湖泊研究所,浙江师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41372184，41672173，41701218） Diatom response to climate changes and anthropogenic disturbances in Jingpo Lake (NE China) Author: Affiliation: Zhejiang Normal University,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球气候变暖和人类活动加剧已经导致中国大量湖泊生态系统功能退化，而目前对东北地区湖泊生态系统变化的认识主要源于短期的监测。以东北镜泊湖为例，通过沉积记录和现代监测资料，分析一个多世纪以来以硅藻群落为代表的湖泊生态系统对气候波动和区域人类活动的响应过程。研究结果表明，在人类干扰显著加强之前，风力扰动是镜泊湖硅藻群落变化的一个重要因子，表现为Aulacoseira属种取代小型浮游种（Cyclostephanos、Stephanodiscus和Discostella）成为优势种。20世纪70年代以来，Asterionella formosa、Nitzschia palea和Fragilaria crotonensis的相继增加则反映了流域农业活动加剧、农业化肥大量施用以及污水排放导致的湖泊营养水平升高。温度的持续上升已经引起东北地区一些湖泊硅藻群落结构发生显著变化，但镜泊湖的硅藻记录却未显示这一气候变化的信号。考虑湖泊-流域形态和人类活动的不同，研究认为近几十年气候变化对镜泊湖硅藻群落结构的影响被强烈的人类干扰所掩盖而未显现出来。 Abstract:Climate warming and intensified human activities have led to the deterioration of lake environments and the degradation of lake ecological services in China over the past few decades. In northeast (NE) China, up to now, information about lake ecological changes responding to climate changes and human activities has derived mainly from short-term observations. In the present study, we choose Jingpo Lake in NE China as the study area. Sediment records and paleolimnological methods, in combination with long-term meteorological observations, were used to determine the patterns of diatom community responses to climate changes and anthropogenic disturbances. The history of diatom assemblage changes over the past 130 years was reconstructed from the sediment of Jingpo Lake. The result was then compared with other diatom records from NE China to evaluate the impacts of climate changes and human activities on diatom community shifts. Our diatom records show a distinct shift from small-type planktonic species (e.g., Cyclostephanos dubius, Cyclostephanos tholiformis, Stephanodiscus parvus, Stephanodiscus invisitatus, Discostella pseudostelligera) to a genus of heavy frustules (Aulacoseira), implying that wind strength played an important role in diatom assemblage changes before the expansion of human activities. Since the end of the 1960s, successive increases in the abundance of Asterionella formosa, Nitzschia palea, and Fragilaria crotonensis have reflected intensified agricultural activities, fertilizer usage, and sewage discharge, which have resulted in a trend to eutrophication. The meteorological observations of the past 60 years reveal obvious climate warming in NE China, especially since the mid-1970s. Previous studies have shown that diatom communities in Lake Xiaolongwan and Erlongwan (NE China) have clearly responded to climate warming, while diatoms in Jingpo Lake have not responded in a similar way. Lake Xiaolongwan and Erlongwan have similar climate conditions to those at Jingpo Lake but much smaller basins and catchments. Additionally, human activities in the catchments of Lake Xiaolongwan and Erlongwan are much less intense. Therefore, it can be speculated that the impacts of climate warming on the diatom community shift in Jingpo Lake have been obscured by intense human disturbances. Additionally, intensified human activity has become the dominant factor leading to the ecological threshold being crossed in Jingpo Lake. 参考文献 相似文献 引证文献

