Overview of Mobile Communications in Colombia and Introduction to 5G.

The deployment of 5G around the world continues to progress at a rapid pace, especially in North America and Asia. Its advantages and efficiency as a data transmission network have been widely demonstrated in different fields such as agriculture, education, health, and surveillance. However, this process does not have the same dynamics in Latin America, specifically in Colombia. The country is currently implementing actions aimed at facilitating the deployment of this technology in the short term, including pilot tests for the use of the radio spectrum, spectrum auctions, the planning of future auctions, and the review of spectrum caps. The results of this review allow us to conclude that despite the forecasts and the intentions of the Colombian government and mobile communication service operators, 5G in standalone mode will not be commercially available in Colombia before the end of 2023. The main failures in its deployment are related to the lack of available spectrum to support the ultrahigh-reliability and low-latency, enhanced mobile broadband, and massive machine-type communications scenarios, as well as the delay in the auction processes for its assignment.

Precision Agriculture and Sensor Systems Applications in Colombia through 5G Networks.

The growing global demand for food and the environmental impact caused by agriculture have made this activity increasingly dependent on electronics, information technology, and telecommunications technologies. In Colombia, agriculture is of great importance not only as a commercial activity, but also as a source of food and employment. However, the concept of smart agriculture has not been widely applied in this country, resulting in the high production of various types of crops due to the planting of large areas of land, rather than optimization of the processes involved in the activity. Due to its technical characteristics and the radio spectrum considered in its deployment, 5G can be seen as one of the technologies that could generate the greatest benefits for the Colombian agricultural sector, especially in the most remote rural areas, which currently lack mobile network coverage. This article provides an overview of the current 5G technology landscape in Colombia and presents examples of possible 5G/IoT applications that could be developed in Colombian fields. The results show that 5G could facilitate the implementation of the smart farm in Colombia, improving current production and efficiency. It is useful when designing 5G implementation plans and strategies, since it categorizes crops by regions and products. This is based on budget availability, population density, and regional development plans, among others.

Empirical Model of Radio Wave Propagation in the Presence of Vegetation inside Greenhouses Using Regularized Regressions.

Spain is Europe's leading exporter of tomatoes harvested in greenhouses. The production of tomatoes should be kept and increased, supported by precision agriculture to meet food and commercial demand. The wireless sensor network (WSN) has demonstrated to be a tool to provide farmers with useful information on the state of their plantations due to its practical deployment. However, in order to measure its deployment within a crop, it is necessary to know the communication coverage of the nodes that make up the network. The multipath propagation of radio waves between the transceivers of the WSN nodes inside a greenhouse is degraded and attenuated by the intricate complex of stems, branches, leaf twigs, and fruits, all randomly oriented, that block the line of sight, consequently generating a signal power loss as the distance increases. Although the COST235 (European Cooperation in Science and Technology - COST), ITU-R (International Telecommunications Union-Radiocommunication Sector), FITU-R (Fitted ITU-R), and Weisbberger models provide an explanation of the radio wave propagation in the presence of vegetation in the 2.4 GHz ICM band, some significant discrepancies were found when they are applied to field tests with tomato greenhouses. In this paper, a novel method is proposed for determining an empirical model of radio wave attenuation for vegetation in the 2.4 GHz band, which includes the vegetation height as a parameter in addition to the distance between transceivers of WNS nodes. The empirical attenuation model was obtained applying regularized regressions with a multiparametric equation using experimental signal RSSI measurements achieved by our own RSSI measurement system for our field tests in four plantations. The evaluation parameters gave 0.948 for R2, 0.946 for R2 Adj considering 5th grade polynomial (20 parameters), and 0.942 for R2, and 0.940 for R2 Adj when a reduction of parameters was applied using the cross validation (15 parameters). These results verify the rationality and reliability of the empirical model. Finally, the model was validated considering experimental data from other plantations, reaching similar results to our proposed model.

Exemestane versus anastrozole as front-line endocrine therapy in postmenopausal patients with hormone receptor-positive, advanced breast cancer: final results from the Spanish Breast Cancer Group 2001-03 phase 2 randomized trial.

