scholarly journals A Dual-Frequency Cloud Radar for Observations of Precipitation and Cloud in Tibet: Description and Preliminary Measurements

2021 ◽  
Vol 13 (22) ◽  
pp. 4685
Author(s):  
Juan Huo ◽  
Yongheng Bi ◽  
Bo Liu ◽  
Congzheng Han ◽  
Minzheng Duan
Keyword(s):  
Detection Sensitivity ◽  
The Tibetan Plateau ◽  
Dual Frequency ◽  
Cloud Droplets ◽  
Cloud Radar ◽  
W Band ◽  
The Mean ◽  
The Difference ◽  
One Year ◽  
Different Characteristics

A new dual-frequency Doppler polarimetric cloud radar (DDCR), working at 35-GHz (Ka-band radar, wavelength: 8.6 mm) and 94-GHz (W-band radar, wavelength: 3.2 mm) frequencies, has been in operation at Yangbajing Observatory on the Tibetan Plateau (China) for more than a year at the time of writing. Calculations and field observations show that the DDCR has a high detection sensitivity of −39.2 dBZ at 10 km and −33 dBZ at 10 km for the 94-GHz radar and 35-GHz radar, respectively. The radar reflectivity measured by the two radars illustrates different characteristics for different types of cloud: for precipitation, the attenuation caused by liquid cloud droplets is obviously more serious for the 94-GHz radar than the 35-GHz radar (the difference reaches 40 dB in some cases), and the 94-GHz radar lost signals due to serious attenuation by heavy rainfall; while for clouds dominated by ice crystals where the attenuation significantly weakens, the 94-GHz radar shows better detection ability than the 35-GHz radar. Observations in the Tibetan region show that the 35-GHz radar is prone to missing cloud near the edge, such as the cloud-top portion, resulting in underestimation of the cloud-top height (CTH). Statistical analysis based on one year of observations shows that the mean CTH measured by the 94-GHz radar in the Tibetan region is approximately 600 m higher than that measured by the 35-GHz radar. The analysis in this paper shows that the DDCR, with its dual-frequency design, provides more valuable information than simpler configurations, and will therefore play an important role in improving our understanding of clouds and precipitation in the Tibetan region.

Identifying Effectors of Outcomes in Patients with Large Umbilical Hernias

2016 ◽  
Vol 82 (7) ◽  
pp. 613-621 ◽  
Author(s):  
Steven A. Groene ◽  
Davis W. Heniford ◽  
Tanushree Prasad ◽  
Amy E. Lincourt ◽  
Vedra A. Augenstein
Keyword(s):  
Umbilical Hernia ◽  
Defect Size ◽  
Long Term Outcomes ◽  
Preoperative Pain ◽  
The Mean ◽  
The Difference ◽  
One Year

Quality of life (QOL) has become an important focus of hernia repair outcomes. This study aims to identify factors which lead to ideal outcomes (asymptomatic and without recurrence) in large umbilical hernias (defect size ≥9 cm2). Review of the prospective International Hernia Mesh Registry was performed. The Carolinas Comfort Scale was used to measure QOL at 1-, 6-, and 12-month follow-up. Demographics, operative details, complications, and QOL data were evaluated using standard statistical methods. Forty-four large umbilical hernia repairs were analyzed. Demographics included: average age 53.6 ± 12.0 and body mass index 34.9 ± 7.2 kg/m2. The mean defect size was 21.7 ± 16.9 cm2, and 72.7 per cent were performed laparoscopically. Complications included hematoma (2.3%), seroma (12.6%), and recurrence (9.1%). Follow-up and ideal outcomes were one month = 28.2 per cent, six months = 42.9 per cent, one year = 55.6 per cent. All patients who remained symptomatic at one and two years were significantly symptomatic before surgery. Symptomatic preoperative activity limitation was a significant predictor of nonideal outcomes at one year ( P = 0.02). Symptomatic preoperative pain was associated with nonideal outcomes at one year, though the difference was not statistically significant ( P = 0.06). Operative technique, mesh choice, and fixation technique did not impact recurrence or QOL. Repair of umbilical hernia with defects ≥9 cm2 had a surprising low rate of ideal outcomes (asymptomatic and no recurrence). All patients with nonideal long-term outcomes had preoperative pain and activity limitations. These data may suggest that umbilical hernia should be repaired when they are small and asymptomatic.

