A Pseudorandom Number Generator Based on the Chaotic Map and Quantum Random Walks

In this paper, a surjective mapping that satisfies the Li-Yorke chaos in the unit area is constructed and a perturbation algorithm (disturbing its parameters and inputs through another high-dimensional chaos) is proposed to enhance the randomness of the constructed chaotic system and expand its key space. An algorithm for the composition of two systems (combining sequence based on quantum random walks with chaotic system's outputs) is designed to improve the distribution of the system outputs and a compound chaotic system is ultimately obtained. The new compound chaotic system is evaluated using some test methods such as time series complexity, autocorrelation and distribution of output frequency. The test results showed that the new system has complex dynamic behavior such as high randomicity, unpredictability and uniform output distribution. Then, a new scheme for generating pseudorandom numbers is presented utilizing the composite chaotic system. The proposed pseudorandom number generator (PRNG) is evaluated using a series test suites such as NIST sp 800-22 soft and other tools or methods. The results of tests are promising, as the proposed PRNG passed all these tests. Thus, the proposed PRNG can be used in the information security field.

The antihypertensive effect of remote ischemic conditioning in spontaneously hypertensive rats

Purpose

Limb remote ischemic conditioning (LRIC) may be an effective method to control hypertension. This study investigated whether LRIC decreases blood pressure by regulating the hypertensive inflammatory response in spontaneously hypertensive rats (SHR).

Method

The SHR and aged-matched Wistar rats with different ages were randomly assigned to the SHR group, SHR+LRIC group, Wistar group, and Wistar + LRIC group. LRIC was conducted by tightening a tourniquet around the upper thigh and releasing it for three cycles daily (10 mins x3 cycles). Blood pressure, the percentage of monocytes and T lymphocytes, and the concentration of pro-inflammatory cytokines in the blood were analyzed.

Results

The blood pressure of SHR was significantly higher than that of age-matched Wistar rats. LRIC decreased blood pressure in SHR at different ages (4, 8, and 16 weeks old), but had no effect on the blood pressure in Wistar rats. Flow cytometry analysis showed that blood monocytes and CD8 T cells of SHR were higher than those of Wistar rats. LRIC significantly decreased the percentage of monocytes and CD8 T cells in SHR. Consistent with the changes of immune cells, the levels of plasma IL-6 and TNF-α in SHR were also higher. And LRIC attenuated the plasma IL-6 and TNF-α levels in SHR.

Conclusion

LRIC may decreased the blood pressure via modulation of the inflammatory response in SHR.

Malignant Middle Cerebral Artery Infarction during Early versus Late Endovascular Treatment in Acute Ischemic Stroke

INTRODUCTION

Endovascular treatment (EVT) performed in the early time window has been shown to decrease the incidence of malignant middle cerebral artery infarction (MMI). However, the incidence of MMI in patients undergoing EVT during the late time window is unclear. This study aimed to investigate the prevalence of MMI in patients undergoing late EVT and compare it with that in patients undergoing early EVT.

METHODS

We retrospectively analyzed consecutive patients with anterior large vessel occlusion stroke who underwent EVT at Xuanwu Hospital between January 2013 and June 2021. Eligible patients were divided into early EVT (within 6 h) and late EVT (6-24 h) groups according to the time from their stroke onset to puncture and compared. The occurrence of MMI post-EVT was the primary outcome.

RESULTS

A total of 605 patients were recruited, of whom 300 (50.4%) underwent EVT within 6 h and 305 (49.6%) underwent EVT within 6-24 h. A total of 119 patients (19.7%) developed MMI. 68 patients (22.7%) in the early EVT group and 51 patients (16.7 %) in the late EVT group developed MMI (p = 0.066). After adjusting for covariate variables, late EVT was independently associated with a lower incidence of MMI (odds ratio, 0.404; 95% confidence interval, 0.242-0.675; p = 0.001).

CONCLUSION

MMI is not an uncommon phenomenon in the modern thrombectomy era. Compared with the early time window, patients selected by stricter radiological criteria to undergo EVT in the late time window are independently associated with a lower incidence of MMI.

Association of platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio with outcomes in stroke patients achieving successful recanalization by endovascular thrombectomy

Objective

Serum inflammatory biomarkers play crucial roles in the development of acute ischemic stroke (AIS). In this study, we explored the association between inflammatory biomarkers including platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-lymphocyte ratio (MLR), and clinical outcomes in AIS patients who achieved successful recanalization.