BACKGROUND: Several aromatase inhibitor studies have reported variations in the inhibitory potency of these agents that could lead to differences in clinical outcomes. In the current study, the authors formally evaluated the activity of anastrozole and exemestane in postmenopausal women with hormone-responsive, advanced breast cancer. METHODS: Postmenopausal women who had measurable disease according to Response Evaluation Criteria in Solid Tumors and had not received previous endocrine therapy for advanced breast cancer were randomized to receive either oral exemestane 25 mg daily or oral anastrozole 1 mg daily until they had disease progression. The primary endpoint was the objective response rate (ORR), and secondary endpoints included the clinical benefit rate (CBR), time to progression (TTP), overall survival, and safety. Crossover to the other aromatase inhibitor was permitted at the time of disease progression; ORR, CBR, and TTP after second-line treatment also were explored. RESULTS: In total, 103 patients were enrolled. The median patient age was 71.6 years, 52.4% of patients had visceral disease, and 75.8% of patients had ≥ 2 disease sites. Half of the patients had received previous tamoxifen, and 60% had received previous chemotherapy. The efficacy observed in the exemestane and anastrozole groups was an ORR of 36.2% and 46%, respectively; a CBR of 59.6% and 68%, respectively, and a TTP of 6.1 months and 12.1 months, respectively. At progression, 28 patients crossed over to the other aromatase inhibitor, including 16 patients who switched to exemestane (CBR, 43.7%; TTP, 4.4 months) and 12 patients who switched to anastrozole (CBR, 8.3%; TTP, 2 months). Both drugs were generally well tolerated, and no study drug-related serious adverse events were reported. CONCLUSIONS: In this phase 2 randomized trial, no significant differences in clinical activity were observed in favor of exemestane to justify a superiority phase 3 trial design in the first-line setting.

Forecasted datasets of electric vehicle consumption on the electricity grid of Spain.

The information included in this study were calculated on the basis of data provided by the Spanish electricity grid, for thirteen years between 2007 and 2019. This data includes: the average consumption demand on the Spanish electricity grid at national level, and its availability. Subsequently, the report looks at the number of electric vehicles that could be supported in the years 2020-2023, depending on the consumption demand and availably of the electricity grid for those future years. The data presented in the article refers to the research study: 'Electric vehicles in Spain: An overview of charging systems'[1] and 'Analysis of charging stations for electric vehicles in Spain' [2].

Plasma zinc levels inversely correlate with vascular cell adhesion molecule-1 concentration in children with sickle cell disease.

Zinc deficiency has been implicated in impaired cell-mediated immunity of children with sickle cell disease (SCD). However, its influence on the expression of vascular cell-adhesion molecule-1 (VCAM-1) on endothelial cells, a protein involved in vasoocclusion, has not been previously investigated. We therefore measured (soluble) sVCAM-1 and zinc in 76 SCD children and 96 non-SCD children, mean age 7.73 years and 11.24 years, respectively. Although mean zinc levels of both groups were within the normal range (approximately 14.5 micromol/l), 14.5 % of SCD and 11% of non-SCD children (without inflammation) had levels below normal (10.7 micromol/L). Mean sVCAM-1 concentrations of SCD children (837 microg/l) were significantly higher than those of controls (627 microg/l) (p < 0.001). Differences persisted after taking into account age, hemoglobin phenotype, and inflammation (alpha-l acid glycoprotein >l g/l and C-reactive protein >10 mg/I). sVCAM-1 negatively correlated with serum (r = -0.444) and red blood cells zinc (r = -0.242, p < 0.05) but not with acute-phase proteins. Mean sVCAM-1 tended to be higher in SCD children with than in those without a history of a health problem (infection, pain crisis or were transfused; not significant). Data suggest that zinc may modulate the clinical status of SCD children through VCAM-1 expression, and zinc supplementation may be beneficial in these patients.

Serum markers and prognosis in locally advanced breast cancer.