Изменения неспецифических протеиназ и провоспалительных цитокинов при остром инфаркте миокарда различной степени тяжести

to study changes of serum levels of nonspecific proteinases, their inhibitors, and proinflammatory cytokines during short term observation of patients with acute myocardial infarction (MI). We included in this prospective short-term study 82 patients (27 with uncomplicated non-Q wave MI, 30 with Q-MI complicated by Killip class I-II acute left ventricular failure [ALVF], 17 with Q-MI complicated by Killip class III-IV ALVF, and 8 non-survivors due to development of cardiogenic shock) and 12 healthy controls. Serum levels of interleukin (IL) - 1β, IL-6 and tumor necrosis factor (TNF)-α were measured by ELISA. Elastaselike (ELA) and trypsin-like (TLA) activities as well as characteristics of proteinase inhibitors (antitrypsin activity and acid-stable inhibitors) were also determined. Blood samples were taken at hospital admission within 24 hours after onset of symptoms. The GUSTO Score at admission was used for risk stratification. All cytokines levels were significantly elevated in MI patients in comparison to controls. Mean concentrations of IL-6 and TNF-α at baseline were higher among patients with MI complicated by ALVF than in the group with uncomplicated MI (27.45 vs 16.04 pikogram / mL, р.

Short-term observation of management of sclera patch grafts used in the scleral defects

Background: To explore the safety and effectiveness of Sclera patch grafts in the management of scleral defects. Methods: This is a retrospective uncontrolled study. Medical records were retrospectively reviewed for 8 eyes of 8 patients with sclera patch grafts. Two patients had necrotizing scleritis, 2 patients had scleral melting/perforation secondary to thermal burns, 4 patients had scleral staphyloma secondary to surgery. Sclera was reconstructed with allogenic sclera patch grafts, 6 in 8 patients combined autologous conjunctival pedicle flap, 1 patient combined partial medial rectus translocation, 1 patient combined autologous pedicle tenon graft, simultaneously. Treatment outcomes were evaluated using structural integrity, best corrected visual acuity (BCVA), scleritis remission, sclera rejection and melt, and ocular symptoms. Results: Eight patients were reviewed. In all of these cases, satisfactory anatomic and functional outcomes were achieved. In the at least half a year follow-up, the BCVA of all the eight patients were no worse than that of preoperative. No eye pain, foreign body sensation and other discomforts showed in all the patients, except one woman, who showed sclera rejection and melt 1 month postoperative. In addition, one patient showed high intraocular pressure (28 mmHg), which can be controlled by a kind of medicine. Conclusions: In this series, sclera patch grafts is an effective method for management scleral defects in the at least half a year following-up. Attention should be paid to the sclera patch rejection and melt post operatively.

Soil nematode communities in the initial stage of agrocenosis formation and under sustainable functioning of potato fields

Soil nematode communities under the influence of potato cultivation were studied in a laboratory experiment (initial stages of agrocenosis formation) and on the basis of field data (long-term crop cultivation). Natural meadows located nearbyPetrozavodsk(RepublicofKarelia) were considered as controls. Soil nematode community structure in agrocenoses was changed as compared with meadows. The number of bacterial feeders was increased in the short-term observation, the contribution of omnivores and predators as K-strategists to the nematode community, and the abundance of nematodes associated with plants decreased under long-term potato cultivation. In all trials (experimental and field data) values of Maturity index and Structure index decreased. In contrast, the Enrichment index of soil food web increased in field samples. The analysis of nematode metabolic footprints characterizing the magnitudes of carbon flow in the soil food webs is suggested as an effective tool in nematological investigations for assessment of nematode contributions to ecosystem functions of agrocenoses and meadows.

Performance studies of planetary boundary layer schemes in WRF-Chem for the Andean region of Southern Ecuador

In tandem with emissions, the dynamics of the Planetary Boundary Layer (PBL) strongly define the concentration of pollutants in the atmosphere. The PBL parameterization schemes of numerical models need to be assessed to identify which one provides the best performance. We simulated the meteorology and transport of pollutants in Cuenca (Andean region of Southern Ecuador, 2400 masl) during September 2014, using the Carbon Bond Mechanism Z (CBMZ) for gaseous species and the Model for Simulation Aerosol Interactions and Chemistry (MOSAIC) for aerosol, from the Weather Research & Forecasting with Chemistry (WRF-Chem) model. Simulations were done under 6 PBL schemes: 1 Yonsei University, YSU; 2 Mellor-Yamada-Janjic, MYJ; 3 Hong and Pang, GFS; 4 Mellor-Yamada Nakanishi and Niino Level 2.5, MYNN2; 5 Mellor-Yamada Nakanishi and Niino Level 3, MYNN3; 6 Asymmetric Convective Model PBL, ACM2. The MYJ (local, 1.5 order of closure) and YSU (nonlocal, first order of closure) schemes showed on average the best skill, with capturing 81% and 78% of short-term air quality observations. For the MYJ scheme, the inclusion of direct effects between aerosol and meteorology increased the percentage of capturing of short and long-term air quality by 5% and 13% respectively, in comparison with modeling without feedbacks. In the future it is necessary to explore the effects in modeling of direct and indirect feedbacks, in combination with other parameterizations and aerosol-chemical mechanisms.

