The investigators selected the water extract for closer phytochemical analysis because it combined the greatest yield with the highest measured activity. Qualitative screening detected carbohydrates, tannins, saponins, terpenoids, flavonoids, phenols, alkaloids and cardiac glycosides in the leaf preparations. These tests indicate classes of chemical compounds but do not measure their concentrations or establish which individual constituents produced the observed effects. The researchers described the plant, commonly called yellow oleander or lucky nut and belonging to the Apocynaceae family, as a medicinal plant containing diverse phytochemicals. They also noted that it is poisonous, an important qualification given that the study examined crude leaf extracts rather than isolated or purified constituents.

For the liquid-nitrogen pretreatment, cleaned leaves were immediately quenched and crushed into fine powder with a pestle and mortar. Approximately 5 g of powder was placed in each solvent composition, with each preparation totaling 100 mL. After two days in the dark, each mixture was sonicated for 30 minutes below 10 °C and agitated on an orbital shaker for three hours. Filtration, rotary evaporation and 72 hours of freeze-drying followed before extract yield was calculated. Rapid freezing at approximately −196 °C was intended to limit oxidative and enzymatic degradation and preserve heat-sensitive metabolites, while ice-crystal formation may also disrupt plant tissue and improve solvent penetration. Those mechanisms were proposed explanations rather than variables independently tested in this experiment.

Yield varied substantially with solvent composition. The aqueous preparation, designated E-1, produced 31.08 ± 0.03% extract, whereas the 60% ethanol preparation, E-4, produced the lowest yield. The pattern supports the researchers’ interpretation that water efficiently recovered polar constituents from the leaf matrix. Because every sample received the same cryogenic preparation, the comparison isolates the effect of solvent composition within the experiment; it does not establish how much the liquid-nitrogen step improved performance relative to ordinary drying or untreated leaves. The study therefore identifies water as the strongest of the six tested extraction media for this material and method, rather than providing a direct estimate of cryogenic extraction efficiency against all conventional alternatives.

Gas chromatography–mass spectrometry was used to examine the highest-yield aqueous extract after derivatization. Thirteen chromatographic peaks appeared in the total-ion chromatogram, and the researchers tentatively retained seven compounds for reporting after comparing retention data and mass spectra with NIST and WILEY library records. They excluded peaks judged likely to represent volatile aromatic hydrocarbons, solvent impurities, di-n-octyl phthalate or other processing-related contamination. The seven reported compounds constitute only the fraction compatible with derivatization and GC–MS, not the full chemical composition of the extract. The authors specifically cautioned that many polar and non-volatile constituents in a water-based plant extract would not be detected by this method, and they identified LC–MS/MS, HPLC and NMR as possible complementary techniques for broader profiling.

In the agar well-diffusion assay, the aqueous extract produced inhibition-zone diameters of 16.30 ± 0.20 mm against Escherichia coli and 15.32 ± 0.19 mm against Staphylococcus aureus. The corresponding bacterial results declined overall as the ethanol proportion rose. Against E. coli, the 20%, 40%, 60%, 80% and 100% ethanol preparations produced zones of 12.00 ± 0.10, 12.63 ± 0.15, 10.97 ± 0.06, 10.23 ± 0.15 and 10.03 ± 0.06 mm, respectively. For S. aureus, the corresponding values were 11.63 ± 0.11, 11.55 ± 0.13, 11.24 ± 0.12, 10.97 ± 0.06 and 11.03 ± 0.06 mm. One-way analysis of variance found significant differences among treatments for both bacteria, and Tukey’s honestly significant difference test distinguished the aqueous extract from the other preparations.

The aqueous preparation also gave the largest measured zone against Aspergillus niger, measuring 13.1 ± 0.19 mm after 72 hours. The 20%, 40%, 60%, 80% and 100% ethanol preparations yielded zones of 10.87 ± 0.15, 10.53 ± 0.14, 10.93 ± 0.18, 10.13 ± 0.18 and 9.93 ± 0.12 mm. Analysis of variance again showed significant variation among the six treatments, while the aqueous extract differed statistically from the others. Ciprofloxacin and nystatin served as reference drugs for the bacterial and fungal assays, respectively. The investigators proposed that polar phytochemicals recovered more efficiently in water may account for the stronger inhibition, while increasing ethanol appeared to hinder activity in their sample mixtures. This does not mean ethanol was chemically destroying the extract; it was present in both extraction and assay media, which complicates attribution of the effect.