BACKGROUND: Locally advanced breast cancer (LABC) represents a heterogeneous subgroup of breast cancer with an often dismal outcome. Identifying prognostic factors has acquired great significance for the selection of optimal treatment in individual patients. METHODS: Between January 1993 and December 1997, 103 patients were treated in our institution with multimodality treatment consisting of neoadjuvant chemotherapy followed by surgery, adjuvant chemotherapy and radiotherapy; tamoxifen was added in hormone receptor-positive cases. In the search for prognostic factors well-established parameters (clinical, pathological and treatment-related) as well as new features with potential value (c-erbB-2, baseline serum levels of CA 15.3 and CEA) were included in the univariate and multivariate analysis. RESULTS: At a median follow-up of 92 months (range, 8-130), the estimated five-year cancer-specific overall survival (OS) and disease-free survival (DFS) were 71.34% and 57.7%, respectively. Among the 22 different variables studied, only 10 were significantly correlated with OS and DFS. In multivariate analysis five retained independent prognostic value for both OS and DFS: tumor grade, serum markers, features of inflammatory breast cancer (IBC), response to neoadjuvant chemotherapy and lymph node status. With cutoff values of 35 U/mL for CA 15.3 and 5 ng/mL for CEA, the probability of five-year OS (Cox hazard ratio 3.91, P = 0.0009) and DFS (Cox hazard ratio 2.40, P = 0.02) decreased from 78% to 52% and from 68% to 47%, respectively, when at least one of these markers was abnormal. CONCLUSIONS: Baseline serum levels of CEA and CA 15.3 emerged from this study as strong independent predictors of outcome in LABC, whose value adds to other established prognostic factors such as postoperative nodal status, IBC, histological grade and response to neoadjuvant chemotherapy.

Sangre de grado Croton palanostigma induces apoptosis in human gastrointestinal cancer cells.

Sangre de grado is an ethnomedicinal red tree sap obtained from Croton spp. that is used to treat gastrointestinal ulcers, cancer and to promote wound healing. To evaluate the potential role of sangre de grado (SdG) in cancer we examined its effects on human cancer cells, AGS (stomach), HT29 and T84 (colon). Viability of cells treated with SdG (10-200 microg/ml) decreased (P<0.01) in a dose dependent manner measured over a 24-h period. Cell proliferation at 48 h decreased (P<0.01) in all cells treated with SdG (>100 microg/ml). When cells in suspension were treated with SdG (100 microg/ml) cell adherence was severely compromised (>85%). Cells treated with SdG (100 microg/ml) underwent apoptosis as detected by nucleus condensation and DNA fragmentation determined by ELISA, and flow cytometry. Morphological changes as assessed by acridine orange. These effects were similar to that observed with Taxol (30 microM). A significant alteration of microtubular architecture was equally observed in both stomach and colon cancer cells exposed to SdG (100 microg/ml). The induction of apoptosis and microtubule damage in AGS, HT29 and T84 cells suggest that sangre de grado should be evaluated further as a potential source of anti-cancer agents.

The Long-HER study: clinical and molecular analysis of patients with HER2+ advanced breast cancer who become long-term survivors with trastuzumab-based therapy.

BACKGROUND: Trastuzumab improves survival outcomes in patients with HER2+ metastatic breast cancer. The Long-Her study was designed to identify clinical and molecular markers that could differentiate long-term survivors from patients having early progression after trastuzumab treatment. METHODS: Data were collected from women with HER2-positive metastatic breast cancer treated with trastuzumab that experienced a response or stable disease during at least 3 years. Patients having a progression in the first year of therapy with trastuzumab were used as a control. Genes related with trastuzumab resistance were identified and investigated for network and gene functional interrelation. Models predicting poor response to trastuzumab were constructed and evaluated. Finally, a mutational status analysis of selected genes was performed in HER2 positive breast cancer samples. RESULTS: 103 patients were registered in the Long-HER study, of whom 71 had obtained a durable complete response. Median age was 58 years. Metastatic disease was diagnosed after a median of 24.7 months since primary diagnosis. Metastases were present in the liver (25%), lungs (25%), bones (23%) and soft tissues (23%), with 20% of patients having multiple locations of metastases. Median duration of response was 55 months. The molecular analysis included 35 patients from the group with complete response and 18 patients in a control poor-response group. Absence of trastuzumab as part of adjuvant therapy was the only clinical factor associated with long-term survival. Gene ontology analysis demonstrated that PI3K pathway was associated with poor response to trastuzumab-based therapy: tumours in the control group usually had four or five alterations in this pathway, whereas tumours in the Long-HER group had two alterations at most. CONCLUSIONS: Trastuzumab may provide a substantial long-term survival benefit in a selected group of patients. Whole genome expression analysis comparing long-term survivors vs. a control group predicted early progression after trastuzumab-based therapy. Multiple alterations in genes related to the PI3K-mTOR pathway seem to be required to confer resistance to this therapy.