Intensive precipitation observation greatly improves hydrological modelling of the poorly gauged high mountain Mabengnong catchment in the Tibetan Plateau

Precipitation is one of the most critical inputs for models used to improve understanding of hydrological processes. In high mountain areas, it is challenging to generate a reliable precipitation data set capturing the spatial and temporal heterogeneity due to the harsh climate, extreme terrain and the lack of observations. This study conducts intensive observation of precipitation in the Mabengnong catchment in the southeast of the Tibetan Plateau during July to August 2013. Because precipitation is greatly influenced by altitude, the observed data are used to characterize the precipitation gradient (PG) and hourly distribution (HD), showing that the average PG is 0.10, 0.28 and 0.26 mm/d/100 m and the average duration is around 0.1, 0.8 and 5.2 h for trace, light and moderate rain, respectively. A distributed biosphere hydrological model based on water and energy budgets with improved physical process for snow (WEB-DHM-S) is applied to simulate the hydrological processes with gridded precipitation data derived from a lower altitude meteorological station and the PG and HD characterized for the study area. The observed runoff, MODIS/Terra snow cover area (SCA) data, and MODIS/Terra land surface temperature (LST) data are used for model calibration and validation. Runoff, SCA and LST simulations all show reasonable results. Sensitivity analyses illustrate that runoff is largely underestimated without considering PG, indicating that short-term intensive precipitation observation has the potential to greatly improve hydrological modelling of poorly gauged high mountain catchments.

Initial recovery of compacted soil—planting and technical treatments decrease CO2 concentrations in soil and promote root growth

The combination of technical treatments and planting of alder trees in a compacted forest soil improves the circulation of air and water through the pore system. This leads to decreases in CO 2 concentrations and increases in root growth in the soil. Both are indicative of an initial recovery of soil structure. The compaction of forest soils, caused by forest machinery, has as a principal consequence: the destruction of soil structure and thus the reduction of the soil aeration status. Thus, the gas exchange between soil and atmosphere is reduced and the depth propagation of roots is limited, resulting in the shortage of water and nutrient supplies for trees. This research aimed at detecting the first stages of recovery of soil structure in a compacted forest soil, which was treated with a combination of techniques (i.e., planting tree species, mulching, addition of lime), which could presumably accelerate the regeneration of soil structure. The variation of CO2 concentrations and the dynamics of root growth were repeatedly measured. Linear mixed models were developed in order to test the effects of the treatments and the planting of trees on soil aeration, as well as to identify the influence of the different environmental effects on CO2 concentration in soil. The planting of root-active trees showed significant effects on decreases in CO2 concentrations. However, during the short-term observation, some negative effects occurred especially for the mulched sites. Nevertheless, all applied technical treatments promoted an improved soil aeration and a higher root growth compared to untreated sites which points to an initial enhanced recovery of soil structure. Pronounced seasonal and interannual variations of soil respiration were highly influenced by soil temperature and soil water content variations. An initial regeneration of soil structure is indicated by distinct changes of the soil aeration status. This regeneration is partially enhanced by the applied treatments. The quantitative potential of the regeneration techniques needs a longer observation period for mid- and long-term soil recoveries.