Two radical-scavenging assays produced the same solvent ranking. In the DPPH assay, the aqueous extract showed the highest scavenging activity and the pure ethanol extract the lowest. Its half-maximal inhibitory concentration, expressed as the concentration required to scavenge 50% of DPPH radicals, was 9.16 µg/mL. The kinetic analysis indicated that scavenging occurred mainly during the first five minutes, after which the curves became nearly horizontal. In the ABTS assay, results were reported as Trolox equivalent antioxidant capacity: the aqueous preparation reached 8.96 mM, compared with 7.6 mM for the pure ethanol preparation. The researchers associated the stronger aqueous activity with polar phenolics, flavonoids and tannins, which can donate electrons or hydrogen atoms to radicals and stabilize the resulting intermediates, but they did not isolate or directly measure the contribution of each compound class.

The findings remain preliminary because the researchers used plate-based in vitro assays and did not determine minimum inhibitory or minimum bactericidal concentrations for bacteria, nor minimum fungicidal concentrations for the fungus. Those measurements would be needed for more precise comparison and to distinguish growth inhibition from killing. The active constituents were not isolated or structurally characterized, and cytotoxicity and animal studies were not performed. The authors therefore recommend follow-up work involving purified fractions, MIC, MBC and MFC assays, mechanistic studies and in vivo safety and efficacy models before any preclinical or clinical consideration. Taken together, the experiment provides a clear laboratory result: within the six solvent compositions tested after liquid-nitrogen pretreatment, pure water gave the highest extraction yield and the strongest measured antioxidant, antibacterial and antifungal performance of Cascabela thevetia leaf extract, without establishing a clinical use.

Subject of Research: In vitro comparison of solvent compositions for extracting bioactive compounds from cryogenically prepared Cascabela thevetia leaves

Article Title: Liquid nitrogen mediated cryogenic extract optimization, phytochemical analysis, antibacterial, antifungal, and antioxidant potential of Cascabela thevetia Leaf

Article References: Shehzad, B., Ahmad, R., Aslam, F., Rehman, T., Shafique, U., Baig, U., Wahab, A., & Ch, A. R. (2026). Liquid nitrogen mediated cryogenic extract optimization, phytochemical analysis, antibacterial, antifungal, and antioxidant potential of Cascabela thevetia Leaf. Discover Chemistry, 3(1), Article 585. https://doi.org/10.1007/s44371-026-01042-4

Image Credits: AI Generated

DOI: 10.1007/s44371-026-01042-4

Keywords: Cascabela thevetia, liquid nitrogen, cryogenic pretreatment, water extraction, phytochemical screening, GC-MS, antibacterial assay, antifungal assay, antioxidant assay, in vitro research, Liquid, nitrogen

Researchers compared untreated and cold-soaked samples using isothermal methane-adsorption experiments, swelling-deformation tests, Fourier transform infrared spectroscopy, nuclear magnetic resonance measurements and low-temperature nitrogen adsorption analysis. The three coal types were examined at different degrees of metamorphism. This experimental design linked the gas-adsorption and deformation responses to changes in pore structure and the chemical groups present on coal surfaces, rather than relying on adsorption measurements alone.

The pore-characterization results indicated that liquid-nitrogen cold soaking shifted the coals’ pore-size distributions toward larger pores and improved pore connectivity. At the same time, the treatment reduced the effective space available for methane adsorption. The study’s Pearson correlation analysis found that adsorption-pore specific surface area and BET specific surface area were strongly positively correlated with saturated adsorption capacity across coals of different metamorphic grades, with correlation coefficients greater than 0.71.

BJH total pore volume and average pore diameter were strongly negatively correlated with saturated adsorption capacity, with coefficients greater than 0.73 in magnitude. The authors describe the pore-network response as having two competing effects. Enhanced connectivity accelerated the initial migration of methane into the coal, whereas the smaller effective adsorption space slowed the subsequent deformation rate during gas uptake.