scholarly journals An Ex-Press implant versus trabeculectomy in a fibrotic bleb with late failure after previous trabeculectomy

2021 ◽  
Vol 14 (3) ◽  
pp. 383-387
Author(s):  
Faried Wagdy ◽  
◽  
Hisham Elsorogy ◽  
Ahmed Alnagdy ◽  
Dina Abd Elfattah ◽  
...  
Keyword(s):  
Postoperative Complications ◽  
Open Angle Glaucoma ◽  
Implant Surgery ◽  
Late Failure ◽  
Group I ◽  
The Mean ◽  
The Difference ◽  
One Year ◽  
Age Range

AIM: To compare the outcome of an Ex-Press implant and subscleral trabeculectomy (SST) in the management of glaucoma after previous trabeculectomy on a fibrotic bleb. METHODS: This randomized prospective study included 28 eyes from 28 patients (age range: 42-55y) with primary open angle glaucoma (POAG) presented with elevated intraocular pressure (IOP) with fibrotic bleb despite previous SST for more than 4mo. The eyes enrolled in the study were divided into two groups: group I (subjected to Ex-Press implant surgery) and group II [subjected to SST with mitomycin C (MMC)]. The follow-up continued one year after surgery to evaluate IOP, visual acuity (VA), visual field (VF), and postoperative complications. RESULTS: A significant decrease in IOP was found in both groups with a higher reduction in Ex-Press implant surgery with the mean IOP of 14.50 mm Hg (P=0.001), while the SST group recorded the mean IOP of 16.50 mm Hg (P=0.001) after one year. However, the difference between the two groups in terms of the decrease in IOP was insignificant. Fewer postoperative complications were recorded in the Ex-Press implant surgery and more cases requiring further anti-glaucomatous medications were seen in the SST group. Both groups showed stability in terms of VA and VF. CONCLUSION: Ex-Press implant surgery and SST with MMC are two surgical alternatives for controlling IOP in late failure that occurs more than 4mo after previous SST with a fibrotic bleb. However, Ex-Press shunt is a safer surgery with fewer complications.

scholarly journals Improving atmospheric path-attenuation estimates for radiopropagation applications by microwave radiometric profiling

2020 ◽  
Author(s):  
Ayham Alyosef ◽  
Domenico Cimini ◽  
Lorenzo Luini ◽  
Carlo Riva ◽  
Frank S. Marzano ◽  
...  
Keyword(s):  
A Priori ◽  
Microwave Radiometer ◽  
Expected Improvement ◽  
Atmospheric Attenuation ◽  
V Band ◽  
W Band ◽  
Novel Approach ◽  
Atmospheric Path ◽  
The Mean ◽  
One Year

Abstract. Ground-based microwave radiometer (MWR) observations of downwelling brightness temperature (TB) are commonly used to estimate the atmospheric attenuation at relative transparent channels for radiopropagation and telecommunication purposes. The atmospheric attenuation is derived from TB by inverting the radiative transfer equation with a priori knowledge of the mean radiating temperature (TMR). TMR is usually estimated by either time-variant site climatology (e.g., monthly average computed from atmospheric thermodynamical profiles) or condition-variant estimation from surface meteorological sensors. However, information on TMR may also be extracted directly from MWR measurements at other channels than those used to estimate atmospheric attenuation. This paper proposes a novel approach to estimate TMR in clear and cloudy sky from independent MWR profiler measurements. A linear regression algorithm is trained with a simulated dataset obtained by processing one year of radiosonde observations of atmospheric thermodynamic profiles. The algorithm is trained to estimate TMR at K-, and V/W-band frequencies (22–31 and 72–82 GHz, respectively) from independent MWR observations at V-band (54–58 GHz). The retrieval coefficients are then applied to a one-year dataset of real V-band observations, and the estimated TMR at K- and V/W-band are compared with estimates from nearly collocated and simultaneous radiosondes. The proposed method provides TMR estimates in better agreement with radiosondes than a traditional method, with 32–38 % improvement depending on frequency. This maps into an expected improvement in atmospheric attenuation of 10–20 % for K-band and ~ 30 % for V/W-band channels.