Rapid adaptation to near extinction in microbial experimental evolution

Theory indicates that responses to natural selection maximize immediate fitness benefits, leading to adaptations to current environmental conditions and those of the immediate past. Over a century of advances in theory, experiment, and observation have documented innumerable adaptations demonstrating the efficacy of natural selection to finely tune species to their respective environments. However, theory also suggests that natural selection is not a panacea, and that improvements in competitive ability do not necessarily increase long-term survival. Here we show that adaptation in experimental populations of microbes can dramatically reduce population sizes to near extinction levels in a stressful environment. The long-term potential for extinction differed from that identified in short-term ecological observations, but the eventual outcome is consistent with limitations on specific modes of adaptation. These results suggest that additional emphasis on the limitations of adaptation can provide insight on when and how improvements in competitive ability provide longer-term benefits.

Contrasting ecophysiological strategies related to drought: the case of a mixed stand of Scots pine (Pinus sylvestris) and a submediterranean oak (Quercus subpyrenaica).

Submediterranean forests are considered an ecotone between Mediterranean and Eurosiberian ecosystems, and are very sensitive to global change. A decline of Scots pine (Pinus sylvestris L.) and a related expansion of oak species (Quercus spp.) have been reported in the Spanish Pre-Pyrenees. Although this has been associated with increasing drought stress, the underlying mechanisms are not fully understood, and suitable monitoring protocols are lacking. The aim of this study is to bring insight into the physiological mechanisms anticipating selective decline of the pines, with particular focus on carbon and water relations. For this purpose, we performed a sampling campaign covering two growing seasons in a mixed stand of P. sylvestris and Quercus subpyrenaica E.H del Villar. We sampled seasonally twig xylem and soil for water isotope composition (δ18O and δ2H), leaves for carbon isotope composition (δ13C) and stems to quantify non-structural carbohydrates (NSC) concentration, and measured water potential and leaf gas exchange. The first summer drought was severe for both species, reaching low predawn water potential (-2.2 MPa), very low stomatal conductance (12 ± 1.0 mmol m-2 s-1) and near-zero or even negative net photosynthesis, particularly in P. sylvestris (-0.6 ± 0.34 μmol m-2 s-1 in oaks, -1.3 ± 0.16 μmol m-2 s-1 in pines). Hence, the tighter stomatal control and more isohydric strategy of P. sylvestris resulted in larger limitations on carbon assimilation, and this was also reflected in carbon storage, showing twofold larger total NSC concentration in oaks than in pines (7.8 ± 2.4% and 4.0 ± 1.3%, respectively). We observed a faster recovery of predawn water potential after summer drought in Q. subpyrenaica than in P. sylvestris (-0.8 MPa and -1.1 MPa, respectively). As supported by the isotopic data, this was probably associated with a deeper and more reliable water supply in Q. subpyrenaica. In line with these short-term observations, we found a more pronounced negative effect of steadily increasing drought stress on long-term growth in pines compared with oaks. All these observations confer evidence of early warning of P. sylvestris decline and indicate the adaptive advantage of Q. subpyrenaica in the area.

Bortezomib Facilitates Reparative Dentin Formation after Pulp Access Cavity Preparation in Mouse Molar

IntroductionThe aim of this study was to evaluate in vitro and ex vivo roles of bortezomib, a proteasome inhibitor that binds to the active site of the 26S proteasome, in tertiary dentin formation. MethodsWe established pulpal access cavity preparation that was treated with or without bortezomib before direct pulp capping with a calcium hydroxide–based material. We also analyzed bone morphogenetic protein (Bmp)- and Wnt-related signaling molecules using quantitative real-time polymerase chain reaction. ResultsIn the short-term observation period, the bortezomib-treated pulp specimens showed the period-altered immunolocalization patterns of nestin, CD31, and myeloperoxidase, whereas the control specimens did not. The bortezomib-treated group showed a complete dentin bridge with very few irregular tubules after 42 days. The micro–computed tomographic images showed more apparent dentin bridge structures in the treated specimens than were in the controls. Quantitative real-time polymerase chain reaction analysis showed up-regulated Bmp and Wnt. ConclusionsThese findings revealed that treatment with 1 μmol/L bortezomib induced reparative dentin formation that facilitated the maintenance of the integrity of the remaining pulpal tissue via early vascularization and regulation of Bmp and Wnt signaling.

