Geminography — The science of twinning applied to the early-stage derivation of non-merohedric twin laws

Author(s):  
Massimo Nespolo ◽  
G. Ferraris

AbstractThe recognition of twinning and the determination of the twin laws are nowadays often entrusted to "black-box" software packages. This approach may be both risky and uneconomical. It is risky because never a procedure should be blindly applied. It is uneconomical if procrastinates the analysis of twinning at the very late stage of structure solution and refinement, whereas in many cases this analysis can and should be applied much earlier. In this paper we present a brief survey of the working strategies to be applied to the structural study of twinned crystals, emphasizing the role of the crystallographer, rather than that of the machine.

2021 ◽  
pp. 074823372110394
Author(s):  
Yujing Zhang ◽  
Shuai Huang ◽  
Shiyi Tan ◽  
Mingke Chen ◽  
Shang Yang ◽  
...  

Occupational exposure to silica dust is related to pulmonary inflammation and silicosis. Lipopolysaccharides (LPSs) could aggravate apoptosis in alveolar macrophages (AMs) of human silicosis through autophagy, yet how the reduction of autophagy attenuated LPS-induced lung injury and the related mechanisms need to be investigated. In the study, we aim to understand the role of 3-methyladenine (3-MA), an inhibitor of autophagy, in LPS-mediated inflammatory responses and fibrosis. We collected AMs from observers/silicosis patients. The results showed that LPS induced NF-κB-related pulmonary inflammation in observers and silicosis patients, as confirmed by an increase in the expression of IL-1β, IL-6, TNF-α, and p65, which could be inhibited by 3-MA treatment. In mice models, at the early stage (7d) of silicosis, but not the late (28d) stage, blocking autophagy reversed the increased levels of IL-1β, IL-6, TNF-α, and p65 caused by LPS. Mechanism study revealed that LPS triggered the expression of LC3 II, p62, and cleaved caspase-3 at the early stage exposed to silica, which could be restored by 3-MA, while there was no difference in the expression of LAMP1 either at the early or late stage of silicosis in different groups. Similarly, 3-MA treatment did not prevent fibrosis characterized by destroyed alveoli, collagen deposition, and increased expression of α-SMA and Col-1 induced by LPS at the late stage of silicosis. The results suggested that 3-MA has a role in the protection of lung injury at the early stage of silicosis and provided an experimental basis for preventive strategies of pulmonary inflammation and silicosis.


1995 ◽  
Vol 62 (2) ◽  
pp. 300-304
Author(s):  
M. Fini ◽  
G. Vagliani

From September 1992 to February 1994, 1441 men aged between 50 and 70 years underwent screening with PSA and ER measurement for early diagnosis of prostatic carcinoma. A neoplasm was diagnosed in 1.73% (25/1441) of cases, which being found at an early stage, made it possible to perform prostatectomy and radical radiotherapy on 37.5% and 16.6% of patients respectively. The incidence of the disease was higher than in a previous screening with just ER dosage (1.73% vs 1.1%). Combined PSA and ER also gave higher sensitivity, specificity, overall accuracy and predictiveness compared to the methods taken individually. This combination seems preferable, in view of the greater efficacy and “practicability” compared to protocols which involve the use of USTR, which is less practicable on a large scale due to the length of time required and high costs. The utility of periodic determination of PSA levels in those over fifty years old is emphasised, both for oncological screening controls and to increase the diagnostic accuracy of other clinical tests.


2003 ◽  
Vol 94 (3) ◽  
pp. 1204-1212 ◽  
Author(s):  
Barbara E. Taylor ◽  
Michael B. Harris ◽  
E. Lee Coates ◽  
Matthew J. Gdovin ◽  
J. C. Leiter

Central CO2 chemoreception and the role of carbonic anhydrase were assessed in brain stems from Rana catesbeiana tadpoles and frogs. Buccal and lung rhythms were recorded from cranial nerve VII and spinal nerve II during normocapnia and hypercapnia before and after treatment with 25 μM acetazolamide. The lung response to acetazolamide mimicked the hypercapnic response in early-stage and midstage metamorphic tadpoles and frogs. In late-stage tadpoles, acetazolamide actually inhibited hypercapnic responses. Acetazolamide and hypercapnia decreased the buccal frequency but had no effect on the buccal duty cycle. Carbonic anhydrase activity was present in the brain stem in every developmental stage. Thus more frequent lung ventilation and concomitantly less frequent buccal ventilation comprised the hypercapnic response, but the response to acetazolamide was not consistent during metamorphosis. Therefore, acetazolamide is not a useful tool for central CO2 chemoreceptor studies in this species. The reversal of the effect of acetazolamide in late-stage metamorphosis may reflect reorganization of central chemosensory processes during the final transition from aquatic to aerial respiration.


2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0016
Author(s):  
Prem Kumar Thirunagari ◽  
Nancy Phu ◽  
David Tramutolo ◽  
Hector Rieiro ◽  
Tanya Polec ◽  
...  

