Phosphorus Accumulation in Extracellular Polymeric Substances (EPS) of Colony-Forming Cyanobacteria Challenges Imbalanced Nutrient Reduction Strategies in Eutrophic Lakes.

Extracellular polymeric substances (EPS) are crucial for cyanobacterial proliferation; however, certain queries, including how EPS affects cellular nutrient processes and what are the implications for nutrient management in lakes, are not well documented. Here, the dynamics of cyanobacterial EPS-associated phosphorus (EPS-P) were examined both in a shallow eutrophic lake (Lake Taihu, China) and in laboratory experiments with respect to nitrogen (N) and phosphorus (P) availability. Results indicated that 40-65% of the total cyanobacterial aggregate/particulate P presented as EPS-P (mainly labile P and Fe/Al-P). Phosphorus-starved cyanobacteria rapidly replenished their EPS-P pools after the P was resupplied, and the P concentration in this pool was stable for long afterward, although the environmental P concentration decreased dramatically. A low-N treatment enhanced the EPS production alongside two-fold EPS-P accumulation (particularly labile P) higher than the control. Such patterns occurred in the lake where EPS and EPS-P contents were high under N limitation. EPS-P enrichment increased the P content in cyanobacteria; subsequently, it could hold the total P concentration higher for longer and make bloom mitigation harder. The findings outline a new insight into EPS functions in the P process of cyanobacterial aggregates and encourage consideration of both N and P reductions in nutrient management.

Study of Kinetic Freeze-Out Parameters as a Function of Rapidity in pp Collisions at CERN SPS Energies.

We used the blast wave model with the Boltzmann-Gibbs statistics and analyzed the experimental data measured by the NA61/SHINE Collaboration in inelastic (INEL) proton-proton collisions at different rapidity slices at different center-of-mass energies. The particles used in this study were π+, π-, K+, K-, and p¯. We extracted the kinetic freeze-out temperature, transverse flow velocity, and kinetic freeze-out volume from the transverse momentum spectra of the particles. We observed that the kinetic freeze-out temperature is rapidity and energy dependent, while the transverse flow velocity does not depend on them. Furthermore, we observed that the kinetic freeze-out volume is energy dependent, but it remains constant with changing the rapidity. We also observed that all three parameters are mass dependent. In addition, with the increase of mass, the kinetic freeze-out temperature increases, and the transverse flow velocity, as well as kinetic freeze-out volume decrease.

Structural Variations Increase the Upper Limit of Colony Size of Microcystis: Implications from Laboratory Cultures and Field Investigations.

Wild Microcystis have highly diverse colonial structures and sizes, including variable colony geometry, cell arrangement, and diameter. These structural and dimensional variations may play an important role in continual, frequent Microcystis blooms during summer and autumn, the cause of which still remains unclear. Here, laboratory cultures and field investigations were applied to assess mechanisms that drive variation in structure and size, as well as factors that influence diversity. The results demonstrated that colonies grew to large sizes at the expense of their structure being loose and inhomogeneous. Furthermore, colonies may spontaneously change structure to relieve the constraints of size in return. Influencing factors (nutrient limits and turbulent shear) tended to promote these variations. Our work highlights that the diversity of Microcystis colonies may be a result of structural variations as survival strategies for gaining a higher upper size limit. Therefore, during seasonal successions, large colonies commonly have porous or loosely arranged structures, such as in M. aeruginosa. Additionally, this study hypothesized three possible transition routes for better understanding structural diversity and variations in Microcystis.

Significance of preoperative acute kidney injury in patients with acute type A aortic dissection.