Methods

Patients with AIS who underwent endovascular thrombectomy (EVT) and achieved a modified thrombolysis in the cerebral infarction scale of 2b or 3 were screened from a prospective cohort at our institution between January 2013 and June 2021. Data on blood parameters and other baseline characteristics were collected. The functional outcome was an unfavorable outcome defined by a modified Rankin Scale of 3-6 at the 3-month follow up. Other clinical outcomes included symptomatic intracranial hemorrhage (sICH) and 3-month mortality. Multivariable logistic regression analysis was performed to evaluate the effects of PLR, NLR, and MLR on clinical outcomes.

Results

A total of 796 patients were enrolled, of which 89 (11.2%) developed sICH, 465 (58.4%) had unfavorable outcomes at 3 months, and 168 (12.1%) died at the 3-month follow up. After adjusting for confounding variables, a higher NLR (OR, 1.076; 95% confidence interval [CI], 1.037-1.117; p < 0.001) and PLR (OR, 1.001; 95%CI, 1.000-1.003; p = 0.045) were significantly associated with unfavorable outcomes, the area under the receiver operating characteristic curve of NLR and PLR was 0.622 and 0.564, respectively. However, NLR, PLR, and MLR were not independently associated with sICH and 3-month mortality (all adjusted p > 0.05).

Conclusion

Overall, our results indicate that higher PLR and NLR were independently associated with unfavorable functional outcomes in AIS patients with successful recanalization after EVT; however, the underlying mechanisms are yet to be elucidated.

MbICE1 Confers Drought and Cold Tolerance through Up-Regulating Antioxidant Capacity and Stress-Resistant Genes in Arabidopsis thaliana

Malus baccata (L.) Borkh is an apple rootstock with good drought and cold resistance. The ICE gene is a key factor in the molecular mechanisms of plant drought and cold resistance. In the present research, the function of drought- and cold-induced MbICE1 of Malus baccata was investigated in Arabidopsis. According to GFP fluorescence images, MbICE1 was determined to be a nuclear protein. The MbICE1 was transferred to Arabidopsis, showing enhanced tolerance to drought and cold stresses. Under drought and cold treatments, the transgenic Arabidopsis had higher chlorophyll content and free proline content than WT plants, but the Malondialdehyde (MDA) content and electrolyte leakage (EL) were lower than those of WT plants. In addition, drought and cold led to a large accumulation of ROS (H₂O₂ and O^2-) content in Arabidopsis, while overexpression of MbICE1 enhanced the antioxidant enzyme activity in Arabidopsis and improved the plant's resistance to stresses. Moreover, the accumulation of MbICE1 promoted the expression of AtCBF1, AtCBF2, AtCBF3, AtCOR15a, AtCOR47 and AtKIN1 genes in Arabidopsis. These data indicate that MbICE1 is a key regulator of drought and cold and can be used as a backup gene for breeding Malus rootstocks.

[Investigation for pathological interpretation criteria and its prognostic value for P53 expression in Chinese diffuse large B-cell lymphoma]

Objective: To explore the feasibility of predicting TP53 mutation risk by immunohistochemical staining (IHC) pattern of P53 in Chinese diffuse large B-cell lymphoma (DLBCL) and its correlation with a prognostic difference. Methods: Between January 2021 and December 2021, 51 DLBCL cases at Beijing Boren Hospital were gathered. These cases had both IHC and next-generation sequencing (NGS) results. IHC classified the P53 protein expression pattern into a loss (<1% ) , diffuse (>80% ) , and heterogeneous (1% -80% ) . The sensitivity and specificity of the predicting TP53 mutation by IHC were assessed by comparing the results of the NGS, and the TP53 high mutation risk group included both loss and diffuse expression of P53. From June 2016 to September 2019, Peking University Cancer Hospital collected 131 DLBCL cases with thorough clinicopathological and follow-up data. From their tumor blocks, tissue microarray blocks were made for IHC evaluation of P53 expression pattern, and prognosis effect of P53 studies. Results: Among 51 cases with both IHC and NGS results, 23 cases were classified as TP53 high mutation risk (7 cases loss and 16 cases diffuse) , 22/23 cases were proved with mutated TP53 by NGS. Only 1 of the 28 cases classified as TP53 low mutation risk was proved with mutated TP53 by NGS. IHC had a sensitivity and specificity of 95.7% and 96.4% for predicting TP53 mutation. NGS identified a total of 26 TP53 mutations with a mutation frequency of 61.57% (13.41% -86.25% ) . In the diffuse group, 16 missense mutations and 2 splice mutations were detected; 6 truncating mutations and 1 splice mutation were detected in the loss group; 1 truncating mutation was detected in the heterogeneous group. Multivariate analysis demonstrated that TP53 cases with high mutation risk have impartial adverse significance for the 131 patients included in survival analysis (HR=2.612, 95% CI 1.145-5.956, P=0.022) . Conclusion: IHC of P53 exhibiting loss (<1% ) or diffuse (>80% ) pattern indicated TP53 high mutation risk, IHC can predict TP53 mutation with high specificity and sensitivity. TP53 high mutation risk is an independent predictor for adverse survival.