These reported mechanisms connect the larger, more connected pore network with the observed reduction in methane-induced swelling. The findings do not mean that all stages of methane migration were slower: the initial migration was accelerated, while the later deformation associated with continued uptake proceeded more slowly. Peak fitting of the Fourier transform infrared spectra showed that liquid-nitrogen treatment did not change the types of functional groups detected on the coal surfaces.

However, the contents of hydroxyl and carboxyl groups increased significantly. The researchers associated these groups with weaker coupling between coal and methane and report that they weakened the methane adsorption process. Together, the spectroscopic and pore-structure observations offer a microscopic explanation for the lower saturated adsorption capacities measured after cold soaking.

The size of the response differed among the coal types. Lignite showed the largest capacity reduction, while bituminous coal and anthracite experienced declines of similar, substantially smaller magnitudes. The reduction in swelling deformation also varied with coal type, although all three treated coals showed less swelling than their untreated counterparts.

The results therefore indicate that liquid-nitrogen cold soaking produced a consistent direction of change in the tested samples, but not an identical effect across coal ranks. The work is an experimental laboratory study, not a field trial, and its conclusions apply to the tested lignite, bituminous coal and anthracite samples under the reported conditions. The supplied findings do not establish whether repeated treatment would produce the same changes, how long the effects persist, or whether the process can reproduce these responses under underground temperature and pressure conditions.

The study also does not demonstrate consequences for methane recovery, mine safety, field-scale gas flow or operational performance in coal seams. Within those limits, the measurements connect surface chemistry, pore geometry, methane adsorption and mechanical deformation at the microscopic scale. The authors present the results as fundamental microscopic data for coal-reservoir research, providing a laboratory basis for examining how liquid-nitrogen treatment affects methane-adsorption behavior in different coal ranks.

Subject of Research: Effects of liquid-nitrogen cold soaking on coal pore structure, methane adsorption and swelling deformation

Article Title: Experimental study on microscopic mechanisms of coal deformation and methane adsorption under liquid nitrogen cold soaking

Article References: Liu, S., Wang, S., Li, X., Wang, D., & Fu, J. (2026). Experimental study on microscopic mechanisms of coal deformation and methane adsorption under liquid nitrogen cold soaking. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-026-38314-6

Image Credits: AI Generated

DOI: 10.1007/s11356-026-38314-6

Keywords: liquid nitrogen, cold soaking, coal deformation, methane adsorption, swelling strain, pore structure, pore connectivity, FTIR spectroscopy, NMR analysis, BET analysis, lignite, anthracite

The study, published as a short communication in CVIR Oncology, analyzed isotherm charts from three FDA-certified cryoablation systems: two argon-based Joule–Thomson platforms, Boston Scientific’s System A and Endocare/Varian’s System B, and a liquid nitrogen system, IceCure Medical’s System C. All measurements had been performed in ultrasonic gels under standardized conditions, with 216 data points covering single needles and clustered needle configurations. The authors defined the LIR as the width of the −20 °C or −40 °C isotherm divided by the width of the visible ice ball, expressed as a percentage. A higher ratio means a larger share of the frozen zone is cold enough to guarantee cell death.

The physics behind the metric is rooted in how cells die under extreme cold. Below −40 °C, intracellular ice crystals form and physically shred cellular structures, triggering immediate necrosis. At temperatures as high as −20 °C, secondary mechanisms come into play, including osmotic stress and ischemic injury that starve tissue of blood supply. Because these lethal zones cannot be seen during a procedure, operators currently rely on the visible ice ball diameter and probe spacing as proxies, a practice the authors argue leaves a dangerous margin of uncertainty that can lead to inadequate tumor coverage and local recurrence.

The results were striking. Across all systems, isotherm widths correlated strongly and linearly with ice ball size, with correlation coefficients ranging from 0.880 to 0.999. But the proportion of lethal territory within the ice ball differed dramatically by technology. The liquid nitrogen System C achieved the highest ratios, with the −20 °C isotherm spanning 80.6 percent of the ice ball on average and the −40 °C isotherm covering 60.3 percent. The argon-based Systems A and B trailed significantly, both reaching about 69.6 percent at −20 °C, while their −40 °C ratios fell to 44 percent and 51.4 percent respectively, differences the authors report as statistically significant.