Combination of terrestrial reference frames based on space geodetic techniques in SHAO: methodology and main issues

Based on years of input from the four geodetic techniques (SLR, GPS, VLBI and DORIS), the strategies of the combination were studied in SHAO to generate a new global terrestrial reference frame as the material realization of the ITRS defined in IERS Conventions. The main input includes the time series of weekly solutions (or fortnightly for SLR 1983–1993) of observational data for satellite techniques and session-wise normal equations for VLBI. The set of estimated unknowns includes 3-dimensional Cartesian coordinates at the reference epoch 2005.0 of the stations distributed globally and their rates as well as the time series of consistent Earth Orientation Parameters (EOPs) at the same epochs as the input. Besides the final solution, namely SOL-2, generated by using all the inputs before 2015.0 obtained from short-term observation processing, another reference solution, namely SOL-1, was also computed by using the input before 2009.0 based on the same combination of procedures for the purpose of comparison with ITRF2008 and DTRF2008 and for evaluating the effect of the latest six more years of data on the combined results. The estimated accuracy of the x-component and y-component of the SOL-1 TRF-origin was better than 0.1 mm at epoch 2005.0 and better than 0.3 mm yr−1 in time evolution, either compared with ITRF2008 or DTRF2008. However, the z-component of the translation parameters from SOL-1 to ITRF2008 and DTRF2008 were 3.4 mm and −1.0 mm, respectively. It seems that the z-component of the SOL-1 TRF-origin was much closer to the one in DTRF2008 than the one in ITRF2008. The translation parameters from SOL-2 to ITRF2014 were 2.2, −1.8 and 0.9 mm in the x-, y- and z-components respectively with rates smaller than 0.4 mm yr−1. Similarly, the scale factor transformed from SOL-1 to DTRF2008 was much smaller than that to ITRF2008. The scale parameter from SOL-2 to ITRF2014 was −0.31 ppb with a rate lower than 0.01 ppb yr−1. The external precision (WRMS) compared with IERS EOP 08 C04 of the combined EOP series was smaller than 0.06 mas for the polar motions, smaller than 0.01 ms for the UT1-UTC and smaller than 0.02 ms for the LODs. The precision of the EOPs in SOL-2 was slightly higher than that of SOL-1.

Observing Mercury’s Brilliant Flares from Earth

Researchers make the first short-term observation of sodium flares in Mercury’s exosphere.

Incidence and risk factors of delayed intracranial hemorrhage in the emergency department

ObjectivesThis study was performed to identify the risk factors for delayed intracranial hemorrhage and develop a risk stratification system for disposition of head trauma patients with negative initial brain imaging. MethodsThe data source was National Health Insurance Service-National Sample Cohort of Korea. We analyzed adult patients presenting to the ER from January 2004 to September 2012, who underwent brain imaging and discharged with or without short-term observation no longer than two days. The primary outcome was defined as any intracranial bleeding within a month defined by a new appearance of any of the diagnostic codes for intracranial hemorrhage accompanied by a new claim for brain imaging(s) within a month of the index visit. We performed a multivariable logistic regression analysis and built a parsimonious model for variable selection to develop a simple scoring system for risk stratification. ResultsDuring the study period, a total of 19,723 head injury cases were identified from the cohort and a total of 149 cases were identified as having delayed intracranial hemorrhage within 30days. In multivariable logistic regression model, old age, craniofacial fracture, neck injury, diabetes mellitus and hypertension were independent risk factors for delayed intracranial hemorrhage. We constructed the parsimonious model included age, craniofacial fracture and diabetes mellitus. The score showed area under the curve of 0.704 and positive predictive value of the score system was 0.014 when the score≥2. ConclusionsWe found old age, associated craniofacial fracture, any neck injury, diabetes mellitus and hypertension are the independent risk factors of delayed intracranial hemorrhage.

Placenta-derived multipotent cells have no effect on the size and number of DMH-induced colon tumors in rats.