scholarly journals Komposisi Jenis Gastropoda di Mangrove Desa Kaliwlingi dan Sawojajar, Jawa Tengah

2020 ◽  
Vol 9 (2) ◽  
pp. 167-174
Author(s):  
Erik Wijaya Kusuma ◽  
Ria Azizah Tri Nuraini ◽  
Retno Hartati
Keyword(s):  
Mangrove Forest ◽  
Diversity Index ◽  
Gastropod Species ◽  
Mangrove Area ◽  
Central Java ◽  
Mangrove Ecosystems ◽  
The Mean ◽  
The Difference ◽  
Different Characteristics

ABSTRAK : Desa Kaliwlingi dan Sawojajar mempunyai kawasan hutan mangrove dengan karakteristik berbeda. Kawasan hutan mangrove Kaliwlingi menjadi ekowisata mangrove sejak tahun 2016, sedangkan di Sawojajar merupakan kawasan mangrove alami. Perbedaan fungsi tersebut diduga dapat mempengaruhi keanekaragaman hayati yaitu salah satunya adalah gastropoda. Tujuan dari penelitian ini adalah untuk mengetahui struktur komunitas Gastropoda di ekosistem mangrove Desa Kaliwlingi dan Sawojajar, Kab.Brebes, Jawa Tengah. Pengambilan sampel dilakukan pada bulan Juni sampai Juli 2018. Penentuan titik sampling menggunakan metode purposive pada 3 stasiun dengan tiga kali pengulangan. Hasil penelitian menunjukan terdapat 2 subkelas yaitu Pulmonata dan Prosobranchiata, dengan 3 famili dan  9 spesies gastropoda dari 3 famili, yaitu Elliobidae; Cassidula aurisfelis (Elliobidae), C. nucleus (Elliobidae), Littoraria articulate (Littorinidae), L. carinifera (Littorinidae), L. melanostoma (Littorinidae), L. scabra (Littorinidae), Telescopium telescopium (Potamididae), Terebralia obtuse (Potamididae), T. palustris (Potaminidae).  Nilai kelimpahan rata-rata gastropoda Desa Kaliwlingi dan Desa Sawojajar masing-masing 20,28 dan 16,36 Ind/m². Indeks Keanekaragaman (H’) gastropoda di kawasan mangrove Desa Kaliwlingi dan Desa Sawojajar termasuk ke dalam kategori rendah ke tinggi, sedangkan indeks keseragamannya  berkategori rendah.  Tidak ada jenis gastropod yang mendominasi di kawasan mangrove Kaliwlingi dan Sawojajar, dengan pola sebaran gastropoda mengelompok.ABSTRACT: Kaliwlingi and Sawojajar villages have mangrove forest areas with different characteristics. The Kaliwlingi mangrove forest area has been established as mangrove ecotourism since 2016, while in Sawojajar it is a natural mangrove area. The difference in function is thought to affect biodiversity, one of which is gastropods. The purpose of this study was to determine the structure of the Gastropoda community in the mangrove ecosystems of Kaliwlingi and Sawojajar Villages, Kab. Brebes, Central Java. Sampling was conducted in June to July 2018. Determination of the sampling points using purposive methods at 3 stations with three repetitions. The results showed that there were 2 subclasses, namely Pulmonata and Prosobranchiata, with 3 families and 9 gastropod species from 3 families, namely Elliobidae; Cassidula aurisfelis (Elliobidae), C. nucleus (Elliobidae), Littoraria articulate (Littorinidae), L. carinifera (Littorinidae), L. melanostoma (Littorinidae), L. scabra (Littorinidae), Telescopium telescopium (Potamebidide) ), T. palustris (Potaminidae). The mean abundance of gastropods in Kaliwlingi Village and Sawojajar Village were 20.28 and 16.36 Ind / m² respectively. Diversity Index (H ') of gastropods in the mangrove areas of Kaliwlingi Village and Sawojajar Village are in the low to high category, while the uniformity index is categorized as low. There is no type of gastropod that dominates in the Kaliwlingi and Sawojajar mangrove areas, and gastropod distributed as a grouped.  