BACKGROUND/PURPOSE: Acute type A aortic dissection (AAD) is a medical emergency with high mortality even with emergency repair. We explored the risk factors for in-hospital mortality and the impact of preoperative acute kidney injury (AKI) in patients with AAD. METHODS: Our hospital database contained records for 156 consecutive patients who underwent AAD repair between March 2000 and February 2013. They were assigned to the in-hospital mortality or the survival group. All data were collected retrospectively. RESULTS: The 30-day mortality, including intraoperative deaths, was 14.1% (22/156). Total in-hospital mortality was 19.2% (30/156). Patients who required preoperative cardiopulmonary resuscitation (CPR) (16.7 vs 3.2%; P = 0.012), or who presented with preoperative cardiac tamponade (46.7 vs 19.0%; P = 0.002), shock/hypotension (56.7 vs 21.4%; P < 0.001), or coma (20.0 vs 6.3%; P = 0.019) had a higher in-hospital mortality rate. There was no difference in in-hospital mortality rate between patients with preoperative AKI or not. Mortality and major complications were significantly correlated with the severity of AKI. Multivariate analysis confirmed that preoperative shock or hypotension (odds ratio = 5.2; 95% CI = 2.2-12.3), and preoperative AKI stage 3 (odds ratio = 4.9; 95% CI = 1.3-19.3) were independent preoperative prognostic factors of in-hospital mortality. CONCLUSION: On the basis of our results, preoperative stage 3 AKI is a crucial prognostic risk factor for patients with AAD repair, Cardiac surgeons should be aware of this condition when dealing with AAD patients.

Pyrexia of postimplantation syndrome for patients undergoing (thoracic) endovascular aortic repair.

OBJECTIVE: While a clear definition and explanation to postimplantation syndrome are yet to be clarified, this study aims to investigate its nature by retrospectively analyzing postprocedural fever pattern with patient characteristics, procedure details, and responses to medical treatments. MATERIALS AND METHOD: Twenty-three patients undergoing (thoracic) endovascular aortic repair between January 2011 and January 2012 were studied for their postimplantation fever pattern. The demographic information, procedure specifications, and postprocedure care details were collected for statistical analysis to find associations between fever pattern and the above-mentioned parameters. RESULTS: None of the postprocedure microbial studies returned positive. Longer fever duration and higher fever frequency are statistically associated with younger age (95% confidence interval [CI] -0.82 to -0.04, p < 0.04 and 95% CI -0.74 to -0.01, p = 0.05 respectively), longer procedure duration (95% CI 0.35-0.90, p < 0.01 and 95% CI 0.02-0.75, p = 0.04 respectively), more entry sites created (95% CI 0.09-0.95 p < 0.03 and 95% CI 0.02-0.88, p < 0.04, respectively), and longer stent grafts implanted (95% CI 0.27-0.89, p < 0.01, fever duration only). Fever pattern and different postprocedure medical treatment did not convey a statistically significant association, but effective and dramatic response to steroids was observed in patients with persistent pyrexia that responded poorly to antibiotics and nonsteroidal anti-inflammatory drugs. CONCLUSION: Our findings support the view that postimplantation syndrome is caused by host immune response; none of our cases are related with infection and no benefits were observed from the prolonged use of antibiotics, thus adding to the plausibility of employing steroids as part of the postprocedure care scheme.

Baicalein, an active component of Scutellaria baicalensis Georgi, prevents lysophosphatidylcholine-induced cardiac injury by reducing reactive oxygen species production, calcium overload and apoptosis via MAPK pathways.

BACKGROUND: Lysophosphatidylcholine (lysoPC), a metabolite from membrane phospholipids, accumulates in the ischemic myocardium and plays an important role in the development of myocardial dysfunction ventricular arrhythmia. In this study, we investigated if baicalein, a major component of Huang Qui, can protect against lysoPC-induced cytotoxicity in rat H9c2 embryonic cardiomyocytes. METHODS: Cell viability was detected by the MTT assay; ROS levels were assessed using DCFH-DA; and intracellular free calcium concentrations were assayed by spectrofluorophotometer. Cell apoptosis and necrosis were evaluated by the flow cytometry assay and Hoechst staining. Mitogen-Activated Protein Kinases (MAPKs), which included the ERK, JNK, and p38, and the apoptotic mechanisms including Bcl-2/Bax, caspase-3, caspase-9 and cytochrome c pathways were examined by Western blot analysis. The activation of MAPKs was examined by enzyme-linked immunosorbent assay. RESULTS: We found that lysoPC induced death and apoptosis of H9c2 cells in a dose-dependent manner. Baicalein could prevent lysoPC-induced cell death, production of reactive oxygen species (ROS), and increase of intracellular calcium concentration in H9c2 cardiomyoctes. In addition, baicalein also inhibited lysoPC-induced apoptosis, with associated decreased pro-apoptotic Bax protein, increased anti-apoptotic Bcl-2 protein, resulting in an increase in the Bcl-2/Bax ratio. Finally, baicalein attenuated lysoPC-induced the expression of cytochrome c, casapase-3, casapase-9, and the phosphorylations of ERK1/2, JNK, and p38. LysoPC-induced ERK1/2, JNK, and p38 activations were inhibited by baicalein. CONCLUSIONS: Baicalein protects cardiomyocytes from lysoPC-induced apoptosis by reducing ROS production, inhibition of calcium overload, and deactivations of MAPK signaling pathways.