Light-Driven Ultrafast Polarization Manipulation in a Relaxor Ferroelectric

Relaxor ferroelectrics have been intensely studied for decades based on their unique electromechanical responses which arise from local structural heterogeneity involving polar nanoregions or domains. Here, we report first studies of the ultrafast dynamics and reconfigurability of the polarization in freestanding films of the prototypical relaxor 0.68PbMg_1/3Nb_2/3O₃-0.32PbTiO₃ (PMN-0.32PT) by probing its atomic-scale response via femtosecond-resolution, electron-scattering approaches. By combining these structural measurements with dynamic phase-field simulations, we show that femtosecond light pulses drive a change in both the magnitude and direction of the polarization vector within polar nanodomains on few-picosecond time scales. This study defines new opportunities for dynamic reconfigurable control of the polarization in nanoscale relaxor ferroelectrics.

Ischemic post-conditioning in acute ischemic stroke thrombectomy: A phase-I duration escalation study

Background

Previous experimental studies have found that ischemic post-conditioning exhibits neuroprotective effects by alleviating ischemia-reperfusion injury in an acute ischemic stroke model, and its efficacy is thought to be related to the duration of ischemic post-conditioning. However, ischemic post-conditioning has not been used in patients with acute ischemic stroke. This study aims to determine the safety, tolerability, and maximum tolerable duration of ischemic post-conditioning in patients with acute ischemic stroke receiving mechanical thrombectomy.

Methods

Patients with acute ischemic stroke with unilateral middle cerebral artery M1 segment occlusion eligible for mechanical thrombectomy will be enrolled. We adopt a 3 + 3 dose-escalation design with a duration escalation schedule of 0, 1, 2, 3, 4, and 5 min × 4 cycles for the ischemic post-conditioning study. After successful reperfusion following mechanical thrombectomy, the balloon for ischemic post-conditioning will be inflated at the site proximal to the culprit lesion four times for 0–5 min with low-pressure (3–4 atmospheres) inflations, each separated by 0–5 min of reflow. We pre-defined the major responses (vessel perforation or rupture, reocclusion of the culprit vessel after ischemic post-conditioning, vessel dissection, severe vasospasm, ischemic post-conditioning related thrombotic events, and rupture of the balloon used for ischemic post-conditioning) as the stopping rules. Each patient will undergo a rigorous evaluation to determine the safety, tolerability, and maximum tolerable duration of ischemic post-conditioning.

Discussion

This will be the first clinical study to ascertain the safety and tolerability of ischemic post-conditioning in patients with acute ischemic stroke receiving mechanical thrombectomy. The maximum tolerable duration obtained in this study will also serve as a starting point for future studies on the efficacy of ischemic post-conditioning.

Clinical trial registration

[https://clinicaltrials.gov], identifier [NCT05153655].