scholarly journals Parameterizing the Difference in Cloud Fraction Defined by Area and by Volume as Observed with Radar and Lidar

2005 ◽  
Vol 62 (7) ◽  
pp. 2248-2260 ◽  
Author(s):  
Malcolm E. Brooks ◽  
Robin J. Hogan ◽  
Anthony J. Illingworth
Keyword(s):  
Wind Shear ◽  
General Circulation ◽  
Cloud Cover ◽  
Cloud Fraction ◽  
Vertical Resolution ◽  
Ice Clouds ◽  
Cloud Radar ◽  
The Mean ◽  
The Difference ◽  
Lidar Observations

Abstract Most current general circulation models (GCMs) calculate radiative fluxes through partially cloudy grid boxes by weighting clear and cloudy fluxes by the fractional area of cloud cover (Ca), but most GCM cloud schemes calculate cloud fraction as the volume of the grid box that is filled with cloud (Cυ). In this paper, 1 yr of cloud radar and lidar observations from Chilbolton in southern England, are used to examine this discrepancy. With a vertical resolution of 300 m it is found that, on average, Ca is 20% greater than Cυ, and with a vertical resolution of 1 km, Ca is greater than Cυ by a factor of 2. The difference is around a factor of 2 larger for liquid water clouds than for ice clouds, and also increases with wind shear. Using Ca rather than Cυ, calculated on an operational model grid, increases the mean total cloud cover from 53% to 63%, and so is of similar importance to the cloud overlap assumption. A simple parameterization, Ca = [1 + e(−f )(C−1υ − 1)]−1, is proposed to correct for this underestimate based on the observation that the observed relationship between the mean Ca and Cυ is symmetric about the line Ca = 1 − Cυ. The parameter f is a simple function of the horizontal (H) and vertical (V) grid-box dimensions, where for ice clouds f = 0.0880 V 0.7696 H−0.2254 and for liquid clouds f = 0.1635 V 0.6694 H−0.1882. Implementing this simple parameterization, which excludes the effect of wind shear, on an independent 6-month dataset of cloud radar and lidar observations, accounts for the mean underestimate of Ca for all horizontal and vertical resolutions considered to within 3% of the observed Ca, and reduces the rms error for each individual box from typically 100% to approximately 30%. Small biases remain for both weakly and strongly sheared cases, but this is significantly reduced by incorporating a simple shear dependence in the calculation of the parameter f, which also slightly improves the overall performance of the parameterization for all of the resolutions considered.

scholarly journals Yield and Fruit Size Comparisons in the First Six Crops of 16 Mango Varieties

1969 ◽  
Vol 56 (4) ◽  
pp. 343-364
Author(s):  
W. Pennock ◽  
A. Torres-Sepulveda ◽  
J. López-García ◽  
I. Reyes-Soto ◽  
S. Valle-Lamboy ◽  
...  
Keyword(s):  
Block Design ◽  
Fruit Size ◽  
Square Lattice ◽  
Total Production ◽  
Potential Productivity ◽  
Incomplete Block Design ◽  
The Mean ◽  
The Difference ◽  
Balanced Incomplete Block ◽  
One Year