Double right coronary artery and its clinical implications.

Congenital anomalies of the coronary arteries are present in 0.2-1.4% of the general population. These anomalies represent one of the most confusing issues in the field of cardiology and challenges for interventional cardiologists and cardiac surgeons if the anomalies are unrecognised. Double right coronary artery is one of the rarest coronary arteries. Previously, the probability of developing atherosclerotic changes in patients with a double right coronary artery was considered to be equal to that in those without it. In reality, however, a high prevalence of atherosclerotic coronary artery disease was found in patients with a double right coronary artery originating from a single ostium after our comprehensive literature search through the PubMed database. Owing to the fact that double right coronary artery is both a congenital and potentially atherosclerotic coronary artery disease at diagnosis, coronary intervention or cardiac operation is more complicated than previously believed. Individuals with a double right coronary artery may be unaware of its presence until an accidental finding during coronary angiography or cardiac operation and are at risk for unsuspected complications of atherosclerotic coronary artery disease or during cardiac operation. Therefore, it is important to obtain information on the anatomic variants of this congenital coronary anomaly in patients who are undergoing either coronary intervention, aortic root operation or myocardial revascularisation. To our knowledge, this is the first comprehensive article to discuss the anomalies and their clinical implications.

Serum levels of interleukin-1 beta, interleukin-6 and melatonin over summer and winter in kidney deficiency syndrome in Bizheng rats.

OBJECTIVE: To observe the seasonal changes in serum levels of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6) and melatonin (MT) in Bizheng rat model, and explore the relationship between MT and the pathogenesis of rheumatoid arthritis. METHODS: One hundred and sixty Sprague-Dawley rats were randomly divided into four groups in summer (n=80) and winter (n=80) respectively: normal group, collagen-induced arthritis (CIA) model group, operation group, and sham-operation group (n=20 in each group). The CIA model group was injected with collagen emulsion at the base of the tail to induce arthritis. The rats in the operation group received pineal gland resection, and 7 days after the first operation, underwent testectomy or oophorectomy. The rats in the sham-operation group were operated to ligature the sagittal sinus, without extracting the pineal gland. After the operations, the operation group and the sham-operation group both were immunized as the CIA group was. The serum levels of IL-1ß, IL-6 and MT in different groups were measured by radioimmunoassay. RESULTS: Compared with the normal group, the serum levels of IL-1ß and IL-6 increased in the CIA model, operation, and sham-operation groups both in summer and in winter (IL-1ß in summer, P=0.008, P<0.01, P=0.012; IL-1ß in winter, P=0.019, P<0.01, P=0.027; IL-6 in summer, P=0.028, P<0.01, P=0.024; IL-6 in winter, P=0.006, P<0.01, P=0.008). In the operation group, the serum levels of IL-1ß and IL-6 in winter were higher than in summer, but with no statistically significant differences (P=0.844, 0.679). Compared with the normal group, the serum level of MT significantly increased in summer and winter in both the CIA model group (P=0.002, 0.008) and the sham-operation group (P=0.003, 0.007), while significantly decreased in the operation group (P=0.023, 0.003). There was no significant difference in MT level in the operation group between summer and winter (P=0.947). CONCLUSIONS: The increase of serum levels of IL-1ß and IL-6 may exacerbate the inflammatory reaction and cause a more severe condition in the rheumatoid arthritis. The concentrations of IL-1ß, IL-6, and MT correspond with the change of seasons, confirming that there are connections between nature and human body.