Association between the time of day at stroke onset and functional outcome of acute ischemic stroke patients treated with endovascular therapy

To investigate the association between time-of-day of stroke onset and functional outcome in patients with acute ischemic stroke(AIS) treated with endovascular thrombectomy(EVT). AIS patients treated with EVT between January 2013 and December 2018 were recruited and divided them into four 6-h interval groups according to the time-of-day of stroke onset. A total of 438 patients were enrolled, 3-month favorable outcome were achieved in 58.6%, 43.7%, 36.6%, and 30.5% of patients in the 00:00-06:00, 06:00-12:00, 12:00-18:00, and 18:00-24:00 groups, respectively (adjusted OR 0.61, 95% CI 0.40-0.93; p = 0.020). Compared with the 18:00-24:00 interval, patients in the 00:00-06:00 interval (adjusted OR 4.01, 95%CI 1.02-15.80, p = 0.047) and the 06:00-12:00 interval (adjusted OR 3.24, 95% CI 1.09-9.64, p = 0.034) were more likely to achieve favorable outcome. The time-of-day of stroke onset was not associated with 3-month mortality (adjusted p = 0.829), symptomatic intracerebral hemorrhage (sICH, adjusted p = 0.296), or early successful recanalization (adjusted p = 0.074). In conclusion, in AIS patients treated with EVT, those onsets either between 00:00 and 06:00 or between 06:00 and 12:00 appeared to be associated with a higher proportion of favorable outcomes at 3 months, but the time-of-day at stroke onset was not associated with the incidence of sICH, rate of early successful recanalization, or 3-month mortality.

Interactive climate-soil forces shape the spatial distribution of foliar N:P stoichiometry in Vaccinium uliginosum planted in agroforests of Northeast China

In regions with a ban on forest logging, fruit-bearing shrubs are favored as an alternative source of ecological products over the harvesting of timber. The introduction of cultured shrubs from their habitat to newly developed lands has to be decided according to nutrient availability. Foliar nitrogen (N) and phosphorus (P) stoichiometry is an easily measured and reliable parameter to quickly indicate possible limits in imbalanced N-P availability. When attempting to create a spatial distribution map of the foliar N:P ratio in an objective shrub species, it is helpful to first explore its potential acclimation to the N:P imbalance caused by the joint forces of soil property and regional climate. This study evaluated the cultivated populations of Vaccinium uliginosum in northeastern China's agroforests, using Vaccinium uliginosum as a model shrub species. A total of 51 populations were selected from 51 managed stands, of which 34 were in forests and 17 on farmlands. Foliar N and P concentrations, soil physical and chemical properties, and topography were investigated in 2018, and regional climatic factors were assessed by averaging previous 5-year records (2013–2018). V. uliginosum was determined to have a foliar N:P ratio lower than 4.4, which can be characterized as a limit of N relative to that of P. On forested lands, soil pH negatively impacted regressed foliar N:P, which was also part of the contributions of soil total P content and average temperature to foliar N concentration. On farmlands, low soil pH also resulted in a reduced foliar N:P ratio with joint contributions of ammonium N, nitrate N, and available P contents in soils and air humidity. Spatial interpolation indicated that western forests could benefit from introduced V. uliginosum with a higher foliar N concentration, while the introduction to eastern farmlands can lead to a higher foliar N:P ratio up to 14.6. Our study demonstrates recommended locations with expected soil and meteorological conditions by mapping spatial distributions, which can be referred to by other species and regions.

[Clinical application of laparoscopic sentinel lymph node mapping in early staged cervical cancer]