Transplantation of placenta-derived multipotent cells (PDMCs) is a promising approach for cell therapy to treat inflammation-associated colon diseases. However, the effect of PDMCs on colon cancer cells remains unknown. The aim of the present study was to characterize PDMCs obtained from human (hPDMCs) and rat (rPDMCs) placentas and to evaluate their impact on colon cancer progression in rats. PDMCs were obtained from human and rat placentas by tissue explant culturing. Stemness- and trophoblast-related gene expression was studied using reverse transcription-polymerase chain reaction (RT-PCR), and surface markers and intracellular proteins were detected using flow cytometry and immunofluorescence, respectively. Experimental colon carcinogenesis was induced in male albino Wistar rats by injecting 20 mg/kg dimethylhydrazine (DMH) once a week for 20 consecutive weeks. The administration of rPDMCs and hPDMC was performed at week 22 after the initial DMH-injection. All animals were sacrificed through carbon dioxide asphyxiation at week 5 after cell transplantation. The number and size of each tumor lesion was calculated. The type of tumor was determined by standard histological methods. Cell engraftment was determined by PCR and immunofluorescence. Results demonstrated that rPDMCs possessed the immunophenotype and differentiation potential inherent in MSCs; however, hPDMCs exhibited a lower expression of cluster of differentiation 44 and did not express trophoblast-associated genes. The data of the present study indicated that PDMCs may engraft in different tissues but do not significantly affect DMH-induced tumor growth during short-term observations.

Effect of extreme oceanic events in the coral formations of Islas del Rosario, Colombian Caribbean

The increase in frequency and intensity of extreme oceanic events limits the capacity of recoveryof ecosystems, threatening their subsistence. Thus, in order to understand the relationship between coral healthand extreme environmental events, data on sea temperature, runoff and / or salinity, turbidity were analyzed in theIslas del Rosario in comparison with coral cover, and coral signs of deterioration (e.g., bleaching, coral diseases).In the time series of environmental variables, oceanic events that exceeded a statistical threshold were calculated,establishing their intensity, duration and frequency. The attributes of the community were studied through observations in two stations of the National Coral Reef Monitoring System in Colombia (SIMAC), assessed in two timewindows (long term, 1998-2013 and short term, 2013-2014). The extreme events of sea surface temperature, riverdischarge and associated turbidity, were the main variables related to the reduction of coral cover. The massivecoral bleaching of 2005 and other subsequent events resulted in a reduction in coral coverage between 2004 and2010. During the short-term observations there were no strong extreme events or changes in coral formations,although thermal stress and reductions in salinity in the rainy season were associated with a slight bleaching inNovember 2014. Although the signs of deterioration are low, it is important to consider them, since the synergybetween continuous disturbances can lead to a loss of coral cover.

Haben Otto Neugebauer und William Feller die Niljahre richtig gemittelt?

Summary Neugebauer critized Meyer’s hypothesis that the 365-day calendar resulted from observation of the heliacal risings of Sothis, maintaining that astronomical observation should have resulted in a year of 365.25 days. Instead, Neugebauer traced the 365-day calendar back to a Nile year based on computational equalization of varying successive intervals between minimum or maximum gauge readings. He did not propose the anachronistic calculation of the arithmetic average but alluded instead to a procedure using stroke marks allegedly resulting in years of 365 full days, while neglecting the quarter-day. Neugebauer and his collaborator Feller overlooked the fact that four successive years of 365.25 days equal 1461 full days and that the sums of numerous successive intervals between the same gauge values fractionize into multiples of Nile years of 365 and 366 full days. Thus, a revised analysis of long-term Nile year statistics produces the same results as a short-term observation of the heliacal risings of Sirius.

Xenotransplantation of human cryopreserved parathyroid tissue isolated from parathyroid adenomas to normocalcemic rabbits.