Potential gap in understanding cyanoHABs: Light-dependent morphological variations in colonial cyanobacterium Microcystis.

Colony formation is a crucial characteristic of Microcystis, a cyanobacterium known for causing cyanobacterial harmful algal blooms (cyanoHABs). It has been observed that as Microcystis colonies grow larger, they often become less densely packed, which correlates with a decrease in light penetration. The objective of this study was to investigate the effects of light limitation on the morphological variations in Microcystis, particularly in relation to the crowded cellular environment. The results indicated that when there was sufficient light (transmittance = 100 %) to support a growth rate of 0.11±0.01 day-1, a significant increase in colony size was found, from 466±15 µm to 1030±111 µm. However, under light limitation (transmittance = 50 % - 1 %) where the growth rate was lower than 0, there was no significant improvement in colony size. Microcystis in the light limitation groups exhibited a loose cell arrangement and even the presence of holes or pores within the colony, confirming the negative correlation between colony size and cell arrangement. This pattern is driven by regional differences in growth within the colony, as internal cells have a significantly lower frequency of division compared to peripheral cells, due to intra-colony self-shading (ICSS). The research demonstrates that Microcystis can adjust its cell arrangement to avoid excessive self-shading, which has implications for predicting and controlling cyanoHABs. These findings also contribute to the understanding of cyanobacterial variations and can potentially inform future research on the diverse phycosphere.

Influence of wind and light on the floating and sinking process of Microcystis.

The vertical migration and accumulation of Microcystis colonies is a critical process in algal bloom formation. This work explored the effect of wind and light intensity on the vertical migration of Microcystis colonies. The wind-driven currents, light-driven changes in mass density of colonies, and the effect of colony size was coupled to simulate the vertical motion of colonies via Ansys Fluent and MATLAB. Results showed that light causes Microcystis to exhibit a 'day-sinking and night-floating' (d-n) phenomenon, however, wind weakens the phenomenon by forming a turbulent drag force that inhibits the vertical movement of Microcystis. This study proposed a kinetic ratio-based method, that there is a specific equilibrium turbulent kinetic energy and when turbulent kinetic energy of the water body is greater than the equilibrium turbulent kinetic energy, the d-n phenomenon does not occur. For Lake Taihu, the wind-driven turbulent kinetic energy is usually greater than the equilibrium turbulent kinetic energy. Therefore, Microcystis colonies may not exhibit the d-n phenomenon. Our findings provide a new theoretical basis for current process-based models in simulating algal blooms in large shallow lakes.

Calcium promotes formation of large colonies of the cyanobacterium Microcystis by enhancing cell-adhesion.

Large Microcystis colonies can lead to the rapid formation of surface accumulations, which are a globally significant environmental issue. Laboratory studies have shown that Ca2+ can quickly promote non-classical Microcystis colony formation via cell-adhesion, but our knowledge of the changes in the morphology of these colonies during subsequent long-term culture with Ca2+ is limited. In this study, a 72-day cultivation experiment was conducted to determine the long-term effects of Ca2+ on Microcystis colony formation. Laboratory results indicate that Ca2+ causes Microcystis to rapidly aggregate and form a colony through cell adhesion, then colony formation by cell-adhesion lost dominance, owing to the decrease in Ca2+ concentrations caused by precipitation/complexation. Although the initial colony morphology by cell adhesion is sparse, the newly divided cells, without separating from the mother cells, constantly fill the gaps in the original colony at Ca2+ concentrations >40 mg L-1 for a long time, which creates colonies on day 72 with a morphology similar to that of M. ichthyoblabe in Lake Taihu. If the Ca2+ levels in Lake Taihu continue to increase, Microcystis growth rate will decrease only slightly, while the colony proportion of total biovolume and biomass will increase. Moreover, higher Ca2+ concentrations do not affect microcystin content, but promote the content of bound extracellular polysaccharides (bEPS), enabling formation of larger colonies, which may promote Microcystis surface accumulation.