Background: Oculomotor and visual processing deficits occur commonly after brain injury in young athletes. A subset of these concussed athletes do experience prolonged recoveries or PPCS with ongoing oculomotor deficits and visual symptoms. There have been limited studies conducted to determine the significance of oculomotor tracking (OMT) testing in the pediatric population, and even less investigating the role of microsaccades. Hence, investigations on microsaccades(MS), physiological adjustive micro eye movements critical in visual processing and central/peripheral visual integration, may provide insight on the role of visual dysfunction in PPCS course, prognosis, and management. Purpose: The purpose of this study is to identify possible MS rate trends and differences between early and late stage PPCS pediatric patients. Methods: A retrospective cohort study of 41 pediatric patients with PPCS or symptoms greater than one month from injury. Data was collected from 7/1/2018 to 12/1/2019 and the age group ranged from 8 to 21 years. For each participant, using the OMT device we measured the number of saccades generated, the size and speed of the microsaccades, the area covered and the ratio of vertical-to-horizontal direction component of the fixational eye movements, using a 250 Hz video-eye tracker mounted inside a HTC Vive VR headset. Participants were instructed to fixate on a central dot for 140 seconds, in 20-second intervals. Patients were classified into early or late stages of PPCS (early stage: 1-6 months; late stage: >6 months) to compare MS rate between stages. Exclusion criteria included history of visual disorders, learning disorders, seizure disorder, or intracranial hemorrhage. Results: 27 patients were in the early stage while 14 patients were in the late stage. The early stage group had a mean MS rate of 125 beats/min while the late stage group had a mean MS rate of 116 beats/min. A two sample t-test assuming no difference between early and late stage patients resulted in a p value of 0.51. Conclusion: There is a potential trend in declining MS numbers with progressive PPCS stage. Although the t-test didn’t show statistical significance, this could be due to the small sample size of our study. Future studies are needed to validate this initial finding and to identify the significance of microsaccade patterns in concussion prognosis and management. [Figure: see text]


2020 ◽  
Vol 8 ◽  
Author(s):  
Xiangwen Xu ◽  
Shuchen Gu ◽  
Xin Huang ◽  
Jieyi Ren ◽  
Yihui Gu ◽  
...  

Abstract Numerous studies have shown that macrophages can orchestrate the microenvironment from the early stage of wound healing to the later stages of scar formation. However, few reviews have highlighted the significance of macrophages during the formation of abnormal scars. The purpose of this review was to outline the polarization of macrophages from early to late stage of pathological scar formation, focusing on spatiotemporal diversity of M1 and M2 macrophages. In this review, the role of macrophages in the formation of hypertrophic scars and keloids is summarized in detail. First, an increased number of M2 cells observed before injuries are significantly associated with susceptibility to abnormal scar pathogenesis. Second, decreased expression of M1 at the early stage and delayed expression of M2 at the late stage results in pathological scar formation. Third, M2 cells are highly expressed at both the margin and the superficial region, which is consistent with the invasive property of keloids. Finally, this review helps to characterize strategies for the prediction and prevention of pathological scar formation.


2015 ◽  
Vol 143 (2) ◽  
pp. 536-562 ◽  
Author(s):  
Robert F. Rogers ◽  
Paul D. Reasor ◽  
Jun A. Zhang

Abstract The structure and evolution of Hurricane Earl (2010) during its rapid intensification as sampled by aircraft is studied here. Rapid intensification occurs in two stages. During the early stage, covering ~24 h, Earl was a tropical storm experiencing moderate northeasterly shear with an asymmetric distribution of convection, and the symmetric structure was shallow, broad, and diffuse. The upper-level circulation center was significantly displaced from the lower-level circulation at the beginning of this stage. Deep, vigorous convection—termed convective bursts—was located on the east side of the storm and appeared to play a role in positioning the upper-level cyclonic circulation center above the low-level center. By the end of this stage the vortex was aligned and extended over a deep layer, and rapid intensification began. During the late stage, rapid intensification continued as Earl intensified ~20 m s−1 during the next 24 h. The vortex remained aligned in the presence of weaker vertical shear, although azimuthal asymmetries persisted that were characteristic of vortices in shear. Convective bursts concentrated near the radius of maximum winds, with the majority located inside the radius of maximum winds. Each of the two stages described here raises questions about the role of convective- and vortex-scale processes in rapid intensification. During the early stage, the focus is on the role of convective bursts and their associated mesoscale convective system on vortex alignment and the onset of rapid intensification. During the late stage, the focus is on the processes that explain the observed radial distribution of convective bursts that peak inside the radius of maximum winds.


2021 ◽  
Vol 15 (9) ◽  
pp. e0009764
Author(s):  
Gabriela C. Olivera ◽  
Leonie Vetter ◽  
Chiara Tesoriero ◽  
Federico Del Gallo ◽  
Gustav Hedberg ◽  
...  

The infection by Trypanosoma brucei brucei (T.b.b.), a protozoan parasite, is characterized by an early-systemic stage followed by a late stage in which parasites invade the brain parenchyma in a T cell-dependent manner. Here we found that early after infection effector-memory T cells were predominant among brain T cells, whereas, during the encephalitic stage T cells acquired a tissue resident memory phenotype (TRM) and expressed PD1. Both CD4 and CD8 T cells were independently redundant for the penetration of T.b.b. and other leukocytes into the brain parenchyma. The role of lymphoid cells during the T.b.b. infection was studied by comparing T- and B-cell deficient rag1-/- and WT mice. Early after infection, parasites located in circumventricular organs, brain structures with increased vascular permeability, particularly in the median eminence (ME), paced closed to the sleep-wake regulatory arcuate nucleus of the hypothalamus (Arc). Whereas parasite levels in the ME were higher in rag1-/- than in WT mice, leukocytes were instead reduced. Rag1-/- infected mice showed increased levels of meca32 mRNA coding for a blood /hypothalamus endothelial molecule absent in the blood-brain-barrier (BBB). Both immune and metabolic transcripts were elevated in the ME/Arc of WT and rag1-/- mice early after infection, except for ifng mRNA, which levels were only increased in WT mice. Finally, using a non-invasive sleep-wake cycle assessment method we proposed a putative role of lymphocytes in mediating sleep alterations during the infection with T.b.b. Thus, the majority of T cells in the brain during the early stage of T.b.b. infection expressed an effector-memory phenotype while TRM cells developed in the late stage of infection. T cells and parasites invade the ME/Arc altering the metabolic and inflammatory responses during the early stage of infection and modulating sleep disturbances.


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