The explanation lies in the cooling technologies themselves. Joule–Thomson systems drop their temperature by expanding high-pressure argon gas, at 3200 PSI, through a throttling orifice, a process that supports multiple cryoprobes working in parallel. Liquid nitrogen systems operate at far lower pressures, around 100 PSI, but reach colder temperatures faster. The trade-off, the study notes, is that liquid nitrogen systems may struggle with very large ice balls, where peripheral warming erodes the lethal core, while clustered cryoprobes enhance energy removal but demand more complex insertion techniques.

That trade-off produced the study’s most clinically actionable finding: a threshold effect at roughly 45 millimeters. Linear regression analysis showed that for ice balls smaller than about 45 mm in width, a single liquid nitrogen needle delivers larger lethal isotherms than any single argon needle. Beyond that threshold, the regression lines intersect and the picture reverses: clusters of Joule–Thomson needles produce bigger lethal zones, with an almost perfect correlation of 0.998 to 0.999. Notably, when System A’s needles were clustered, their LIRs rose to 79.3 percent at −20 °C and 60.9 percent at −40 °C, statistically indistinguishable from the liquid nitrogen system’s single-needle performance.

For interventional radiologists, the implications could reshape device selection and preoperative planning. If a tumor is expected to generate an ice ball under 45 mm, the data suggest a single liquid nitrogen probe may be the more efficient choice. For larger targets, clustered argon probes offer superior coverage. Because the LIR quantifies the relationship between what is visible on screen and the effective ablation zone, it could allow operators to estimate the required number of probes and their optimal spacing before the first incision, potentially shortening procedures and reducing complications. The finding that the −20 °C isotherm can encompass up to 80 percent of the ice ball even hints that real-time thermometry might become unnecessary if LIR values reliably predict ablation zones.

The metric also fills a gap in how the field compares competing technologies. Until now, manufacturers’ claims rested on raw ice ball dimensions and probe spacing, figures that say nothing about the lethal fraction of the frozen volume. By normalizing lethal isotherm widths to the visible freezing front, the LIR offers a common currency for benchmarking cryoprobes, needle gauges, and chamber lengths across vendors. The authors suggest it could become a standardized yardstick for regulators, buyers, and clinicians alike, in the same way that metrics like specific absorption rate structure comparisons in other energy-based therapies.

The study is not without caveats, and the authors are candid about them. All isotherm data came from ultrasonic gels, not living tissue. Biological tissue brings perfusion, heterogeneity, and variable thermal conductivity, all of which alter heat transfer in vivo and could shift LIR values in real patients. Testing conditions also varied somewhat between manufacturers, with ambient temperatures of 20 to 23 °C, probe depths of 2 to 3 cm, and freeze durations of 10 to 15 minutes, and although FDA certification imposed standardized protocols, cross-vendor methodological differences could introduce bias. The corresponding author has consulted for all three companies whose systems were analyzed, a potential conflict the authors state was mitigated through standardized data collection and analysis.

Future work, the team argues, should validate LIR against histologically confirmed ablation zones in animal and human tissue, run prospective trials comparing procedures planned with and without the metric, and build computational models that fold tissue-specific properties into the calculation. If those steps succeed, the Lethal Isotherm Ratio could transform a field that has long judged its instruments by the size of the ice they make rather than the death they deliver. For now, the message is clear: not all ice balls are created equal, and the difference between 44 percent and 80 percent lethal coverage may be the difference between a cured tumor and one that comes back.

Subject of Research: A standardized metric, the lethal isotherm ratio, for comparing cryoablation needles and systems based on lethal temperature zones within visible ice balls.

Article Title: Lethal isotherm ratio to standardize the comparison of cryoablation needles and systems

Article References: Cornelis, A. A., Bodard, S., & Cornelis, F. H. (2025). Lethal isotherm ratio to standardize the comparison of cryoablation needles and systems. CVIR Oncology, 1(1), Article 3. https://doi.org/10.1007/s44343-025-00004-4

Image Credits: AI Generated

DOI: 10.1007/s44343-025-00004-4

Keywords: cryoablation, lethal isotherm ratio, cryoprobes, liquid nitrogen, Joule-Thomson, interventional radiology, tumor ablation, isotherms, ice ball, device comparison, oncology, Lethal