Cyanobacterial bloom expansion caused by typhoon disturbance in Lake Taihu China.

It remains unclear why the area of a cyanobacterial bloom increases in a shallow lake after a typhoon passes. In this study, the mechanisms of cyanobacterial bloom expansion were investigated by studying meteorological factors, water quality, algal biomass, and bloom area in Lake Taihu before and after typhoons (2007-2016). Our results showed that typhoon-induced sediment resuspension caused a short-term increase in nutrients, but nutrients returned to pre-typhoon levels after the typhoon passages. The short-term nutrient release during a typhoon did not result in an obvious increase in Microcystis cell density in two bays of Lake Taihu (Gonghu and Meiliang). Under strong winds, Microcystis aggregates were uniformly distributed in the water column downwind and then dispersed into different directions by wind-driven currents. In particular, Microcystis in the surface water were transported to the center of Lake Taihu. After a typhoon, dispersed Microcystis refloated and formed blooms. Thus, the bloom area was enlarged compared with before a typhoon. Several days after a typhoon, the bloom area gradually reduced as a result of a steady breeze on the horizontal accumulation of Microcystis.

Mechanism of separation and removal of water from dewatered sludge using L-DME to dissolve hydrophilic organic matter.

Difficulties in advanced dewatering of dewatered sludge hinder sludge reduction and resource utilization. L-DME (liquified dimethyl ether) has been recently used for dewatering, but the effect of organic matter dissolution using L-DME during desorption and dehydration on water removal is not clear. In this study, dewatered sludge from urban sewage treatment plants was used to conduct experiments in sequencing dissolution-separation reactors. The changes in the dehydration rate, bound water and various organic matter levels at different times, L-DME additions, and the temperature were measured. The results show that L-DME can remove 90% of water, 100% of lipids, and 8-12% of organic matter in dewatered sludge. L-DME was mixed with the semi-like colloidal sludge, and high separation of water was achieved by mixing the L-DME with water and dissolving the hydrophilic organic matter to convert the solid-like into a two-phase (solid and liquid) substance, which can be easily separated. The dissolution of hydrophilic organic matter such as polysaccharides and proteins by L-DME promotes the conversion of bound water into free water, which is key to total water removal.

Attenuation of light influences the size of Microcystis colonies.

Colony formation provides excellent advantages for the dominance of Microcystis. However, studies on microenvironments during the process of colony formation are rare, especially regarding intra-colony light usage. This study analyzed the attenuation of light intensity in Microcystis colonies, where most objects followed Lambert-Beer law ( [Formula: see text] ). Intra-colony light limited the maximum thickness of the colony (BMax=4.3×105c-1) and thus affected colony size. Field data showed that the colony size for M. ichthyoblabe was small and limited to approximately 300 µm, while larger colonies were mainly formed by M. aeruginosa and M. wesenbergii respectively. These results imply that the strategies used by morphospecies to allow colonies to tolerate intra-colony light limitation might be different; M. aeruginosa benefited from a reticular growth pattern, and M. wesenbergii colonies were large (500 µm), obtaining a large thickness by lowering cell concentration. The results obtained in this work suggest that M. aeruginosa and M. wesenbergii had more advantages regarding intra-colony light usage, colony size level and bloom formation ability in summer and autumn.

Hydrothermal pretreatment of salvaged cyanobacteria and use of pretreated medium for cultivating Scenedesmus obliquus.

This work studied the hydrothermal Pretreatment of Salvaged Cyanobacteria and used the pretreated slurry as medium for cultivating Scenedesmus obliquus. The cyanobacterial slurry was pretreated by chemical oxidation, hydrothermal treatment and hydrothermal oxidation, and then the cultivation experiment of oil-producing microalgae (Scenedesmus obliquus) was carried out. The results showed that hydrothermal oxidation could transform the hard-to-treat salvaged cyanobacteria into culture medium for microalgae. The oil yield from S. obliquus cultured in that was higher than that in conventional BG11 medium.