Objective: To investigate the application of sentinel lymph node biopsy (SLNB) in early-staged cervical cancer by laparoscopy. Methods: It was a prospective, single-arm, single-center clinical study. Seventy-eight cases of cervical cancer patients were collected from July 2015 to December 2018 at the Fourth Hospital of Hebei Medical University. All the patients were injected with tracer into the disease-free block of cervical tissue after anesthesia by the same surgeon who learned sentinel lymph node (SLN) mapping technique in Memorial Sloan-Kettering Cancer Center, and underwent SLN mapping followed by complete pelvic lymphadenectomy. Moreover, all the dissected lymph nodes were stained with hematoxylin eosin staining (HE) pathological examination. Besides, the negative SLN on hematoxylin-eosin staining were detected by immunohistochemistry cytokeratin staining micro-metastasis. To analyze the distribution, detection rate, false negative rate the sensitivity and negative predictive value of the SLN in early-staged cervical cancer by laparoscopy, and explore the value of SLN mapping in predicting the lymph nodes metastasis in early-staged cervical cancer. Results: The overall detection rate of SLN in cervical cancer was 99% (77/78), bilateral detection rate was 87% (68/78). The average of 12.4 lymph node (LN) and 3.6 SLN were dissected for each patients each side. SLN of cervical cancer were mainly distributed in the obturator space (61.5%, 343/558), followed by external iliac (23.5%, 131/558), common iliac (7.3%, 41/558), para-uterine (3.8%, 21/558), internal iliac (2.2%, 12/558), para abdominal aorta (1.1%, 6/558), and anterior sacral lymphatic drainage area (0.7%, 4/558). Fourteen cases of LN metastasis were found among all 78 cases. There were a total of 38 positive LN, including 26 SLN metastasis and 12 none sentinel LN metastasis. Through immunohistochemical staining and pathological ultra-staging, 1 SLN was found to be isolated tumor cells (ITC), and 5 SLNs were found to be micro-metastases (MIC), accounting for 23% (6/26) of positive SLN. SLN mapping with pathological ultra-staging improved the prediction of LN metastasis in cervical cancer (2/14). Metastatic SLN mainly distributed in the obturator space (65%, 17/26), peri-uterine region (12%, 3/26), common iliac region (15%, 4/26), and external iliac region (8%, 2/26). The consistency of the diagnosis of lymph node metastasis by SLN biopsy and postoperative retroperitoneal lymph node metastasis showed that the Kappa value was 1.000 (P<0.001), indicated that the metastasis status of SLN and retroperitoneal lymph node were completely consistent. The sensitivity, specificity, accuracy, false-negative rate, and negative predictive value of SLN biopsy in the diagnosis of lymph node metastasis were 100%, 100%, 100%, 0, and 100%, respectively. Conclusions: SLN in early-staged cervical cancer patients were mainly distributed in the obturator and external iliac space, pathalogical ultra-staging of SLN could improve the prediction of LN metastasis. Intraoperative SLN mapping is safe, feasible and could predict the state of retroperitoneal LN metastasis in early-staged cervical cancer. SLNB may replace systemic pelvic lymphadenectomy.

Imaging features of adult moyamoya disease patients with anterior intracerebral hemorrhage based on high-resolution magnetic resonance imaging

This study aimed to identify the high-resolution magnetic resonance imaging (HRMRI) features of moyamoya disease (MMD) patients with anterior intracerebral hemorrhage (ICH) and attempted to reveal potential mechanisms of anterior ICH. Eligible adult MMD patients were consecutively included, and the morphological features of lenticulostriate arteries (LSAs), vessel wall structure of terminal internal carotid artery (ICA) and periventricular anastomosis were evaluated by HRMRI. 78 MMD patients containing 21 patients with anterior ICH, 31 ischemic patients and 26 asymptomatic patients were included. The mean value of total length of LSAs in anterior ICH group (90.79 ± 37.00 mm) was distinctively lower (p < 0.001) compared with either ischemic group (138.04 ± 46.01 mm) or asymptomatic group (170.50 ± 39.18 mm). Lumen area of terminal ICA was significantly larger (p < 0.001) in hemorrhagic group (4.33 ± 2.02 mm²) compared with ischemic group (2.29 ± 1.17 mm²) or asymptomatic group (3.00 ± 1.34 mm²). Multivariate analysis revealed the total length of LSAs (OR 0.689, 95%CI, 0.565-0.840; p < 0.001) and lumen area of terminal ICA (OR 2.085, 95%, 1.214-3.582; p = 0.008) were significantly associated with anterior ICH. Coexistence of reduced LSAs and relatively preserved lumen area of terminal ICA with an AUC of 0.901 (95%CI, 0.812-0.990) could be a potential predictor of anterior ICH in MMD patients.

TRAUMATIC “ANGIOEDEMA”: EXTENSIVE SUBCUTANEOUS EMPHYSEMA MASQUERADING AS ANGIOEDEMA

Introduction

COVID 19 pandemic related precautions have resulted in suboptimal physical examination of the patients which may have affected the patient care and training of medical professionals. We present a case of a patient whose subcutaneous emphysema was misdiagnosed as angioedema.