Parathyroid allotransplantation is a new method for the treatment of permanent hypoparathyrodism. Adenoma cells are not used for transplantation because of the potential for functional or histopathologic transformation. In this study, we transplanted human adenomatous parathyroid cells to rabbits. Parathyroid adenoma tissue taken from a male patient was cryopreserved and transplanted into seven New Zealand white rabbits (mean weight, 3700±220 g; mean age, 4.5 months) under immunosuppression. The levels of parathormone, calcium and phosphorus were measured before and after transplantation, and the parathyroid cells were observed histopathologically. Mean parathyroid hormone level was 0.5 pg/dL before transplantation and 6.6 pg/dL after transplantation (p<0.05). Preoperative mean calciumlevel was 14.1 mg/dL, and mean phosporus level was 3.5 mg/dL before transplantation while these values were 14.4 mg/dL and 3.3 mg/dL, respectively, after transplantation (p>0.05). Morphologic transformation was not observed in parathyroid cells after transplantation. In short-term observation, adenomatous parathyroid cells can function without malignant transformation. In the future, the preliminary methodology in this study may serve as a safe alternative for allotransplantation into patients with permanent hypoparathyroidism.

The microbial changes in subgingival plaques of orthodontic patients: a systematic review and meta-analysis of clinical trials

BackgroundOrthodontic treatment was found to have an impact on the quantity and constitution of subgingival microbiota. However, contradictory findings regarding the effects of fixed appliances on microbial changes were reported. The aim of this systematic review was to investigate the microbial changes in subgingival plaques of orthodontic patients.MethodsThe PubMed, Cochrane Library, and EMBASE databases were searched up to November 20, 2016. Longitudinal studies observing microbial changes in subgingival plaques at different time points of orthodontic treatment are included. The methodological quality of the included studies was assessed by Methodological index for non-randomized studies (MINORS). The studies that reported the frequency of subgingival periodontopathogens were used for quantitative analysis. Other studies were analysed qualitatively to describe the microbial changes during orthodontic treatment.ResultsThirteen studies were selected, including two controlled clinical trials, three cohort studies and eight self-controlled studies. Four periodontopathogens, including Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi) and Tannerella forsythia (Tf), were analysed. Following orthodontic appliance placement, the frequencies of Pg and Aa showed no significant change (P = 0.97 and P = 0.77), whereas the frequency of Tf significantly increased (P < 0.01) during short-term observation (0–3 months). The frequency of Pi showed a tooth-specific difference, as it presented no significant difference (P = 0.25) at the site of the first molar but was significantly increased (P = 0.01) at the incisor. During long-term observation (> = 6 months), two studies reported that the levels of subgingival periodontopathogens exhibited a transient increase but decreased to the pretreatment levels afterwards. After removal of the orthodontic appliance, the four periodontopathogens showed no significant difference compared with before removal.ConclusionThe levels of subgingival pathogens presented temporary increases after orthodontic appliance placement, and appeared to return to pretreatment levels several months later. This indicates that orthodontic treatment might not permanently induce periodontal disease by affecting the level of subgingival periodontal pathogen levels. Further studies of high methodological quality are required to provide more reliable evidence regarding this issue.

Effects of quadriceps functional exercise with isometric contraction in the treatment of knee osteoarthritis.

This study aims to investigate the effects of a quadriceps isometric contraction exercise method in the treatment of knee osteoarthritis (OA). A total of 250 patients with a confirmed diagnosis of knee OA were enrolled. The patients were randomly divided into an exercise treatment test group (128 patients) and a traditional treatment control group (122 patients). Quadriceps isometric contraction exercise was used in the test group, and local physiotherapy and oral nonsteroidal anti-inflammatory drugs were used in the control group. Knee joint function was evaluated with a visual analog scale (VAS) score and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire before treatment, and 1 and 3months after treatment. VAS scoring and the WOMAC questionnaire showed significant relief in pain 1month after treatment in the test group (P<0.05), but minimal relief in the control group; at 1month, there was also minimal joint function improvement in the test group (P>0.05), but significant improvement in the control group (P<0.05). However, 3months after treatment, pain relief and knee joint function were more improved in the test group than in the control group, with a significant difference (P<0.05). Through our short-term observation, joint pain was effectively relieved and knee joint function was improved with systematic quadriceps isometric contraction exercise.