Sixteen mango varieties planted at 30 feet by 30 feet spacing in a partially balanced incomplete block design, which included 32 trees of each variety, were compared with respect to production, and fruit and tree size. Production for all varieties in general started on the fifth year after planting when in accordance with linear regression it amounted to 5 pounds of fruit per tree, and increased at the rate of about 28 pounds per year per tree during the following five crops. The varieties were classified with regard to consistency in bearing, according to a mean index derived from the difference in yield per tree from one year to the next divided by its mean yield for the 2 years being compared. The varieties Kent, Eldon, Palmer, Haden, and Keitt were highly inconsistent. Varieties Sensation, Santaella, Parvin, Earlygold and Jacquelin were intermediately consistent. The varieties Edward, Zill, Pillsbury, Ruby, and Irwin were regular bearers. The potential productivity per acre for each variety was calculated hypothetically for a square-lattice pattern of planting at a distance of 1 1/2 times the mean tree-crown diameter at 10 years of age. These distances varied from 28.1 feet for Palmer to 18.9 feet for Lippens. The varieties Lippens, Irwin, Sensation, Eldon and Keitt, in descending order, gave the highest yields ranging in total production for the six crops from 67,079 pounds per acre for Lippens to 45,608 pounds per acre for Keitt. The last crop of these same varieties at 10 years of age ranged from 10 to 11 tons per acre. The varieties Earlygold, Kent, Zill, and Parvin in descending order gave intermediate yields ranging in total production for the six crops from 42,310 pounds per acre for Earlygold to 38,369 pounds per acre for Parvin. The last crop of these same varieties at 10 years of age ranged from 6 to 10 tons per acre. The varieties Haden, Ruby, Pillsbury, Santaella, Jacquelin, Edward and Palmer, in descending order, gave yields at 10 years of age, which ranged from 6 to 10 tons per acre. The varieties Haden, Ruby, Pillsbury, Santaella, Jacquelin, Edward and Palmer in descending order, gave the lowest yields ranging in total production for the six crops from 32,732 pounds per acre for Haden to 23,868 pounds per acre for Palmer. The last crop of these same varieties, at 10 years of age, ranged from 2 1/2 to 6 tons per acre. The mean fruit size for each variety was determined in terms of weight in pounds per fruit utilizing all of the available data from the six crops. The varieties Jacquelin, Kent, Keitt, Palmer and Edward, in descending order, gave the largest fruit. The size ranged from a mean weight of 1.220 pounds for Jacquelin to 0.945 pounds for Edward. The varieties Eldon, Parvin, Haden, Earlygold, and Irwin, in descending order, gave intermediate sized fruit ranging from 0.842 pounds for Eldon to 0.657 pounds for Irwin. The varieties Zill, Lippens, Sensation, Pillsbury, Santaella, and Ruby, in descending order, gave small fruit ranging from 0.620 pounds for Zill to 0.452 pounds for Ruby.

Spawning population characteristics of pike Esox lucius L. in Lake Rubikiai (Lithuania)

2012 ◽  
Vol 7 (5) ◽  
pp. 867-877 ◽  
Author(s):  
Vida Žiliukienė ◽  
Valdemaras Žiliukas
Keyword(s):  
Water Level ◽  
Population Characteristics ◽  
Spawning Period ◽  
Maximum Water Level ◽  
Class Strength ◽  
Maximum Water ◽  
The Mean ◽  
The Difference ◽  
One Year ◽  
Old Females

AbstractThe aim of the study was to describe the peculiarities of pike spawning in mesotrophic Lake Rubikiai, to determine the spawning population structure and evaluate the influence of some environmental factors on year-class strength formation. The data were collected in April and May (1994–2011). A total of 1586 individuals were caught. The age of pike ranged from 1 to 12 years; 2–5-yearold males (96.0%) and 3–8-year-old females (89.1%) prevailed. The overall sex ratio of females to males was 1:4.1. One-year-old spawning males (26.5–28.5 cm) and two-year-old spawning females (31.5–35.5 cm) constituted 2.1% and 2.6%, respectively. Water temperature during the spawning period was relatively stable, between 4 and 6°C, during March and increased slightly towards 10°C in the middle of April. No correlation was observed between female length and spawning date. Year-class strength did not correlate with the last day of ice presence and the minimal water level at the end of spawning (WLmin), but statistically significantly negatively correlated with the maximum water level at the beginning of spawning (WLmax) and the difference between WLmax and WLmin. The mean annual survival rate for pike (aged ≥2) was 0.74 and the mean annual instantaneous mortality rate was 0.45.