Modelling the vertical migration of different-sized Microcystis colonies: coupling turbulent mixing and buoyancy regulation.

Exceptional vertical migration ability provides the cyanobacterium Microcystis with competitive advantages in bloom formation and dominance establishment. Studies have been conducted on the vertical migration patterns of Microcystis since the 1970s; however, bloom simulations remain limited. Here, we used a simple model based on the viscous drag force of turbulence and analysed the motion characteristics of Microcystis colonies. The vertical distribution of turbulent kinetic energy (KZ), cell concentration and colony size profiles in Lake Taihu (Meiliang Bay and Gonghu Bay) and the critical vertical turbulent kinetic energy of colonies (TKZ, i.e. the anti-turbulence ability of colonies) were tested. The results showed that, under steady KZ profiles, colonies had relative rest positions (RRPs) where KZ ≈ TKZ and colonies of the same size gathered together. The vertical migration patterns were affected more by turbulence than by density (colony mass density) if the average KZ of the water column (MKZ) was not equal to TKZ. If MKZ ≈ TKZ, the colonies could exhibit a diurnal pattern of sinking at noon and floating upwards before dawn without steady RRPs. Our results suggest that studies on RRPs may offer optimizations for bloom forecast and control in the future due to easier simulation of KZ profiles than that of flow fields.

Fate of distal aorta after acute type A aortic dissection repair: Change and persistency of postoperative false lumen status.

BACKGROUND: The role of false lumen patency related to aortic growth, re-interventions, and post-discharge mortality in the chronic phase of repaired type A acute aortic dissection (TAAAD) remains controversial. We investigated the role of postoperative false lumen patency during long-term follow-up. METHODS: Based on postoperative CT images of 70 candidates, 58 eligible patients without alteration of false lumen status were assigned into three groups: complete patency, partial patency, and complete thrombosis. Aortic growth of 7 levels was analyzed. RESULTS: Persistent complete patency in post-operative TAAAD presents faster expansion of aortic diameter (95% CI, 0.35 to 11.52; P=0.038; B=5.935) and more patients with growth rate>5mm/year (P=0.029). The persistent status of false lumen does not predict post-discharge mortality (P=0.479). History of coronary artery disease (CAD) is the only independent predictor of post-discharge mortality. CONCLUSIONS: In TAAAD patients without change of postoperative false lumen status, completely patent false lumen presents faster aortic growth and more patients with growth rate>5mm/year. False lumen status does not correlate with late survival. Here we provide an insight into persistent postoperative false lumen in TAAAD patients and may help cast light on aortic dissection in this specific subgroup to improve their late outcomes.

Easy category for complex congenital cardiac segmental connections.

To clarify the variant complex congenital cardiac defects, Van Praagh introduced a system of segmental sets to classify the majority of congenital heart diseases, but the code system entails some confusion for complete understanding. We attempted to recategorize the variant sets into four subgroups according to the connection of the atrial-ventricular and ventricular-arterial segments. This complexity can simply be grouped into four subgroups with regularities. From a simple table so formed, we can quickly ascertain the hemodynamics and the circulatory physiology, and therefore quickly determine the treatment protocol for variant complex hearts.

An avoidable complication of percutaneous coronary intervention-entrapment of stent and disconnected balloon catheter.

During percutaneous coronary intervention, entrapment of catheter materials is a rare but life-threatening complication that sometimes requires emergency surgical treatment. Coronary artery stents have been developed to prevent acute coronary closure and reduce restenosis after coronary angioplasty. The most frequently reported complications of coronary stents are related to stent thrombosis and anticoagulation problems. This case study describes a 60-year-old female who had stable angina pectoris and underwent stent insertion into the left circumflex artery. Unfortunately, the coronary stent with balloon catheter was entrapped while crossing the angulated segment between the left circumflex and left main coronary artery. The stent catheter was surgically removed, and the patient underwent coronary artery bypass grafting successfully. Physicians should keep in mind that extremely angulated segments may reduce the successful rate of coronary stenting and contribute to the stent entrapment complication.