Liposomal Doxorubicin in the treatment of breast cancer patients: a review.

Drug delivery systems can provide enhanced efficacy and/or reduced toxicity for anticancer agents. Liposome drug delivery systems are able to modify the pharmacokinetics and biodistribution of cytostatic agents, increasing the concentration of the drug released to neoplastic tissue and reducing the exposure of normal tissue. Anthracyclines are a key drug in the treatment of both metastatic and early breast cancer, but one of their major limitations is cardiotoxicity. One of the strategies designed to minimize this side effect is liposome encapsulation. Liposomal anthracyclines have achieved highly efficient drug encapsulation and they have proven to be effective and with reduced cardiotoxicity, as a single agent or in combination with other drugs for the treatment of either anthracyclines-treated or naïve metastatic breast cancer patients. Of particular interest is the use of the combination of liposomal anthracyclines and trastuzumab in patients with HER2-overexpressing breast cancer. In this paper, we discuss the different studies on liposomal doxorubicin in metastatic and early breast cancer therapy.

Biweekly vinorelbine and tegafur/uracil in patients with metastatic breast cancer previously treated with anthracyclines and taxanes: GEICAM 2000-02 phase II study.

INTRODUCTION: To assess the efficacy and safety profile of biweekly vinorelbine and tegafur/uracil (UFT) as treatment in patients with metastatic breast cancer previously treated with anthracyclines and taxanes. PATIENTS AND METHODS: Patients with histologically confirmed breast cancer, measurable disease, no more than one prior chemotherapy regimen for metastatic disease, an Eastern Cooperative Oncology Group (ECOG) performance status ≤2, and adequate bone marrow, renal and liver function were eligible. Patients received vinorelbine (30 mg/m(2) on day 1) and UFT (250 mg/m(2) daily) every two weeks for 12 cycles unless progression or unacceptable toxicity was observed. RESULTS: Thirty-seven patients were included and received 311 cycles of chemotherapy. Efficacy and toxicity analyses were carried out on an intention-to-treat basis. The overall response rate was 35% (95% CI: 20-53). With a median follow-up of 18.6 months (95% CI: 1.0-74.3), the median time to progression was 7.0 months (96% CI: 5.2-8.9) and the median overall survival was 19.4 months (95% CI: 11.1-27.8). The most common severe toxicities were neutropenia (38% of patients) and asthenia (11% of patients). CONCLUSION: The combination of biweekly vinorelbine and UFT in patients with metastatic breast cancer pretreated with anthracyclines and taxanes is a well tolerated and effective regimen. AEMPS Trial Registration No.: 00-0534.

Phase I study of oral vinorelbine and capecitabine in patients with metastatic breast cancer.

BACKGROUND: To determine the recommended doses of oral vinorelbine (VN) and capecitabine (C) in metastatic breast cancer. PATIENTS AND METHODS: Eighteen patients with metastatic breast cancer received oral VN (on days 1 and 8) and C (on days 1 to 14) every three weeks at one of four dose levels: I) 60 mg/m(2) and 1650 mg/m(2)/day; II) 70 mg/m(2) and 1650 mg/m(2)/day; III) 70 mg/m(2) and 2000 mg/m(2)/day; IV) 80 mg/m(2) and 2000 mg/m(2)/day, respectively. The primary endpoint was to determine the recommended doses for the combination of oral VN and C in metastatic breast cancer. Secondary endpoints include evaluating response rate, safety profile and whether or not VN dosage escalation was required. RESULTS: Severe neutropenia occurred in 28% of patients; and severe anaemia and leucopenia were observed in one patient each (6%). One patient developed febrile neutropenia. Non-hematological toxicities were rare. The response rate was 28% (95% CI: 10-54) in the intention-to-treat population. CONCLUSION: The recommended dose is 80 mg/m(2) of oral VN on days 1 and 8, and 2000 mg/m(2)/day of C from days 1 to 14 in three weekly cycles. A phase II study with this schedule is currently under way.