scholarly journals The Effect of Low and High Cowshed Temperatures on the Behaviour and Milk Performance of Czech Fleckvieh Cows

2016 ◽  
Vol 16 (4) ◽  
pp. 1153-1162 ◽  
Author(s):  
Milan Večeřa ◽  
Daniel Falta ◽  
Radek Filipčík ◽  
Gustav Chládek ◽  
Francois Lategan
Keyword(s):  
Relative Humidity ◽  
Side Wall ◽  
Daily Basis ◽  
Cold Period ◽  
Milk Performance ◽  
The Mean ◽  
The Difference ◽  
Total Capacity ◽  
One Year ◽  
Lying Down

Abstract A group of 98 Czech Fleckvieh cows (one section) was observed over the period of one year with the aim to determine the variation in their milk performance and behaviour at different cowshed temperatures. Behaviour and milk yield were recorded once a week (on the same day) at 10:00. Periods of 8 weeks with the highest temperature (hot period - H) and of 8 weeks with the lowest temperature (cold period - L) were then compared. The cows were housed in one section (1/4 of the total capacity) of the free-stall cubicle shed and where the cubicles were distributed into three rows. Row A (32 cubicles) was close to the feeding plateau, row B (33 cubicles) was in the centre and row C (38 cubicles) was peripheral, close to the side wall. The cowshed temperature was monitored on a daily basis and the mean temperature was 23.2°C in the hot period and -1.7°C in the cold period, relative humidity 60.2% (H) and 74.6% (L), and THI 69.4 (H) and 33.4 (L). The behaviour of the cows was recorded 1568 times, showing them mostly lying down (1037) or standing (531). The cows tended to prefer lying down on their left sides (594 observations) as opposed to their right sides (443). Row A was favoured by the cows (418) and row B was the least popular (377). The cows produced significantly more milk in H period than in L period (0.3 kg per day). The cows lying down were older (3.18 lactations) than the standing cows (2.99 lactations) and they tended to produce more milk per day (by 0.6 kg) but the difference was found to be insignificant. The cows lying resting on their left side produced more milk per day (0.9 kg) and were older (0.02 lactations). The cows in row C were the youngest (2.94 lactations) and the cows in row B were in the last days in milk (144.1 days).

scholarly journals Effects of milk protein loci on content of their proteins

2003 ◽  
Vol 46 (4) ◽  
pp. 331-340 ◽  
Author(s):  
R. Graml ◽  
F. Pirchner
Keyword(s):  
Milk Protein ◽  
Genetic Variance ◽  
Gene Action ◽  
Milk Proteins ◽  
Brown Swiss ◽  
Allele Specific ◽  
Locus Allele ◽  
The Mean ◽  
The Difference ◽  
One Year