Case Description

25 years old female with cerebral palsy and developmental delay presented to hospital in June, 2020 with asymmetric left facial and periorbital swelling which developed an hour after her regular Depo-Provera injection. She had elevated blood pressure readings with tachycardia without hives, respiratory or gastrointestinal symptoms. Facial swelling did not improve after IM epinephrine, IV steroids and antihistamines. Flexible laryngoscopy noted mild edema of lingual surface of the epiglottis. Allergy service was consulted to evaluate for drug-induced anaphylaxis. Our physical examination revealed significant asymmetric periorbital edema, neck and chest swelling with distant breath sounds and distinct palpable crepitus. Serum Trytpase and C1-Estrase inhibitor levels were normal at 3.2ug/L and 28 mg/dl, respectively. Emergent imaging was recommended, which demonstrated multiple rib fractures, pneumomediastinum with extensive chest wall subcutaneous emphysema tracking to extra-cranial soft tissue. Patient was intubated and chest tube was placed due to concerns for airway compromise. She stayed in ICU for one week before being discharged to home.

Discussion

Facial edema, concerning for angioedema, is potentially life threatening condition and an allergic reaction should be higher on the differential diagnoses. Our case represents a learning opportunity regarding other potentially life threatening conditions that can mimic angioedema, requiring higher index of clinical suspicion and thorough physical examination.

Scoring model based on the signature of non-m6A-related neoantigen-coding lncRNAs assists in immune microenvironment analysis and TCR-neoantigen pair selection in gliomas

Background

Small peptides encoded by long non-coding RNAs (lncRNAs) have attracted attention for their various functions. Recent studies indicate that these small peptides participate in immune responses and antigen presentation. However, the significance of RNA modifications remains unclear.

Methods

Thirteen non-m6A-related neoantigen-coding lncRNAs were selected for analysis from the TransLnc database. Next, a neoantigen activation score (NAS) model was established based on the characteristics of the lncRNAs. Machine learning was employed to expand the model to two additional RNA-seq and two single-cell sequencing datasets for further validation. The DLpTCR algorithm was used to predict T cell receptor (TCR)-peptide binding probability.

Results

The non-m6A-related NAS model predicted patients’ overall survival outcomes more precisely than the m6A-related NAS model. Furthermore, the non-m6A-related NAS was positively correlated with tumor cells’ evolutionary level, immune infiltration, and antigen presentation. However, high NAS gliomas also showed more PD-L1 expression and high mutation frequencies of T-cell positive regulators. Interestingly, results of intercellular communication analysis suggest that T cell-high neoplastic cell interaction is weaker in both of the NAS groups which might arise from decreased IFNGR1 expression. Moreover, we identified unique TCR-peptide pairs present in all glioma samples based on peptides encoded by the 13 selected lncRNAs. And increased levels of neoantigen-active TCR patterns were found in high NAS gliomas.

Conclusions

Our work suggests that non-m6A-related neoantigen-coding lncRNAs play an essential role in glioma progression and that screened TCR clonotypes might provide potential avenues for chimeric antigen receptor T cell (CAR-T) therapy for gliomas.

Identification and Localisation Algorithm for Sugarcane Stem Nodes by Combining YOLOv3 and Traditional Methods of Computer Vision

Sugarcane stem node identification is the core technology required for the intelligence and mechanization of the sugarcane industry. However, detecting stem nodes quickly and accurately is still a significant challenge. In this paper, in order to solve this problem, a new algorithm combining YOLOv3 and traditional methods of computer vision is proposed, which can improve the identification rate during automated cutting. First, the input image is preprocessed, during which affine transformation is used to correct the posture of the sugarcane and a rotation matrix is established to obtain the region of interest of the sugarcane. Then, a dataset is built to train the YOLOv3 network model and the position of the stem nodes is initially determined using the YOLOv3 model. Finally, the position of the stem nodes is further located accurately. In this step, a new gradient operator is proposed to extract the edge of the image after YOLOv3 recognition. Then, a local threshold determination method is proposed, which is used to binarize the image after edge extraction. Finally, a localization algorithm for stem nodes is designed to accurately determine the number and location of the stem nodes. The experimental results show that the precision rate, recall rate, and harmonic mean of the stem node recognition algorithm in this paper are 99.68%, 100%, and 99.84%, respectively. Compared to the YOLOv3 network, the precision rate and the harmonic mean are improved by 2.28% and 1.13%, respectively. Compared to other methods introduced in this paper, this algorithm has the highest recognition rate.