Abstract. Allele specific milk proteins were measured in 4544 samples from 2054 Fleckvieh (FV) cows in two succeeding years and in one year from 1809 Braunvieh (BV) cows partly crossbreds with Brown Swiss. The cows were from 454 and 403 sires, and in 316 and 46 farms, respectively. The allele specific milk proteins were measured photometrically. Gene action was mainly additive, but the aS1-CN BC was 2 to 4 % above the mean of the homozygotes and the heterozygotes at the CSN2 locus deviated from –2 to + 8 % from the means of the respective homozygotes. The extent of expression of the alleles varied. At CSN1S1 higher expression was shown by the B alleles in heterozygotes, and by the C alleles in homozygotes. At the CSN2 locus the statistically highly significant order of degree of expression was C>B>A. At the LGB locus allele both breeds showed higher expression than allele B and the difference between the expression of the two alleles in heterozygotes is twice of that observed in homozygotes. The CSN1S1 and CSN2 loci affected the synthesis of all caseins. The CSN3 locus shows statistically significant influence on κ-CN in FV. κ-CN appears to be influenced in particular by C2N2 alleles. The LGB locus shows much influence on the ß-LG content but little on caseins. The effects of CSN1S1 and CSN2 loci on the contents of αS2-CN and k-CN indicate epistasis. Polygenic influence accounted for one third to one half of the overall genetic variance of contents of Ca-sensitive caseins. k-CN shows much greater polygenic influence (two thirds to four fifth of the genetic variance) and ß-LG less (1/6 and less). The action of LGB was specific with none or very little influence on the caseins. Moreover, ß-LG was also unaffected by the casein loci. The effects of the alleles on the contents were similar in the two breeds. Repeatabilities were 2/5 to almost 3/5, heritabilities 1/4 to 1/3 with the exception of αS2-CN and k-CN where it was lower.

scholarly journals Histological and Histomorphometric Evaluation of Post-Extractive Sites Filled with a New Bone Substitute with or without Autologous Plate Concentrates: One-Year Randomized Controlled Trial

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 254
Author(s):  
Marco Tallarico ◽  
Erta Xhanari ◽  
Aurea Maria Immacolata Lumbau ◽  
Adela Alushi ◽  
Irene Ieria ◽  
...  
Keyword(s):  
Tooth Extraction ◽  
Controlled Trial ◽  
Test Group ◽  
Compact Bone ◽  
Control Group ◽  
Socket Preservation ◽  
Randomized Controlled ◽  
The Mean ◽  
The Difference ◽  
One Year

The purpose of the present study was to evaluate the histological and histomorphometric characteristics of post-extraction sites grafted with decellularized bovine compact bone from bovine femur, mixed and unmixed with leukocyte- and platelet-rich fibrin after four months of healing. This study was designed as a randomized controlled trial of parallel groups. Patients in need of a single, implant-supported restoration to replace a hopeless tooth were recruited for tooth extraction and implant placement four months after socket preservation procedure. After tooth extraction, patients were randomly allocated to receive decellularized bovine compact bone from bovine femur, mixed and unmixed with leukocyte- and platelet-rich fibrin. After four months of healing, tapered implants were inserted with an insertion torque between 35 and 45 Ncm. Two months later, implants were loaded with screw-retained definitive crowns. Outcome measures were implant (ISR) and prosthesis (PSR) survival rates, complications, histological and histomorphometric analyses, radiographic marginal bone-level changes, and patients’ satisfaction. Clinical data were collected up to one year after tooth extraction and socket preservation procedures. Thirty patients were consecutively enrolled in the trial (15 in each group). Unfortunately, due to the COVID-19 pandemic, bone samples were collected only in 19 patients. Two implants failed before definitive prosthesis delivery (ISR 93.3%). No prosthesis failed (PSR 100%). Three complications were experienced in the control group. The mean bone percentage was 40.64 ± 18.76 in the test group and 33.40 ± 22.38 in the control group. The difference was not statistically significant (p = 0.4846). The mean soft tissue percentage was 32.55 ± 19.45 in the test group and 55.23 ± 17.64 in the control group. The difference was statistically significant (p = 0.0235). The mean residual graft was 24.59 ± 18.39 in the test group and 11.37 ± 12.12 in the control group. The difference was not statistically significant (p = 0.0992). Mean marginal bone loss, as well as patient satisfaction, showed no differences between groups. With the limitations of the present study, socket preservation with L-PRF mixed with decellularized bovine compact bone demonstrated favorable results, comparing with decellularized bovine compact bone from bovine femur alone. Further studies with larger sample size and longer follow-up are needed to confirm these preliminary results.

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